fix: refine mutual pass matching and radar overlay

- Radar pager now defaults to Transceivers tab (initialPage=0)
- Transceivers don't auto-expand (selectedUuid defaults to null)
- Mutual page default minElev changed from settings value to 0.0
- Display filters out portions below the minElev threshold

.github/copilot-instructions.md

@@ -0,0 +1,5 @@
+# GitHub Copilot Instructions
+
+Read `AGENTS.md` first, then `CLAUDE.md`.
+
+`AGENTS.md` contains the architecture, module boundaries, implementation details, conventions, and gotchas.

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/release.yml

@@ -16,59 +16,64 @@ jobs:
       contents: write
     steps:
       - name: Checkout Repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Setup Java
         uses: actions/setup-java@v5
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
 
       - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v5
+        uses: gradle/actions/setup-gradle@v6
 
       - name: Assemble Artifacts
-        run: |
+        run: ./gradlew assembleRelease bundleRelease
-          ./gradlew assembleRelease
-          ./gradlew bundleRelease
 
       - name: Sign APK
-        uses: r0adkll/sign-android-release@v1
+        run: |
-        id: sign_apk
+          echo "${{ secrets.KEY_STORE }}" | base64 -d > keystore.jks
-        with:
+          APK=$(find app/build/outputs/apk/release -name "*.apk" | head -1)
-          releaseDirectory: app/build/outputs/apk/release
+          BUILD_TOOLS=$(ls -d ${ANDROID_HOME}/build-tools/*/ | sort -V | tail -1)
-          signingKeyBase64: ${{ secrets.KEY_STORE }}
+          ${BUILD_TOOLS}apksigner sign \
-          keyStorePassword: ${{ secrets.KEY_STORE_PASSWORD }}
+            --ks keystore.jks \
-          alias: ${{ secrets.KEY_ALIAS }}
+            --ks-pass pass:${{ secrets.KEY_STORE_PASSWORD }} \
-          keyPassword: ${{ secrets.KEY_PASSWORD }}
+            --ks-key-alias ${{ secrets.KEY_ALIAS }} \
-        env:
+            --key-pass pass:${{ secrets.KEY_PASSWORD }} \
-          BUILD_TOOLS_VERSION: "36.0.0"
+            --out app/build/outputs/apk/release/look4sat.apk \
+            "$APK"
+          rm keystore.jks
 
       - name: Sign Bundle
-        uses: r0adkll/sign-android-release@v1
-        id: sign_bundle
-        with:
-          releaseDirectory: app/build/outputs/bundle/release
-          signingKeyBase64: ${{ secrets.KEY_STORE }}
-          keyStorePassword: ${{ secrets.KEY_STORE_PASSWORD }}
-          alias: ${{ secrets.KEY_ALIAS }}
-          keyPassword: ${{ secrets.KEY_PASSWORD }}
-        env:
-          BUILD_TOOLS_VERSION: "36.0.0"
-
-      - name: Rename Artifacts
         run: |
-          mv ${{steps.sign_apk.outputs.signedReleaseFile}} app/build/outputs/apk/release/look4sat.apk
+          echo "${{ secrets.KEY_STORE }}" | base64 -d > keystore.jks
-          mv ${{steps.sign_bundle.outputs.signedReleaseFile}} app/build/outputs/apk/release/look4sat.aab
+          AAB=$(find app/build/outputs/bundle/release -name "*.aab" | head -1)
+          jarsigner -verbose -sigalg SHA256withRSA -digestalg SHA-256 \
+            -keystore keystore.jks \
+            -storepass ${{ secrets.KEY_STORE_PASSWORD }} \
+            -keypass ${{ secrets.KEY_PASSWORD }} \
+            "$AAB" ${{ secrets.KEY_ALIAS }}
+          rm keystore.jks
 
-      - name: Deploy Bundle
+      - name: Setup Ruby
-        uses: r0adkll/upload-google-play@v1
+        uses: ruby/setup-ruby@v1
         with:
-          serviceAccountJsonPlainText: ${{secrets.SERVICE_ACCOUNT_JSON}}
+          ruby-version: '3.4'
-          packageName: com.rtbishop.look4sat
+
-          releaseFiles: app/build/outputs/apk/release/look4sat.aab
+      - name: Deploy Bundle to Google Play
-          track: production
+        run: |
-          whatsNewDirectory: fastlane/metadata/android/en-US/whatsnew
+          gem install multi_json
+          gem install fastlane --no-document
+          AAB=$(find app/build/outputs/bundle/release -name "*.aab" | head -1)
+          echo '${{ secrets.SERVICE_ACCOUNT_JSON }}' > service_account.json
+          fastlane supply \
+            --aab "$AAB" \
+            --json_key service_account.json \
+            --package_name com.rtbishop.look4sat \
+            --track production \
+            --skip_upload_images true \
+            --skip_upload_screenshots true \
+          rm service_account.json
 
       - name: Create Release
         run: |

.gitignore

@@ -1,6 +1,9 @@
 # Built application files
 *.ap_
 
+# Hermes AI plans and metadata
+.hermes/
+
 # Files for the ART/Dalvik VM
 *.dex
 

AGENTS.md

@@ -0,0 +1,122 @@
+# Look4Sat AI Agent Instructions
+
+This is the canonical project guide for all AI assistants working on Look4Sat.
+All assistant-specific files (`CLAUDE.md`, `.github/copilot-instructions.md`) point here.
+
+---
+
+## Project Overview
+
+Look4Sat is an open-source, fully offline Android satellite tracker and pass predictor. It tracks 9000+ active
+satellites using TLE/OMM data from Celestrak/SatNOGS, calculates orbital positions via SGP4/SDP4 models, and displays
+passes relative to the user's location. Features include polar radar visualization, SSTV image decoding, satellite
+ground track mapping, and pass predictions up to 10 days ahead. No ads, no tracking, no network required after initial
+data download.
+
+## Architecture
+
+**MVI (Model-View-Intent)** with unidirectional data flow:
+- `State` data class → exposed via `StateFlow` from ViewModel
+- `Action` sealed interface → user intents dispatched to ViewModel's `onAction()`
+- Jetpack Compose UI observes state and recomposes reactively
+
+**Clean Architecture layers:**
+
+| Module               | Responsibility                                                      |
+|----------------------|---------------------------------------------------------------------|
+| `app`                | Entry point. Aggregates all modules                                 |
+| `core:data`          | Android library. Room DB, OkHttp networking, repo implementations   |
+| `core:domain`        | Pure Kotlin (JVM). Orbital math (SGP4/SDP4), models, repo contracts |
+| `core:presentation`  | Android library. Compose theme, shared UI components, NavKeys       |
+| `feature:map`        | OSMDroid map with ground tracks                                     |
+| `feature:passes`     | Pass predictions and upcoming events                                |
+| `feature:radar`      | Polar radar view of satellite positions, SSTV image decoding        |
+| `feature:satellites` | Satellite list, filtering, selection                                |
+| `feature:settings`   | User preferences                                                    |
+
+- `feature:*` modules depend only on `core:domain` + `core:presentation`. Features never depend on each other.
+
+## Build & Run
+
+```shell
+# Debug build
+./gradlew assembleDebug
+
+# Release build (minified, shrunk resources)
+./gradlew assembleRelease
+
+# Run tests
+./gradlew test
+```
+
+- **Min SDK**: 24 | **Target SDK**: 36 | **JDK**: 17
+- **Gradle**: Uses version catalog (`gradle/libs.versions.toml`) + convention plugins in `build-logic/`
+
+## Key Libraries
+
+- **Compose** (BOM 2026.05.01) + Material3 Adaptive
+- **Navigation3** (type-safe, uses `@Serializable` NavKeys)
+- **Room** (KSP code generation) for local satellite/TLE storage
+- **OkHttp** 5.x for TLE downloads
+- **OSMDroid** for map rendering
+- **Kotlin Serialization** for navigation args and data parsing
+- **Coroutines** + `StateFlow` for async/reactive patterns
+
+## Conventions
+
+- **Minimal dependencies**: Avoid adding libraries when a simple manual solution exists. Fewer deps = less maintenance.
+- **DI**: Manual — ViewModels use companion `factory()` methods with `IMainContainer` interface.
+- **Navigation**: Type-safe Compose Navigation3 with `@Serializable` data classes as nav keys.
+- **State naming**: `<Feature>State` data class + `<Feature>Action` sealed interface per feature.
+- **No feature-to-feature deps**: All cross-feature communication goes through core layers.
+- **Localization**: 7 languages (en, es, ru, si, tr, uk, zh).
+
+## Data Formats & Migration
+
+**TLE vs. OMM/CSV format:**
+
+Look4Sat supports both TLE and OMM (Orbit Mean-Elements Message) formats for backward compatibility:
+
+- **TLE format**: Traditional 3-line element format (deprecated). NORAD catalog numbers are 5-digit integers, which
+  are running out of space. Celestrak has signaled that TLE format will eventually be phased out.
+- **OMM/CSV format**: The future standard. CSV files contain the same orbital parameters as TLE but use ISO 8601
+  timestamps and support larger NORAD IDs. Celestrak and SatNOGS already provide OMM data in CSV format.
+
+**Current implementation:**
+- `DataParser.kt` handles both `parseTLEStream()` and `parseCSVStream()` seamlessly
+- TLE data is downloaded from configured sources and stored in Room database
+- When downloading satellite data, the app automatically detects format and parses accordingly
+- Both formats produce identical `OrbitalData` objects, ensuring transparent format switching
+
+**Migration path:**
+As NORAD catalog space becomes constrained, OMM/CSV will become the primary format. Look4Sat is already positioned
+to handle this transition without code changes — existing users can continue using TLE files while new sources
+transition to OMM/CSV automatically.
+
+## Code Style
+
+- Prefer **short, focused functions** — single responsibility, easy to read.
+- **Exceptions**: Composable functions and math-heavy algorithms (SGP4/SDP4) may be longer.
+- Strict code style — no dead code, no unused imports, consistent formatting.
+
+## Roadmap
+
+- **KMP migration**: `core:domain` is to become a fully shareable KMM module. Keep it pure Kotlin/JVM.
+
+## Gotchas
+
+- Orbital math lives in `core:domain/predict/` — it's dense vector math (SGP4/SDP4). Tread carefully.
+- TLE/OMM data must be refreshed weekly for accurate predictions (satellite orbits decay). TLE format is legacy and
+  will eventually be deprecated in favor of OMM/CSV as NORAD catalog numbers approach the 5-digit limit.
+- SSTV decoding in `feature:radar` is experimental; image quality depends on signal strength during satellite pass.
+- `build-logic/convention/` contains all shared Gradle configuration — edit there, not in individual modules.
+- ProGuard is enabled for release builds — don't add reflection-based libs or any other dependencies without asking.
+
+## Copilot Working Mode: Code-Only
+
+- Default to code changes only. Provide explanations in chat only.
+- If documentation seems useful, ask first before creating files.
+- Do NOT create any `.md` documentation files unless explicitly requested.
+- Do NOT add README, guides, summaries, migration notes, or how-to files unless asked.
+- Prefer minimal diffs focused on requested implementation.
+- Default validation is static checks (`get_errors`). Do NOT run Gradle compile/test tasks unless explicitly requested.

CLAUDE.md

@@ -0,0 +1,5 @@
+# CLAUDE.md
+
+Read `AGENTS.md` first, then follow the instructions there.
+
+`AGENTS.md` contains the architecture, module boundaries, implementation details, conventions, and gotchas.

README.md

@@ -33,3 +33,13 @@ It is now and always will be completely ad-free and open-source.
 *  Showing the satellite positional data, footprint and ground track on the map
 *  Custom TLE satellite data import is available via Three Line Element .txt files
 *  Offline first: calculations are made offline. Weekly TLE data update is recommended.
+
+## Star History
+
+<a href="https://www.star-history.com/?repos=rt-bishop%2FLook4Sat&type=timeline&legend=top-left">
+ <picture>
+   <source media="(prefers-color-scheme: dark)" srcset="https://api.star-history.com/chart?repos=rt-bishop/Look4Sat&type=timeline&theme=dark&legend=top-left" />
+   <source media="(prefers-color-scheme: light)" srcset="https://api.star-history.com/chart?repos=rt-bishop/Look4Sat&type=timeline&legend=top-left" />
+   <img alt="Star History Chart" src="https://api.star-history.com/chart?repos=rt-bishop/Look4Sat&type=timeline&legend=top-left" />
+ </picture>
+</a>

app/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_LOCAL_NETWORK" />
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <uses-permission
@@ -11,21 +12,33 @@
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
     <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
 
     <application
         android:name=".MainApplication"
+        android:allowBackup="false"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
+        android:networkSecurityConfig="@xml/network_security_config"
         android:roundIcon="@mipmap/ic_launcher_round">
 
         <activity
             android:name=".MainActivity"
             android:exported="true"
+            android:screenOrientation="portrait"
             android:theme="@style/Theme.Look4Sat.SplashScreen">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+<!--            <intent-filter android:autoVerify="true">-->
+<!--                <action android:name="android.intent.action.VIEW" />-->
+<!--                <category android:name="android.intent.category.DEFAULT" />-->
+<!--                <category android:name="android.intent.category.BROWSABLE" />-->
+<!--                <data android:scheme="https" />-->
+<!--                <data android:host="github.com" />-->
+<!--                <data android:pathPattern="/rt-bishop/Look4Sat/passes.*" />-->
+<!--            </intent-filter>-->
         </activity>
 
         <meta-data

app/src/main/java/com/rtbishop/look4sat/MainActivity.kt

@@ -19,12 +19,21 @@ package com.rtbishop.look4sat
 
 import android.content.Context
 import android.content.res.Configuration
+import android.graphics.ColorMatrix
+import android.graphics.ColorMatrixColorFilter
+import android.graphics.Paint
 import android.os.Bundle
+import android.view.View
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
+import androidx.lifecycle.lifecycleScope
+import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
 import com.rtbishop.look4sat.core.presentation.MainTheme
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.launch
 
 class MainActivity : ComponentActivity() {
 
@@ -38,8 +47,37 @@ class MainActivity : ComponentActivity() {
         installSplashScreen()
         enableEdgeToEdge()
         super.onCreate(savedInstanceState)
+        observeNightFilterState()
         setContent {
             MainTheme(isDarkTheme = true) { MainScreen() }
         }
     }
+
+    private fun observeNightFilterState() {
+        val mainContainer = (applicationContext as IContainerProvider).getMainContainer()
+        lifecycleScope.launch {
+            mainContainer.settingsRepo.otherSettings
+                .map { it.stateOfNightMode }
+                .distinctUntilChanged()
+                .collect { nightMode -> applyNightFilter(nightMode) }
+        }
+    }
+
+    private fun applyNightFilter(enabled: Boolean) {
+        if (enabled) {
+            val nightMatrix = ColorMatrix(
+                floatArrayOf(
+                    1f, 0f, 0f, 0f, 0f,   // R → R
+                    0f, 0f, 0f, 0f, 0f,   // G → 0
+                    0f, 0f, 0f, 0f, 0f,   // B → 0
+                    0f, 0f, 0f, 1f, 0f    // A → A
+                )
+            )
+            window.decorView.setLayerType(View.LAYER_TYPE_HARDWARE, Paint().apply {
+                colorFilter = ColorMatrixColorFilter(nightMatrix)
+            })
+        } else {
+            window.decorView.setLayerType(View.LAYER_TYPE_NONE, null)
+        }
+    }
 }

app/src/main/java/com/rtbishop/look4sat/MainScreen.kt

@@ -25,6 +25,10 @@ import androidx.compose.animation.core.rememberInfiniteTransition
 import androidx.compose.animation.core.tween
 import androidx.compose.animation.fadeIn
 import androidx.compose.animation.fadeOut
+import androidx.compose.animation.scaleIn
+import androidx.compose.animation.scaleOut
+import androidx.compose.animation.slideInHorizontally
+import androidx.compose.animation.slideOutHorizontally
 import androidx.compose.animation.togetherWith
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
@@ -32,6 +36,7 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
@@ -39,11 +44,14 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
 import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteDefaults
 import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteScaffold
 import androidx.compose.material3.adaptive.navigationsuite.NavigationSuiteType
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
@@ -55,151 +63,219 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.lifecycle.ViewModelStoreOwner
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+import androidx.lifecycle.viewmodel.compose.viewModel
+import androidx.lifecycle.viewmodel.navigation3.rememberViewModelStoreNavEntryDecorator
 import androidx.navigation3.runtime.entryProvider
 import androidx.navigation3.runtime.rememberNavBackStack
+import androidx.navigation3.runtime.rememberSaveableStateHolderNavEntryDecorator
 import androidx.navigation3.ui.NavDisplay
 import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
+import com.rtbishop.look4sat.core.domain.repository.MutualPassData
+import com.rtbishop.look4sat.core.presentation.DeeplinkResolver
+import com.rtbishop.look4sat.core.presentation.ElevationThresholds
+import com.rtbishop.look4sat.core.presentation.LocalElevationThresholds
+import com.rtbishop.look4sat.core.presentation.RadarDestination
 import com.rtbishop.look4sat.core.presentation.Screen
 import com.rtbishop.look4sat.core.presentation.hasEnoughHeight
 import com.rtbishop.look4sat.core.presentation.hasEnoughWidth
 import com.rtbishop.look4sat.feature.map.MapDestination
+import com.rtbishop.look4sat.feature.mutual.MutualScreen
+import com.rtbishop.look4sat.feature.mutual.MutualViewModel
 import com.rtbishop.look4sat.feature.passes.PassesDestination
 import com.rtbishop.look4sat.feature.radar.RadarDestination
-import com.rtbishop.look4sat.feature.radiocontrol.RadioControlDestination
 import com.rtbishop.look4sat.feature.satellites.SatellitesDestination
 import com.rtbishop.look4sat.feature.settings.SettingsDestination
 
 @Composable
-fun MainScreen() {
+fun NavRoot(deeplink: String? = null) {
+    val rootBackStack = rememberNavBackStack(Screen.Passes)
+    val deeplinkResolver = DeeplinkResolver()
+    LaunchedEffect(deeplink) {
+        deeplink?.let {
+            val destination = deeplinkResolver.resolve(it) // rootBackStack.clear()
+            rootBackStack.add(destination)
+        }
+    }
+    val navigateBack: () -> Unit = { rootBackStack.removeLastOrNull() }
+    val slideInTransition = slideInHorizontally(initialOffsetX = { it }) togetherWith scaleOut(targetScale = 0.9f)
+    val slideOutTransition = scaleIn(initialScale = 0.9f) togetherWith slideOutHorizontally(targetOffsetX = { it })
+    NavDisplay(
+        modifier = Modifier.fillMaxSize(),
+        backStack = rootBackStack,
+        onBack = navigateBack,
+        transitionSpec = { slideInTransition },
+        popTransitionSpec = { slideOutTransition },
+        predictivePopTransitionSpec = { slideOutTransition },
+        entryDecorators = listOf(
+            rememberSaveableStateHolderNavEntryDecorator(), // Required for saving Compose state per entry
+            rememberViewModelStoreNavEntryDecorator() // Required for ViewModel scoping per entry
+        ),
+        entryProvider = entryProvider {
+            entry<Screen.Passes> { MainScreen(navigateToRadar = { rootBackStack.add(RadarDestination) }) }
+            entry<RadarDestination> {
+                Scaffold { innerPadding ->
+                    RadarDestination(navigateUp = navigateBack)
+                    innerPadding.calculateTopPadding()
+                }
+            }
+        }
+    )
+}
+
+@Composable
+fun MainScreen(navigateToRadar: () -> Unit = {}) {
     val backStack = rememberNavBackStack(Screen.Passes)
     val currentKey = backStack.lastOrNull()
-    val navigateBack: () -> Unit = { backStack.removeAt(backStack.size - 1) }
+    val navigateBack: () -> Unit = { backStack.removeLastOrNull() }
     val fadeTransition = fadeIn(animationSpec = tween(350)) togetherWith fadeOut(animationSpec = tween(350))
-    val navItems = listOf(Screen.Satellites, Screen.Passes, Screen.Radar(), Screen.Map, Screen.Settings)
+    val navItems = listOf(Screen.Satellites, Screen.Passes, Screen.Radar, Screen.Mutual, Screen.Map, Screen.Settings)
 
     val context = LocalContext.current
     val container = (context.applicationContext as IContainerProvider).getMainContainer()
     val trackingState by container.radioTrackingService.state.collectAsStateWithLifecycle()
+    val otherSettings by container.settingsRepo.otherSettings.collectAsStateWithLifecycle()
+    // Activity-scoped so the mutual query results survive navigation to Radar and back
+    val mutualViewModel: MutualViewModel = viewModel(
+        viewModelStoreOwner = context as ViewModelStoreOwner,
+        factory = MutualViewModel.factory(container)
+    )
 
-    NavigationSuiteScaffold(
+    CompositionLocalProvider(
-        navigationSuiteItems = {
+        LocalElevationThresholds provides ElevationThresholds(
-            navItems.forEach { screen ->
+            low = otherSettings.lowElevation,
-                val isSelected = when (currentKey) {
+            high = otherSettings.highElevation
-                    is Screen.Satellites -> screen is Screen.Satellites
+        )
-                    is Screen.Passes -> screen is Screen.Passes
-                    is Screen.Radar -> screen is Screen.Radar
-                    is Screen.Map -> screen is Screen.Map
-                    is Screen.Settings -> screen is Screen.Settings
-                    else -> false
-                }
-                item(
-                    icon = { Icon(painterResource(screen.iconResId), stringResource(screen.titleResId)) },
-                    label = { Text(stringResource(screen.titleResId)) },
-                    selected = isSelected,
-                    onClick = {
-                        if (isSelected) return@item
-                        while (backStack.size > 1) backStack.removeAt(backStack.size - 1)
-                        if (screen !is Screen.Passes) backStack.add(screen)
-                    }
-                )
-            }
-        },
-        navigationSuiteColors = NavigationSuiteDefaults.colors(
-            navigationRailContainerColor = MaterialTheme.colorScheme.surfaceContainer
-        ),
-        layoutType = when {
-            !hasEnoughHeight() && hasEnoughWidth() -> NavigationSuiteType.NavigationRail
-            !hasEnoughWidth() -> NavigationSuiteType.ShortNavigationBarCompact
-            else -> NavigationSuiteType.ShortNavigationBarMedium
-        }
     ) {
-        Column {
+        NavigationSuiteScaffold(
-            NavDisplay(
+            navigationSuiteItems = {
-                backStack = backStack,
+                navItems.forEach { screen ->
-                modifier = Modifier.weight(1f),
+                    val isSelected = when (currentKey) {
-                onBack = navigateBack,
+                        is Screen.Satellites -> screen is Screen.Satellites
-                transitionSpec = { fadeTransition },
+                        is Screen.Passes -> screen is Screen.Passes
-                popTransitionSpec = { fadeTransition },
+                        is Screen.Radar -> screen is Screen.Radar
-                predictivePopTransitionSpec = { fadeTransition },
+                        is Screen.Mutual -> screen is Screen.Mutual
-                entryProvider = entryProvider {
+                        is Screen.Map -> screen is Screen.Map
-                    entry<Screen.Satellites> {
+                        is Screen.Settings -> screen is Screen.Settings
-                        SatellitesDestination(navigateUp = navigateBack)
+                        else -> false
                     }
-                    entry<Screen.Passes> {
+                    item(
-                        PassesDestination { catNum, aosTime ->
+                        icon = { Icon(painterResource(screen.iconResId), stringResource(screen.titleResId)) },
-                            backStack.add(Screen.Radar(catNum, aosTime))
+                        label = { Text(stringResource(screen.titleResId)) },
+                        selected = isSelected,
+                        onClick = {
+                            if (isSelected) return@item
+                            while (backStack.size > 1) backStack.removeAt(backStack.size - 1)
+                            if (screen !is Screen.Passes) backStack.add(screen)
                         }
-                    }
+                    )
-                    entry<Screen.Radar> { route ->
-                        RadarDestination(
-                            catNum = route.catNum,
-                            aosTime = route.aosTime,
-                            navigateUp = navigateBack,
-                            navigateToRadioControl = { catNum, aosTime ->
-                                backStack.add(Screen.RadioControl(catNum, aosTime))
-                            }
-                        )
-                    }
-                    entry<Screen.RadioControl> { route ->
-                        RadioControlDestination(
-                            catNum = route.catNum,
-                            aosTime = route.aosTime,
-                            navigateUp = navigateBack
-                        )
-                    }
-                    entry<Screen.Map> {
-                        MapDestination()
-                    }
-                    entry<Screen.Settings> {
-                        SettingsDestination()
-                    }
                 }
-            )
+            },
-            // Radio tracking status banner
+            navigationSuiteColors = NavigationSuiteDefaults.colors(
-            if (trackingState.isActive) {
+                navigationRailContainerColor = MaterialTheme.colorScheme.surfaceContainer
-                val infiniteTransition = rememberInfiniteTransition(label = "trackingPulse")
+            ),
-                val alpha by infiniteTransition.animateFloat(
+            layoutType = when {
-                    initialValue = 1f, targetValue = 0.4f,
+                !hasEnoughHeight() && hasEnoughWidth() -> NavigationSuiteType.NavigationRail
-                    animationSpec = infiniteRepeatable(
+                !hasEnoughWidth() -> NavigationSuiteType.ShortNavigationBarCompact
-                        animation = tween(1000, easing = LinearEasing),
+                else -> NavigationSuiteType.ShortNavigationBarMedium
-                        repeatMode = RepeatMode.Reverse
+            }
-                    ), label = "pulseAlpha"
+        ) {
-                )
+            Column {
-                Row(
+                NavDisplay(
-                    verticalAlignment = Alignment.CenterVertically,
+                    backStack = backStack,
-                    modifier = Modifier
+                    modifier = Modifier.weight(1f),
-                        .fillMaxWidth()
+                    onBack = navigateBack,
-                        .background(MaterialTheme.colorScheme.primaryContainer)
+                    transitionSpec = { fadeTransition },
-                        .clickable {
+                    popTransitionSpec = { fadeTransition },
-                            val pass = trackingState.currentPass
+                    predictivePopTransitionSpec = { fadeTransition },
-                            if (pass != null) {
+                    entryDecorators = listOf(
-                                backStack.add(Screen.RadioControl(pass.catNum, pass.aosTime))
+                        // Required for saving Compose state per entry
+                        rememberSaveableStateHolderNavEntryDecorator(),
+                        // Required for ViewModel scoping per entry
+                        rememberViewModelStoreNavEntryDecorator()
+                    ),
+                    entryProvider = entryProvider {
+                        entry<Screen.Satellites> {
+                            SatellitesDestination(navigateUp = navigateBack)
+                        }
+                        entry<Screen.Passes> {
+                            PassesDestination { catNum, aosTime ->
+                                container.setMutualPassData(MutualPassData())
+                                container.satelliteRepo.selectPass(catNum, aosTime)
+                                backStack.add(Screen.Radar)
+//                            navigateToRadar()
                             }
                         }
-                        .padding(horizontal = 12.dp, vertical = 6.dp)
+                        entry<Screen.Radar> {
-                ) {
+                            RadarDestination(navigateUp = navigateBack)
-                    Box(
+                        }
+                        entry<Screen.Map> {
+                            MapDestination()
+                        }
+                        entry<Screen.Mutual> {
+                            MutualScreen(
+                                viewModel = mutualViewModel,
+                                navigateUp = navigateBack,
+                                navigateToRadar = { catNum, aosTime, pass ->
+                                    container.setMutualPassData(pass ?: MutualPassData())
+                                    container.satelliteRepo.selectPass(catNum, aosTime)
+                                    backStack.add(Screen.Radar)
+                                }
+                            )
+                        }
+                        entry<Screen.Settings> {
+                            SettingsDestination()
+                        }
+                    }
+                )
+                // Radio tracking status banner
+                if (trackingState.isActive) {
+                    val infiniteTransition = rememberInfiniteTransition(label = "trackingPulse")
+                    val alpha by infiniteTransition.animateFloat(
+                        initialValue = 1f, targetValue = 0.4f,
+                        animationSpec = infiniteRepeatable(
+                            animation = tween(1000, easing = LinearEasing),
+                            repeatMode = RepeatMode.Reverse
+                        ), label = "pulseAlpha"
+                    )
+                    Row(
+                        verticalAlignment = Alignment.CenterVertically,
                         modifier = Modifier
-                            .size(8.dp)
+                            .fillMaxWidth()
-                            .clip(CircleShape)
+                            .background(MaterialTheme.colorScheme.primaryContainer)
-                            .background(Color(0xFF4CAF50).copy(alpha = alpha))
+                            .clickable {
-                    )
+                                val pass = trackingState.currentPass
-                    Spacer(modifier = Modifier.width(8.dp))
+                                if (pass != null) {
-                    Text(
+                                    container.setMutualPassData(MutualPassData())
-                        text = "Tracking: ${trackingState.currentPass?.name ?: ""}",
+                                    container.satelliteRepo.selectPass(pass.catNum, pass.aosTime)
-                        fontSize = 13.sp,
+                                    backStack.add(Screen.Radar)
-                        fontWeight = FontWeight.Medium,
+                                }
-                        color = MaterialTheme.colorScheme.onPrimaryContainer,
+                            }
-                        modifier = Modifier.weight(1f)
+                            .padding(horizontal = 12.dp, vertical = 6.dp)
-                    )
+                    ) {
-                    val txOk = if (trackingState.txConnected) "TX" else ""
+                        Box(
-                    val rxOk = if (trackingState.rxConnected) "RX" else ""
+                            modifier = Modifier
-                    Text(
+                                .size(8.dp)
-                        text = listOf(txOk, rxOk).filter { it.isNotBlank() }.joinToString("/"),
+                                .clip(CircleShape)
-                        fontSize = 12.sp,
+                                .background(Color(0xFF4CAF50).copy(alpha = alpha))
-                        color = MaterialTheme.colorScheme.onPrimaryContainer
+                        )
-                    )
+                        Spacer(modifier = Modifier.width(8.dp))
+                        Text(
+                            text = "Tracking: ${trackingState.currentPass?.name ?: ""}",
+                            fontSize = 13.sp,
+                            fontWeight = FontWeight.Medium,
+                            color = MaterialTheme.colorScheme.onPrimaryContainer,
+                            modifier = Modifier.weight(1f)
+                        )
+                        val txOk = if (trackingState.txConnected) "TX" else ""
+                        val rxOk = if (trackingState.rxConnected) "RX" else ""
+                        Text(
+                            text = listOf(txOk, rxOk).filter { it.isNotBlank() }.joinToString("/"),
+                            fontSize = 12.sp,
+                            color = MaterialTheme.colorScheme.onPrimaryContainer
+                        )
+                    }
                 }
             }
         }

app/src/main/res/xml/network_security_config.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<network-security-config>
+    <base-config cleartextTrafficPermitted="true" />
+</network-security-config>

build-logic/convention/src/main/java/com/rtbishop/look4sat/convention/ApplicationPlugin.kt

@@ -32,9 +32,9 @@ internal class ApplicationPlugin : Plugin<Project> {
             implementation(project(":core:domain"))
             implementation(project(":core:presentation"))
             implementation(project(":feature:map"))
+            implementation(project(":feature:mutual"))
             implementation(project(":feature:passes"))
             implementation(project(":feature:radar"))
-            implementation(project(":feature:radiocontrol"))
             implementation(project(":feature:satellites"))
             implementation(project(":feature:settings"))
             implementation(libs.androidx.core.splashscreen)

build.gradle.kts

@@ -8,5 +8,6 @@ plugins {
 }
 
 tasks.register("clean", Delete::class.java) {
+    description = "Cleans the build directory"
     delete(rootProject.layout.buildDirectory)
 }

core/data/src/main/AndroidManifest.xml

@@ -2,6 +2,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <uses-permission android:name="android.permission.ACCESS_LOCAL_NETWORK" />
     <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
     <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
     <uses-permission
@@ -11,5 +12,6 @@
     <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
     <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
     <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.RECORD_AUDIO" />
 
 </manifest>

core/data/src/main/java/com/rtbishop/look4sat/core/data/framework/Ft817CatProtocol.kt

@@ -17,6 +17,9 @@
  */
 package com.rtbishop.look4sat.core.data.framework
 
+import java.util.Locale
+import kotlin.math.roundToLong
+
 object Ft817CatProtocol {
 
     const val CMD_SET_FREQ: Byte = 0x01
@@ -50,7 +53,7 @@ object Ft817CatProtocol {
     fun encodeFrequencyBcd(frequencyHz: Long): ByteArray {
         val freq10Hz = frequencyHz / 10
         val bcd = ByteArray(4)
-        val digits = String.format("%08d", freq10Hz)
+        val digits = String.format(Locale.US, "%08d", freq10Hz)
         for (i in 0 until 4) {
             val high = digits[i * 2] - '0'
             val low = digits[i * 2 + 1] - '0'
@@ -78,8 +81,8 @@ object Ft817CatProtocol {
      * 67.0 Hz → 670 (in 0.1 Hz) → BCD [0x06, 0x70]
      */
     fun encodeCtcssToneBcd(toneHz: Double): ByteArray {
-        val tone01Hz = (toneHz * 10).toLong()
+        val tone01Hz = (toneHz * 10).roundToLong()
-        val digits = String.format("%04d", tone01Hz)
+        val digits = String.format(Locale.US, "%04d", tone01Hz)
         val bcd = ByteArray(2)
         for (i in 0 until 2) {
             val high = digits[i * 2] - '0'
@@ -95,7 +98,7 @@ object Ft817CatProtocol {
     }
 
     fun buildSetModeCommand(mode: String): ByteArray? {
-        val modeByte = MODE_TO_BYTE[mode.uppercase()] ?: return null
+        val modeByte = MODE_TO_BYTE[mode.uppercase(Locale.US)] ?: return null
         return byteArrayOf(modeByte, 0x00, 0x00, 0x00, CMD_SET_MODE)
     }
 

core/data/src/main/java/com/rtbishop/look4sat/core/data/framework/Ft817Controller.kt

@@ -29,6 +29,7 @@ import kotlinx.coroutines.withContext
 import java.io.InputStream
 import java.io.OutputStream
 import java.util.UUID
+import kotlin.time.Duration.Companion.milliseconds
 
 class Ft817Controller(
     private val bluetoothManager: BluetoothManager,
@@ -39,10 +40,12 @@ class Ft817Controller(
     private val sppId: UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb")
     private val ioMutex = Mutex()
     private val commandDelayMs = 200L
+    private val maxAckReadFailures = 3
 
     private var socket: BluetoothSocket? = null
     private var outputStream: OutputStream? = null
     private var inputStream: InputStream? = null
+    private var ackReadFailureCount = 0
 
     override var isConnected: Boolean = false
         private set
@@ -57,6 +60,7 @@ class Ft817Controller(
             socket = btSocket
             outputStream = btSocket.outputStream
             inputStream = btSocket.inputStream
+            ackReadFailureCount = 0
             isConnected = true
             Log.i(tag, "Connected to $deviceAddress")
             true
@@ -79,6 +83,7 @@ class Ft817Controller(
                 inputStream = null
                 outputStream = null
                 socket = null
+                ackReadFailureCount = 0
                 isConnected = false
                 Log.i(tag, "Disconnected from $deviceAddress")
             }
@@ -112,8 +117,8 @@ class Ft817Controller(
         ioMutex.withLock {
             val sent = sendCommand(Ft817CatProtocol.buildReadFreqModeCommand())
             if (!sent) return@withContext null
-            delay(commandDelayMs)
+            delay(commandDelayMs.milliseconds)
-            val response = readResponse(5) ?: return@withContext null
+            val response = readResponse() ?: return@withContext null
             Ft817CatProtocol.parseReadResponse(response)
         }
     }
@@ -127,44 +132,76 @@ class Ft817Controller(
     }
 
     private suspend fun sendCommand(bytes: ByteArray): Boolean {
-        return try {
+        return withContext(Dispatchers.IO) {
-            outputStream?.write(bytes) ?: return false
+            try {
-            outputStream?.flush()
+                outputStream?.write(bytes) ?: return@withContext false
-            delay(commandDelayMs)
+                outputStream?.flush()
-            true
+                delay(commandDelayMs.milliseconds)
-        } catch (e: Exception) {
+                true
-            Log.e(tag, "Send error: ${e.message}")
+            } catch (e: Exception) {
-            isConnected = false
+                Log.e(tag, "Send error: ${e.message}")
-            false
+                isConnected = false
+                false
+            }
         }
     }
 
     /** Send command and read the 1-byte ACK response (0x00 = OK). */
     private suspend fun sendCommandWithAck(bytes: ByteArray): Boolean {
         if (!sendCommand(bytes)) return false
-        return try {
+        return withContext(Dispatchers.IO) {
-            val ack = inputStream?.read() ?: return false
+            try {
-            ack == 0x00
+                val ack = inputStream?.read() ?: run {
-        } catch (e: Exception) {
+                    ackReadFailureCount = 0
-            Log.e(tag, "ACK read error: ${e.message}")
+                    isConnected = false
-            true // command was sent, ACK read failed - continue anyway
+                    return@withContext false
+                }
+                if (ack < 0) {
+                    ackReadFailureCount = 0
+                    Log.i(tag, "ACK stream closed by remote device")
+                    isConnected = false
+                    return@withContext false
+                }
+                ackReadFailureCount = 0
+                ack == 0x00
+            } catch (e: Exception) {
+                ackReadFailureCount += 1
+                Log.w(tag, "ACK read error (${ackReadFailureCount}/$maxAckReadFailures): ${e.message}")
+                if (ackReadFailureCount >= maxAckReadFailures) {
+                    Log.e(tag, "Too many ACK read errors, marking radio disconnected")
+                    isConnected = false
+                    false
+                } else {
+                    true // Command was sent, treat transient ACK read failures as best-effort
+                }
+            }
         }
     }
 
-    private fun readResponse(length: Int): ByteArray? {
+    private suspend fun readResponse(): ByteArray? {
-        return try {
+        return withContext(Dispatchers.IO) {
-            val buffer = ByteArray(length)
+            try {
-            var read = 0
+                val responseSize = 5
-            while (read < length) {
+                val buffer = ByteArray(responseSize)
-                val count = inputStream?.read(buffer, read, length - read) ?: return null
+                var read = 0
-                if (count < 0) return null
+                while (read < responseSize) {
-                read += count
+                    val count = inputStream?.read(buffer, read, responseSize - read) ?: run {
+                        isConnected = false
+                        return@withContext null
+                    }
+                    if (count < 0) {
+                        Log.i(tag, "Response stream closed by remote device")
+                        isConnected = false
+                        return@withContext null
+                    }
+                    read += count
+                }
+                buffer
+            } catch (e: Exception) {
+                Log.e(tag, "Read error: ${e.message}")
+                isConnected = false
+                null
             }
-            buffer
-        } catch (e: Exception) {
-            Log.e(tag, "Read error: ${e.message}")
-            isConnected = false
-            null
         }
     }
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/framework/Ic705Controller.kt

@@ -0,0 +1,364 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.data.framework
+
+import android.bluetooth.BluetoothManager
+import android.bluetooth.BluetoothSocket
+import android.util.Log
+import com.rtbishop.look4sat.core.domain.repository.IRadioController
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlinx.coroutines.withContext
+import java.io.InputStream
+import java.io.OutputStream
+import java.util.UUID
+
+/**
+ * Icom IC-705 CI-V controller over Bluetooth SPP.
+ *
+ * The IC-705 emits broadcast frames continuously (band scope, UTC, signal
+ * level, …).  A reply to any command we send may therefore be buried in
+ * that noise.  All response reads drain up to [ACK_TIMEOUT_MS] and scan the
+ * entire accumulated buffer for the frame we expect rather than assuming
+ * the very next byte is the response.
+ */
+class Ic705Controller(
+    private val bluetoothManager: BluetoothManager,
+    private val deviceAddress: String
+) : IRadioController {
+
+    private val tag = "IC705"
+    private val sppId: UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb")
+    private val ioMutex = Mutex()
+
+    /** Time budget (ms) to wait for a response amid broadcast noise. */
+    private val ACK_TIMEOUT_MS = 500L
+    /** Polling interval while draining the input buffer. */
+    private val POLL_INTERVAL_MS = 20L
+    /** Small pause after writing a command before reading the response. */
+    private val WRITE_SETTLE_MS = 50L
+
+    private var socket: BluetoothSocket? = null
+    private var outputStream: OutputStream? = null
+    private var inputStream: InputStream? = null
+
+    override var isConnected: Boolean = false
+        private set
+
+    // ── Connection ──────────────────────────────────────────────────────────
+
+    override suspend fun connect(): Boolean = withContext(Dispatchers.IO) {
+        if (isConnected) return@withContext true
+        if (deviceAddress.isBlank()) return@withContext false
+        try {
+            val device  = bluetoothManager.adapter.getRemoteDevice(deviceAddress)
+            val btSocket = device.createInsecureRfcommSocketToServiceRecord(sppId)
+            btSocket.connect()
+            socket       = btSocket
+            outputStream = btSocket.outputStream
+            inputStream  = btSocket.inputStream
+            isConnected  = true
+            // Enter VFO mode — frequency/mode commands return FA if the radio
+            // is in memory-channel mode. Safe to send regardless of current state.
+            Log.i(tag, "Connected to $deviceAddress — entering VFO mode")
+            val vfoCmd = IcomCivProtocol.buildEnterVfoModeCommand()
+            Log.d(tag, "CMD enterVfoMode → ${IcomCivProtocol.toHex(vfoCmd)}")
+            ioMutex.withLock { sendAndWaitAck(vfoCmd) }
+            true
+        } catch (e: Exception) {
+            Log.e(tag, "Connect error: ${e.message}")
+            isConnected = false
+            false
+        }
+    }
+
+    override suspend fun disconnect() {
+        withContext(Dispatchers.IO) {
+            try {
+                inputStream?.close()
+                outputStream?.close()
+                socket?.close()
+            } catch (e: Exception) {
+                Log.e(tag, "Disconnect error: ${e.message}")
+            } finally {
+                inputStream  = null
+                outputStream = null
+                socket       = null
+                isConnected  = false
+                Log.i(tag, "Disconnected from $deviceAddress")
+            }
+        }
+    }
+
+    // ── IRadioController – standard operations ──────────────────────────────
+
+    override suspend fun setFrequency(frequencyHz: Long): Boolean = withContext(Dispatchers.IO) {
+        Log.d(tag, "setFrequency: ${frequencyHz}Hz")
+        ioMutex.withLock {
+            val cmd = IcomCivProtocol.buildSetFreqCommand(frequencyHz)
+            Log.d(tag, "CMD setFreq → ${IcomCivProtocol.toHex(cmd)}")
+            sendAndWaitAck(cmd)
+        }
+    }
+
+    override suspend fun setMode(mode: String): Boolean = withContext(Dispatchers.IO) {
+        val cmd = IcomCivProtocol.buildSetModeCommand(mode) ?: run {
+            Log.w(tag, "setMode: unknown mode '$mode'")
+            return@withContext false
+        }
+        Log.d(tag, "setMode: $mode")
+        Log.d(tag, "CMD setMode → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    override suspend fun setCtcssMode(enabled: Boolean): Boolean = withContext(Dispatchers.IO) {
+        Log.d(tag, "setCtcssMode: $enabled")
+        val cmd = IcomCivProtocol.buildCtcssModeCommand(enabled)
+        Log.d(tag, "CMD ctcssMode → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    override suspend fun setCtcssTone(toneHz: Double): Boolean = withContext(Dispatchers.IO) {
+        Log.d(tag, "setCtcssTone: ${toneHz}Hz")
+        val cmd = IcomCivProtocol.buildSetCtcssToneCommand(toneHz)
+        Log.d(tag, "CMD ctcssTone → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    override suspend fun readFrequencyAndMode(): Pair<Long, String>? = withContext(Dispatchers.IO) {
+        ioMutex.withLock {
+            val cmd = IcomCivProtocol.buildReadFreqCommand()
+            Log.d(tag, "CMD readFreq → ${IcomCivProtocol.toHex(cmd)}")
+            val payload = sendAndReadResponse(cmd, IcomCivProtocol.CMD_READ_FREQ) ?: return@withContext null
+            // Read-freq reply payload: [cmd byte already stripped by parseResponse] [5 freq bytes] [mode] [filter]
+            IcomCivProtocol.parseFreqModePayload(payload).also {
+                if (it != null) Log.d(tag, "readFreqMode: ${it.first}Hz, ${it.second}")
+                else Log.w(tag, "readFreqMode: parse failed, payload=${IcomCivProtocol.toHex(payload)}")
+            }
+        }
+    }
+
+    override suspend fun pttOn(): Boolean = withContext(Dispatchers.IO) {
+        Log.w(tag, "pttOn: not used for IC-705")
+        true
+    }
+
+    override suspend fun pttOff(): Boolean = withContext(Dispatchers.IO) {
+        Log.w(tag, "pttOff: not used for IC-705")
+        true
+    }
+
+    // ── IRadioController – IC-705 extended operations ───────────────────────
+
+    /** Select the band for [frequencyHz] via CMD 0x1A sub 0x00 (band stacking register). */
+    override suspend fun setBand(frequencyHz: Long): Boolean = withContext(Dispatchers.IO) {
+        val cmd = IcomCivProtocol.buildBandSelectCommand(frequencyHz) ?: run {
+            Log.w(tag, "setBand: no band code for ${frequencyHz}Hz — skipping")
+            return@withContext false
+        }
+        Log.d(tag, "CMD setBand (${frequencyHz}Hz) → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    /** Select VFO-A (main/RX) or VFO-B (sub/TX). */
+    override suspend fun setVfo(vfoA: Boolean): Boolean = withContext(Dispatchers.IO) {
+        val cmd = if (vfoA) IcomCivProtocol.buildSelectVfoACommand()
+                  else      IcomCivProtocol.buildSelectVfoBCommand()
+        Log.d(tag, "CMD selectVFO${if (vfoA) "A" else "B"} → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    /**
+     * Enable or disable SPLIT mode (TX on sub-VFO while listening on main VFO).
+     */
+    override suspend fun setSplitMode(enabled: Boolean): Boolean = withContext(Dispatchers.IO) {
+        val cmd = IcomCivProtocol.buildSplitModeCommand(enabled)
+        Log.d(tag, "CMD split ${if (enabled) "ON" else "OFF"} → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    /**
+     * Set the frequency of the **currently active** VFO (CMD 0x25 sub 0x00).
+     * In split mode the radio automatically switches active VFO on PTT, so
+     * always writing to the active VFO is the correct strategy.
+     */
+    override suspend fun setWorkingFrequency(frequencyHz: Long): Boolean = withContext(Dispatchers.IO) {
+        Log.d(tag, "setWorkingFrequency (0x25/00): ${frequencyHz}Hz")
+        val cmd = IcomCivProtocol.buildSetWorkingFreqCommand(frequencyHz)
+        Log.d(tag, "CMD setWorkingFreq → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    /**
+     * Set TX VFO frequency via CMD 0x25 sub 0x01 (unselected VFO).
+     * Sent every tracking cycle in split mode alongside [setWorkingFrequency].
+     */
+    override suspend fun setTxVfoFrequency(frequencyHz: Long): Boolean = withContext(Dispatchers.IO) {
+        Log.d(tag, "setTxVfoFrequency (0x25/01): ${frequencyHz}Hz")
+        val cmd = IcomCivProtocol.buildSetUnselectedVfoFreqCommand(frequencyHz)
+        Log.d(tag, "CMD setTxVfoFreq → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
+    /**
+     * Read the frequency of the currently active VFO (CMD 0x25 sub 0x00).
+     * Used for tuning detection in split mode.
+     */
+    override suspend fun readWorkingFrequency(): Long? = withContext(Dispatchers.IO) {
+        ioMutex.withLock {
+            val cmd = IcomCivProtocol.buildReadWorkingFreqCommand()
+            Log.d(tag, "CMD readWorkingFreq → ${IcomCivProtocol.toHex(cmd)}")
+            val payload = sendAndReadResponse(cmd, IcomCivProtocol.CMD_SELECTED_VFO_FREQ) ?: return@withContext null
+            // Response payload: [sub] [5 freq bytes] — CMD byte already stripped by parseResponse
+            Log.d(tag, "readWorkingFreq: got ${payload.size} bytes: ${IcomCivProtocol.toHex(payload)}")
+            if (payload.size < 6) {
+                Log.w(tag, "readWorkingFreq: payload too short (${payload.size} bytes)")
+                return@withContext null
+            }
+            val freqBcd = payload.sliceArray(1..5)
+            val freq = IcomCivProtocol.decodeFrequencyBcd(freqBcd)
+            Log.d(tag, "readWorkingFreq: ${freq}Hz")
+            freq
+        }
+    }
+
+    /**
+     * Read the frequency of the inactive/TX VFO (CMD 0x25 sub 0x01).
+     * Used for tuning detection in split mode.
+     */
+    override suspend fun readTxVfoFrequency(): Long? = withContext(Dispatchers.IO) {
+        ioMutex.withLock {
+            val cmd = IcomCivProtocol.buildReadTxVfoFreqCommand()
+            Log.d(tag, "CMD readTxVfoFreq → ${IcomCivProtocol.toHex(cmd)}")
+            val payload = sendAndReadResponse(cmd, IcomCivProtocol.CMD_SELECTED_VFO_FREQ) ?: return@withContext null
+            // Response payload: [sub] [5 freq bytes] — CMD byte already stripped by parseResponse
+            Log.d(tag, "readTxVfoFreq: got ${payload.size} bytes: ${IcomCivProtocol.toHex(payload)}")
+            if (payload.size < 6) {
+                Log.w(tag, "readTxVfoFreq: payload too short (${payload.size} bytes)")
+                return@withContext null
+            }
+            val freqBcd = payload.sliceArray(1..5)
+            val freq = IcomCivProtocol.decodeFrequencyBcd(freqBcd)
+            Log.d(tag, "readTxVfoFreq: ${freq}Hz")
+            freq
+        }
+    }
+
+    // ── Internal I/O helpers ────────────────────────────────────────────────
+
+    /**
+     * Write [cmd] to the radio and drain the input stream for up to
+     * [ACK_TIMEOUT_MS], looking for an OK/NG acknowledgement frame.
+     */
+    private suspend fun sendAndWaitAck(cmd: ByteArray): Boolean {
+        if (!write(cmd)) return false
+        delay(WRITE_SETTLE_MS)
+        val buf = drainWithTimeout(ACK_TIMEOUT_MS)
+        val ok  = IcomCivProtocol.containsAck(buf)
+        if (!ok) Log.w(tag, "ACK not found in ${buf.size} bytes: ${IcomCivProtocol.toHex(buf)}")
+        return ok
+    }
+
+    /**
+     * Write [cmd] to the radio and drain the input stream for up to
+     * [ACK_TIMEOUT_MS], scanning for a response frame carrying [expectCmd].
+     * Returns the payload bytes of that frame, or null on timeout/error.
+     */
+    private suspend fun sendAndReadResponse(cmd: ByteArray, expectCmd: Byte): ByteArray? {
+        if (!write(cmd)) return null
+        delay(WRITE_SETTLE_MS)
+        val buf      = drainWithTimeout(ACK_TIMEOUT_MS)
+        val response = IcomCivProtocol.parseResponse(buf, expectCmd)
+        if (response == null) {
+            Log.w(tag, "No response for cmd 0x${String.format("%02X", expectCmd.toInt() and 0xFF)} " +
+                    "in ${buf.size} bytes: ${IcomCivProtocol.toHex(buf)}")
+        }
+        return response?.payload
+    }
+
+    /**
+     * Drain whatever bytes the radio has buffered within a [timeoutMs] window.
+     * Exits early as soon as a complete CI-V frame addressed to us is present
+     * in the buffer (i.e., FE FE E0 A4 … FD), so we don't waste the remaining
+     * timeout on responses that already arrived.
+     */
+    private suspend fun drainWithTimeout(timeoutMs: Long): ByteArray {
+        val result   = mutableListOf<Byte>()
+        val deadline = System.currentTimeMillis() + timeoutMs
+        val stream   = inputStream ?: return ByteArray(0)
+        while (System.currentTimeMillis() < deadline) {
+            try {
+                val available = stream.available()
+                if (available > 0) {
+                    val chunk = ByteArray(available)
+                    val read  = stream.read(chunk)
+                    if (read > 0) {
+                        result.addAll(chunk.take(read))
+                        // Exit early once we have a complete frame for us
+                        if (hasCompleteFrameForUs(result)) break
+                    }
+                } else {
+                    delay(POLL_INTERVAL_MS)
+                }
+            } catch (e: Exception) {
+                Log.e(tag, "Drain error: ${e.message}")
+                isConnected = false
+                break
+            }
+        }
+        return result.toByteArray()
+    }
+
+    /**
+     * Returns true if [buf] contains a complete CI-V frame addressed to the
+     * controller (FE FE [ADDR_CTRL] [ADDR_IC705] … FD).
+     * CI-V data bytes cannot be 0xFD, so the first 0xFD after the header is
+     * always the frame terminator.
+     */
+    private fun hasCompleteFrameForUs(buf: List<Byte>): Boolean {
+        var i = 0
+        while (i < buf.size - 4) {
+            if (buf[i]     == IcomCivProtocol.PREAMBLE    &&
+                buf[i + 1] == IcomCivProtocol.PREAMBLE    &&
+                buf[i + 2] == IcomCivProtocol.ADDR_CTRL   &&
+                buf[i + 3] == IcomCivProtocol.ADDR_IC705
+            ) {
+                for (k in i + 4 until buf.size) {
+                    if (buf[k] == IcomCivProtocol.END_OF_MSG) return true
+                }
+                return false  // header found but no FD yet
+            }
+            i++
+        }
+        return false
+    }
+
+    private fun write(bytes: ByteArray): Boolean {
+        return try {
+            outputStream?.write(bytes)
+            outputStream?.flush()
+            true
+        } catch (e: Exception) {
+            Log.e(tag, "Write error: ${e.message}")
+            isConnected = false
+            false
+        }
+    }
+}

core/data/src/main/java/com/rtbishop/look4sat/core/data/framework/IcomCivProtocol.kt

@@ -0,0 +1,352 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.data.framework
+
+import java.util.Locale
+
+/**
+ * Icom CI-V protocol encoder/decoder for the IC-705.
+ *
+ * Frame structure:
+ *   FE FE <DEST> <SRC> <CMD> [<SUB>] [<DATA...>] FD
+ *
+ * IC-705 default CI-V address : 0xA4
+ * Controller (us) address     : 0xE0
+ */
+object IcomCivProtocol {
+
+    // ── Framing constants ──────────────────────────────────────────────────
+    const val PREAMBLE: Byte      = 0xFE.toByte()
+    const val END_OF_MSG: Byte    = 0xFD.toByte()
+    const val ACK_OK: Byte        = 0xFB.toByte()
+    const val ACK_NG: Byte        = 0xFA.toByte()
+
+    // ── Address constants ──────────────────────────────────────────────────
+    /** Default CI-V address of the IC-705. */
+    const val ADDR_IC705: Byte    = 0xA4.toByte()
+    /** Default CI-V address of the controller (us). */
+    const val ADDR_CTRL: Byte     = 0xE0.toByte()
+
+    // ── Command bytes ──────────────────────────────────────────────────────
+    /** Read operating frequency (main VFO). */
+    const val CMD_READ_FREQ: Byte           = 0x03
+    /** Set operating frequency (main VFO). */
+    const val CMD_SET_FREQ: Byte            = 0x05
+    /** Set operating mode. */
+    const val CMD_SET_MODE: Byte            = 0x06
+    /** Select VFO / memory. */
+    const val CMD_SELECT_VFO: Byte          = 0x07
+    /**
+     * Select operating mode (VFO vs memory-channel).
+     * Sub 0x00 = VFO mode. Must be sent after connect if the radio is in
+     * memory-channel mode — frequency/mode commands return FA until it is.
+     */
+    const val CMD_SELECT_OP_MODE: Byte      = 0x08
+    /** Set repeater duplex / SPLIT. */
+    const val CMD_DUPLEX_SPLIT: Byte        = 0x0F
+    /** Band stacking register / band select (sub 0x00 = select, data = BCD band number). */
+    const val CMD_BAND_SELECT: Byte         = 0x1A
+    /** Read/write CTCSS tone frequency. */
+    const val CMD_CTCSS_TONE: Byte          = 0x1B
+    /** Read/write misc settings (used for enabling CTCSS encode). */
+    const val CMD_MISC_SETTING: Byte        = 0x16
+    /** Read/write selected-VFO frequency (cmd 0x25). */
+    const val CMD_SELECTED_VFO_FREQ: Byte   = 0x25
+
+    // ── Sub-command bytes ──────────────────────────────────────────────────
+    /** Sub for CMD_SELECT_VFO: select VFO-A (main). */
+    const val SUB_VFO_A: Byte   = 0x00
+    /** Sub for CMD_SELECT_VFO: select VFO-B (sub). */
+    const val SUB_VFO_B: Byte   = 0x01
+    /** Sub for CMD_DUPLEX_SPLIT: simplex / split OFF. */
+    const val SUB_SPLIT_OFF: Byte = 0x00
+    /** Sub for CMD_DUPLEX_SPLIT: SPLIT ON. */
+    const val SUB_SPLIT_ON: Byte  = 0x01
+    /** Sub for CMD_SELECTED_VFO_FREQ: selected (active) VFO frequency. */
+    const val SUB_SELECTED_VFO: Byte = 0x00
+    /** Sub for CMD_SELECTED_VFO_FREQ: unselected (inactive / TX in split) VFO frequency. */
+    const val SUB_UNSELECTED_VFO: Byte = 0x01
+    /** Sub for CMD_MISC_SETTING: CTCSS/DTCS tone squelch. */
+    const val SUB_CTCSS_SETTING: Byte = 0x42.toByte()
+
+    // ── Mode bytes ────────────────────────────────────────────────────────
+    /** Maps mode strings (upper-case) → IC-705 mode bytes. */
+    val MODE_TO_BYTE: Map<String, Byte> = mapOf(
+        "LSB"    to 0x00,
+        "USB"    to 0x01,
+        "AM"     to 0x02,
+        "CW"     to 0x03,
+        "RTTY"   to 0x04,
+        "FM"     to 0x05,
+        "WFM"    to 0x06,
+        "CW-R"   to 0x07,
+        "RTTY-R" to 0x08,
+        "DV"     to 0x12,
+        "AFSK"   to 0x05  // AFSK uses FM modulation
+    )
+
+    val BYTE_TO_MODE: Map<Byte, String> = MODE_TO_BYTE.entries.associate { it.value to it.key }
+
+    // ── Frequency BCD encoding ─────────────────────────────────────────────
+
+    /**
+     * Encode a frequency in Hz to the IC-705's 5-byte BCD format.
+     *
+     * The IC-705 uses 5 bytes, LSB pair first, with 1 Hz resolution.
+     * Example: 145,500,000 Hz → "0145500000" → pairs LSB→MSB:
+     *   [00, 00, 50, 45, 01]
+     */
+    fun encodeFrequencyBcd(frequencyHz: Long): ByteArray {
+        val digits = String.format(Locale.US, "%010d", frequencyHz)
+        val bcd = ByteArray(5)
+        for (i in 0 until 5) {
+            // digits are MSB first; we want pair index 0 = LSB pair
+            val pairIndex = 4 - i
+            val high = digits[pairIndex * 2] - '0'
+            val low  = digits[pairIndex * 2 + 1] - '0'
+            bcd[i] = ((high shl 4) or low).toByte()
+        }
+        return bcd
+    }
+
+    /**
+     * Decode 5-byte BCD frequency (LSB pair first) to Hz.
+     */
+    fun decodeFrequencyBcd(bcd: ByteArray): Long {
+        // Build digit string MSB→LSB by reversing the byte order
+        var freqHz = 0L
+        for (i in 4 downTo 0) {
+            val b    = bcd[i].toInt() and 0xFF
+            val high = b shr 4
+            val low  = b and 0x0F
+            freqHz   = freqHz * 100 + high * 10 + low
+        }
+        return freqHz
+    }
+
+    /**
+     * Encode a CTCSS tone (Hz, e.g. 67.0) to 2-byte BCD (0.1 Hz resolution).
+     * 67.0 → 670 (tenths of Hz) → BCD bytes [0x06, 0x70].
+     */
+    fun encodeCtcssToneBcd(toneHz: Double): ByteArray {
+        val tone01 = (toneHz * 10).toLong()
+        val digits = String.format(Locale.US, "%04d", tone01)
+        return byteArrayOf(
+            ((digits[0] - '0') shl 4 or (digits[1] - '0')).toByte(),
+            ((digits[2] - '0') shl 4 or (digits[3] - '0')).toByte()
+        )
+    }
+
+    // ── Message builders ───────────────────────────────────────────────────
+
+    /** Wrap payload bytes in a CI-V frame: FE FE DEST SRC ... FD. */
+    private fun frame(vararg payload: Byte): ByteArray {
+        return byteArrayOf(PREAMBLE, PREAMBLE, ADDR_IC705, ADDR_CTRL) +
+                payload +
+                byteArrayOf(END_OF_MSG)
+    }
+
+    /** Set operating frequency via CMD 0x05 (main VFO). */
+    fun buildSetFreqCommand(frequencyHz: Long): ByteArray {
+        return frame(CMD_SET_FREQ, *encodeFrequencyBcd(frequencyHz))
+    }
+
+    /**
+     * Set selected-VFO frequency via CMD 0x25 sub 0x00.
+     * This updates whichever VFO is currently active (RX or TX after split).
+     */
+    fun buildSetWorkingFreqCommand(frequencyHz: Long): ByteArray {
+        return frame(CMD_SELECTED_VFO_FREQ, SUB_SELECTED_VFO, *encodeFrequencyBcd(frequencyHz))
+    }
+
+    /**
+     * Set unselected-VFO frequency via CMD 0x25 sub 0x01.
+     * In split mode while PTT is pressed the IC-705 makes VFO-B active, so
+     * this command targets VFO-A (the RX VFO) — and vice-versa when in RX.
+     * Use this to update the TX VFO when PTT is on.
+     */
+    fun buildSetUnselectedVfoFreqCommand(frequencyHz: Long): ByteArray {
+        return frame(CMD_SELECTED_VFO_FREQ, SUB_UNSELECTED_VFO, *encodeFrequencyBcd(frequencyHz))
+    }
+
+    /** Read operating frequency (CMD 0x03). */
+    fun buildReadFreqCommand(): ByteArray = frame(CMD_READ_FREQ)
+
+    /** Read selected (active) VFO frequency (CMD 0x25 sub 0x00). */
+    fun buildReadWorkingFreqCommand(): ByteArray = frame(CMD_SELECTED_VFO_FREQ, SUB_SELECTED_VFO)
+
+    /** Read unselected (inactive/TX in split) VFO frequency (CMD 0x25 sub 0x01). */
+    fun buildReadTxVfoFreqCommand(): ByteArray = frame(CMD_SELECTED_VFO_FREQ, SUB_UNSELECTED_VFO)
+
+    /**
+     * Select band via CMD 0x1A sub 0x00.
+     * Band codes are BCD-numbered: 1=160m, 2=80m, …, 9=10m, 0x10=6m, 0x11=2m, 0x12=70cm, 0x13=23cm.
+     * Returns null if [frequencyHz] doesn't fall in a known amateur band.
+     */
+    fun buildBandSelectCommand(frequencyHz: Long): ByteArray? {
+        val code = bandCodeForFrequency(frequencyHz) ?: return null
+        return frame(CMD_BAND_SELECT, 0x00, code)
+    }
+
+    /**
+     * Map a frequency in Hz to the IC-705 band stacking register code.
+     * Codes are BCD (band number in decimal expressed as hex nibbles).
+     */
+    fun bandCodeForFrequency(frequencyHz: Long): Byte? = when {
+        frequencyHz in 1_800_000L     ..1_999_999L     -> 0x01 // 160 m
+        frequencyHz in 3_500_000L     ..3_999_999L     -> 0x02 // 80 m
+        frequencyHz in 7_000_000L     ..7_299_999L     -> 0x03 // 40 m
+        frequencyHz in 10_100_000L    ..10_149_999L    -> 0x04 // 30 m
+        frequencyHz in 14_000_000L    ..14_349_999L    -> 0x05 // 20 m
+        frequencyHz in 18_068_000L    ..18_167_999L    -> 0x06 // 17 m
+        frequencyHz in 21_000_000L    ..21_449_999L    -> 0x07 // 15 m
+        frequencyHz in 24_890_000L    ..24_989_999L    -> 0x08 // 12 m
+        frequencyHz in 28_000_000L    ..29_699_999L    -> 0x09 // 10 m
+        frequencyHz in 50_000_000L    ..53_999_999L    -> 0x10 // 6 m  (BCD 10)
+        frequencyHz in 144_000_000L   ..147_999_999L   -> 0x11 // 2 m  (BCD 11)
+        frequencyHz in 420_000_000L   ..449_999_999L   -> 0x12 // 70 cm (BCD 12)
+        frequencyHz in 1_240_000_000L ..1_299_999_999L -> 0x13 // 23 cm (BCD 13)
+        else -> null
+    }
+
+    /** Set operating mode (CMD 0x06). Filter byte is omitted — radio uses its default filter for the mode. */
+    fun buildSetModeCommand(mode: String): ByteArray? {
+        val modeByte = MODE_TO_BYTE[mode.uppercase(Locale.US)] ?: return null
+        return frame(CMD_SET_MODE, modeByte)
+    }
+
+    /** Select VFO-A (CMD 0x07 sub 0x00). */
+    fun buildSelectVfoACommand(): ByteArray = frame(CMD_SELECT_VFO, SUB_VFO_A)
+
+    /** Select VFO-B (CMD 0x07 sub 0x01). */
+    fun buildSelectVfoBCommand(): ByteArray = frame(CMD_SELECT_VFO, SUB_VFO_B)
+
+    /**
+     * Enter VFO operating mode (CMD 0x08 sub 0x00).
+     * Sent after connect — if the radio is in memory-channel mode frequency
+     * and mode commands return FA until this is issued.
+     */
+    fun buildEnterVfoModeCommand(): ByteArray = frame(CMD_SELECT_OP_MODE, 0x00)
+
+    /** Enable or disable SPLIT mode (CMD 0x0F). */
+    fun buildSplitModeCommand(enable: Boolean): ByteArray {
+        val sub = if (enable) SUB_SPLIT_ON else SUB_SPLIT_OFF
+        return frame(CMD_DUPLEX_SPLIT, sub)
+    }
+
+    /**
+     * Enable/disable CTCSS encode (CMD 0x16 sub 0x42).
+     * 0x01 = CTCSS encoder ON, 0x00 = OFF.
+     */
+    fun buildCtcssModeCommand(enabled: Boolean): ByteArray {
+        val value: Byte = if (enabled) 0x01 else 0x00
+        return frame(CMD_MISC_SETTING, SUB_CTCSS_SETTING, value)
+    }
+
+    /**
+     * Set CTCSS tone frequency (CMD 0x1B sub 0x00).
+     */
+    fun buildSetCtcssToneCommand(toneHz: Double): ByteArray {
+        val bcd = encodeCtcssToneBcd(toneHz)
+        return frame(CMD_CTCSS_TONE, 0x00, *bcd)
+    }
+
+    // ── Response parsing ───────────────────────────────────────────────────
+
+    /**
+     * Find and parse a complete CI-V response frame from a buffer.
+     *
+     * Returns the bytes between "FE FE E0 A4 <CMD>" and FD, or null if no
+     * complete frame was found. The search is tolerant of interleaved
+     * broadcast traffic.
+     *
+     * @param buf       bytes accumulated from the radio
+     * @param expectCmd the command byte we are looking for in the reply, or
+     *                  null to accept any command response from the radio
+     */
+    fun parseResponse(buf: ByteArray, expectCmd: Byte?): ParsedResponse? {
+        var i = 0
+        while (i < buf.size - 5) {
+            // Look for FE FE preamble
+            if (buf[i] != PREAMBLE || buf[i + 1] != PREAMBLE) { i++; continue }
+            val dest = buf[i + 2]
+            val src  = buf[i + 3]
+            val cmd  = buf[i + 4]
+            // We only care about frames addressed to us from the radio
+            if (dest != ADDR_CTRL || src != ADDR_IC705) { i++; continue }
+            // Find the terminating FD
+            val fdIdx = buf.indexOf(END_OF_MSG, startIndex = i + 5)
+            if (fdIdx < 0) break  // incomplete frame, wait for more data
+            val payload = buf.copyOfRange(i + 5, fdIdx)
+            if (expectCmd == null || cmd == expectCmd) {
+                return ParsedResponse(cmd, payload, fdIdx + 1)
+            }
+            i = fdIdx + 1
+        }
+        return null
+    }
+
+    private fun ByteArray.indexOf(b: Byte, startIndex: Int): Int {
+        for (k in startIndex until size) if (this[k] == b) return k
+        return -1
+    }
+
+    /**
+     * Check whether a buffer contains an OK acknowledgement (FB FD) from
+     * the radio. Tolerates broadcast noise before the ACK.
+     */
+    fun containsAck(buf: ByteArray): Boolean {
+        var i = 0
+        while (i < buf.size - 5) {
+            if (buf[i] != PREAMBLE || buf[i + 1] != PREAMBLE) { i++; continue }
+            val dest = buf[i + 2]
+            val src  = buf[i + 3]
+            val cmd  = buf[i + 4]
+            if (dest != ADDR_CTRL || src != ADDR_IC705) { i++; continue }
+            // Skip to FD
+            val fdIdx = buf.indexOf(END_OF_MSG, startIndex = i + 5)
+            if (fdIdx < 0) break
+            if (cmd == ACK_OK) return true
+            if (cmd == ACK_NG) return false
+            i = fdIdx + 1
+        }
+        return false
+    }
+
+    /**
+     * Parse frequency + mode from a CMD_READ_FREQ reply payload.
+     * Payload layout after stripping command byte: [5 freq bytes] [mode byte] [filter byte]
+     */
+    fun parseFreqModePayload(payload: ByteArray): Pair<Long, String>? {
+        if (payload.size < 6) return null
+        val freqHz = decodeFrequencyBcd(payload.copyOfRange(0, 5))
+        val mode   = BYTE_TO_MODE[payload[5]] ?: return null
+        return freqHz to mode
+    }
+
+    /** Hex dump of bytes, useful for debug logging. */
+    fun toHex(bytes: ByteArray): String =
+        bytes.joinToString(" ") { String.format(Locale.US, "%02X", it.toInt() and 0xFF) }
+
+    data class ParsedResponse(
+        val cmd: Byte,
+        val payload: ByteArray,
+        /** Index in the source buffer immediately after the FD terminator. */
+        val nextOffset: Int
+    )
+}

core/data/src/main/java/com/rtbishop/look4sat/core/data/framework/RadioTrackingService.kt

@@ -19,8 +19,10 @@ package com.rtbishop.look4sat.core.data.framework
 
 import android.bluetooth.BluetoothManager
 import android.util.Log
+import com.rtbishop.look4sat.core.domain.model.RadioControlSettings
 import com.rtbishop.look4sat.core.domain.model.SatRadio
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
+import com.rtbishop.look4sat.core.domain.predict.SPEED_OF_LIGHT
 import com.rtbishop.look4sat.core.domain.repository.IRadioController
 import com.rtbishop.look4sat.core.domain.repository.IRadioTrackingService
 import com.rtbishop.look4sat.core.domain.repository.ISatelliteRepo
@@ -29,6 +31,7 @@ import com.rtbishop.look4sat.core.domain.repository.RadioTrackingState
 import com.rtbishop.look4sat.core.domain.utility.TransponderMapper
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.currentCoroutineContext
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -44,6 +47,8 @@ class RadioTrackingService(
 ) : IRadioTrackingService {
 
     private val tag = "RadioTracking"
+    /** Delay between each step of the split-mode init sequence (ms). */
+    private val INIT_STEP_DELAY_MS = 200L
     private val _state = MutableStateFlow(RadioTrackingState())
     override val state: StateFlow<RadioTrackingState> = _state
 
@@ -51,227 +56,427 @@ class RadioTrackingService(
     private var rxController: IRadioController? = null
     private var trackingJob: Job? = null
 
+    // ── Connection ──────────────────────────────────────────────────────────
+
     override suspend fun connectRadios() {
-        // Disconnect old controllers if any
         txController?.disconnect()
         rxController?.disconnect()
 
-        // Read current addresses from settings
         val rcSettings = settingsRepo.radioControlSettings.value
-        val txAddr = rcSettings.txRadioAddress
+        val txAddr     = rcSettings.txRadioAddress
-        val rxAddr = rcSettings.rxRadioAddress
+        val rxAddr     = rcSettings.rxRadioAddress
+        val isIcom     = rcSettings.radioModel == RadioControlSettings.MODEL_ICOM_IC705
+        val isSplit    = isIcom && rcSettings.splitMode
 
-        Log.i(tag, "Connecting TX=$txAddr RX=$rxAddr")
+        Log.i(tag, "connectRadios model=${rcSettings.radioModel} split=$isSplit TX=$txAddr RX=$rxAddr")
 
-        if (txAddr.isBlank() && rxAddr.isBlank()) {
+        if (isSplit) {
-            _state.update { it.copy(errorMessage = "No radio addresses configured. Set them in Settings → FT-817.") }
+            // Single-radio split mode: only TX slot is used
-            return
+            if (txAddr.isBlank()) {
-        }
+                _state.update { it.copy(errorMessage = "No radio address configured in Settings") }
-
+                return
-        val tx = Ft817Controller(bluetoothManager, txAddr)
+            }
-        val rx = Ft817Controller(bluetoothManager, rxAddr)
+            val tx = makeController(isIcom, txAddr)
-        txController = tx
+            txController = tx
-        rxController = rx
+            rxController = null
-
+            _state.update { it.copy(errorMessage = null) }
-        _state.update { it.copy(errorMessage = null) }
+            val txOk = tx.connect()
-        val txOk = if (txAddr.isNotBlank()) tx.connect() else false
+            _state.update {
-        val rxOk = if (rxAddr.isNotBlank()) rx.connect() else false
+                it.copy(
-        _state.update {
+                    txConnected = txOk,
-            it.copy(
+                    rxConnected = false,
-                txConnected = txOk,
+                    errorMessage = if (!txOk) "Could not connect to radio ($txAddr)" else null
-                rxConnected = rxOk,
+                )
-                errorMessage = when {
+            }
-                    !txOk && !rxOk -> "Could not connect to TX and RX radios"
+            Log.i(tag, "IC-705 split mode connected: txOk=$txOk")
-                    !txOk -> "Could not connect to TX radio ($txAddr)"
+        } else {
-                    !rxOk -> "Could not connect to RX radio ($rxAddr)"
+            if (txAddr.isBlank() && rxAddr.isBlank()) {
-                    else -> null
+                _state.update { it.copy(errorMessage = "No radio addresses configured in Settings") }
-                }
+                return
-            )
+            }
+            val tx = makeController(isIcom, txAddr)
+            val rx = makeController(isIcom, rxAddr)
+            txController = tx
+            rxController = rx
+            _state.update { it.copy(errorMessage = null) }
+            val txOk = if (txAddr.isNotBlank()) tx.connect() else false
+            val rxOk = if (rxAddr.isNotBlank()) rx.connect() else false
+            _state.update {
+                it.copy(
+                    txConnected = txOk,
+                    rxConnected = rxOk,
+                    errorMessage = when {
+                        !txOk && !rxOk -> "Could not connect to TX and RX radios"
+                        !txOk          -> "Could not connect to TX radio ($txAddr)"
+                        !rxOk          -> "Could not connect to RX radio ($rxAddr)"
+                        else           -> null
+                    }
+                )
+            }
+            Log.i(tag, "Dual-radio connected: txOk=$txOk rxOk=$rxOk")
         }
     }
 
+    private fun makeController(isIcom: Boolean, address: String): IRadioController =
+        if (isIcom) Ic705Controller(bluetoothManager, address)
+        else        Ft817Controller(bluetoothManager, address)
+
     override suspend fun disconnectRadios() {
         stopTracking()
         txController?.disconnect()
         rxController?.disconnect()
         txController = null
         rxController = null
-        _state.update {
+        _state.update { it.copy(txConnected = false, rxConnected = false, isActive = false) }
-            it.copy(
-                txConnected = false,
-                rxConnected = false,
-                isActive = false
-            )
-        }
     }
 
+    // ── Tracking ────────────────────────────────────────────────────────────
+
     override fun startTracking(pass: OrbitalPass, transponder: SatRadio, txBaseFreqHz: Long?) {
         _state.update {
             it.copy(
-                isActive = true,
+                isActive             = true,
-                currentPass = pass,
+                currentPass          = pass,
-                selectedTransponder = transponder,
+                selectedTransponder  = transponder,
-                txBaseFrequencyHz = txBaseFreqHz
+                txBaseFrequencyHz    = txBaseFreqHz
             )
         }
         trackingJob?.cancel()
-        trackingJob = appScope.launch {
-            // Set modes on both radios at tracking start
-            val tx = txController
-            val rx = rxController
-            val txMode = transponder.uplinkMode
-            val rxMode = transponder.downlinkMode
-                ?: transponder.uplinkMode?.let {
-                    TransponderMapper.mapUplinkModeToDownlinkMode(it, transponder.isInverted)
-                }
-            if (tx != null && tx.isConnected && txMode != null) {
-                tx.setMode(txMode)
-                Log.i(tag, "TX mode set to $txMode")
-            }
-            if (rx != null && rx.isConnected && rxMode != null) {
-                rx.setMode(rxMode)
-                Log.i(tag, "RX mode set to $rxMode")
-            }
-            // Set CTCSS if FM
-            if (txMode?.uppercase() == "FM") {
-                _state.value.ctcssTone?.let { tone ->
-                    tx?.setCtcssTone(tone)
-                    tx?.setCtcssMode(true)
-                }
-            }
-            _state.update { it.copy(txMode = txMode, rxMode = rxMode) }
 
-            var lastSetTxFreq = 0.0
+        val rcSettings = settingsRepo.radioControlSettings.value
-            var lastSetRxFreq = 0.0
+        val isIcom     = rcSettings.radioModel == RadioControlSettings.MODEL_ICOM_IC705
-            var tuningRadio = "" // "", "tx", or "rx" - which radio the user is tuning
+        val isSplit    = isIcom && rcSettings.splitMode
-            var lastReadFreq = 0L
-            var stableCount = 0
 
-            while (isActive) {
+        if (isSplit) {
-                val currentState = _state.value
+            trackingJob = appScope.launch { runSplitTracking(transponder, txBaseFreqHz) }
-                if (!currentState.isActive) break
+        } else {
-
+            trackingJob = appScope.launch { runDualRadioTracking(transponder, txBaseFreqHz) }
-                val satPass = currentState.currentPass ?: break
-                val xpdr = currentState.selectedTransponder ?: break
-                var txBaseFreq = currentState.txBaseFrequencyHz
-                val stationPos = settingsRepo.stationPosition.value
-                val timeNow = System.currentTimeMillis()
-
-                val pos = satelliteRepo.getPosition(satPass.orbitalObject, stationPos, timeNow)
-                val tx = txController
-                val rx = rxController
-                val hasUplink = txBaseFreq != null
-                val c = com.rtbishop.look4sat.core.domain.predict.SPEED_OF_LIGHT
-                val v = pos.distanceRate * 1000.0
-
-                if (tuningRadio.isNotEmpty()) {
-                    // --- User is tuning: keep reading, wait for stabilization ---
-                    val radio = if (tuningRadio == "tx") tx else rx
-                    if (radio != null && radio.isConnected) {
-                        val readResult = radio.readFrequencyAndMode()
-                        if (readResult != null) {
-                            val (freq, _) = readResult
-                            if (kotlin.math.abs(freq - lastReadFreq) <= 20) {
-                                stableCount++
-                            } else {
-                                stableCount = 0
-                                lastReadFreq = freq
-                            }
-                            // Stable for 2 reads → user stopped turning
-                            if (stableCount >= 2) {
-                                if (tuningRadio == "tx" && txBaseFreq != null) {
-                                    val newBase = (freq.toDouble() * c / (c + v)).toLong()
-                                    if (newBase > 0) {
-                                        txBaseFreq = newBase
-                                        _state.update { it.copy(txBaseFrequencyHz = newBase) }
-                                        Log.i(tag, "TX tuning done → base=$newBase")
-                                    }
-                                } else if (tuningRadio == "rx") {
-                                    val rxNominal = (freq.toDouble() * c / (c - v)).toLong()
-                                    val newTxBase = TransponderMapper.mapDownlinkToUplink(rxNominal, xpdr)
-                                    if (newTxBase != null && newTxBase > 0) {
-                                        txBaseFreq = newTxBase
-                                        _state.update { it.copy(txBaseFrequencyHz = newTxBase) }
-                                        Log.i(tag, "RX tuning done → txBase=$newTxBase")
-                                    }
-                                }
-                                tuningRadio = ""
-                                stableCount = 0
-                                lastSetTxFreq = 0.0
-                                lastSetRxFreq = 0.0
-                            }
-                        }
-                    }
-                } else {
-                    // --- Normal tracking: read, detect changes, command ---
-
-                    // TX dial feedback
-                    if (hasUplink && tx != null && tx.isConnected && lastSetTxFreq > 0.0) {
-                        val readResult = tx.readFrequencyAndMode()
-                        if (readResult != null) {
-                            val (actualTxFreq, _) = readResult
-                            if (kotlin.math.abs(actualTxFreq - lastSetTxFreq) >= 20.0) {
-                                tuningRadio = "tx"
-                                lastReadFreq = actualTxFreq
-                                stableCount = 0
-                                Log.i(tag, "TX tuning detected (read=$actualTxFreq, lastSet=$lastSetTxFreq)")
-                            }
-                        }
-                    }
-
-                    // RX dial feedback (only if TX not tuning)
-                    if (tuningRadio.isEmpty() && rx != null && rx.isConnected && lastSetRxFreq > 0.0) {
-                        val readResult = rx.readFrequencyAndMode()
-                        if (readResult != null) {
-                            val (actualRxFreq, _) = readResult
-                            if (kotlin.math.abs(actualRxFreq - lastSetRxFreq) >= 20.0) {
-                                tuningRadio = "rx"
-                                lastReadFreq = actualRxFreq
-                                stableCount = 0
-                                Log.i(tag, "RX tuning detected (read=$actualRxFreq, lastSet=$lastSetRxFreq)")
-                            }
-                        }
-                    }
-                }
-
-                // Compute Doppler-corrected frequencies
-                val txRadioFreq = txBaseFreq?.let { pos.getUplinkFreq(it) }
-                val rxBaseFreq = if (txBaseFreq != null) {
-                    TransponderMapper.mapUplinkToDownlink(txBaseFreq, xpdr)
-                } else {
-                    xpdr.downlinkLow
-                }
-                val rxRadioFreq = rxBaseFreq?.let { pos.getDownlinkFreq(it) }
-
-                // Command radios (only when not tuning)
-                if (tuningRadio.isEmpty()) {
-                    if (tx != null && tx.isConnected && txRadioFreq != null) {
-                        tx.setFrequency(txRadioFreq)
-                        lastSetTxFreq = txRadioFreq.toDouble()
-                    }
-                    if (rx != null && rx.isConnected && rxRadioFreq != null) {
-                        rx.setFrequency(rxRadioFreq)
-                        lastSetRxFreq = rxRadioFreq.toDouble()
-                    }
-                }
-
-                _state.update {
-                    it.copy(
-                        txConnected = tx?.isConnected ?: false,
-                        rxConnected = rx?.isConnected ?: false,
-                        txFrequencyHz = txRadioFreq,
-                        rxFrequencyHz = rxRadioFreq,
-                        azimuth = Math.toDegrees(pos.azimuth),
-                        elevation = Math.toDegrees(pos.elevation),
-                        distance = pos.distance
-                    )
-                }
-
-                delay(1000)
-            }
         }
     }
 
+    // ── Dual-radio tracking (Yaesu or two IC-705s) ──────────────────────────
+
+    private suspend fun runDualRadioTracking(transponder: SatRadio, initialTxBaseFreqHz: Long?) {
+        val tx = txController
+        val rx = rxController
+
+        // Initial setup: set band/mode/CTCSS on both radios
+        val txMode = transponder.uplinkMode
+        val rxMode = transponder.downlinkMode
+            ?: transponder.uplinkMode?.let {
+                TransponderMapper.mapUplinkModeToDownlinkMode(it, transponder.isInverted)
+            }
+
+        Log.i(tag, "DualRadio start: txMode=$txMode rxMode=$rxMode")
+
+        if (tx != null && tx.isConnected && txMode != null) {
+            Log.d(tag, "Setting TX mode: $txMode")
+            tx.setMode(txMode)
+        }
+        if (rx != null && rx.isConnected && rxMode != null) {
+            Log.d(tag, "Setting RX mode: $rxMode")
+            rx.setMode(rxMode)
+        }
+        if (txMode?.uppercase() == "FM") {
+            _state.value.ctcssTone?.let { tone ->
+                Log.d(tag, "Setting CTCSS: ${tone}Hz")
+                tx?.setCtcssTone(tone)
+                tx?.setCtcssMode(true)
+            }
+        }
+        _state.update { it.copy(txMode = txMode, rxMode = rxMode) }
+
+        var lastSetTxFreq = 0.0
+        var lastSetRxFreq = 0.0
+        var tuningRadio   = ""
+        var lastReadFreq  = 0L
+        var stableCount   = 0
+
+        while (currentCoroutineContext().isActive) {
+            val currentState = _state.value
+            if (!currentState.isActive) break
+
+            val satPass = currentState.currentPass ?: break
+            val xpdr    = currentState.selectedTransponder ?: break
+            var txBaseFreq = currentState.txBaseFrequencyHz
+            val stationPos = settingsRepo.stationPosition.value
+            val pos = satelliteRepo.getPosition(satPass.orbitalObject, stationPos, System.currentTimeMillis())
+            val txNow = txController
+            val rxNow = rxController
+            val v = pos.distanceRate * 1000.0
+
+            if (tuningRadio.isNotEmpty()) {
+                val radio = if (tuningRadio == "tx") txNow else rxNow
+                if (radio != null && radio.isConnected) {
+                    val read = radio.readFrequencyAndMode()
+                    if (read != null) {
+                        val (freq, _) = read
+                        if (kotlin.math.abs(freq - lastReadFreq) <= 20) stableCount++
+                        else { stableCount = 0; lastReadFreq = freq }
+                        if (stableCount >= 2) {
+                            if (tuningRadio == "tx" && txBaseFreq != null) {
+                                val newBase = (freq.toDouble() * SPEED_OF_LIGHT / (SPEED_OF_LIGHT + v)).toLong()
+                                if (newBase > 0) {
+                                    txBaseFreq = newBase
+                                    _state.update { it.copy(txBaseFrequencyHz = newBase) }
+                                    Log.i(tag, "TX tuning done → base=$newBase")
+                                }
+                            } else if (tuningRadio == "rx") {
+                                val rxNominal = (freq.toDouble() * SPEED_OF_LIGHT / (SPEED_OF_LIGHT - v)).toLong()
+                                val newTxBase = TransponderMapper.mapDownlinkToUplink(rxNominal, xpdr)
+                                if (newTxBase != null && newTxBase > 0) {
+                                    txBaseFreq = newTxBase
+                                    _state.update { it.copy(txBaseFrequencyHz = newTxBase) }
+                                    Log.i(tag, "RX tuning done → txBase=$newTxBase")
+                                }
+                            }
+                            tuningRadio   = ""
+                            stableCount   = 0
+                            lastSetTxFreq = 0.0
+                            lastSetRxFreq = 0.0
+                        }
+                    }
+                }
+            } else {
+                // Detect manual dial changes
+                if (txBaseFreq != null && txNow != null && txNow.isConnected && lastSetTxFreq > 0.0) {
+                    val read = txNow.readFrequencyAndMode()
+                    if (read != null && kotlin.math.abs(read.first - lastSetTxFreq) >= 20.0) {
+                        tuningRadio  = "tx"
+                        lastReadFreq = read.first
+                        stableCount  = 0
+                        Log.i(tag, "TX tuning detected (read=${read.first}, lastSet=$lastSetTxFreq)")
+                    }
+                }
+                if (tuningRadio.isEmpty() && rxNow != null && rxNow.isConnected && lastSetRxFreq > 0.0) {
+                    val read = rxNow.readFrequencyAndMode()
+                    if (read != null && kotlin.math.abs(read.first - lastSetRxFreq) >= 20.0) {
+                        tuningRadio  = "rx"
+                        lastReadFreq = read.first
+                        stableCount  = 0
+                        Log.i(tag, "RX tuning detected (read=${read.first}, lastSet=$lastSetRxFreq)")
+                    }
+                }
+            }
+
+            val txRadioFreq = txBaseFreq?.let { pos.getUplinkFreq(it) }
+            val rxBaseFreq  = if (txBaseFreq != null) {
+                TransponderMapper.mapUplinkToDownlink(txBaseFreq, xpdr)
+            } else xpdr.downlinkLow
+            val rxRadioFreq = rxBaseFreq?.let { pos.getDownlinkFreq(it) }
+
+            if (tuningRadio.isEmpty()) {
+                if (txNow != null && txNow.isConnected && txRadioFreq != null) {
+                    txNow.setFrequency(txRadioFreq)
+                    lastSetTxFreq = txRadioFreq.toDouble()
+                }
+                if (rxNow != null && rxNow.isConnected && rxRadioFreq != null) {
+                    rxNow.setFrequency(rxRadioFreq)
+                    lastSetRxFreq = rxRadioFreq.toDouble()
+                }
+            }
+
+            _state.update {
+                it.copy(
+                    txConnected  = txNow?.isConnected ?: false,
+                    rxConnected  = rxNow?.isConnected ?: false,
+                    txFrequencyHz = txRadioFreq,
+                    rxFrequencyHz = rxRadioFreq,
+                    azimuth      = Math.toDegrees(pos.azimuth),
+                    elevation    = Math.toDegrees(pos.elevation),
+                    distance     = pos.distance
+                )
+            }
+            delay(1000)
+        }
+    }
+
+    // ── IC-705 split-radio tracking ─────────────────────────────────────────
+
+    private suspend fun runSplitTracking(transponder: SatRadio, initialTxBaseFreqHz: Long?) {
+        val radio = txController ?: return
+        if (!radio.isConnected) return
+
+        val txMode = transponder.uplinkMode
+        val rxMode = transponder.downlinkMode
+            ?: transponder.uplinkMode?.let {
+                TransponderMapper.mapUplinkModeToDownlinkMode(it, transponder.isInverted)
+            }
+
+        // Compute nominal base frequencies
+        val txCenter = when {
+            transponder.uplinkLow != null && transponder.uplinkHigh != null ->
+                (transponder.uplinkLow!! + transponder.uplinkHigh!!) / 2
+            transponder.uplinkLow != null -> transponder.uplinkLow!!
+            else -> null
+        }
+        val rxNominal = if (txCenter != null) {
+            TransponderMapper.mapUplinkToDownlink(txCenter, transponder)
+        } else transponder.downlinkLow
+
+        val txBase = initialTxBaseFreqHz ?: txCenter
+        Log.i(tag, "IC-705 split setup: txBase=${txBase}Hz rxNominal=${rxNominal}Hz txMode=$txMode rxMode=$rxMode")
+
+        // ── Initial setup sequence ──────────────────────────────────────────
+        // Sequence per IC-705: explicitly select VFO, then band → freq → mode.
+        // ACK from each command gates the next — no fixed delays needed.
+
+        // VFO-A = RX (downlink)
+        Log.d(tag, "Split init: selecting VFO-A for RX (downlink)")
+        radio.setVfo(vfoA = true)
+        if (rxNominal != null) {
+            Log.d(tag, "Split init: VFO-A band for ${rxNominal}Hz")
+            radio.setBand(rxNominal)
+            Log.d(tag, "Split init: VFO-A freq=${rxNominal}Hz")
+            radio.setFrequency(rxNominal)
+        }
+        if (rxMode != null) {
+            Log.d(tag, "Split init: VFO-A mode=$rxMode")
+            radio.setMode(rxMode)
+        }
+
+        // VFO-B = TX (uplink)
+        Log.d(tag, "Split init: selecting VFO-B for TX (uplink)")
+        radio.setVfo(vfoA = false)
+        if (txBase != null) {
+            Log.d(tag, "Split init: VFO-B band for ${txBase}Hz")
+            radio.setBand(txBase)
+            Log.d(tag, "Split init: VFO-B freq=${txBase}Hz")
+            radio.setFrequency(txBase)
+        }
+        if (txMode != null) {
+            Log.d(tag, "Split init: VFO-B mode=$txMode")
+            radio.setMode(txMode)
+        }
+        if (txMode?.uppercase() == "FM") {
+            val tone = _state.value.ctcssTone
+            if (tone != null) {
+                Log.d(tag, "Split init: CTCSS=${tone}Hz")
+                radio.setCtcssTone(tone)
+                radio.setCtcssMode(true)
+            } else {
+                radio.setCtcssMode(false)
+            }
+        }
+
+        // Enable SPLIT on VFO-A (return display to RX VFO first)
+        Log.d(tag, "Split init: returning to VFO-A, then enabling SPLIT mode")
+        radio.setVfo(vfoA = true)
+        radio.setSplitMode(enabled = true)
+
+        _state.update { it.copy(txMode = txMode, rxMode = rxMode, txBaseFrequencyHz = txBase) }
+        Log.i(tag, "IC-705 split init done — entering tracking loop")
+
+        // ── Tracking loop with tuning detection ─────────────────────────────
+        var lastSetTxFreq = 0.0
+        var lastSetRxFreq = 0.0
+        var tuningRadio   = ""  // "tx" or "rx" when manual tuning detected
+        var lastReadFreq  = 0L
+        var stableCount   = 0
+
+        while (currentCoroutineContext().isActive) {
+            val currentState = _state.value
+            if (!currentState.isActive) break
+
+            val satPass = currentState.currentPass ?: break
+            val xpdr    = currentState.selectedTransponder ?: break
+            var txBaseFreq = currentState.txBaseFrequencyHz
+            val stationPos = settingsRepo.stationPosition.value
+            val pos = satelliteRepo.getPosition(satPass.orbitalObject, stationPos, System.currentTimeMillis())
+            val v = pos.distanceRate * 1000.0
+
+            if (tuningRadio.isNotEmpty()) {
+                // User is tuning — wait for frequency to stabilize
+                val readFreq = if (tuningRadio == "tx") radio.readTxVfoFrequency() else radio.readWorkingFrequency()
+                if (readFreq != null) {
+                    if (kotlin.math.abs(readFreq - lastReadFreq) <= 20) stableCount++
+                    else { stableCount = 0; lastReadFreq = readFreq }
+
+                    if (stableCount >= 2) {
+                        // Frequency stable — reverse-calculate base frequency
+                        if (tuningRadio == "tx" && txBaseFreq != null) {
+                            val newBase = (readFreq.toDouble() * SPEED_OF_LIGHT / (SPEED_OF_LIGHT + v)).toLong()
+                            if (newBase > 0) {
+                                txBaseFreq = newBase
+                                _state.update { it.copy(txBaseFrequencyHz = newBase) }
+                                Log.i(tag, "Split TX tuning done → base=$newBase")
+                            }
+                        } else if (tuningRadio == "rx") {
+                            val rxNominal = (readFreq.toDouble() * SPEED_OF_LIGHT / (SPEED_OF_LIGHT - v)).toLong()
+                            val newTxBase = TransponderMapper.mapDownlinkToUplink(rxNominal, xpdr)
+                            if (newTxBase != null && newTxBase > 0) {
+                                txBaseFreq = newTxBase
+                                _state.update { it.copy(txBaseFrequencyHz = newTxBase) }
+                                Log.i(tag, "Split RX tuning done → txBase=$newTxBase")
+                            }
+                        }
+                        tuningRadio   = ""
+                        stableCount   = 0
+                        lastSetTxFreq = 0.0
+                        lastSetRxFreq = 0.0
+                    }
+                }
+            } else {
+                // Detect manual dial changes
+                if (txBaseFreq != null && lastSetTxFreq > 0.0) {
+                    val readTx = radio.readTxVfoFrequency()
+                    if (readTx != null && kotlin.math.abs(readTx - lastSetTxFreq) >= 20.0) {
+                        tuningRadio  = "tx"
+                        lastReadFreq = readTx
+                        stableCount  = 0
+                        Log.i(tag, "Split TX tuning detected (read=${readTx}, lastSet=$lastSetTxFreq)")
+                    }
+                }
+                if (tuningRadio.isEmpty() && lastSetRxFreq > 0.0) {
+                    val readRx = radio.readWorkingFrequency()
+                    if (readRx != null && kotlin.math.abs(readRx - lastSetRxFreq) >= 20.0) {
+                        tuningRadio  = "rx"
+                        lastReadFreq = readRx
+                        stableCount  = 0
+                        Log.i(tag, "Split RX tuning detected (read=${readRx}, lastSet=$lastSetRxFreq)")
+                    }
+                }
+            }
+
+            // Determine Doppler-corrected frequencies
+            val txRadioFreq = txBaseFreq?.let { pos.getUplinkFreq(it) }
+            val rxBaseCalc  = if (txBaseFreq != null) {
+                TransponderMapper.mapUplinkToDownlink(txBaseFreq, xpdr)
+            } else xpdr.downlinkLow
+            val rxRadioFreq = rxBaseCalc?.let { pos.getDownlinkFreq(it) }
+
+            if (radio.isConnected && tuningRadio.isEmpty()) {
+                // Update both VFOs every cycle — no PTT polling needed.
+                // 0x25/00 = active (RX) VFO, 0x25/01 = inactive (TX) VFO.
+                if (rxRadioFreq != null) {
+                    Log.d(tag, "Split loop RX (0x25/00): ${rxRadioFreq}Hz")
+                    radio.setWorkingFrequency(rxRadioFreq)
+                    lastSetRxFreq = rxRadioFreq.toDouble()
+                }
+                if (txRadioFreq != null) {
+                    Log.d(tag, "Split loop TX (0x25/01): ${txRadioFreq}Hz")
+                    radio.setTxVfoFrequency(txRadioFreq)
+                    lastSetTxFreq = txRadioFreq.toDouble()
+                }
+            }
+
+            _state.update {
+                it.copy(
+                    txConnected   = radio.isConnected,
+                    rxConnected   = false,  // single radio
+                    txFrequencyHz = txRadioFreq,
+                    rxFrequencyHz = rxRadioFreq,
+                    azimuth       = Math.toDegrees(pos.azimuth),
+                    elevation     = Math.toDegrees(pos.elevation),
+                    distance      = pos.distance
+                )
+            }
+            delay(1000)
+        }
+    }
+
+    // ── Other IRadioTrackingService methods ─────────────────────────────────
+
     override fun stopTracking() {
         trackingJob?.cancel()
         trackingJob = null
@@ -288,7 +493,6 @@ class RadioTrackingService(
                     TransponderMapper.mapUplinkModeToDownlinkMode(it, transponder.isInverted)
                 }
             rxMode?.let { rx?.setMode(it) }
-
             if (transponder.uplinkMode?.uppercase() == "FM") {
                 _state.value.ctcssTone?.let { tone ->
                     tx?.setCtcssTone(tone)
@@ -302,21 +506,17 @@ class RadioTrackingService(
             transponder.uplinkLow != null -> transponder.uplinkLow!!
             else -> null
         }
-        // Show nominal frequencies immediately
         val rxNominal = if (txCenter != null) {
             TransponderMapper.mapUplinkToDownlink(txCenter, transponder)
-        } else {
+        } else transponder.downlinkLow
-            // Downlink-only transponder (beacon etc.) - use downlink directly
-            transponder.downlinkLow
-        }
         _state.update {
             it.copy(
                 selectedTransponder = transponder,
-                txBaseFrequencyHz = txCenter,
+                txBaseFrequencyHz   = txCenter,
-                txFrequencyHz = txCenter,
+                txFrequencyHz       = txCenter,
-                rxFrequencyHz = rxNominal,
+                rxFrequencyHz       = rxNominal,
-                txMode = transponder.uplinkMode,
+                txMode              = transponder.uplinkMode,
-                rxMode = transponder.downlinkMode
+                rxMode              = transponder.downlinkMode
                     ?: transponder.uplinkMode?.let { m ->
                         TransponderMapper.mapUplinkModeToDownlinkMode(m, transponder.isInverted)
                     }
@@ -353,5 +553,4 @@ class RadioTrackingService(
         }
         _state.update { it.copy(txMode = txMode, rxMode = rxMode) }
     }
-
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/injection/MainContainer.kt

@@ -1,15 +1,32 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 package com.rtbishop.look4sat.core.data.injection
 
 import android.bluetooth.BluetoothManager
 import android.content.Context
-import android.hardware.Sensor
 import android.hardware.SensorManager
+import android.hardware.display.DisplayManager
 import android.location.LocationManager
-import android.view.WindowManager
 import androidx.room.Room
 import com.rtbishop.look4sat.core.data.database.Look4SatDb
 import com.rtbishop.look4sat.core.data.framework.BluetoothReporter
 import com.rtbishop.look4sat.core.data.framework.Ft817Controller
+import com.rtbishop.look4sat.core.data.framework.Ic705Controller
 import com.rtbishop.look4sat.core.data.framework.NetworkReporter
 import com.rtbishop.look4sat.core.data.framework.RadioTrackingService
 import com.rtbishop.look4sat.core.data.repository.DatabaseRepo
@@ -20,7 +37,10 @@ import com.rtbishop.look4sat.core.data.repository.SettingsRepo
 import com.rtbishop.look4sat.core.data.source.LocalSource
 import com.rtbishop.look4sat.core.data.source.RemoteSource
 import com.rtbishop.look4sat.core.data.usecase.AddToCalendar
+import com.rtbishop.look4sat.core.data.usecase.AudioCapture
+import com.rtbishop.look4sat.core.data.usecase.SaveImage
 import com.rtbishop.look4sat.core.data.usecase.ShowToast
+import com.rtbishop.look4sat.core.domain.model.RadioControlSettings
 import com.rtbishop.look4sat.core.domain.repository.IDatabaseRepo
 import com.rtbishop.look4sat.core.domain.repository.IMainContainer
 import com.rtbishop.look4sat.core.domain.repository.IRadioController
@@ -30,15 +50,21 @@ import com.rtbishop.look4sat.core.domain.repository.ISatelliteRepo
 import com.rtbishop.look4sat.core.domain.repository.ISelectionRepo
 import com.rtbishop.look4sat.core.domain.repository.ISensorsRepo
 import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
+import com.rtbishop.look4sat.core.domain.repository.MutualPassData
 import com.rtbishop.look4sat.core.domain.source.ILocalSource
 import com.rtbishop.look4sat.core.domain.source.IRemoteSource
 import com.rtbishop.look4sat.core.domain.usecase.IAddToCalendar
+import com.rtbishop.look4sat.core.domain.usecase.IAudioCapture
+import com.rtbishop.look4sat.core.domain.usecase.ISaveImage
 import com.rtbishop.look4sat.core.domain.usecase.IShowToast
 import com.rtbishop.look4sat.core.domain.utility.DataParser
 import kotlinx.coroutines.CoroutineExceptionHandler
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import okhttp3.OkHttpClient
 
 class MainContainer(private val context: Context) : IMainContainer {
@@ -55,10 +81,21 @@ class MainContainer(private val context: Context) : IMainContainer {
         RadioTrackingService(appScope, manager, satelliteRepo, settingsRepo)
     }
 
+    private val _mutualPassData = MutableStateFlow(MutualPassData())
+    override val mutualPassData: StateFlow<MutualPassData> = _mutualPassData.asStateFlow()
+
+    override fun setMutualPassData(data: MutualPassData) {
+        _mutualPassData.value = data
+    }
+
     override fun provideAddToCalendar(): IAddToCalendar = AddToCalendar(context)
 
     override fun provideShowToast(): IShowToast = ShowToast(context)
 
+    override fun provideAudioCapture(): IAudioCapture = AudioCapture()
+
+    override fun provideSaveImage(): ISaveImage = SaveImage(context)
+
     override fun provideBluetoothReporter(): IReporter {
         val manager = context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
         val rc = settingsRepo.rcSettings.value
@@ -82,22 +119,31 @@ class MainContainer(private val context: Context) : IMainContainer {
     }
 
     override fun provideTxRadioController(): IRadioController {
-        val manager = context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
+        val manager  = context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
-        val address = settingsRepo.radioControlSettings.value.txRadioAddress
+        val settings = settingsRepo.radioControlSettings.value
-        return Ft817Controller(manager, address)
+        val address  = settings.txRadioAddress
+        return if (settings.radioModel == RadioControlSettings.MODEL_ICOM_IC705) {
+            Ic705Controller(manager, address)
+        } else {
+            Ft817Controller(manager, address)
+        }
     }
 
     override fun provideRxRadioController(): IRadioController {
-        val manager = context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
+        val manager  = context.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
-        val address = settingsRepo.radioControlSettings.value.rxRadioAddress
+        val settings = settingsRepo.radioControlSettings.value
-        return Ft817Controller(manager, address)
+        val address  = settings.rxRadioAddress
+        return if (settings.radioModel == RadioControlSettings.MODEL_ICOM_IC705) {
+            Ic705Controller(manager, address)
+        } else {
+            Ft817Controller(manager, address)
+        }
     }
 
     override fun provideSensorsRepo(): ISensorsRepo {
         val manager = context.getSystemService(Context.SENSOR_SERVICE) as SensorManager
-        val sensor = manager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR)
+        val displayManager = context.getSystemService(DisplayManager::class.java)
-        val window = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
+        return SensorsRepo(manager, displayManager)
-        return SensorsRepo(manager,sensor,window)
     }
 
     private fun provideDatabaseRepo(): IDatabaseRepo {

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/DatabaseRepo.kt

@@ -40,57 +40,55 @@ class DatabaseRepo(
     private val settingsRepo: ISettingsRepo
 ) : IDatabaseRepo {
 
-    private companion object {
+    private val customSourceType = "Other"
-        val tleTypes = setOf("Amsat", "R4UAB", "Other")
-        val zippedTleTypes = setOf("McCants", "Classified")
-    }
 
-    override suspend fun updateTLEFromFile(uri: String) = withContext(dispatcher) {
+    override suspend fun updateTLEFromFile(uri: String): Int = withContext(dispatcher) {
+        var importedCount = 0
         remoteSource.getFileStream(uri)?.let { stream ->
-            val entries = dataParser.parseTLEStream(stream)
+            val entries = parseSatelliteStream(uri, unwrapIfZipped(uri, stream))
             localSource.insertEntries(entries)
-            settingsRepo.setSatelliteTypeIds("Other", entries.map { it.catnum })
+            settingsRepo.setSatelliteTypeIds(customSourceType, entries.map { it.catnum })
+            importedCount = entries.size
         }
         setUpdateSuccessful(System.currentTimeMillis())
+        importedCount
     }
 
-    override suspend fun updateTransceiversFromFile(uri: String) = withContext(dispatcher) {
+    override suspend fun updateTransceiversFromFile(uri: String): Int = withContext(dispatcher) {
-        remoteSource.getFileStream(uri)
+        var importedCount = 0
-            ?.let { dataParser.parseJSONStream(it) }
+        remoteSource.getFileStream(uri)?.let { stream ->
-            ?.takeIf { it.isNotEmpty() }
+            val transceivers = dataParser.parseJSONStream(unwrapIfZipped(uri, stream))
-            ?.let {
+            localSource.insertRadios(transceivers)
-                localSource.deleteRadios()
+            importedCount = transceivers.size
-                localSource.insertRadios(it)
+        }
-            }
         setUpdateSuccessful(System.currentTimeMillis())
+        importedCount
     }
 
     override suspend fun updateFromRemote() = withContext(dispatcher) {
         val dataSourcesSettings = settingsRepo.dataSourcesSettings.value
         val tleUrls = buildMap {
             putAll(Sources.satelliteDataUrls)
-            if (dataSourcesSettings.useCustomTLE) put("Other", dataSourcesSettings.tleUrl)
+            if (dataSourcesSettings.useCustomTLE) put(customSourceType, dataSourcesSettings.tleUrl)
-        }.filterValues { it.isNotEmpty() }
+        }.filterValues { it.isNotBlank() }
-
+        val radioUrls = buildMap {
-        val radioUrls = buildList {
+            putAll(Sources.transceiversDataUrls)
-            add(Sources.RADIO_DATA_URL)
+            if (dataSourcesSettings.useCustomTransceivers) put(customSourceType, dataSourcesSettings.transceiversUrl)
-            if (dataSourcesSettings.useCustomTransceivers) add(dataSourcesSettings.transceiversUrl)
+        }.filterValues { it.isNotBlank() }
-        }
-
         // launch all network requests concurrently
-        val tleJobs = tleUrls.map { (type, url) -> async { type to remoteSource.getNetworkStream(url) } }
+        val tleJobs = tleUrls.values.map { url -> async { url to remoteSource.getNetworkStream(url) } }
-        val radioJobs = radioUrls.map { url -> async { remoteSource.getNetworkStream(url) } }
+        val radioJobs = radioUrls.values.map { url -> async { url to remoteSource.getNetworkStream(url) } }
-
+        // parse fetched data concurrently and associate with types
-        // parse satellite data
+        val importedEntries = tleJobs.awaitAll().flatMap { (url, stream) ->
-        val importedEntries = tleJobs.awaitAll().flatMap { (type, stream) ->
+            val type = tleUrls.entries.find { it.value == url }?.key ?: customSourceType
-            stream?.let { parseSatelliteStream(type, it) }.orEmpty().also { satellites ->
+            stream?.let { parseSatelliteStream(url, unwrapIfZipped(url, it)) }.orEmpty().also { entries ->
-                settingsRepo.setSatelliteTypeIds(type, satellites.map { it.catnum })
+                settingsRepo.setSatelliteTypeIds(type, entries.map { it.catnum })
             }
         }
-
+        val importedRadios = radioJobs.awaitAll().flatMap { (url, stream) ->
-        // parse radio data
+            stream?.let { dataParser.parseJSONStream(unwrapIfZipped(url, it)) }.orEmpty()
-        val importedRadios = radioJobs.awaitAll().filterNotNull().flatMap { dataParser.parseJSONStream(it) }
+        }
-
+        // insert parsed data into the database
         localSource.insertEntries(importedEntries)
         localSource.insertRadios(importedRadios)
         setUpdateSuccessful(System.currentTimeMillis())
@@ -102,10 +100,31 @@ class DatabaseRepo(
         setUpdateSuccessful(0L)
     }
 
-    private suspend fun parseSatelliteStream(type: String, stream: InputStream): List<OrbitalData> = when (type) {
+    private suspend fun parseSatelliteStream(url: String, stream: InputStream): List<OrbitalData> {
-        in tleTypes -> dataParser.parseTLEStream(stream)
+        val bufferedStream = stream.buffered()
-        in zippedTleTypes -> dataParser.parseTLEStream(ZipInputStream(stream).apply { nextEntry })
+        return when {
-        else -> dataParser.parseCSVStream(stream)
+            hasCsvHint(url) || looksLikeCsv(bufferedStream) -> dataParser.parseCSVStream(bufferedStream)
+            else -> dataParser.parseTLEStream(bufferedStream)
+        }
+    }
+
+    private fun hasCsvHint(url: String): Boolean {
+        return url.contains("FORMAT=csv", ignoreCase = true) ||
+            url.endsWith(".csv", ignoreCase = true) ||
+            url.endsWith(".csv.zip", ignoreCase = true)
+    }
+
+    private fun looksLikeCsv(stream: InputStream): Boolean {
+        if (!stream.markSupported()) return false
+        stream.mark(4096)
+        val preview = ByteArray(4096)
+        val length = stream.read(preview)
+        stream.reset()
+        if (length <= 0) return false
+        val line = preview.decodeToString(0, length).lineSequence().firstOrNull()?.trim().orEmpty()
+        return line.contains("OBJECT_NAME", ignoreCase = true) ||
+            line.contains("NORAD_CAT_ID", ignoreCase = true) ||
+            line.count { it == ',' } >= 4
     }
 
     private suspend fun setUpdateSuccessful(timestamp: Long) {
@@ -113,4 +132,7 @@ class DatabaseRepo(
             DatabaseState(localSource.getRadiosTotal(), localSource.getEntriesTotal(), timestamp)
         )
     }
+
+    private fun unwrapIfZipped(url: String, stream: InputStream): InputStream =
+        if (url.endsWith(".zip", ignoreCase = true)) ZipInputStream(stream).apply { nextEntry } else stream
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/SatelliteRepo.kt

@@ -36,6 +36,7 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.withContext
+import java.util.TimeZone
 
 class SatelliteRepo(
     private val dispatcher: CoroutineDispatcher,
@@ -52,13 +53,28 @@ class SatelliteRepo(
     private val _satellites = MutableStateFlow<List<OrbitalObject>>(emptyList())
     override val satellites: StateFlow<List<OrbitalObject>> = _satellites
 
+    private val _selectedPass = MutableStateFlow(0 to 0L)
+    override val selectedPass: StateFlow<Pair<Int, Long>> = _selectedPass
+
+    override fun selectPass(catNum: Int, aosTime: Long) {
+        _selectedPass.value = catNum to aosTime
+    }
+
     override suspend fun getRadiosWithId(id: Int) = localStorage.getRadiosWithId(id)
 
     override suspend fun initRepository() = withContext(dispatcher) {
         settingsRepo.selectedIds.collect { selectedIds ->
             _satellites.update { localStorage.getEntriesWithIds(selectedIds) }
-            val (_, hoursAhead, minElevation, modes) = settingsRepo.passesSettings.value
+            val settings = settingsRepo.passesSettings.value
-            calculatePasses(System.currentTimeMillis(), hoursAhead, minElevation, modes)
+            calculatePasses(
+                time = System.currentTimeMillis(),
+                hoursAhead = settings.hoursAhead,
+                minElevation = settings.minElevation,
+                aosStartMinute = settings.aosStartMinute,
+                aosEndMinute = settings.aosEndMinute,
+                invertAosTimeWindow = settings.invertAosTimeWindow,
+                modes = settings.selectedModes
+            )
         }
     }
 
@@ -98,7 +114,15 @@ class SatelliteRepo(
         }
     }
 
-    override suspend fun calculatePasses(time: Long, hoursAhead: Int, minElevation: Double, modes: List<String>) {
+    override suspend fun calculatePasses(
+        time: Long,
+        hoursAhead: Int,
+        minElevation: Double,
+        aosStartMinute: Int,
+        aosEndMinute: Int,
+        invertAosTimeWindow: Boolean,
+        modes: List<String>
+    ) {
         _isCalculating.value = true
         // Normalize to the start of the current minute so that coarse 60-second stepping
         // in getLeoPass always begins from the same phase, producing stable AOS/LOS times
@@ -123,7 +147,12 @@ class SatelliteRepo(
             val newPasses = ArrayList<OrbitalPass>()
             for (list in passLists) {
                 for (pass in list) {
-                    if (pass.losTime > time && pass.aosTime < timeFuture && pass.maxElevation > minElevation) {
+                    if (
+                        pass.losTime > time
+                        && pass.aosTime < timeFuture
+                        && pass.maxElevation > minElevation
+                        && (pass.isDeepSpace || isAosInRange(pass.aosTime, aosStartMinute, aosEndMinute, invertAosTimeWindow))
+                    ) {
                         newPasses.add(pass)
                     }
                 }
@@ -135,21 +164,39 @@ class SatelliteRepo(
         _isCalculating.value = false
     }
 
+    private fun isAosInRange(
+        aosTime: Long,
+        aosStartMinute: Int,
+        aosEndMinute: Int,
+        invertAosTimeWindow: Boolean
+    ): Boolean {
+        val offsetMillis = TimeZone.getDefault().getOffset(aosTime).toLong()
+        val localMillis = Math.floorMod(aosTime + offsetMillis, 24L * 60L * 60L * 1000L)
+        val aosMinute = (localMillis / 60_000L).toInt()
+        val inRange = if (aosStartMinute <= aosEndMinute) {
+            aosMinute in aosStartMinute..aosEndMinute
+        } else {
+            aosMinute >= aosStartMinute || aosMinute <= aosEndMinute
+        }
+        return if (invertAosTimeWindow) !inRange else inRange
+    }
+
     private fun OrbitalObject.getPasses(pos: GeoPos, time: Long, hours: Int): List<OrbitalPass> {
         val passes = mutableListOf<OrbitalPass>()
         val endDate = time + hours * 60L * 60L * 1000L
         val quarterOrbitMin = (this.data.orbitalPeriod / 4.0).toInt()
+        val decayed = this.data.hasDecayed(time)
         var startDate = time
         var shouldRewind = true
         var lastAosDate: Long
         var count = 0
         if (this.willBeSeen(pos)) {
             if (this.data.isDeepSpace) {
-                passes.add(getGeoPass(this, pos, time))
+                passes.add(getGeoPass(this, pos, time, decayed))
             } else {
                 do {
                     if (count > 0) shouldRewind = false
-                    val pass = getLeoPass(this, pos, startDate, shouldRewind)
+                    val pass = getLeoPass(this, pos, startDate, shouldRewind, decayed)
                     lastAosDate = pass.aosTime
                     passes.add(pass)
                     startDate = pass.losTime + (quarterOrbitMin * 3) * 60L * 1000L
@@ -160,17 +207,17 @@ class SatelliteRepo(
         return passes
     }
 
-    private fun getGeoPass(sat: OrbitalObject, pos: GeoPos, time: Long): OrbitalPass {
+    private fun getGeoPass(sat: OrbitalObject, pos: GeoPos, time: Long, decayed: Boolean): OrbitalPass {
         val satPos = sat.getPosition(pos, time)
         val aos = time - 24 * 60L * 60L * 1000L
         val los = time + 24 * 60L * 60L * 1000L // val tca = (aos + los) / 2
         val az = satPos.azimuth.toDegrees().round(1)
         val elev = satPos.elevation.toDegrees().round(1)
         val alt = satPos.altitude
-        return OrbitalPass(aos, az, los, az, alt.toInt(), elev, sat)
+        return OrbitalPass(aos, az, los, az, alt.toInt(), elev, sat, hasDecayed = decayed)
     }
 
-    private fun getLeoPass(sat: OrbitalObject, pos: GeoPos, time: Long, rewind: Boolean): OrbitalPass {
+    private fun getLeoPass(sat: OrbitalObject, pos: GeoPos, time: Long, rewind: Boolean, decayed: Boolean): OrbitalPass {
         val quarterOrbitMin = (sat.data.orbitalPeriod / 4.0).toInt()
         var calendarTimeMillis = time
         var elevation: Double
@@ -234,6 +281,6 @@ class SatelliteRepo(
         val alt = tcaPos.altitude
 
         val elev = maxElevation.toDegrees().round(1)
-        return OrbitalPass(aos, aosAz, los, losAz, alt.toInt(), elev, sat)
+        return OrbitalPass(aos, aosAz, los, losAz, alt.toInt(), elev, sat, hasDecayed = decayed)
     }
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/SensorsRepo.kt

@@ -22,8 +22,9 @@ import android.hardware.Sensor
 import android.hardware.SensorEvent
 import android.hardware.SensorEventListener
 import android.hardware.SensorManager
+import android.hardware.display.DisplayManager
+import android.view.Display
 import android.view.Surface
-import android.view.WindowManager
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.RAD2DEG
 import com.rtbishop.look4sat.core.domain.repository.ISensorsRepo
@@ -31,13 +32,16 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlin.math.round
 
+private const val SMOOTHING_FACTOR = 0.15f
+private const val SENSOR_RATE_US = 16_000
+
 class SensorsRepo(
     private val sensorManager: SensorManager,
-    private val sensor: Sensor?,
+    private val displayManager: DisplayManager?
-    private val windowManager: WindowManager
+) : ISensorsRepo, SensorEventListener {
-) : SensorEventListener, ISensorsRepo {
 
-    private val _orientation = MutableStateFlow(Pair(0f, 0f))
+    private val _sensorData = MutableStateFlow(Pair(0f, 0f))
+    private val sensor: Sensor? = sensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR)
     private val rotationMatrix = FloatArray(9)
     private val tempMatrix = FloatArray(9)
     private val orientationValues = FloatArray(3)
@@ -45,11 +49,7 @@ class SensorsRepo(
     private var smoothPitch = 0f
     private var hasInitialReading = false
 
-    companion object {
+    override val sensorData: StateFlow<Pair<Float, Float>> = _sensorData
-        private const val SMOOTHING_FACTOR = 0.15f
-    }
-
-    override val orientation: StateFlow<Pair<Float, Float>> = _orientation
 
     override fun getMagDeclination(geoPos: GeoPos, time: Long): Float {
         return GeomagneticField(
@@ -62,7 +62,7 @@ class SensorsRepo(
 
     override fun enableSensor() {
         hasInitialReading = false
-        sensor?.let { sensorManager.registerListener(this, it, 8000) }
+        sensor?.let { sensorManager.registerListener(this, it, SENSOR_RATE_US) }
     }
 
     override fun disableSensor() = sensorManager.unregisterListener(this)
@@ -70,16 +70,11 @@ class SensorsRepo(
     override fun onAccuracyChanged(sensor: Sensor, accuracy: Int) = Unit
 
     override fun onSensorChanged(event: SensorEvent) {
-        if (event.sensor == sensor) updateOrientation(event.values)
+        if (event.sensor.type == Sensor.TYPE_ROTATION_VECTOR) handleSensorEvent(event)
     }
 
     private fun getDisplayRotation(): Int {
-        return try {
+        return displayManager?.getDisplay(Display.DEFAULT_DISPLAY)?.rotation ?: Surface.ROTATION_0
-            @Suppress("DEPRECATION")
-            windowManager.defaultDisplay.rotation
-        } catch (_: Exception) {
-            Surface.ROTATION_0
-        }
     }
 
     private fun remapForRotation(rotation: Int) {
@@ -101,30 +96,23 @@ class SensorsRepo(
         if (remapped) System.arraycopy(tempMatrix, 0, rotationMatrix, 0, 9)
     }
 
-    private fun updateOrientation(rotationVector: FloatArray) {
+    private fun handleSensorEvent(event: SensorEvent) {
-        SensorManager.getRotationMatrixFromVector(rotationMatrix, rotationVector)
+        SensorManager.getRotationMatrixFromVector(rotationMatrix, event.values)
         remapForRotation(getDisplayRotation())
         SensorManager.getOrientation(rotationMatrix, orientationValues)
-        val azimuth = (orientationValues[0] * RAD2DEG).toFloat()
+        val azimuth = normalizeAzimuth((orientationValues[0] * RAD2DEG).toFloat())
         val pitch = (orientationValues[1] * RAD2DEG).toFloat()
-        val magneticAzimuth = (azimuth + 360f) % 360f
-
         if (!hasInitialReading) {
-            smoothAzimuth = magneticAzimuth
+            smoothAzimuth = azimuth
             smoothPitch = pitch
             hasInitialReading = true
         } else {
-            smoothAzimuth = lowPassAngle(smoothAzimuth, magneticAzimuth)
+            smoothAzimuth = lowPassAngle(smoothAzimuth, azimuth)
             smoothPitch = lowPass(smoothPitch, pitch)
         }
-
+        _sensorData.value = Pair(round(smoothAzimuth * 10) / 10, round(smoothPitch * 10) / 10)
-        _orientation.value = Pair(
-            round(smoothAzimuth * 10) / 10,
-            round(smoothPitch * 10) / 10
-        )
     }
 
-    /** Standard exponential low-pass filter. */
     private fun lowPass(previous: Float, current: Float): Float {
         return previous + SMOOTHING_FACTOR * (current - previous)
     }
@@ -135,9 +123,10 @@ class SensorsRepo(
      */
     private fun lowPassAngle(previous: Float, current: Float): Float {
         var delta = current - previous
-        // Normalise delta into the range (-180, 180]
         while (delta > 180f) delta -= 360f
         while (delta <= -180f) delta += 360f
-        return (previous + SMOOTHING_FACTOR * delta + 360f) % 360f
+        return normalizeAzimuth(previous + SMOOTHING_FACTOR * delta)
     }
+
+    private fun normalizeAzimuth(value: Float): Float = (value + 360f) % 360f
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/repository/SettingsRepo.kt

@@ -54,6 +54,9 @@ class SettingsRepo(
     private val keyFilterShowDeepSpace = "filterShowDeepSpace"
     private val keyFilterHoursAhead = "filterHoursAhead"
     private val keyFilterMinElevation = "filterMinElevation"
+    private val keyFilterAosStartMinute = "filterAosStartMinute"
+    private val keyFilterAosEndMinute = "filterAosEndMinute"
+    private val keyFilterAosInvert = "filterAosInvert"
     private val keyNumberOfRadios = "numberOfRadios"
     private val keyNumberOfSatellites = "numberOfSatellites"
     private val keyRotatorAddress = "rotatorAddress"
@@ -72,6 +75,7 @@ class SettingsRepo(
     private val keyStateOfSweep = "stateOfSweep"
     private val keyStateOfUtc = "stateOfUtc"
     private val keyStateOfLightTheme = "stateOfLightTheme"
+    private val keyStateOfNightMode = "stateOfNightMode"
     private val keyStationAltitude = "stationAltitude"
     private val keyStationLatitude = "stationLatitude"
     private val keyStationLongitude = "stationLongitude"
@@ -80,6 +84,9 @@ class SettingsRepo(
     private val keyUpdateTimestamp = "updateTimestamp"
     private val keyShouldSeeWarning = "shouldSeeWarning"
     private val keyShouldSeeWhatsNew = "shouldSeeWhatsNew_v$appVersionName"
+    private val keySstvMode = "sstvMode"
+    private val keyLowElevation = "lowElevation"
+    private val keyHighElevation = "highElevation"
     private val keyUseCustomTle = "useCustomTle"
     private val keyUseCustomTransceivers = "useCustomTransceivers"
     private val keyTleUrl = "tleUrl"
@@ -111,8 +118,8 @@ class SettingsRepo(
     }
 
     private fun getSelectedTypes(): List<String> {
-        val typesString = preferences.getString(keySelectedTypes, null)
+        val typesString = preferences.getString(keySelectedTypes, "Amateur")
-        if (typesString.isNullOrEmpty()) return listOf("Amateur")
+        if (typesString.isNullOrEmpty()) return emptyList()
         return typesString.split(separatorComma)
     }
     //endregion
@@ -125,6 +132,9 @@ class SettingsRepo(
         putBoolean(keyFilterShowDeepSpace, settings.showDeepSpace)
         putInt(keyFilterHoursAhead, settings.hoursAhead)
         putLong(keyFilterMinElevation, settings.minElevation.toRawBits())
+        putInt(keyFilterAosStartMinute, settings.aosStartMinute)
+        putInt(keyFilterAosEndMinute, settings.aosEndMinute)
+        putBoolean(keyFilterAosInvert, settings.invertAosTimeWindow)
         putString(keySelectedModes, settings.selectedModes.joinToString(separatorComma))
         _passesSettings.value = settings
     }
@@ -133,9 +143,20 @@ class SettingsRepo(
         val showDeepSpace = preferences.getBoolean(keyFilterShowDeepSpace, true)
         val hoursAhead = preferences.getInt(keyFilterHoursAhead, 24)
         val minElevation = Double.fromBits(preferences.getLong(keyFilterMinElevation, 16.0.toRawBits()))
+        val aosStartMinute = preferences.getInt(keyFilterAosStartMinute, 0).coerceIn(0, 23 * 60 + 59)
+        val aosEndMinute = preferences.getInt(keyFilterAosEndMinute, 23 * 60 + 59).coerceIn(0, 23 * 60 + 59)
+        val invertAosTimeWindow = preferences.getBoolean(keyFilterAosInvert, false)
         val selectedModesString = preferences.getString(keySelectedModes, null)
         val selectedModes = selectedModesString?.split(separatorComma)?.sorted() ?: emptyList()
-        return PassesSettings(showDeepSpace, hoursAhead, minElevation, selectedModes)
+        return PassesSettings(
+            showDeepSpace,
+            hoursAhead,
+            minElevation,
+            aosStartMinute,
+            aosEndMinute,
+            invertAosTimeWindow,
+            selectedModes
+        )
     }
     //endregion
 
@@ -329,8 +350,12 @@ class SettingsRepo(
                 putBoolean(keyStateOfSweep, new.stateOfSweep)
                 putBoolean(keyStateOfUtc, new.stateOfUtc)
                 putBoolean(keyStateOfLightTheme, new.stateOfLightTheme)
+                putBoolean(keyStateOfNightMode, new.stateOfNightMode)
                 putBoolean(keyShouldSeeWarning, new.shouldSeeWarning)
                 putBoolean(keyShouldSeeWhatsNew, new.shouldSeeWhatsNew)
+                putString(keySstvMode, new.sstvMode)
+                putLong(keyLowElevation, new.lowElevation.toRawBits())
+                putLong(keyHighElevation, new.highElevation.toRawBits())
             }
             new
         }
@@ -342,8 +367,12 @@ class SettingsRepo(
         stateOfSweep = preferences.getBoolean(keyStateOfSweep, true),
         stateOfUtc = preferences.getBoolean(keyStateOfUtc, false),
         stateOfLightTheme = preferences.getBoolean(keyStateOfLightTheme, false),
+        stateOfNightMode = preferences.getBoolean(keyStateOfNightMode, false),
         shouldSeeWarning = preferences.getBoolean(keyShouldSeeWarning, true),
-        shouldSeeWhatsNew = preferences.getBoolean(keyShouldSeeWhatsNew, true)
+        shouldSeeWhatsNew = preferences.getBoolean(keyShouldSeeWhatsNew, true),
+        sstvMode = preferences.getString(keySstvMode, null) ?: "Auto",
+        lowElevation = Double.fromBits(preferences.getLong(keyLowElevation, 15.0.toRawBits())),
+        highElevation = Double.fromBits(preferences.getLong(keyHighElevation, 45.0.toRawBits()))
     )
     //endregion
 
@@ -377,6 +406,7 @@ class SettingsRepo(
     private val keyTxRadioName = "txRadioName"
     private val keyRxRadioName = "rxRadioName"
     private val keyRadioBaudRate = "radioBaudRate"
+    private val keyRadioSplitMode = "radioSplitMode"
 
     private val _radioControlSettings = MutableStateFlow(getRadioControlSettings())
     override val radioControlSettings: StateFlow<RadioControlSettings> = _radioControlSettings
@@ -390,18 +420,20 @@ class SettingsRepo(
             putString(keyTxRadioName, settings.txRadioName)
             putString(keyRxRadioName, settings.rxRadioName)
             putInt(keyRadioBaudRate, settings.baudRate)
+            putBoolean(keyRadioSplitMode, settings.splitMode)
         }
         _radioControlSettings.value = settings
     }
 
     private fun getRadioControlSettings(): RadioControlSettings = RadioControlSettings(
         enabled = preferences.getBoolean(keyRadioControlEnabled, false),
-        radioModel = preferences.getString(keyRadioModel, null) ?: "Yaesu FT-817/818",
+        radioModel = preferences.getString(keyRadioModel, null) ?: RadioControlSettings.MODEL_YAESU_FT817,
         txRadioAddress = preferences.getString(keyTxRadioAddress, null) ?: "",
         rxRadioAddress = preferences.getString(keyRxRadioAddress, null) ?: "",
         txRadioName = preferences.getString(keyTxRadioName, null) ?: "TX Radio",
         rxRadioName = preferences.getString(keyRxRadioName, null) ?: "RX Radio",
-        baudRate = preferences.getInt(keyRadioBaudRate, 4800)
+        baudRate = preferences.getInt(keyRadioBaudRate, 4800),
+        splitMode = preferences.getBoolean(keyRadioSplitMode, false)
     )
     //endregion
 }

core/data/src/main/java/com/rtbishop/look4sat/core/data/source/LocalSource.kt

@@ -74,7 +74,6 @@ class LocalSource(private val look4SatDao: Look4SatDao) : ILocalSource {
     }
 
     override suspend fun insertRadios(radios: List<SatRadio>) {
-        look4SatDao.deleteRadios()
         look4SatDao.insertRadios(radios.toFrameworkRadios())
     }
 

core/data/src/main/java/com/rtbishop/look4sat/core/data/source/RemoteSource.kt

@@ -24,6 +24,7 @@ import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.withContext
 import okhttp3.OkHttpClient
 import okhttp3.Request
+import java.io.ByteArrayInputStream
 import java.io.InputStream
 
 class RemoteSource(
@@ -45,7 +46,10 @@ class RemoteSource(
     override suspend fun getNetworkStream(url: String): InputStream? = withContext(dispatcher) {
         try {
             val networkRequest = Request.Builder().url(url).build()
-            httpClient.newCall(networkRequest).execute().body.byteStream()
+            httpClient.newCall(networkRequest).execute().use { response ->
+                if (!response.isSuccessful) return@withContext null
+                ByteArrayInputStream(response.body.bytes())
+            }
         } catch (exception: Exception) {
             println("RemoteSource network stream exception: $exception")
             null

core/data/src/main/java/com/rtbishop/look4sat/core/data/usecase/AudioCapture.kt

@@ -0,0 +1,63 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.data.usecase
+
+import android.media.AudioFormat
+import android.media.AudioRecord
+import android.media.MediaRecorder
+import androidx.annotation.RequiresPermission
+import com.rtbishop.look4sat.core.domain.usecase.IAudioCapture
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.currentCoroutineContext
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.isActive
+
+class AudioCapture : IAudioCapture {
+
+    override val sampleRate: Int = 44100
+
+    private val channelConfig = AudioFormat.CHANNEL_IN_MONO
+    private val audioFormat = AudioFormat.ENCODING_PCM_FLOAT
+    private val bufferSize = AudioRecord.getMinBufferSize(sampleRate, channelConfig, audioFormat)
+        .coerceAtLeast(sampleRate) // at least 1 second buffer
+
+    @RequiresPermission(android.Manifest.permission.RECORD_AUDIO)
+    override fun audioFlow(): Flow<FloatArray> = flow {
+        val recorder = AudioRecord(
+            MediaRecorder.AudioSource.MIC,
+            sampleRate,
+            channelConfig,
+            audioFormat,
+            bufferSize * 4 // bytes for float
+        )
+        try {
+            recorder.startRecording()
+            val chunkSize = sampleRate / 10 // ~100ms chunks
+            val buffer = FloatArray(chunkSize)
+            while (currentCoroutineContext().isActive) {
+                val read = recorder.read(buffer, 0, chunkSize, AudioRecord.READ_BLOCKING)
+                if (read > 0) emit(if (read == chunkSize) buffer.copyOf() else buffer.copyOfRange(0, read))
+            }
+        } finally {
+            recorder.stop()
+            recorder.release()
+        }
+    }.flowOn(Dispatchers.IO)
+}

core/data/src/main/java/com/rtbishop/look4sat/core/data/usecase/SaveImage.kt

@@ -0,0 +1,84 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.data.usecase
+
+import android.content.ContentValues
+import android.content.Context
+import android.graphics.Bitmap
+import android.os.Build
+import android.os.Environment
+import android.provider.MediaStore
+import com.rtbishop.look4sat.core.domain.usecase.ISaveImage
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import java.io.File
+import java.io.FileOutputStream
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+
+//Saves images to the device gallery using MediaStore (API 29+) or direct file write (API < 29)
+class SaveImage(private val context: Context) : ISaveImage {
+
+    override suspend fun invoke(pixels: IntArray, width: Int, height: Int, modeName: String): Boolean {
+        return withContext(Dispatchers.IO) {
+            try {
+                val bitmap = Bitmap.createBitmap(pixels, width, height, Bitmap.Config.ARGB_8888)
+                val timestamp = SimpleDateFormat("yyyyMMdd_HHmmss", Locale.US).format(Date())
+                val filename = "SSTV_${modeName}_$timestamp.png"
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                    saveWithMediaStore(bitmap, filename)
+                } else {
+                    saveToExternalStorage(bitmap, filename)
+                }
+                bitmap.recycle()
+                true
+            } catch (_: Exception) {
+                false
+            }
+        }
+    }
+
+    private fun saveWithMediaStore(bitmap: Bitmap, filename: String) {
+        val values = ContentValues().apply {
+            put(MediaStore.Images.Media.DISPLAY_NAME, filename)
+            put(MediaStore.Images.Media.MIME_TYPE, "image/png")
+            put(MediaStore.Images.Media.RELATIVE_PATH, "${Environment.DIRECTORY_PICTURES}/Look4Sat")
+            put(MediaStore.Images.Media.IS_PENDING, 1)
+        }
+        val resolver = context.contentResolver
+        val uri = resolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values)
+            ?: throw IllegalStateException("Failed to create MediaStore entry")
+        resolver.openOutputStream(uri)?.use { stream ->
+            bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream)
+        }
+        values.clear()
+        values.put(MediaStore.Images.Media.IS_PENDING, 0)
+        resolver.update(uri, values, null, null)
+    }
+
+    private fun saveToExternalStorage(bitmap: Bitmap, filename: String) {
+        val picturesDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES)
+        val dir = File(picturesDir, "Look4Sat")
+        if (!dir.exists()) dir.mkdirs()
+        val file = File(dir, filename)
+        FileOutputStream(file).use { stream ->
+            bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream)
+        }
+    }
+}

core/data/src/test/java/com/rtbishop/look4sat/core/data/framework/Ft817CatProtocolTest.kt

@@ -1,30 +1,29 @@
-package com.rtbishop.look4sat.core.data
+package com.rtbishop.look4sat.core.data.framework
 
-import com.rtbishop.look4sat.core.data.framework.Ft817CatProtocol
+import org.junit.Assert.assertArrayEquals
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Assert.assertNull
 import org.junit.Test
-import kotlin.test.assertContentEquals
-import kotlin.test.assertEquals
-import kotlin.test.assertNotNull
-import kotlin.test.assertNull
 
 class Ft817CatProtocolTest {
 
     @Test
     fun encodeFrequencyBcd_145500000() {
         val bcd = Ft817CatProtocol.encodeFrequencyBcd(145500000L)
-        assertContentEquals(byteArrayOf(0x14, 0x55, 0x00, 0x00), bcd)
+        assertArrayEquals(byteArrayOf(0x14, 0x55, 0x00, 0x00), bcd)
     }
 
     @Test
     fun encodeFrequencyBcd_435100000() {
         val bcd = Ft817CatProtocol.encodeFrequencyBcd(435100000L)
-        assertContentEquals(byteArrayOf(0x43, 0x51, 0x00, 0x00), bcd)
+        assertArrayEquals(byteArrayOf(0x43, 0x51, 0x00, 0x00), bcd)
     }
 
     @Test
     fun encodeFrequencyBcd_7074000() {
         val bcd = Ft817CatProtocol.encodeFrequencyBcd(7074000L)
-        assertContentEquals(byteArrayOf(0x00, 0x70, 0x74, 0x00), bcd)
+        assertArrayEquals(byteArrayOf(0x00, 0x70, 0x74, 0x00), bcd)
     }
 
     @Test
@@ -42,21 +41,21 @@ class Ft817CatProtocolTest {
         val cmd = Ft817CatProtocol.buildSetFreqCommand(145500000L)
         assertEquals(5, cmd.size)
         assertEquals(0x01.toByte(), cmd[4])
-        assertContentEquals(byteArrayOf(0x14, 0x55, 0x00, 0x00, 0x01), cmd)
+        assertArrayEquals(byteArrayOf(0x14, 0x55, 0x00, 0x00, 0x01), cmd)
     }
 
     @Test
     fun buildSetModeCommand_usb() {
         val cmd = Ft817CatProtocol.buildSetModeCommand("USB")
         assertNotNull(cmd)
-        assertContentEquals(byteArrayOf(0x01, 0x00, 0x00, 0x00, 0x07), cmd)
+        assertArrayEquals(byteArrayOf(0x01, 0x00, 0x00, 0x00, 0x07), cmd)
     }
 
     @Test
     fun buildSetModeCommand_fm() {
         val cmd = Ft817CatProtocol.buildSetModeCommand("FM")
         assertNotNull(cmd)
-        assertContentEquals(byteArrayOf(0x08, 0x00, 0x00, 0x00, 0x07), cmd)
+        assertArrayEquals(byteArrayOf(0x08, 0x00, 0x00, 0x00, 0x07), cmd)
     }
 
     @Test
@@ -67,19 +66,19 @@ class Ft817CatProtocolTest {
     @Test
     fun encodeCtcssTone_67_0() {
         val bcd = Ft817CatProtocol.encodeCtcssToneBcd(67.0)
-        assertContentEquals(byteArrayOf(0x06, 0x70), bcd)
+        assertArrayEquals(byteArrayOf(0x06, 0x70), bcd)
     }
 
     @Test
     fun encodeCtcssTone_74_4() {
         val bcd = Ft817CatProtocol.encodeCtcssToneBcd(74.4)
-        assertContentEquals(byteArrayOf(0x07, 0x44), bcd)
+        assertArrayEquals(byteArrayOf(0x07, 0x44), bcd)
     }
 
     @Test
     fun encodeCtcssTone_141_3() {
         val bcd = Ft817CatProtocol.encodeCtcssToneBcd(141.3)
-        assertContentEquals(byteArrayOf(0x14, 0x13), bcd)
+        assertArrayEquals(byteArrayOf(0x14, 0x13), bcd)
     }
 
     @Test
@@ -87,13 +86,13 @@ class Ft817CatProtocolTest {
         val cmd = Ft817CatProtocol.buildSetCtcssToneCommand(67.0)
         assertEquals(5, cmd.size)
         assertEquals(0x0B.toByte(), cmd[4])
-        assertContentEquals(byteArrayOf(0x06, 0x70, 0x00, 0x00, 0x0B), cmd)
+        assertArrayEquals(byteArrayOf(0x06, 0x70, 0x00, 0x00, 0x0B), cmd)
     }
 
     @Test
     fun buildCtcssModeCommand_enable() {
         val cmd = Ft817CatProtocol.buildCtcssModeCommand(true)
-        assertContentEquals(byteArrayOf(0x2A, 0x00, 0x00, 0x00, 0x0A), cmd)
+        assertArrayEquals(byteArrayOf(0x2A, 0x00, 0x00, 0x00, 0x0A), cmd)
     }
 
     @Test
@@ -108,6 +107,7 @@ class Ft817CatProtocolTest {
         val response = byteArrayOf(0x14, 0x55, 0x00, 0x00, 0x01)
         val result = Ft817CatProtocol.parseReadResponse(response)
         assertNotNull(result)
+        result ?: return
         assertEquals(145500000L, result.first)
         assertEquals("USB", result.second)
     }
@@ -117,6 +117,7 @@ class Ft817CatProtocolTest {
         val response = byteArrayOf(0x14, 0x60, 0x00, 0x00, 0x08)
         val result = Ft817CatProtocol.parseReadResponse(response)
         assertNotNull(result)
+        result ?: return
         assertEquals(146000000L, result.first)
         assertEquals("FM", result.second)
     }
@@ -135,7 +136,7 @@ class Ft817CatProtocolTest {
     @Test
     fun buildPttCommands() {
         val on = Ft817CatProtocol.buildPttOnCommand()
-        assertContentEquals(byteArrayOf(0x00, 0x00, 0x00, 0x00, 0x08), on)
+        assertArrayEquals(byteArrayOf(0x00, 0x00, 0x00, 0x00, 0x08), on)
 
         val off = Ft817CatProtocol.buildPttOffCommand()
         assertEquals(0x88.toByte(), off[4])
@@ -144,6 +145,6 @@ class Ft817CatProtocolTest {
     @Test
     fun buildReadCommand() {
         val cmd = Ft817CatProtocol.buildReadFreqModeCommand()
-        assertContentEquals(byteArrayOf(0x00, 0x00, 0x00, 0x00, 0x03), cmd)
+        assertArrayEquals(byteArrayOf(0x00, 0x00, 0x00, 0x00, 0x03), cmd)
     }
 }

core/data/src/test/java/com/rtbishop/look4sat/core/data/repository/DatabaseRepoTest.kt

@@ -0,0 +1,234 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.data.repository
+
+import com.rtbishop.look4sat.core.domain.model.DataSourcesSettings
+import com.rtbishop.look4sat.core.domain.model.DatabaseState
+import com.rtbishop.look4sat.core.domain.model.OtherSettings
+import com.rtbishop.look4sat.core.domain.model.PassesSettings
+import com.rtbishop.look4sat.core.domain.model.RCSettings
+import com.rtbishop.look4sat.core.domain.model.RadioControlSettings
+import com.rtbishop.look4sat.core.domain.model.SatItem
+import com.rtbishop.look4sat.core.domain.model.SatRadio
+import com.rtbishop.look4sat.core.domain.predict.GeoPos
+import com.rtbishop.look4sat.core.domain.predict.OrbitalData
+import com.rtbishop.look4sat.core.domain.predict.OrbitalObject
+import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
+import com.rtbishop.look4sat.core.domain.source.ILocalSource
+import com.rtbishop.look4sat.core.domain.source.IRemoteSource
+import com.rtbishop.look4sat.core.domain.utility.DataParser
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import java.io.InputStream
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class DatabaseRepoTest {
+
+    private val dispatcher = StandardTestDispatcher()
+    private val dataParser = DataParser(dispatcher)
+
+    @Test
+    fun `manual satellite import parses csv stream from content uri`() = runTest(dispatcher) {
+        val uri = "content://look4sat/import/satellites"
+        val localSource = FakeLocalSource()
+        val remoteSource = FakeRemoteSource().apply {
+            fileStreams[uri] = { validCsvStream() }
+        }
+        val settingsRepo = FakeSettingsRepo()
+        val repository = DatabaseRepo(dispatcher, dataParser, localSource, remoteSource, settingsRepo)
+
+        repository.updateTLEFromFile(uri)
+
+        assertEquals(1, localSource.insertedEntries.size)
+        assertEquals(25544, localSource.insertedEntries.first().catnum)
+        assertEquals(listOf(25544), settingsRepo.satelliteTypeIdsByType["Other"])
+        assertTrue(settingsRepo.databaseState.value.numberOfSatellites > 0)
+    }
+
+    @Test
+    fun `manual satellite import keeps tle support`() = runTest(dispatcher) {
+        val uri = "content://look4sat/import/legacy"
+        val localSource = FakeLocalSource()
+        val remoteSource = FakeRemoteSource().apply {
+            fileStreams[uri] = { validTleStream() }
+        }
+        val settingsRepo = FakeSettingsRepo()
+        val repository = DatabaseRepo(dispatcher, dataParser, localSource, remoteSource, settingsRepo)
+
+        repository.updateTLEFromFile(uri)
+
+        assertEquals(1, localSource.insertedEntries.size)
+        assertEquals(25544, localSource.insertedEntries.first().catnum)
+    }
+
+    @Test
+    fun `custom data source imports omm csv from web`() = runTest(dispatcher) {
+        val customCsvUrl = "https://example.com/custom-omm.csv"
+        val localSource = FakeLocalSource()
+        val remoteSource = FakeRemoteSource().apply {
+            networkStreams[customCsvUrl] = { validCsvStream() }
+        }
+        val settingsRepo = FakeSettingsRepo(
+            dataSources = DataSourcesSettings(
+                useCustomTLE = true,
+                useCustomTransceivers = false,
+                tleUrl = customCsvUrl,
+                transceiversUrl = ""
+            )
+        )
+        val repository = DatabaseRepo(dispatcher, dataParser, localSource, remoteSource, settingsRepo)
+
+        repository.updateFromRemote()
+
+        assertTrue(localSource.insertedEntries.any { it.catnum == 25544 })
+        assertEquals(listOf(25544), settingsRepo.satelliteTypeIdsByType["Other"])
+    }
+
+    private fun validCsvStream(): InputStream = """
+        OBJECT_NAME,OBJECT_ID,EPOCH,MEAN_MOTION,ECCENTRICITY,INCLINATION,RA_OF_ASC_NODE,ARG_OF_PERICENTER,MEAN_ANOMALY,EPHEMERIS_TYPE,CLASSIFICATION_TYPE,NORAD_CAT_ID,ELEMENT_SET_NO,REV_AT_EPOCH,BSTAR,MEAN_MOTION_DOT,MEAN_MOTION_DDOT
+        ISS (ZARYA),1998-067A,2021-11-16T12:28:09.322176,15.48582035,.0004694,51.6447,309.4881,203.6966,299.8876,0,U,25544,999,31220,.31985E-4,.1288E-4,0
+    """.trimIndent().byteInputStream()
+
+    private fun validTleStream(): InputStream = """
+        ISS (ZARYA)
+        1 25544U 98067A   21320.51955234  .00001288  00000+0  31985-4 0  9990
+        2 25544  51.6447 309.4881 0004694 203.6966 299.8876 15.48582035312205
+    """.trimIndent().byteInputStream()
+}
+
+private class FakeRemoteSource : IRemoteSource {
+    val fileStreams: MutableMap<String, () -> InputStream> = mutableMapOf()
+    val networkStreams: MutableMap<String, () -> InputStream> = mutableMapOf()
+
+    override suspend fun getFileStream(uri: String): InputStream? = fileStreams[uri]?.invoke()
+
+    override suspend fun getNetworkStream(url: String): InputStream? = networkStreams[url]?.invoke()
+}
+
+private class FakeLocalSource : ILocalSource {
+    val insertedEntries = mutableListOf<OrbitalData>()
+    private val insertedRadios = mutableListOf<SatRadio>()
+
+    override suspend fun getEntriesTotal(): Int = insertedEntries.size
+
+    override suspend fun getEntriesList(): List<SatItem> = emptyList()
+
+    override suspend fun getEntriesWithIds(ids: List<Int>): List<OrbitalObject> = emptyList()
+
+    override suspend fun insertEntries(entries: List<OrbitalData>) {
+        insertedEntries += entries
+    }
+
+    override suspend fun deleteEntries() {
+        insertedEntries.clear()
+    }
+
+    override suspend fun getIdsWithModes(modes: List<String>): List<Int> = emptyList()
+
+    override suspend fun getRadiosTotal(): Int = insertedRadios.size
+
+    override suspend fun getRadiosWithId(id: Int): List<SatRadio> = emptyList()
+
+    override suspend fun insertRadios(radios: List<SatRadio>) {
+        insertedRadios += radios
+    }
+
+    override suspend fun deleteRadios() {
+        insertedRadios.clear()
+    }
+}
+
+private class FakeSettingsRepo(dataSources: DataSourcesSettings = defaultDataSourcesSettings()) : ISettingsRepo {
+
+    override val appVersionName: String = "test"
+
+    override val selectedIds: StateFlow<List<Int>> = MutableStateFlow(emptyList())
+
+    override val selectedTypes: StateFlow<List<String>> = MutableStateFlow(emptyList())
+
+    override val passesSettings: StateFlow<PassesSettings> = MutableStateFlow(
+        PassesSettings(hoursAhead = 24, minElevation = 0.0, selectedModes = emptyList())
+    )
+
+    override val stationPosition: StateFlow<GeoPos> = MutableStateFlow(GeoPos(0.0, 0.0))
+
+    override val databaseState: MutableStateFlow<DatabaseState> = MutableStateFlow(DatabaseState(0, 0, 0L))
+
+    override val rcSettings: StateFlow<RCSettings> = MutableStateFlow(
+        RCSettings(false, "", "", "", false, "", "", "", false, "", "", "", false, "", "")
+    )
+
+    override val otherSettings: StateFlow<OtherSettings> = MutableStateFlow(
+        OtherSettings(false, false, false, false, false, false, false, false)
+    )
+
+    override val dataSourcesSettings: MutableStateFlow<DataSourcesSettings> = MutableStateFlow(dataSources)
+
+    override val radioControlSettings: StateFlow<RadioControlSettings> = MutableStateFlow(
+        RadioControlSettings(false, RadioControlSettings.MODEL_YAESU_FT817, "", "", "", "", 9600)
+    )
+
+    val satelliteTypeIdsByType = mutableMapOf<String, List<Int>>()
+
+    override fun setSelectedIds(ids: List<Int>) = Unit
+
+    override fun setSelectedTypes(types: List<String>) = Unit
+
+    override fun setPassesSettings(settings: PassesSettings) = Unit
+
+    override fun setStationPosition(latitude: Double, longitude: Double, altitude: Double): Boolean = true
+
+    override fun setStationPosition(): Boolean = true
+
+    override fun setStationPosition(locator: String): Boolean = true
+
+    override fun getSatelliteTypesIds(types: List<String>): List<Int> = emptyList()
+
+    override fun setSatelliteTypeIds(type: String, ids: List<Int>) {
+        satelliteTypeIdsByType[type] = ids
+    }
+
+    override fun updateDatabaseState(state: DatabaseState) {
+        databaseState.value = state
+    }
+
+    override fun updateRCSettings(settings: RCSettings) = Unit
+
+    override fun updateOtherSettings(transform: (OtherSettings) -> OtherSettings) = Unit
+
+    override fun updateDataSourcesSettings(settings: DataSourcesSettings) {
+        dataSourcesSettings.value = settings
+    }
+
+    override fun updateRadioControlSettings(settings: RadioControlSettings) = Unit
+}
+
+private fun defaultDataSourcesSettings(): DataSourcesSettings {
+    return DataSourcesSettings(
+        useCustomTLE = false,
+        useCustomTransceivers = false,
+        tleUrl = "",
+        transceiversUrl = ""
+    )
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwBayesianDecoder.kt

@@ -0,0 +1,154 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+/**
+ * Bayesian Morse timing decoder.
+ * Replaces hard thresholds with probability-based decision making.
+ *
+ * Inspired by VE3NEA's CW Skimmer approach:
+ * "Instead of making a hard decision at every input sample whether the signal
+ * is present or not, compute the probability that the signal is present."
+ *
+ * Uses Gaussian probability density centered on expected durations:
+ *   P(dit | duration) = exp(-(duration - dotMs)^2 / (2 * variance^2))
+ *   P(dash | duration) = exp(-(duration - 3*dotMs)^2 / (2 * variance^2))
+ */
+internal class CwBayesianDecoder {
+
+    // Morse timing parameters
+    private var dotDurationMs = 60f // initial 20 WPM
+    private var speedWpm = 20f
+
+    // Current symbol being accumulated
+    private var currentSymbol = StringBuilder()
+    private var textBuffer = StringBuilder()
+
+    // Recent dit lengths for speed estimation
+    private val recentDits = mutableListOf<Float>()
+
+    // Output
+    private var _decodedText = ""
+    val decodedText: String get() = _decodedText
+
+    /** Gaussian probability. */
+    private fun gaussianProb(durationMs: Float, expectedMs: Float, varianceMs: Float): Float {
+        if (varianceMs <= 0f) return 0f
+        val diff = durationMs - expectedMs
+        return kotlin.math.exp(-(diff * diff) / (2 * varianceMs * varianceMs))
+    }
+
+    /** Process a tone duration. Returns the symbol type with highest probability. */
+    fun processTone(durationMs: Float): ToneResult {
+        val ditProb = gaussianProb(durationMs, dotDurationMs, dotDurationMs * 0.4f)
+        val dashProb = gaussianProb(durationMs, dotDurationMs * 3f, dotDurationMs * 0.6f)
+
+        return if (ditProb > dashProb && ditProb > 0.05f) {
+            currentSymbol.append('0')
+            recentDits.add(durationMs)
+            updateSpeed()
+            ToneResult('0', ditProb)
+        } else if (dashProb > 0.05f) {
+            currentSymbol.append('1')
+            ToneResult('1', dashProb)
+        } else {
+            ToneResult(null, 0f)
+        }
+    }
+
+    /** Process a gap duration. Returns decoded character or null. */
+    fun processGap(durationMs: Float): Char? {
+        if (currentSymbol.isEmpty()) {
+            val wordProb = gaussianProb(durationMs, dotDurationMs * 7f, dotDurationMs * 1.2f)
+            if (wordProb > 0.2f) {
+                textBuffer.append(' ')
+                _decodedText = textBuffer.toString()
+                return ' '
+            }
+            return null
+        }
+
+        val interCharProb = gaussianProb(durationMs, dotDurationMs * 3f, dotDurationMs * 0.6f)
+        val wordProb = gaussianProb(durationMs, dotDurationMs * 7f, dotDurationMs * 1.2f)
+
+        if (wordProb > interCharProb && wordProb > 0.2f) {
+            val char = flushSymbol()
+            textBuffer.append(' ')
+            _decodedText = textBuffer.toString()
+            return char
+        }
+        if (interCharProb > 0.15f) {
+            val char = flushSymbol()
+            _decodedText = textBuffer.toString()
+            return char
+        }
+        return null
+    }
+
+    private fun flushSymbol(): Char? {
+        if (currentSymbol.isEmpty()) return null
+        val morse = currentSymbol.toString()
+        currentSymbol.clear()
+        val char = morseToChar(morse)
+        if (char != null) textBuffer.append(char)
+        return char
+    }
+
+    private fun updateSpeed() {
+        if (recentDits.size < 3) return
+        val sorted = recentDits.sorted()
+        val median = sorted[sorted.size / 2]
+        if (median > 0f) {
+            dotDurationMs = dotDurationMs * 0.7f + median * 0.3f
+            val wpm = 60.0f / (50.0f * dotDurationMs / 1000.0f)
+            if (wpm in 5f..55f) speedWpm = wpm
+        }
+    }
+
+    fun getSpeed(): Float = speedWpm
+
+    fun reset() {
+        dotDurationMs = 60f
+        speedWpm = 20f
+        recentDits.clear()
+        currentSymbol.clear()
+        textBuffer.clear()
+        _decodedText = ""
+    }
+
+    companion object {
+        private val MORSE_TABLE = mapOf(
+            "01" to 'A', "1000" to 'B', "1010" to 'C', "100" to 'D', "0" to 'E',
+            "0010" to 'F', "110" to 'G', "0000" to 'H', "00" to 'I', "0111" to 'J',
+            "101" to 'K', "0100" to 'L', "11" to 'M', "10" to 'N', "111" to 'O',
+            "0110" to 'P', "1101" to 'Q', "010" to 'R', "000" to 'S', "1" to 'T',
+            "001" to 'U', "0001" to 'V', "011" to 'W', "1001" to 'X', "1011" to 'Y',
+            "1100" to 'Z', "01111" to '1', "00111" to '2', "00011" to '3',
+            "00001" to '4', "00000" to '5', "10000" to '6', "11000" to '7',
+            "11100" to '8', "11110" to '9', "11111" to '0',
+            "010101" to '.', "110011" to ',', "001100" to '?', "011110" to '\'',
+            "101011" to '!', "10010" to '/', "10110" to '(', "101101" to ')',
+            "01000" to '&', "111000" to ':', "101010" to ';', "10001" to '=',
+            "01010" to '+', "100001" to '-', "001101" to '_', "010010" to '"',
+            "0001001" to '$', "011010" to '@'
+        )
+        fun morseToChar(morse: String): Char? = MORSE_TABLE[morse]
+    }
+}
+
+data class ToneResult(val symbol: Char?, val probability: Float)

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwChannelTracker.kt

@@ -0,0 +1,114 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+/**
+ * Multi-channel CW signal tracker.
+ * Monitors the spectrogram for active frequency bins and extracts
+ * energy envelopes for each detected signal.
+ *
+ * Inspired by CW Skimmer's multi-channel approach:
+ * tracks all active signals in the passband simultaneously,
+ * selects the best one for decoded output.
+ */
+internal class CwChannelTracker(
+    private val spectrogram: CwSpectrogram,
+    private val maxChannels: Int = 3
+) {
+    data class Channel(
+        val bin: Int,
+        val frequency: Float,
+        var active: Boolean = false,
+        var energy: Float = 0f,
+        val history: MutableList<Float> = mutableListOf(),
+        var confidence: Float = 0f
+    )
+
+    private val channels = Array(maxChannels) { Channel(0, 0f) }
+
+    /** Scan the current spectrogram column and update channel tracking. */
+    fun update(): List<Channel> {
+        val col = spectrogram.getCurrentColumn()
+        val peaks = findPeaks(col, threshold = 0.3f, minDistance = 2)
+
+        // Update existing channels
+        for (ch in channels) {
+            if (ch.active) {
+                if (peaks.contains(ch.bin)) {
+                    ch.energy = col[ch.bin]
+                    ch.history.add(ch.energy)
+                    if (ch.history.size > 40) ch.history.removeAt(0)
+                    ch.confidence = computeConfidence(ch.history)
+                } else {
+                    // Signal lost — decay confidence
+                    ch.history.add(0f)
+                    if (ch.history.size > 40) ch.history.removeAt(0)
+                    ch.confidence *= 0.9f
+                    if (ch.confidence < 0.1f) ch.active = false
+                }
+            }
+        }
+
+        // Assign new peaks to inactive channels
+        var peakIdx = 0
+        for (ch in channels) {
+            if (!ch.active && peakIdx < peaks.size) {
+                val bin = peaks[peakIdx]
+                val freq = spectrogram.binToFreq(bin)
+                // Re-initialize channel
+                channels[peakIdx] = Channel(bin, freq, true, col[bin], mutableListOf(), 0.5f)
+                peakIdx++
+            }
+        }
+
+        return channels.filter { it.active }
+    }
+
+    /** Find peak bins in the spectrum. */
+    private fun findPeaks(spectrum: FloatArray, threshold: Float, minDistance: Int): List<Int> {
+        val peaks = mutableListOf<Int>()
+        for (i in 1 until spectrum.size - 1) {
+            if (spectrum[i] > spectrum[i - 1] && spectrum[i] > spectrum[i + 1] && spectrum[i] > threshold) {
+                if (peaks.isEmpty() || i - peaks.last() >= minDistance) {
+                    peaks.add(i)
+                }
+            }
+        }
+        return peaks.sortedByDescending { spectrum[it] }
+    }
+
+    /** Compute confidence from energy history. Lower variance = higher confidence. */
+    private fun computeConfidence(history: List<Float>): Float {
+        if (history.size < 10) return 0.3f
+        val recent = history.takeLast(10)
+        val mean = recent.average().toFloat()
+        val variance = recent.map { (it - mean) * (it - mean) }.average().toFloat()
+        return if (mean > 0f) (mean / (mean + variance + 0.1f)).coerceIn(0f, 1f) else 0f
+    }
+
+    /** Get the channel with highest confidence. */
+    fun getBestChannel(): Channel? {
+        return channels.filter { it.active }.maxByOrNull { it.confidence }
+    }
+
+    fun reset() {
+        for (i in channels.indices) {
+            channels[i] = Channel(0, 0f)
+        }
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwDecoder.kt

@@ -0,0 +1,165 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+
+/**
+ * CW (Morse code) decoder v3 — Spectrogram-based multi-channel Bayesian decoder.
+ *
+ * Architecture inspired by Morse Expert / CW Skimmer (VE3NEA):
+ *   1. FFT spectrogram creates a frequency×time matrix
+ *   2. Multi-channel peak detector finds all active signals
+ *   3. Per-channel energy envelope extraction
+ *   4. Bayesian probability for symbol timing (Gaussian likelihood)
+ *   5. Best channel selected for output
+ *
+ * Timing analysis is performed per spectrogram column (hop).
+ * Each column represents hopSize/sampleRate seconds of audio.
+ */
+class CwDecoder(
+    val sampleRate: Int = 8000,
+    cwToneFreq: Float = -1f // ignored in v3 (auto-detect via spectrogram)
+) {
+    companion object {
+        private const val FFT_SIZE = 256
+        private const val HOP_SIZE = 64
+    }
+
+    private val spectrogram = CwSpectrogram(
+        fftSize = FFT_SIZE,
+        hopSize = HOP_SIZE,
+        sampleRate = sampleRate,
+        minBin = 6,
+        maxBin = 38,
+        historyCols = 40
+    )
+    private val channelTracker = CwChannelTracker(spectrogram, maxChannels = 3)
+    private val bayesianDecoder = CwBayesianDecoder()
+
+    // Timing state per channel
+    private data class ChannelTiming(
+        var isSignal: Boolean = false,
+        var toneTicks: Int = 0,
+        var gapTicks: Int = 0
+    )
+    private val timingStates = Array(3) { ChannelTiming() }
+
+    // Time per spectrogram column in milliseconds
+    private val tickMs = 1000f * HOP_SIZE / sampleRate
+
+    // Output flows
+    private val _decodedTextFlow = MutableStateFlow("")
+    val decodedTextFlow: StateFlow<String> = _decodedTextFlow
+
+    private val _signalStrength = MutableStateFlow(0f)
+    val signalStrength: StateFlow<Float> = _signalStrength
+
+    private val _estimatedPitch = MutableStateFlow<Float?>(null)
+    val estimatedPitch: StateFlow<Float?> = _estimatedPitch
+
+    private val _estimatedSpeed = MutableStateFlow<Float?>(null)
+    val estimatedSpeed: StateFlow<Float?> = _estimatedSpeed
+
+    private var frameCount = 0
+
+    init {
+        if (cwToneFreq > 0f) {
+            _estimatedPitch.value = cwToneFreq
+        }
+    }
+
+    fun processBuffer(buffer: FloatArray) {
+        // 1. Feed samples to spectrogram
+        spectrogram.addSamples(buffer)
+
+        // 2. Get number of new columns generated
+        val newCols = spectrogram.getNewColumns()
+        if (newCols == 0) return
+
+        // 3. Update channel tracker (uses latest column for peak detection)
+        val activeChannels = channelTracker.update()
+
+        // 4. Process each new column for timing analysis
+        //    Columns are indexed 0..historyCols-1, where historyCols-1 is the newest
+        val baseIdx = (spectrogram.historyCols - newCols).coerceAtLeast(0)
+        for (colOffset in 0 until newCols) {
+            val col = spectrogram.getColumn(baseIdx + colOffset)
+
+            for ((idx, channel) in activeChannels.withIndex()) {
+                if (idx >= timingStates.size) break
+                val state = timingStates[idx]
+                val energy = if (channel.bin in col.indices) col[channel.bin] else 0f
+
+                // Adaptive threshold
+                val threshold = 0.3f + (energy - 0.3f) * 0.3f
+
+                if (energy > threshold) {
+                    if (!state.isSignal) {
+                        if (state.gapTicks > 0) {
+                            val gapMs = state.gapTicks * tickMs
+                            bayesianDecoder.processGap(gapMs)
+                        }
+                        state.gapTicks = 0
+                        state.isSignal = true
+                    }
+                    state.toneTicks++
+                } else {
+                    if (state.isSignal) {
+                        if (state.toneTicks > 0) {
+                            val toneMs = state.toneTicks * tickMs
+                            bayesianDecoder.processTone(toneMs)
+                        }
+                        state.toneTicks = 0
+                        state.isSignal = false
+                    }
+                    state.gapTicks++
+                }
+            }
+        }
+
+        // 5. Update outputs
+        frameCount++
+        if (frameCount % 5 == 0) {
+            val bestChannel = channelTracker.getBestChannel()
+            if (bestChannel != null) {
+                _estimatedPitch.value = bestChannel.frequency
+                _signalStrength.value = bestChannel.confidence
+                _estimatedSpeed.value = bayesianDecoder.getSpeed()
+            }
+            _decodedTextFlow.value = bayesianDecoder.decodedText
+        }
+    }
+
+    fun resetDecoder() {
+        spectrogram.reset()
+        channelTracker.reset()
+        bayesianDecoder.reset()
+        for (state in timingStates) {
+            state.isSignal = false
+            state.toneTicks = 0
+            state.gapTicks = 0
+        }
+        frameCount = 0
+        _decodedTextFlow.value = ""
+        _signalStrength.value = 0f
+        _estimatedPitch.value = null
+        _estimatedSpeed.value = null
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwDsp.kt

@@ -0,0 +1,102 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+import kotlin.math.PI
+import kotlin.math.cos
+import kotlin.math.sin
+import kotlin.math.sqrt
+
+/**
+ * DSP utilities for CW (Morse code) decoding.
+ * Pure Kotlin, no NDK required.
+ */
+internal object CwDsp {
+
+    /**
+     * Design a simple bandpass FIR filter coefficients using windowed sinc method.
+     * @param lowCutoff  lower cutoff frequency (Hz) as fraction of sampleRate
+     * @param highCutoff upper cutoff frequency (Hz) as fraction of sampleRate
+     * @param taps       filter length (must be odd)
+     */
+    fun bandpassFir(lowCutoff: Double, highCutoff: Double, taps: Int): FloatArray {
+        val n = if (taps % 2 == 0) taps + 1 else taps
+        val half = n / 2
+        val coeffs = FloatArray(n)
+        for (i in 0 until n) {
+            val idx = i - half
+            if (idx == 0) {
+                coeffs[i] = (2.0 * (highCutoff - lowCutoff)).toFloat()
+            } else {
+                val x = PI * idx
+                coeffs[i] = ((sin(2 * highCutoff * x) - sin(2 * lowCutoff * x)) / x).toFloat()
+            }
+            // Hamming window
+            coeffs[i] = (coeffs[i] * (0.54 - 0.46 * cos(2 * PI * i / (n - 1)))).toFloat()
+        }
+        // Normalize
+        val sum = coeffs.sum()
+        if (sum != 0f) for (i in 0 until n) coeffs[i] /= sum
+        return coeffs
+    }
+
+    /** Apply FIR filter to a buffer. */
+    fun applyFir(buffer: FloatArray, coeffs: FloatArray): FloatArray {
+        val out = FloatArray(buffer.size)
+        for (i in buffer.indices) {
+            var sum = 0f
+            for (j in coeffs.indices) {
+                val idx = i - j
+                if (idx >= 0) sum += buffer[idx] * coeffs[j]
+            }
+            out[i] = sum
+        }
+        return out
+    }
+
+    /** Simple envelope detector: abs + low-pass smoothing. */
+    fun envelope(signal: FloatArray, alpha: Float = 0.1f): FloatArray {
+        val env = FloatArray(signal.size)
+        var s = 0f
+        for (i in signal.indices) {
+            s = alpha * kotlin.math.abs(signal[i]) + (1 - alpha) * s
+            env[i] = s
+        }
+        return env
+    }
+
+    /** Estimate noise floor from envelope for adaptive thresholding. */
+    fun noiseFloor(env: FloatArray, fraction: Float = 0.3f): Float {
+        val sorted = env.sortedArray()
+        val median = sorted[sorted.size / 2]
+        return median + (sorted[sorted.size * 9 / 10] - median) * fraction
+    }
+
+    /** Simple Goertzel to detect a specific tone frequency. */
+    fun goertzel(buffer: FloatArray, targetFreq: Float, sampleRate: Int): Float {
+        val omega = 2.0 * PI * targetFreq / sampleRate
+        val coeff = 2.0 * cos(omega)
+        var s0 = 0.0; var s1 = 0.0; var s2 = 0.0
+        for (sample in buffer) {
+            s0 = sample.toDouble() + coeff * s1 - s2
+            s2 = s1; s1 = s0
+        }
+        val power = s2 * s2 + s1 * s1 - coeff * s1 * s2
+        return sqrt(kotlin.math.abs(power)).toFloat()
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwFFT.kt

@@ -0,0 +1,87 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+import kotlin.math.cos
+import kotlin.math.sqrt
+
+/**
+ * Radix-2 FFT for real-valued input.
+ * Produces magnitude spectrum for the first N/2+1 bins.
+ * Used by CwSpectrogram for time-frequency analysis.
+ */
+internal class CwFFT(private val n: Int) {
+    init {
+        require(n > 0 && n and (n - 1) == 0) { "FFT size must be power of 2, got $n" }
+    }
+
+    private val cosTable = FloatArray(n / 2)
+    private val sinTable = FloatArray(n / 2)
+
+    init {
+        for (i in 0 until n / 2) {
+            val angle = -2.0 * kotlin.math.PI * i / n
+            cosTable[i] = cos(angle).toFloat()
+            sinTable[i] = kotlin.math.sin(angle).toFloat()
+        }
+    }
+
+    /** Compute magnitude spectrum for real input. Returns array of size n/2+1. */
+    fun magnitudeSpectrum(input: FloatArray): FloatArray {
+        require(input.size == n) { "Input size must be $n, got ${input.size}" }
+
+        val real = input.copyOf()
+        val imag = FloatArray(n)
+
+        // Bit-reversal permutation
+        var j = 0
+        for (i in 1 until n) {
+            var bit = n shr 1
+            while (j and bit != 0) { j = j xor bit; bit = bit shr 1 }
+            j = j xor bit
+            if (i < j) {
+                var tmp = real[i]; real[i] = real[j]; real[j] = tmp
+            }
+        }
+
+        // Radix-2 Cooley-Tukey FFT
+        var len = 2
+        while (len <= n) {
+            val half = len / 2
+            val step = n / len
+            for (i in 0 until n step len) {
+                for (k in 0 until half) {
+                    val tReal = real[i + k + half] * cosTable[k * step] - imag[i + k + half] * sinTable[k * step]
+                    val tImag = real[i + k + half] * sinTable[k * step] + imag[i + k + half] * cosTable[k * step]
+                    real[i + k + half] = real[i + k] - tReal
+                    imag[i + k + half] = imag[i + k] - tImag
+                    real[i + k] += tReal
+                    imag[i + k] += tImag
+                }
+            }
+            len = len shl 1
+        }
+
+        // Magnitude spectrum (first N/2+1 bins)
+        val mag = FloatArray(n / 2 + 1)
+        for (i in 0..n / 2) {
+            mag[i] = sqrt(real[i] * real[i] + imag[i] * imag[i]) / n
+        }
+        return mag
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwFilter.kt

@@ -0,0 +1,48 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+/**
+ * First-order IIR filters.
+ * Ported from ggmorse/src/filter.h
+ */
+internal class CwFilter {
+    private var z1 = 0f
+
+    companion object {
+        private const val PI_F = 3.141592653589793f
+    }
+
+    fun highPass(sample: Float, cutoffHz: Float, sampleRate: Float): Float {
+        val rc = 1.0f / (2f * PI_F * cutoffHz)
+        val dt = 1.0f / sampleRate
+        val alpha = dt / (rc + dt)
+        z1 = alpha * (z1 + sample - z1)
+        return sample - z1
+    }
+
+    fun lowPass(sample: Float, cutoffHz: Float, sampleRate: Float): Float {
+        val rc = 1.0f / (2f * PI_F * cutoffHz)
+        val dt = 1.0f / sampleRate
+        val alpha = dt / (rc + dt)
+        z1 += alpha * (sample - z1)
+        return z1
+    }
+
+    fun reset() { z1 = 0f }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwGoertzel.kt

@@ -0,0 +1,54 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+import kotlin.math.cos
+import kotlin.math.sqrt
+
+/**
+ * Running Goertzel filter for CW tone detection.
+ * Tracks a specific frequency over time with a sliding window.
+ * Ported from ggmorse/src/goertzel.h
+ */
+internal class CwGoertzel {
+    private var s1 = 0.0
+    private var s2 = 0.0
+    private var coeff = 0.0
+
+    fun init(sampleRate: Float, targetFreq: Float) {
+        val omega = 2.0 * kotlin.math.PI * targetFreq / sampleRate
+        coeff = 2.0 * cos(omega)
+        s1 = 0.0
+        s2 = 0.0
+    }
+
+    fun process(sample: Float) {
+        val s0 = sample.toDouble() + coeff * s1 - s2
+        s2 = s1
+        s1 = s0
+    }
+
+    fun getPower(): Float {
+        return sqrt(s2 * s2 + s1 * s1 - coeff * s1 * s2).toFloat()
+    }
+
+    fun reset() {
+        s1 = 0.0
+        s2 = 0.0
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwResampler.kt

@@ -0,0 +1,53 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+/**
+ * Simple linear resampler.
+ * Downsamples from input sample rate to output sample rate.
+ * Ported from ggmorse/src/resampler.h
+ */
+internal class CwResampler(private val inputRate: Float, private val outputRate: Float) {
+    private val ratio = inputRate / outputRate
+    private var lastSample = 0f
+
+    fun process(input: FloatArray): FloatArray {
+        if (ratio <= 0f || input.isEmpty()) return input
+        val outputLen = (input.size / ratio).toInt() + 1
+        val output = FloatArray(outputLen)
+        var idx = 0f
+        for (i in output.indices) {
+            val intIdx = idx.toInt()
+            val frac = idx - intIdx
+            if (intIdx + 1 < input.size) {
+                output[i] = input[intIdx] * (1 - frac) + input[intIdx + 1] * frac
+            } else if (intIdx < input.size) {
+                output[i] = input[intIdx] * (1 - frac) + lastSample * frac
+            } else {
+                output[i] = lastSample
+            }
+            idx += ratio
+        }
+        lastSample = input.lastOrNull() ?: lastSample
+        return output
+    }
+
+    fun reset() {
+        lastSample = 0f
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwSTFFT.kt

@@ -0,0 +1,61 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+import kotlin.math.cos
+import kotlin.math.sin
+import kotlin.math.sqrt
+
+/**
+ * Lightweight pitch detector using DFT at specific frequency bins.
+ * Only scans [200, 1200] Hz in configurable steps — much faster than full FFT.
+ * Ported from ggmorse/src/stfft.h (simplified for CW use case).
+ */
+internal class CwPitchDetector(
+    private val sampleRate: Float,
+    private val minFreq: Float = 200f,
+    private val maxFreq: Float = 1200f,
+    private val stepHz: Float = 10f
+) {
+    /**
+     * Find the dominant pitch frequency in the buffer.
+     * Returns null if no significant pitch found.
+     */
+    fun findPitch(buffer: FloatArray): Float? {
+        if (buffer.isEmpty()) return null
+        var bestFreq = 0f
+        var bestPower = 0f
+        var freq = minFreq
+        while (freq <= maxFreq) {
+            var real = 0.0
+            var imag = 0.0
+            val omega = 2.0 * kotlin.math.PI * freq / sampleRate
+            for (i in buffer.indices) {
+                real += buffer[i] * cos(omega * i)
+                imag += buffer[i] * -sin(omega * i)
+            }
+            val power = (real * real + imag * imag).toFloat()
+            if (power > bestPower) {
+                bestPower = power
+                bestFreq = freq
+            }
+            freq += stepHz
+        }
+        return if (bestPower > 0.001f) bestFreq else null
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/cw/CwSpectrogram.kt

@@ -0,0 +1,170 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+/**
+ * Sliding-window spectrogram for CW decoding.
+ * Maintains a time-frequency matrix updated with each audio frame.
+ *
+ * FFT size: 256, hop size: 64, sample rate: 4000 (or native)
+ * Frequency bins: 6..38 (187-1187 Hz, covers typical CW range)
+ * History: 40 columns (320 ms window)
+ * Time resolution: 64/4000 = 16 ms, Frequency resolution: 4000/256 = 15.625 Hz
+ */
+internal class CwSpectrogram(
+    private val fftSize: Int = 256,
+    private val hopSize: Int = 64,
+    private val sampleRate: Int = 4000,
+    private val minBin: Int = 6,
+    private val maxBin: Int = 38,
+    val historyCols: Int = 40
+) {
+    private val fft = CwFFT(fftSize)
+    val numBins: Int get() = maxBin - minBin + 1
+
+    // Hanning window
+    private val hanning = FloatArray(fftSize) {
+        (0.5 - 0.5 * kotlin.math.cos(2.0 * kotlin.math.PI * it / (fftSize - 1))).toFloat()
+    }
+
+    // Spectrogram data: [timeCol][freqBin]
+    private val spectrogram = Array(historyCols) { FloatArray(numBins) }
+    private var currentCol = 0
+    private var samplesBuffered = 0
+    private val buffer = FloatArray(fftSize)
+
+    // Per-bin running energy for normalization
+    private val binEnergy = FloatArray(numBins) { 1f }
+    private val alpha = 0.95f
+
+    // Counter for new columns generated since last check
+    private var newColumnCount = 0
+
+    /** Add audio samples, compute FFTs for each complete hop. */
+    fun addSamples(samples: FloatArray) {
+        var offset = 0
+        while (offset < samples.size) {
+            val needed = fftSize - samplesBuffered
+            val copyLen = minOf(needed, samples.size - offset)
+            System.arraycopy(samples, offset, buffer, samplesBuffered, copyLen)
+            samplesBuffered += copyLen
+            offset += copyLen
+
+            if (samplesBuffered >= fftSize) {
+                processFrame()
+                newColumnCount++
+                // Shift buffer: keep last (fftSize - hopSize) samples
+                System.arraycopy(buffer, hopSize, buffer, 0, fftSize - hopSize)
+                samplesBuffered = fftSize - hopSize
+            }
+        }
+    }
+
+    /** Get number of new columns generated since the last call to this method. */
+    fun getNewColumns(): Int {
+        val count = newColumnCount
+        newColumnCount = 0
+        return count
+    }
+
+    private fun processFrame() {
+        // Apply Hanning window
+        val windowed = FloatArray(fftSize) { buffer[it] * hanning[it] }
+
+        // Compute FFT magnitude spectrum
+        val mag = fft.magnitudeSpectrum(windowed)
+
+        // Update spectrogram column
+        val col = spectrogram[currentCol]
+        for (b in 0 until numBins) {
+            val binIdx = minBin + b
+            val rawMag = mag[binIdx]
+            // Running energy normalization
+            binEnergy[b] = alpha * binEnergy[b] + (1 - alpha) * rawMag
+            col[b] = if (binEnergy[b] > 1e-6f) rawMag / binEnergy[b] else 0f
+        }
+
+        currentCol = (currentCol + 1) % historyCols
+    }
+
+    /** Get the current spectrogram as a 2D array in chronological order. */
+    fun getSpectrogram(): Array<FloatArray> {
+        val result = Array(historyCols) { i ->
+            val srcIdx = (currentCol + i) % historyCols
+            spectrogram[srcIdx].copyOf()
+        }
+        return result
+    }
+
+    /** Get the most recent column (current energy across all frequencies). */
+    fun getCurrentColumn(): FloatArray {
+        val prevCol = (currentCol - 1 + historyCols) % historyCols
+        return spectrogram[prevCol].copyOf()
+    }
+
+    /** Get a column by index from the history (0 = oldest, historyCols-1 = newest). */
+    fun getColumn(index: Int): FloatArray {
+        val clamped = index.coerceIn(0, historyCols - 1)
+        val srcIdx = (currentCol - historyCols + clamped + historyCols) % historyCols
+        return spectrogram[srcIdx].copyOf()
+    }
+
+    /** Find the frequency bin with peak energy. Returns -1 if no significant signal. */
+    fun findPeakBin(): Int {
+        val col = getCurrentColumn()
+        var maxBin = -1
+        var maxVal = 0f
+        for (i in col.indices) {
+            if (col[i] > maxVal) {
+                maxVal = col[i]
+                maxBin = i
+            }
+        }
+        return if (maxVal > 0.3f) maxBin else -1
+    }
+
+    /** Get energy at a specific bin over the last N columns in chronological order. */
+    fun getBinEnergy(bin: Int, numCols: Int): FloatArray {
+        val clamped = minOf(numCols, historyCols)
+        val result = FloatArray(clamped)
+        for (i in 0 until clamped) {
+            val colIdx = (currentCol - clamped + i + historyCols) % historyCols
+            result[i] = spectrogram[colIdx][bin]
+        }
+        return result
+    }
+
+    /** Get the bin index for a frequency in Hz. */
+    fun freqToBin(freqHz: Float): Int {
+        val bin = (freqHz * fftSize / sampleRate).toInt()
+        return (bin - minBin).coerceIn(0, numBins - 1)
+    }
+
+    /** Get the center frequency for a bin. */
+    fun binToFreq(bin: Int): Float {
+        return (minBin + bin).toFloat() * sampleRate / fftSize
+    }
+
+    fun reset() {
+        for (col in spectrogram) col.fill(0f)
+        currentCol = 0
+        samplesBuffered = 0
+        buffer.fill(0f)
+        binEnergy.fill(1f)
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/model/Settings.kt

@@ -27,6 +27,9 @@ data class PassesSettings(
     val showDeepSpace: Boolean = true,
     val hoursAhead: Int,
     val minElevation: Double,
+    val aosStartMinute: Int = 0,
+    val aosEndMinute: Int = 23 * 60 + 59,
+    val invertAosTimeWindow: Boolean = false,
     val selectedModes: List<String>
 )
 
@@ -54,8 +57,12 @@ data class OtherSettings(
     val stateOfSweep: Boolean,
     val stateOfUtc: Boolean,
     val stateOfLightTheme: Boolean,
+    val stateOfNightMode: Boolean = false,
     val shouldSeeWarning: Boolean,
-    val shouldSeeWhatsNew: Boolean
+    val shouldSeeWhatsNew: Boolean,
+    val sstvMode: String = "Auto",
+    val lowElevation: Double = 15.0,
+    val highElevation: Double = 45.0
 )
 
 data class DataSourcesSettings(
@@ -72,12 +79,20 @@ data class RadioControlSettings(
     val rxRadioAddress: String,
     val txRadioName: String,
     val rxRadioName: String,
-    val baudRate: Int
+    val baudRate: Int,
+    /** IC-705 only: use single-radio split-VFO mode instead of two radios. */
+    val splitMode: Boolean = false
 ) {
     companion object {
-        val SUPPORTED_RADIOS = listOf(
+        const val MODEL_YAESU_FT817   = "Yaesu FT-817/818"
-            "Yaesu FT-817/818",
+        const val MODEL_YAESU_FT857   = "Yaesu FT-857/897"
-            "Yaesu FT-857/897"
+        const val MODEL_ICOM_IC705    = "Icom IC-705"
-        )
+
+        val SUPPORTED_RADIOS = listOf(MODEL_YAESU_FT817, MODEL_YAESU_FT857, MODEL_ICOM_IC705)
+
+        /** Baud rates available for Yaesu radios. */
+        val BAUD_RATES_YAESU = listOf(4800, 9600, 38400)
+        /** Baud rates available for Icom IC-705 (higher speeds supported via CI-V USB/BT). */
+        val BAUD_RATES_ICOM  = listOf(4800, 9600, 19200, 38400, 57600, 115200)
     }
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/CelestialComputer.kt

@@ -0,0 +1,667 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.predict
+
+import com.rtbishop.look4sat.core.domain.utility.toDegrees
+import com.rtbishop.look4sat.core.domain.utility.toRadians
+import kotlin.math.PI
+import kotlin.math.abs
+import kotlin.math.acos
+import kotlin.math.asin
+import kotlin.math.atan
+import kotlin.math.atan2
+import kotlin.math.cos
+import kotlin.math.floor
+import kotlin.math.log10
+import kotlin.math.pow
+import kotlin.math.sin
+import kotlin.math.sqrt
+import kotlin.math.tan
+
+/**
+ * Standalone celestial computations extracted from PREDICT v2.2.5.
+ * Provides Sun position, Moon position, satellite visibility classification,
+ * orbital metadata, RA/Dec conversion, and rise/set finding for Sun and Moon.
+ *
+ * All angles are in degrees unless noted. Time is Unix epoch milliseconds.
+ *
+ * Shared math utilities (thetaGJD, modulus, mod2PI, deltaET, millisToDaynum,
+ * solarPositionECI, eciToGeodetic) live in OrbitalMath.kt in the same package.
+ */
+object CelestialComputer {
+
+    // ── Result types ──
+
+    /** Sun position as seen from a ground observer. */
+    data class SunPosition(
+        val azimuth: Double,         // degrees, 0=N, 90=E
+        val elevation: Double,       // degrees, >0 above horizon
+        val distance: Double,        // normalized: 1.0 + ((range - AU) / AU)
+        val rangeRate: Double,       // km/s
+        val latitude: Double,        // sub-solar point latitude, degrees
+        val longitude: Double,       // sub-solar point longitude, degrees
+        val rightAscension: Double,  // degrees
+        val declination: Double      // degrees
+    )
+
+    /** Moon position as seen from a ground observer. */
+    data class MoonPosition(
+        val azimuth: Double,         // degrees, 0=N, 90=E
+        val elevation: Double,       // degrees
+        val rightAscension: Double,  // degrees
+        val declination: Double,     // degrees
+        val gha: Double,             // Greenwich Hour Angle, degrees
+        val angularDiameter: Double, // apparent diameter relative to Earth's diameter
+        val radialVelocity: Double   // m/s, Doppler radial velocity for EME
+    )
+
+    /**
+     * 3-state satellite visibility classification.
+     * - [VISIBLE]: satellite is sunlit, observer is in darkness (sun below -12°) — optically visible
+     * - [DAYLIGHT]: satellite is sunlit, observer is in daylight
+     * - [ECLIPSED]: satellite is in Earth's shadow
+     */
+    enum class SatVisibility { VISIBLE, DAYLIGHT, ECLIPSED }
+
+    /** Orbital metadata not typically included in pass data. */
+    data class OrbitalMetadata(
+        val footprintDiameter: Double, // km, ground coverage circle diameter
+        val orbitNumber: Long,         // current orbit/revolution number
+        val betaAngle: Double,         // degrees, angle between orbital plane and Sun
+        val orbitalPhase: Double       // 0-256 phase within current orbit
+    )
+
+    // ── Sun position ──
+
+    /**
+     * Compute the Sun's full position as seen from [observer] at [timeMillis].
+     * Includes az/el, RA/Dec, sub-solar lat/lon, range, and range rate.
+     * Based on FindSun() from PREDICT v2.2.5.
+     */
+    fun getSunPosition(observer: GeoPos, timeMillis: Long): SunPosition {
+        val daynum = millisToDaynum(timeMillis)
+        val julUtc = daynum + 2444238.5
+        val sunVec = solarPositionECI(julUtc)
+        val zeroVel = doubleArrayOf(0.0, 0.0, 0.0)
+        val obsGeo = observerGeodetic(observer)
+
+        // Az, El, Range, RangeRate
+        val obsSet = computeObsAngles(julUtc, sunVec, zeroVel, obsGeo)
+
+        // Lat/Lon of sub-solar point
+        val latLon = eciToGeodetic(julUtc, sunVec)
+
+        // RA/Dec
+        val raDec = calculateRADec(julUtc, sunVec, zeroVel, obsGeo)
+
+        return SunPosition(
+            azimuth = obsSet[0].toDegrees(),
+            elevation = obsSet[1].toDegrees(),
+            distance = 1.0 + ((obsSet[2] - ASTRONOMICAL_UNIT) / ASTRONOMICAL_UNIT),
+            rangeRate = 1000.0 * obsSet[3],
+            latitude = latLon[0].toDegrees(),
+            longitude = latLon[1].toDegrees().let { if (it > 180.0) it - 360.0 else it },
+            rightAscension = raDec[0].toDegrees(),
+            declination = raDec[1].toDegrees()
+        )
+    }
+
+    // ── Moon position ──
+
+    /**
+     * Compute the Moon's position as seen from [observer] at [timeMillis].
+     * Full Meeus lunar ephemeris from PREDICT v2.2.5 with expanded terms
+     * and radial velocity approximation for EME Doppler.
+     */
+    fun getMoonPosition(observer: GeoPos, timeMillis: Long): MoonPosition {
+        val daynum = millisToDaynum(timeMillis)
+        val jd = daynum + 2444238.5
+        var t = (jd - 2415020.0) / 36525.0
+        val t2 = t * t
+        val t3 = t2 * t
+
+        var l1 = 270.434164 + 481267.8831 * t - 0.001133 * t2 + 0.0000019 * t3
+        var mSun = 358.475833 + 35999.0498 * t - 0.00015 * t2 - 0.0000033 * t3
+        var m1 = 296.104608 + 477198.8491 * t + 0.009192 * t2 + 0.0000144 * t3
+        var d = 350.737486 + 445267.1142 * t - 0.001436 * t2 + 0.0000019 * t3
+        var ff = 11.250889 + 483202.0251 * t - 0.003211 * t2 - 0.0000003 * t3
+        val om = (259.183275 - 1934.142 * t + 0.002078 * t2 + 0.0000022 * t3) * DEG2RAD
+
+        val correction512 = sin((51.2 + 20.2 * t) * DEG2RAD)
+        val ss = 0.003964 * sin((346.56 + 132.87 * t - 0.0091731 * t2) * DEG2RAD)
+        l1 += 0.000233 * correction512 + ss + 0.001964 * sin(om)
+        mSun -= 0.001778 * correction512
+        m1 += 0.000817 * correction512 + ss + 0.002541 * sin(om)
+        d += 0.002011 * correction512 + ss + 0.001964 * sin(om)
+        ff += ss - 0.024691 * sin(om) - 0.004328 * sin(om + (275.05 - 2.3 * t) * DEG2RAD)
+
+        val ex = 1.0 - 0.002495 * t - 0.00000752 * t2
+        l1 = primeAngle(l1); mSun = primeAngle(mSun); m1 = primeAngle(m1)
+        d = primeAngle(d); ff = primeAngle(ff)
+
+        val mR = mSun * DEG2RAD
+        val m1R = m1 * DEG2RAD
+        val dR = d * DEG2RAD
+        val ffR = ff * DEG2RAD
+
+        // Ecliptic longitude — expanded v225 terms
+        var l = l1 + 6.28875 * sin(m1R) + 1.274018 * sin(2 * dR - m1R) + 0.658309 * sin(2 * dR)
+        l += 0.213616 * sin(2 * m1R) - ex * 0.185596 * sin(mR) - 0.114336 * sin(2 * ffR)
+        l += 0.058793 * sin(2 * dR - 2 * m1R) + ex * 0.057212 * sin(2 * dR - mR - m1R) + 0.05332 * sin(2 * dR + m1R)
+        l += ex * 0.045874 * sin(2 * dR - mR) + ex * 0.041024 * sin(m1R - mR) - 0.034718 * sin(dR)
+        l -= ex * 0.030465 * sin(mR + m1R) + 0.015326 * sin(2 * dR - 2 * ffR) - 0.012528 * sin(2 * ffR + m1R)
+        l -= 0.01098 * sin(2 * ffR - m1R) + 0.010674 * sin(4 * dR - m1R) + 0.010034 * sin(3 * m1R)
+        l += 0.008548 * sin(4 * dR - 2 * m1R) - ex * 0.00791 * sin(mR - m1R + 2 * dR)
+        l -= ex * 0.006783 * sin(2 * dR + mR)
+        l += 0.005162 * sin(m1R - dR) + ex * 0.005 * sin(mR + dR) + ex * 0.004049 * sin(m1R - mR + 2 * dR)
+        l += 0.003996 * sin(2 * m1R + 2 * dR) + 0.003862 * sin(4 * dR) + 0.003665 * sin(2 * dR - 3 * m1R)
+        l += ex * 0.002695 * sin(2 * m1R - mR) + 0.002602 * sin(m1R - 2 * ffR - 2 * dR)
+        l += ex * 0.002396 * sin(2 * dR - mR - 2 * m1R)
+        l -= 0.002349 * sin(m1R + dR) + ex * ex * 0.002249 * sin(2 * dR - 2 * mR)
+        l -= ex * 0.002125 * sin(2 * m1R + mR)
+        l -= ex * ex * 0.002079 * sin(2 * mR) + ex * ex * 0.002059 * sin(2 * dR - m1R - 2 * mR)
+        l -= 0.001773 * sin(m1R + 2 * dR - 2 * ffR)
+        l += ex * 0.00122 * sin(4 * dR - mR - m1R) - 0.00111 * sin(2 * m1R + 2 * ffR) + 0.000892 * sin(m1R - 3 * dR)
+        l -= ex * 0.000811 * sin(mR + m1R + 2 * dR) + ex * 0.000761 * sin(4 * dR - mR - 2 * m1R)
+        l += ex * ex * 0.000717 * sin(m1R - 2 * mR)
+        l += ex * ex * 0.000704 * sin(m1R - 2 * mR - 2 * dR) + ex * 0.000693 * sin(mR - 2 * m1R + 2 * dR)
+        l += ex * 0.000598 * sin(2 * dR - mR - 2 * ffR) + 0.00055 * sin(m1R + 4 * dR)
+        l += 0.000538 * sin(4 * m1R) + ex * 0.000521 * sin(4 * dR - mR) + 0.000486 * sin(2 * m1R - dR)
+        l -= 0.001595 * sin(2 * ffR + 2 * dR)
+
+        // Ecliptic latitude — expanded v225 terms
+        var b =
+            5.128189 * sin(ffR) + 0.280606 * sin(m1R + ffR) + 0.277693 * sin(m1R - ffR) + 0.173238 * sin(2 * dR - ffR)
+        b += 0.055413 * sin(2 * dR + ffR - m1R) + 0.046272 * sin(2 * dR - ffR - m1R) + 0.032573 * sin(2 * dR + ffR)
+        b += 0.017198 * sin(2 * m1R + ffR) + 9.266999e-03 * sin(2 * dR + m1R - ffR) + 0.008823 * sin(2 * m1R - ffR)
+        b += ex * 0.008247 * sin(2 * dR - mR - ffR) + 0.004323 * sin(2 * dR - ffR - 2 * m1R)
+        b += 0.0042 * sin(2 * dR + ffR + m1R)
+        b += ex * 0.003372 * sin(ffR - mR - 2 * dR) + ex * 0.002472 * sin(2 * dR + ffR - mR - m1R)
+        b += ex * 0.002222 * sin(2 * dR + ffR - mR)
+        b += 0.002072 * sin(2 * dR - ffR - mR - m1R) + ex * 0.001877 * sin(ffR - mR + m1R)
+        b += 0.001828 * sin(4 * dR - ffR - m1R)
+        b -= ex * 0.001803 * sin(ffR + mR) - 0.00175 * sin(3 * ffR)
+        b += ex * 0.00157 * sin(m1R - mR - ffR) - 0.001487 * sin(ffR + dR)
+        b -= ex * 0.001481 * sin(ffR + mR + m1R) + ex * 0.001417 * sin(ffR - mR - m1R)
+        b += ex * 0.00135 * sin(ffR - mR) + 0.00133 * sin(ffR - dR)
+        b += 0.001106 * sin(ffR + 3 * m1R) + 0.00102 * sin(4 * dR - ffR) + 0.000833 * sin(ffR + 4 * dR - m1R)
+        b += 0.000781 * sin(m1R - 3 * ffR) + 0.00067 * sin(ffR + 4 * dR - 2 * m1R)
+        b += 0.000606 * sin(2 * dR - 3 * ffR)
+        b += 0.000597 * sin(2 * dR + 2 * m1R - ffR) + ex * 0.000492 * sin(2 * dR + m1R - mR - ffR)
+        b += 0.00045 * sin(2 * m1R - ffR - 2 * dR)
+        b += 0.000439 * sin(3 * m1R - ffR) + 0.000423 * sin(ffR + 2 * dR + 2 * m1R)
+        b += 0.000422 * sin(2 * dR - ffR - 3 * m1R)
+        b -= ex * 0.000367 * sin(mR + ffR + 2 * dR - m1R) - ex * 0.000353 * sin(mR + ffR + 2 * dR)
+        b += 0.000331 * sin(ffR + 4 * dR)
+        b += ex * 0.000317 * sin(2 * dR + ffR - mR + m1R) + ex * ex * 0.000306 * sin(2 * dR - 2 * mR - ffR)
+        b -= 0.000283 * sin(m1R + 3 * ffR)
+
+        val w1 = 0.0004664 * cos(om)
+        val w2 = 0.0000754 * cos(om + (275.05 - 2.3 * t) * DEG2RAD)
+        val bt = b * (1.0 - w1 - w2)
+
+        // Parallax — expanded v225 terms
+        var p =
+            0.950724 + 0.051818 * cos(m1R) + 0.009531 * cos(2 * dR - m1R) + 0.007843 * cos(2 * dR) + 0.002824 * cos(2 * m1R)
+        p += 0.000857 * cos(2 * dR + m1R) + ex * 0.000533 * cos(2 * dR - mR) + ex * 0.000401 * cos(2 * dR - mR - m1R)
+        p += 0.000173 * cos(3 * m1R) + 0.000167 * cos(4 * dR - m1R) - ex * 0.000111 * cos(mR)
+        p += 0.000103 * cos(4 * dR - 2 * m1R) - 0.000084 * cos(2 * m1R - 2 * dR) - ex * 0.000083 * cos(2 * dR + mR)
+        p += 0.000079 * cos(2 * dR + 2 * m1R)
+        p += 0.000072 * cos(4 * dR) + ex * 0.000064 * cos(2 * dR - mR + m1R) - ex * 0.000063 * cos(2 * dR + mR - m1R)
+        p += ex * 0.000041 * cos(mR + dR) + ex * 0.000035 * cos(2 * m1R - mR) - 0.000033 * cos(3 * m1R - 2 * dR)
+        p -= 0.00003 * cos(m1R + dR) - 0.000029 * cos(2 * ffR - 2 * dR) - ex * 0.000029 * cos(2 * m1R + mR)
+        p += ex * ex * 0.000026 * cos(2 * dR - 2 * mR) - 0.000023 * cos(2 * ffR - 2 * dR + m1R)
+        p += ex * 0.000019 * cos(4 * dR - mR - m1R)
+
+        val bRad = bt * DEG2RAD
+        val lm = l * DEG2RAD
+        val moonDx = 3.0 / (PI * p)
+
+        // Ecliptic → equatorial
+        val z = (jd - 2415020.5) / 365.2422
+        val ob = (23.452294 - (0.46845 * z + 5.9e-07 * z * z) / 3600.0).toRadians()
+        val dec = asin(sin(bRad) * cos(ob) + cos(bRad) * sin(ob) * sin(lm))
+        var ra = acos(cos(bRad) * cos(lm) / cos(dec)); if (lm > PI) ra = TWO_PI - ra
+
+        val n = observer.latitude * DEG2RAD
+        t = (jd - 2451545.0) / 36525.0
+        var teg = 280.46061837 + 360.98564736629 * (jd - 2451545.0) + (0.000387933 * t - t * t / 38710000.0) * t
+        while (teg > 360.0) teg -= 360.0
+        // LST = GMST + east longitude (positive east convention)
+        val th = mod2PI((teg + observer.longitude) * DEG2RAD)
+        val h = th - ra
+        val azVal = atan2(sin(h), cos(h) * sin(n) - tan(dec) * cos(n)) + PI
+        val el = asin(sin(n) * sin(dec) + cos(n) * cos(dec) * cos(h))
+
+        // Moon radial velocity approximation (from "Amateur Radio Software", GM4ANB, RSGB 1985)
+        val mm = fixAngle(1.319238 + daynum * 0.228027135)
+        val radT2 = 0.10976
+        val radT1 = mm + radT2 * sin(mm)
+        var dv = 0.01255 * moonDx * moonDx * sin(radT1) * (1.0 + radT2 * cos(mm))
+        dv *= 4449.0
+        val earthR = 6378.0
+        val moonDist = 384401.0
+        val radT3 = earthR * moonDist * (cos(dec) * cos(n) * sin(h)) /
+            sqrt(moonDist * moonDist - moonDist * earthR * sin(el))
+        val moonDv = dv + radT3 * 0.0753125
+
+        val moonRa = ra / DEG2RAD
+        var moonGha = teg - moonRa
+        if (moonGha < 0.0) moonGha += 360.0
+
+        return MoonPosition(
+            azimuth = azVal / DEG2RAD,
+            elevation = el / DEG2RAD,
+            rightAscension = moonRa,
+            declination = dec / DEG2RAD,
+            gha = moonGha,
+            angularDiameter = moonDx,
+            radialVelocity = moonDv
+        )
+    }
+
+    // ── Satellite visibility ──
+
+    /**
+     * Classify satellite visibility given its eclipse state and the Sun's elevation
+     * at the observer's location.
+     *
+     * @param isEclipsed whether the satellite is in Earth's shadow
+     * @param sunElevationDeg Sun elevation at observer in degrees
+     * @param satElevationDeg satellite elevation at observer in degrees (must be >= 0)
+     */
+    fun classifyVisibility(
+        isEclipsed: Boolean,
+        sunElevationDeg: Double,
+        satElevationDeg: Double
+    ): SatVisibility {
+        if (isEclipsed) return SatVisibility.ECLIPSED
+        return if (sunElevationDeg <= -12.0 && satElevationDeg >= 0.0) SatVisibility.VISIBLE
+        else SatVisibility.DAYLIGHT
+    }
+
+    // ── Orbital metadata ──
+
+    /**
+     * Compute orbital metadata for a satellite at its current position.
+     *
+     * @param altitudeKm satellite altitude in km
+     * @param meanMotion revolutions per day from TLE
+     * @param bstar drag term from TLE
+     * @param meanAnomaly mean anomaly at epoch (radians)
+     * @param revNumAtEpoch revolution number at TLE epoch
+     * @param ageDays days since TLE epoch (julUTC - julEpoch)
+     * @param phase orbital phase in radians (from SGP4/SDP4 output)
+     * @param satPosECI satellite ECI position [x, y, z]
+     * @param satVelECI satellite ECI velocity [vx, vy, vz]
+     * @param sunPosECI sun ECI position [x, y, z]
+     */
+    fun computeOrbitalMetadata(
+        altitudeKm: Double,
+        meanMotion: Double,
+        bstar: Double,
+        meanAnomaly: Double,
+        revNumAtEpoch: Int,
+        ageDays: Double,
+        phase: Double,
+        satPosECI: DoubleArray,
+        satVelECI: DoubleArray,
+        sunPosECI: DoubleArray
+    ): OrbitalMetadata {
+        // Footprint diameter (km)
+        val footprint = 12756.33 * acos(EARTH_RADIUS / (EARTH_RADIUS + altitudeKm))
+
+        // Orbit number
+        val xmnpda = 1.44E3
+        val orbitNum = floor(
+            (meanMotion * xmnpda / TWO_PI + ageDays * bstar) * ageDays + meanAnomaly / TWO_PI
+        ).toLong() + revNumAtEpoch
+
+        // Beta angle: angle between orbital plane and Sun direction
+        // Orbital plane normal = cross(pos, vel)
+        val nx = satPosECI[1] * satVelECI[2] - satPosECI[2] * satVelECI[1]
+        val ny = satPosECI[2] * satVelECI[0] - satPosECI[0] * satVelECI[2]
+        val nz = satPosECI[0] * satVelECI[1] - satPosECI[1] * satVelECI[0]
+        val nMag = sqrt(nx * nx + ny * ny + nz * nz)
+        val sMag = sqrt(sunPosECI[0] * sunPosECI[0] + sunPosECI[1] * sunPosECI[1] + sunPosECI[2] * sunPosECI[2])
+        val dotNS = nx * sunPosECI[0] + ny * sunPosECI[1] + nz * sunPosECI[2]
+        val betaAngle = if (nMag > 0 && sMag > 0) {
+            (PI / 2.0 - acos(dotNS / (nMag * sMag))).toDegrees()
+        } else 0.0
+
+        // Phase (0-256 scale, matching PREDICT convention)
+        val orbitalPhase = 256.0 * (phase / TWO_PI)
+
+        return OrbitalMetadata(footprint, orbitNum, betaAngle, orbitalPhase)
+    }
+
+    // ── Satellite status checks ──
+
+    /** Check if a satellite is geostationary (mean motion ≈ 1.0027 rev/day). */
+    fun isGeostationary(meanMotion: Double): Boolean = abs(meanMotion - 1.0027) < 0.0002
+
+    /**
+     * Check if a satellite has likely decayed based on drag and time since epoch.
+     *
+     * @param meanMotion revolutions per day
+     * @param drag first derivative of mean motion / 2 (from TLE line 1)
+     * @param epochDaynum TLE epoch as daynum (days since 31Dec79)
+     * @param currentDaynum current time as daynum
+     */
+    fun hasDecayed(meanMotion: Double, drag: Double, epochDaynum: Double, currentDaynum: Double): Boolean {
+        return epochDaynum + ((16.666666 - meanMotion) / (10.0 * abs(drag))) < currentDaynum
+    }
+
+    // ── Rise/Set finding ──
+
+    /** Rise and set times for a celestial body. */
+    data class RiseSetTimes(
+        val riseTimeMillis: Long,  // 0 if not found
+        val setTimeMillis: Long    // 0 if not found
+    )
+
+    /**
+     * Find the next sunrise and sunset times from [startMillis] for [observer].
+     * Uses elevation threshold of -0.8333° to match the standard civil definition:
+     * upper limb on geometric horizon with standard atmospheric refraction (~0.57°)
+     * and solar semidiameter (~0.27°) corrections applied, matching USNO/timeanddate.com.
+     */
+    fun findSunRiseSet(observer: GeoPos, startMillis: Long): RiseSetTimes {
+        // Standard civil threshold: center elevation when upper limb meets geometric horizon
+        // -0.8333° = standard refraction (~0.5667°) + solar semidiameter (~0.2667°)
+        val threshold = 0.8333
+        var daynum = millisToDaynum(startMillis)
+        var sunPos = getSunPosition(observer, daynumToMillis(daynum))
+
+        // Phase 1: if sun is above threshold, fast-forward to well past sunset into night
+        if (sunPos.elevation > -threshold) {
+            var guard = 0
+            while (sunPos.elevation > -threshold && guard++ < 500) {
+                daynum += 0.008  // fixed ~11.5 min steps past the setting sun
+                sunPos = getSunPosition(observer, daynumToMillis(daynum))
+            }
+            // Now advance until sun is clearly below minimum (deep night)
+            guard = 0
+            while (sunPos.elevation > -12.0 && guard++ < 500) {
+                daynum += 0.02
+                sunPos = getSunPosition(observer, daynumToMillis(daynum))
+            }
+        }
+
+        // Phase 2: advance until sun starts rising toward threshold (elevation increasing)
+        var guard = 0
+        while (sunPos.elevation < -threshold && guard++ < 500) {
+            daynum += 0.008
+            sunPos = getSunPosition(observer, daynumToMillis(daynum))
+        }
+
+        // Phase 3: converge symmetrically on elevation = -threshold (sunrise)
+        var sunrise = 0.0
+        guard = 0
+        while (sunrise == 0.0 && guard++ < 200) {
+            val delta = sunPos.elevation + threshold
+            if (abs(delta) < 0.01) {
+                sunrise = daynum
+            } else {
+                daynum -= 0.004 * delta
+                sunPos = getSunPosition(observer, daynumToMillis(daynum))
+            }
+        }
+        if (sunrise == 0.0) sunrise = daynum
+
+        // Phase 4: fast-forward through the day until sun drops back below threshold
+        daynum = sunrise
+        sunPos = getSunPosition(observer, daynumToMillis(daynum))
+        guard = 0
+        while (sunPos.elevation > -threshold && guard++ < 500) {
+            daynum += 0.008
+            sunPos = getSunPosition(observer, daynumToMillis(daynum))
+        }
+
+        // Phase 5: converge symmetrically on elevation = -threshold (sunset)
+        var sunset = 0.0
+        guard = 0
+        while (sunset == 0.0 && guard++ < 200) {
+            val delta = sunPos.elevation + threshold
+            if (abs(delta) < 0.01) {
+                sunset = daynum
+            } else {
+                daynum += 0.004 * delta
+                sunPos = getSunPosition(observer, daynumToMillis(daynum))
+            }
+        }
+        if (sunset == 0.0) sunset = daynum
+
+        return RiseSetTimes(daynumToMillis(sunrise), daynumToMillis(sunset))
+    }
+
+    /**
+     * Find the next moonrise and moonset times from [startMillis] for [observer].
+     * Uses the adaptive iteration from PREDICT v2.2.5's PredictMoon().
+     */
+    fun findMoonRiseSet(observer: GeoPos, startMillis: Long): RiseSetTimes {
+        var daynum = millisToDaynum(startMillis)
+        var moonPos = getMoonPosition(observer, daynumToMillis(daynum))
+
+        // If moon is already up, move forward until it sets
+        var guard = 0
+        if (moonPos.elevation > 0) {
+            while (moonPos.elevation > 0 && guard++ < 1000) {
+                daynum += 0.004 * sin(DEG2RAD * (moonPos.elevation + 0.5))
+                moonPos = getMoonPosition(observer, daynumToMillis(daynum))
+            }
+            daynum += 0.4
+            moonPos = getMoonPosition(observer, daynumToMillis(daynum))
+        }
+        // Find moonrise
+        var moonrise = 0.0
+        guard = 0
+        while (moonrise == 0.0 && guard++ < 1000) {
+            if (abs(moonPos.elevation) < 0.03) {
+                moonrise = daynum
+            } else {
+                daynum -= 0.004 * moonPos.elevation
+                moonPos = getMoonPosition(observer, daynumToMillis(daynum))
+            }
+        }
+        if (moonrise == 0.0) moonrise = daynum
+
+        // Find moonset from moonrise
+        daynum = moonrise
+        moonPos = getMoonPosition(observer, daynumToMillis(daynum))
+        guard = 0
+        while (moonPos.elevation > -1 && guard++ < 1000) {
+            daynum += 0.04 * cos(DEG2RAD * (moonPos.elevation + 0.5))
+            moonPos = getMoonPosition(observer, daynumToMillis(daynum))
+        }
+        var moonset = 0.0
+        guard = 0
+        while (moonset == 0.0 && guard++ < 1000) {
+            if (abs(moonPos.elevation) < 0.03) {
+                moonset = daynum
+            } else {
+                daynum += 0.004 * moonPos.elevation
+                moonPos = getMoonPosition(observer, daynumToMillis(daynum))
+            }
+        }
+        if (moonset == 0.0) moonset = daynum
+
+        return RiseSetTimes(daynumToMillis(moonrise), daynumToMillis(moonset))
+    }
+
+    // ── Visual magnitude estimation ──
+
+    /**
+     * Estimate the apparent visual magnitude of a satellite.
+     *
+     * Uses the standard formula from McCants/Heavens-Above:
+     *   apparentMag = stdMag + 5 * log10(range / 1000) - 15 * log10(cos(phaseAngle / 2))
+     *
+     * @param rangeKm slant range from observer to satellite in km
+     * @param phaseAngleDeg Sun-satellite-observer angle in degrees
+     * @param stdMag intrinsic/standard magnitude (default 4.0)
+     * @return estimated apparent visual magnitude
+     */
+    fun estimateVisualMagnitude(rangeKm: Double, phaseAngleDeg: Double, stdMag: Double = 4.0): Double {
+        if (rangeKm <= 0) return stdMag
+        val halfPhaseRad = phaseAngleDeg.toRadians() / 2.0
+        val cosHalfPhase = cos(halfPhaseRad)
+        val phaseTerm = if (cosHalfPhase > 1e-6) -15.0 * log10(cosHalfPhase) else 99.0
+        return stdMag + 5.0 * log10(rangeKm / 1000.0) + phaseTerm
+    }
+
+    /**
+     * Compute the phase angle (Sun-satellite-observer) in degrees.
+     *
+     * @param satPosECI satellite ECI position [x, y, z] in km
+     * @param sunPosECI sun ECI position [x, y, z] in km
+     * @param obsPosECI observer ECI position [x, y, z] in km
+     * @return phase angle in degrees (0 = fully illuminated face toward observer)
+     */
+    fun computePhaseAngle(satPosECI: DoubleArray, sunPosECI: DoubleArray, obsPosECI: DoubleArray): Double {
+        val toSunX = sunPosECI[0] - satPosECI[0]
+        val toSunY = sunPosECI[1] - satPosECI[1]
+        val toSunZ = sunPosECI[2] - satPosECI[2]
+        val toObsX = obsPosECI[0] - satPosECI[0]
+        val toObsY = obsPosECI[1] - satPosECI[1]
+        val toObsZ = obsPosECI[2] - satPosECI[2]
+        val dot = toSunX * toObsX + toSunY * toObsY + toSunZ * toObsZ
+        val magSun = sqrt(toSunX * toSunX + toSunY * toSunY + toSunZ * toSunZ)
+        val magObs = sqrt(toObsX * toObsX + toObsY * toObsY + toObsZ * toObsZ)
+        if (magSun == 0.0 || magObs == 0.0) return 90.0
+        val cosAngle = (dot / (magSun * magObs)).coerceIn(-1.0, 1.0)
+        return acos(cosAngle).toDegrees()
+    }
+
+    // ── Doppler ──
+
+    /**
+     * Compute Doppler shift for a given base frequency and range rate.
+     *
+     * @param frequencyHz base frequency in Hz
+     * @param rangeRateKmS range rate in km/s (negative = approaching)
+     * @return shifted frequency in Hz
+     */
+    fun dopplerShift(frequencyHz: Double, rangeRateKmS: Double): Double {
+        return frequencyHz * (299792.458 - rangeRateKmS) / 299792.458
+    }
+
+    // ── Internal helpers ──
+
+    private fun observerGeodetic(pos: GeoPos): DoubleArray {
+        // [lat_rad, lon_rad, alt_km] — longitude positive east, matching OrbitalObject convention.
+        // LST = thetaGJD(julUtc) + obsGeo[1] = GMST + lon_rad (correct).
+        return doubleArrayOf(pos.latitude * DEG2RAD, pos.longitude * DEG2RAD, pos.altitude / 1000.0)
+    }
+
+    /**
+     * Convert az/el observation to Right Ascension / Declination.
+     * Returns [ra_rad, dec_rad].
+     * Based on Calculate_RADec() from PREDICT v2.2.5 (Escobal method).
+     */
+    private fun calculateRADec(
+        julUtc: Double,
+        targetPos: DoubleArray,
+        targetVel: DoubleArray,
+        obsGeo: DoubleArray
+    ): DoubleArray {
+        val obsSet = computeObsAngles(julUtc, targetPos, targetVel, obsGeo)
+        val az = obsSet[0]
+        val el = obsSet[1]
+        val phi = obsGeo[0]
+        val theta = mod2PI(thetaGJD(julUtc) + obsGeo[1])
+        val sinTheta = sin(theta)
+        val cosTheta = cos(theta)
+        val sinPhi = sin(phi)
+        val cosPhi = cos(phi)
+        val lxh = -cos(az) * cos(el)
+        val lyh = sin(az) * cos(el)
+        val lzh = sin(el)
+        val sx = sinPhi * cosTheta
+        val ex2 = -sinTheta
+        val zx = cosTheta * cosPhi
+        val sy = sinPhi * sinTheta
+        val zy = sinTheta * cosPhi
+        val sz = -cosPhi
+        val lx = sx * lxh + ex2 * lyh + zx * lzh
+        val ly = sy * lxh + cosTheta * lyh + zy * lzh
+        val lz = sz * lxh + 0.0 * lyh + sinPhi * lzh
+        val dec = asin(lz)
+        val cosDelta = sqrt(1.0 - lz * lz)
+        val sinAlpha = ly / cosDelta
+        val cosAlpha = lx / cosDelta
+        val ra = mod2PI(atan2(sinAlpha, cosAlpha))
+        return doubleArrayOf(ra, dec)
+    }
+
+    /**
+     * Compute observer look-angles (az, el, range, rangeRate) to a target at ECI position.
+     * Returns [azimuth_rad, elevation_rad, range_km, rangeRate_km/s].
+     * Azimuth is north-referenced (0=N, π/2=E), matching OrbitalObject's convention.
+     */
+    private fun computeObsAngles(
+        julUtc: Double,
+        targetPos: DoubleArray,
+        targetVel: DoubleArray,
+        obsGeo: DoubleArray // [lat_rad, lon_rad, alt_km]
+    ): DoubleArray {
+        val theta = mod2PI(thetaGJD(julUtc) + obsGeo[1])
+        val c = 1.0 / sqrt(1 + FLAT_FACT * (FLAT_FACT - 2) * sin(obsGeo[0]).pow(2))
+        val sq = (1 - FLAT_FACT).pow(2) * c
+        val achcp = (EARTH_RADIUS * c + obsGeo[2]) * cos(obsGeo[0])
+        val ox = achcp * cos(theta)
+        val oy = achcp * sin(theta)
+        val oz = (EARTH_RADIUS * sq + obsGeo[2]) * sin(obsGeo[0])
+        val ovx = -MFACTOR * oy
+        val ovy = MFACTOR * ox
+
+        val rx = targetPos[0] - ox
+        val ry = targetPos[1] - oy
+        val rz = targetPos[2] - oz
+        val rMag = sqrt(rx * rx + ry * ry + rz * rz)
+        val rvx = targetVel[0] - ovx
+        val rvy = targetVel[1] - ovy
+        val rvz = targetVel[2]
+
+        val sinLat = sin(obsGeo[0])
+        val cosLat = cos(obsGeo[0])
+        val sinTheta = sin(theta)
+        val cosTheta = cos(theta)
+        val topS = sinLat * cosTheta * rx + sinLat * sinTheta * ry - cosLat * rz
+        val topE = -sinTheta * rx + cosTheta * ry
+        val topZ = cosLat * cosTheta * rx + cosLat * sinTheta * ry + sinLat * rz
+
+        // Match north-based convention (0=N, 90=E) used by OrbitalObject.calculateObs
+        // Must use atan(-topE / topS) not atan2(-topE, topS) — they differ in quadrant handling
+        var azim = atan(-topE / topS)
+        if (topS > 0.0) azim += PI
+        if (azim < 0.0) azim += TWO_PI
+        val el = asin(topZ / rMag)
+        val rangeRate = (rx * rvx + ry * rvy + rz * rvz) / rMag
+
+        return doubleArrayOf(azim, el, rMag, rangeRate)
+    }
+
+    private const val MFACTOR = 7.292115E-5
+
+    private fun primeAngle(x: Double) = x - 360.0 * floor(x / 360.0)
+
+    private fun fixAngle(x: Double): Double {
+        var a = x; while (a > TWO_PI) a -= TWO_PI; return a
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/Constants.kt

@@ -21,6 +21,7 @@ const val ASTRONOMICAL_UNIT = 1.49597870691E8
 const val DEG2RAD = 0.017453292519943295
 const val RAD2DEG = 57.29577951308232
 const val EARTH_RADIUS = 6378.137
+const val EARTH_ROT_PER_SID_DAY = 1.00273790934
 const val EPSILON = 1.0E-12
 const val FLAT_FACT = 3.35281066474748E-3
 const val J3_HARMONIC = -2.53881E-6

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/OrbitalData.kt

@@ -27,7 +27,8 @@ data class OrbitalData(
     val argper: Double,
     val meanan: Double,
     val catnum: Int,
-    val bstar: Double
+    val bstar: Double,
+    val ndot: Double = 0.0
 ) {
     val xincl: Double = incl * DEG2RAD
     val xnodeo: Double = raan * DEG2RAD
@@ -37,4 +38,29 @@ data class OrbitalData(
     val orbitalPeriod: Double = MIN_PER_DAY / meanmo
     val isDeepSpace: Boolean = orbitalPeriod >= 225.0 // NearEarth (period < 225 min) or DeepSpace (period >= 225 min)
     fun getObject(): OrbitalObject = if (isDeepSpace) DeepSpaceObject(this) else NearEarthObject(this)
+
+    /** Check if satellite has likely decayed by the given time. */
+    fun hasDecayed(currentTimeMillis: Long): Boolean {
+        if (ndot == 0.0) return false
+        val currentDaynum = (currentTimeMillis - 315446400000L) / 86400000.0
+        val epochDaynum = epochToDaynum(epoch)
+        return CelestialComputer.hasDecayed(meanmo, ndot, epochDaynum, currentDaynum)
+    }
+
+    private fun epochToDaynum(epoch: Double): Double {
+        var year = kotlin.math.floor(epoch * 1E-3)
+        val day = (epoch * 1E-3 - year) * 1000.0
+        year = if (year < 57) year + 2000 else year + 1900
+        // daynum = days since 31 Dec 1979, Julian date of 31Dec79 = 2444238.5
+        val jan1Jd = julianDateOfYear(year)
+        return jan1Jd + day - 2444238.5
+    }
+
+    private fun julianDateOfYear(theYear: Double): Double {
+        val aYear = theYear - 1
+        val a = kotlin.math.floor(aYear / 100).toLong()
+        val b = 2 - a + a / 4
+        val i = kotlin.math.floor(365.25 * aYear).toLong()
+        return i + (30.6001 * 14).toLong() + 1720994.5 + b
+    }
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/OrbitalMath.kt

@@ -0,0 +1,141 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.predict
+
+import kotlin.math.abs
+import kotlin.math.atan2
+import kotlin.math.cos
+import kotlin.math.floor
+import kotlin.math.sin
+import kotlin.math.sqrt
+
+// ── Shared orbital math utilities ──
+// Used by both CelestialComputer (sun/moon/celestial) and OrbitalObject (SGP4/SDP4).
+// Package-internal — not part of the public API.
+
+/**
+ * Greenwich Mean Sidereal Time from Julian Date, in radians [0, 2π).
+ * Identical algorithm used in PREDICT v2.2.5 for both solar and satellite calculations.
+ */
+internal fun thetaGJD(jd: Double): Double {
+    val ut = fraction(jd + 0.5)
+    val aJD = jd - ut
+    val tu = (aJD - 2451545.0) / 36525.0
+    var gmst = 24110.54841 + tu * (8640184.812866 + tu * (0.093104 - tu * 6.2E-6))
+    gmst = modulus(gmst + SEC_PER_DAY * EARTH_ROT_PER_SID_DAY * ut, SEC_PER_DAY)
+    return TWO_PI * gmst / SEC_PER_DAY
+}
+
+/** Fractional part of [arg]. */
+internal fun fraction(arg: Double): Double = arg - floor(arg)
+
+/** Modulo: returns [arg1] mod [arg2], result always in [0, arg2). */
+internal fun modulus(arg1: Double, arg2: Double): Double {
+    var r = arg1
+    val i = floor(r / arg2).toInt()
+    r -= i * arg2
+    if (r < 0.0) r += arg2
+    return r
+}
+
+/** Reduce [value] to [0, 2π). */
+internal fun mod2PI(value: Double): Double {
+    var r = value
+    val i = (r / TWO_PI).toInt()
+    r -= i * TWO_PI
+    if (r < 0.0) r += TWO_PI
+    return r
+}
+
+/**
+ * Delta-ET: difference between Universal Time and Ephemeris Time (seconds).
+ * Based on least-squares fit from 1950 to 1991 (PREDICT v2.2.5).
+ */
+internal fun deltaET(year: Double): Double =
+    26.465 + 0.747622 * (year - 1950) + 1.886913 * sin(TWO_PI * (year - 1975) / 33)
+
+/**
+ * Convert Unix epoch milliseconds to daynum (days since 31 Dec 1979 00:00:00 UTC).
+ */
+internal fun millisToDaynum(timeMillis: Long): Double =
+    (timeMillis - 315446400000L) / 86400000.0
+
+/** Convert daynum back to Unix epoch milliseconds. */
+internal fun daynumToMillis(daynum: Double): Long =
+    ((daynum + 3651.0) * 86400000.0).toLong()
+
+/**
+ * Compute the Sun's ECI position vector at [julUtc] (Julian UTC).
+ * Returns [x, y, z, magnitude] in km.
+ * Based on Calculate_Solar_Position() / FindSun() from PREDICT v2.2.5.
+ */
+internal fun solarPositionECI(julUtc: Double): DoubleArray {
+    val mjd = julUtc - 2415020.0
+    val year = 1900 + mjd / 365.25
+    val t = (mjd + deltaET(year) / SEC_PER_DAY) / 36525.0
+    val mDeg = mod360(358.47583 + mod360(35999.04975 * t) - (0.000150 + 0.0000033 * t) * t * t)
+    val m = mDeg * DEG2RAD
+    val lDeg = mod360(279.69668 + mod360(36000.76892 * t) + 0.0003025 * t * t)
+    val l = lDeg * DEG2RAD
+    val e = 0.01675104 - (0.0000418 + 0.000000126 * t) * t
+    val cDeg = (1.919460 - (0.004789 + 0.000014 * t) * t) * sin(m) +
+        (0.020094 - 0.000100 * t) * sin(2 * m) + 0.000293 * sin(3 * m)
+    val c = cDeg * DEG2RAD
+    val oDeg = mod360(259.18 - 1934.142 * t)
+    val o = oDeg * DEG2RAD
+    val lsa = mod2PI(l + c - (0.00569 - 0.00479 * sin(o)) * DEG2RAD)
+    val nu = mod2PI(m + c)
+    var r = 1.0000002 * (1.0 - e * e) / (1.0 + e * cos(nu))
+    val epsDeg = 23.452294 - (0.0130125 + (0.00000164 - 0.000000503 * t) * t) * t + 0.00256 * cos(o)
+    val eps = epsDeg * DEG2RAD
+    r *= ASTRONOMICAL_UNIT
+    return doubleArrayOf(r * cos(lsa), r * sin(lsa) * cos(eps), r * sin(lsa) * sin(eps), r)
+}
+
+/**
+ * Convert ECI position [eciPos] = [x, y, z] (km) to geodetic [lat_rad, lon_rad, alt_km].
+ * Based on Calculate_LatLonAlt() from PREDICT v2.2.5.
+ */
+internal fun eciToGeodetic(julUtc: Double, eciPos: DoubleArray): DoubleArray {
+    val thetaPos = atan2(eciPos[1], eciPos[0])
+    val lon = mod2PI(thetaPos - thetaGJD(julUtc))
+    val r = sqrt(eciPos[0] * eciPos[0] + eciPos[1] * eciPos[1])
+    val e2 = FLAT_FACT * (2.0 - FLAT_FACT)
+    var lat = atan2(eciPos[2], r)
+    var phi: Double
+    var c: Double
+    var i = 0
+    do {
+        phi = lat
+        c = 1.0 / sqrt(1.0 - e2 * sin(phi) * sin(phi))
+        lat = atan2(eciPos[2] + EARTH_RADIUS * c * e2 * sin(phi), r)
+    } while (i++ < 10 && abs(lat - phi) >= 1E-10)
+    val alt = r / cos(lat) - EARTH_RADIUS * c
+    if (lat > PI_2) lat -= TWO_PI
+    return doubleArrayOf(lat, lon, alt)
+}
+
+// Private helpers
+
+private fun mod360(x: Double): Double {
+    var r = x
+    val i = (r / 360.0).toInt()
+    r -= i * 360.0
+    if (r < 0.0) r += 360.0
+    return r
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/OrbitalObject.kt

@@ -314,14 +314,8 @@ abstract class OrbitalObject(val data: OrbitalData) {
         return 1.0 / value
     }
 
-    // Calculates the modulus of 2 * PI
+    // Delegates to package-level mod2PI in OrbitalMath.kt
-    internal fun mod2PI(value: Double): Double {
+    internal fun mod2PI(value: Double): Double = com.rtbishop.look4sat.core.domain.predict.mod2PI(value)
-        var retVal = value
-        val i = (retVal / TWO_PI).toInt()
-        retVal -= i * TWO_PI
-        if (retVal < 0.0) retVal += TWO_PI
-        return retVal
-    }
 
     // Solves Keplers' Equation
     internal fun converge(temp: DoubleArray, axn: Double, ayn: Double, capu: Double) {
@@ -423,19 +417,8 @@ abstract class OrbitalObject(val data: OrbitalData) {
         return acos(dot(v1, v2) / (v1.w * v2.w))
     }
 
-    /**
+    // Delegates to package-level deltaET in OrbitalMath.kt
-     * The function Delta_ET has been added to allow calculations on the
+    private fun deltaEt(year: Double): Double = deltaET(year)
-     * position of the sun. It provides the difference between UT (approximately
-     * the same as UTC) and ET (now referred to as TDT) This function is based
-     * on the least squares fit of data from 1950 to 1991 and will need to be
-     * updated periodically.
-     *
-     * Values determined using data from 1950-1991 in the 1990 Astronomical
-     * Almanac. See DELTA_ET.WQ1 for details.
-     */
-    private fun deltaEt(year: Double): Double {
-        return 26.465 + 0.747622 * (year - 1950) + (1.886913 * sin(TWO_PI * (year - 1975) / 33))
-    }
 
     private fun radians(degrees: Double): Double {
         return degrees * DEG2RAD
@@ -446,23 +429,13 @@ abstract class OrbitalObject(val data: OrbitalData) {
         return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z
     }
 
-    // Returns fractional part of double argument
-    private fun fraction(arg: Double): Double {
-        return arg - floor(arg)
-    }
-
     // Calculates scalar magnitude of a vector4 argument
     private fun magnitude(v: Vector4) {
         v.w = sqrt(sqr(v.x) + sqr(v.y) + sqr(v.z))
     }
 
-    private fun modulus(arg1: Double, arg2: Double = SEC_PER_DAY): Double {
+    private fun modulus(arg1: Double, arg2: Double = SEC_PER_DAY): Double =
-        var returnValue = arg1
+        com.rtbishop.look4sat.core.domain.predict.modulus(arg1, arg2)
-        val i = floor(returnValue / arg2).toInt()
-        returnValue -= i * arg2
-        if (returnValue < 0.0) returnValue += arg2
-        return returnValue
-    }
 
     // Multiplies the vector v1 by the scalar k
     private fun scaleVector(k: Double, v: Vector4) {
@@ -470,13 +443,6 @@ abstract class OrbitalObject(val data: OrbitalData) {
         magnitude(v)
     }
 
-    private fun thetaGJD(theJD: Double): Double {
+    // Delegates to package-level thetaGJD in OrbitalMath.kt
-        val earthRotPerSidDay = 1.00273790934
+    private fun thetaGJD(theJD: Double): Double = com.rtbishop.look4sat.core.domain.predict.thetaGJD(theJD)
-        val ut = fraction(theJD + 0.5)
-        val aJD = theJD - ut
-        val tu = (aJD - 2451545.0) / 36525.0
-        var gmst = 24110.54841 + tu * (8640184.812866 + tu * (0.093104 - tu * 6.2E-6))
-        gmst = modulus(gmst + SEC_PER_DAY * earthRotPerSidDay * ut)
-        return TWO_PI * gmst / SEC_PER_DAY
-    }
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/OrbitalPass.kt

@@ -25,9 +25,10 @@ data class OrbitalPass(
     val altitude: Int = 1000,
     val maxElevation: Double = 75.0,
     val orbitalObject: OrbitalObject,
-    val progress: Float = 0.0f
+    val progress: Float = 0.0f,
+    val hasDecayed: Boolean = false
 ) {
     val catNum: Int = orbitalObject.data.catnum
-    val name: String = orbitalObject.data.name
+    val name: String = if (hasDecayed) "${orbitalObject.data.name} (decayed?)" else orbitalObject.data.name
     val isDeepSpace: Boolean = orbitalObject.data.isDeepSpace
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/predict/OrbitalPos.kt

@@ -63,10 +63,8 @@ data class OrbitalPos(
         val sinBeta = sin(beta)
         for (azimuth in 0..720) {
             val rads = azimuth * DEG2RAD
-            val sinRads = sin(rads)
+            val lat = asin(sinLat * cosBeta + cosLat * sinBeta * cos(rads))
-            val cosRads = cos(rads)
+            val lon = longitude + atan2(sin(rads) * sinBeta * cosLat, cosBeta - sinLat * sin(lat))
-            val lat = asin(sinLat * cosBeta + cosLat * sinBeta * cosRads)
-            val lon = longitude + atan2(sinRads * sinBeta * cosLat, cosBeta - sinLat * sin(lat))
             rangeCirclePoints.add(GeoPos(lat * RAD2DEG, lon * RAD2DEG))
         }
         return rangeCirclePoints

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/IDatabaseRepo.kt

@@ -18,8 +18,8 @@
 package com.rtbishop.look4sat.core.domain.repository
 
 interface IDatabaseRepo {
-    suspend fun updateTLEFromFile(uri: String)
+    suspend fun updateTLEFromFile(uri: String): Int
-    suspend fun updateTransceiversFromFile(uri: String)
+    suspend fun updateTransceiversFromFile(uri: String): Int
     suspend fun updateFromRemote()
     suspend fun clearAllData()
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/IMainContainer.kt

@@ -1,8 +1,28 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 package com.rtbishop.look4sat.core.domain.repository
-
+import com.rtbishop.look4sat.core.domain.model.SatRadio
 import com.rtbishop.look4sat.core.domain.usecase.IAddToCalendar
+import com.rtbishop.look4sat.core.domain.usecase.IAudioCapture
+import com.rtbishop.look4sat.core.domain.usecase.ISaveImage
 import com.rtbishop.look4sat.core.domain.usecase.IShowToast
 import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.flow.StateFlow
 
 interface IMainContainer {
     val appScope: CoroutineScope
@@ -10,6 +30,9 @@ interface IMainContainer {
     val selectionRepo: ISelectionRepo
     val satelliteRepo: ISatelliteRepo
     val databaseRepo: IDatabaseRepo
+    val radioTrackingService: IRadioTrackingService
+    val mutualPassData: StateFlow<MutualPassData>
+    fun setMutualPassData(data: MutualPassData)
     fun provideAddToCalendar(): IAddToCalendar
     fun provideShowToast(): IShowToast
     fun provideBluetoothReporter(): IReporter
@@ -17,9 +40,29 @@ interface IMainContainer {
     fun provideSensorsRepo(): ISensorsRepo
     fun provideTxRadioController(): IRadioController
     fun provideRxRadioController(): IRadioController
-    val radioTrackingService: IRadioTrackingService
+    fun provideAudioCapture(): IAudioCapture
+    fun provideSaveImage(): ISaveImage
 }
 
+data class MutualPassData(
+    val samples: List<Pair<Long, Pair<Double, Double>>> = emptyList(),
+    val trackSamples: List<TrackSampleData> = emptyList(),
+    val startTime: Long = 0L,
+    val endTime: Long = 0L,
+    val maxElev: Double = 10.0,
+    val labelA: String = "你",
+    val labelB: String = "友台"
+)
+
+/** Minimal track sample for cross-module sharing (angles in degrees). */
+data class TrackSampleData(
+    val time: Long = 0L,
+    val azimuthA: Double,
+    val elevationA: Double,
+    val azimuthB: Double,
+    val elevationB: Double
+)
+
 interface IContainerProvider {
     fun getMainContainer(): IMainContainer
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/IRadioController.kt

@@ -38,4 +38,51 @@ interface IRadioController {
     suspend fun pttOn(): Boolean
 
     suspend fun pttOff(): Boolean
+
+    // ── Extended operations (IC-705 / CI-V) ──────────────────────────────
+
+    /**
+     * Select the band matching [frequencyHz] via the band stacking register.
+     * Must be called before [setFrequency] and [setMode] when first tracking.
+     * Default: no-op (Yaesu radios auto-switch band via frequency).
+     */
+    suspend fun setBand(frequencyHz: Long): Boolean = false
+
+    /**
+     * Select the active VFO.
+     * @param vfoA true → VFO-A (main/RX), false → VFO-B (sub/TX in split).
+     */
+    suspend fun setVfo(vfoA: Boolean): Boolean = false
+
+    /**
+     * Enable or disable SPLIT mode (TX on sub-VFO, RX on main VFO).
+     * Default: not supported.
+     */
+    suspend fun setSplitMode(enabled: Boolean): Boolean = false
+
+    /**
+     * Set the frequency of the currently active VFO (IC-705: CMD 0x25 sub 0x00).
+     * Default: delegates to [setFrequency].
+     */
+    suspend fun setWorkingFrequency(frequencyHz: Long): Boolean = setFrequency(frequencyHz)
+
+    /**
+     * Set the frequency of the inactive/TX VFO (IC-705: CMD 0x25 sub 0x01).
+     * Sent every tracking cycle alongside [setWorkingFrequency] in split mode.
+     * Default: delegates to [setWorkingFrequency].
+     */
+    suspend fun setTxVfoFrequency(frequencyHz: Long): Boolean = setWorkingFrequency(frequencyHz)
+
+    /**
+     * Read the frequency of the currently active VFO (IC-705: CMD 0x25 sub 0x00).
+     * Default: delegates to [readFrequencyAndMode].
+     */
+    suspend fun readWorkingFrequency(): Long? = readFrequencyAndMode()?.first
+
+    /**
+     * Read the frequency of the inactive/TX VFO (IC-705: CMD 0x25 sub 0x01).
+     * Used for tuning detection in split mode.
+     * Default: delegates to [readWorkingFrequency].
+     */
+    suspend fun readTxVfoFrequency(): Long? = readWorkingFrequency()
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ISatelliteRepo.kt

@@ -34,11 +34,25 @@ interface ISatelliteRepo {
     /** Whether the repo is currently calculating passes. */
     val isCalculating: StateFlow<Boolean>
 
+    /** Currently selected pass (catNum + aosTime), persisted across screen navigations. */
+    val selectedPass: StateFlow<Pair<Int, Long>>
+
+    /** Set the currently selected pass. */
+    fun selectPass(catNum: Int, aosTime: Long)
+
     /** Load satellite objects from DB based on the current selection. */
     suspend fun initRepository()
 
     /** Recalculate passes with the given filter parameters. */
-    suspend fun calculatePasses(time: Long, hoursAhead: Int, minElevation: Double, modes: List<String>)
+    suspend fun calculatePasses(
+        time: Long,
+        hoursAhead: Int,
+        minElevation: Double,
+        aosStartMinute: Int,
+        aosEndMinute: Int,
+        invertAosTimeWindow: Boolean,
+        modes: List<String>
+    )
 
     /** Get the current position of a single satellite. */
     suspend fun getPosition(sat: OrbitalObject, pos: GeoPos, time: Long): OrbitalPos

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/repository/ISensorsRepo.kt

@@ -21,7 +21,7 @@ import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import kotlinx.coroutines.flow.StateFlow
 
 interface ISensorsRepo {
-    val orientation: StateFlow<Pair<Float, Float>>
+    val sensorData: StateFlow<Pair<Float, Float>>
     fun getMagDeclination(geoPos: GeoPos, time: Long = System.currentTimeMillis()): Float
     fun enableSensor()
     fun disableSensor()

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/source/Sources.kt

@@ -18,7 +18,6 @@
 package com.rtbishop.look4sat.core.domain.source
 
 object Sources {
-    const val RADIO_DATA_URL = "https://db.satnogs.org/api/transmitters/?format=json&status=active"
     val satelliteDataUrls = mapOf(
         "All" to "https://celestrak.org/NORAD/elements/gp.php?GROUP=active&FORMAT=csv",
         "Amateur" to "https://celestrak.org/NORAD/elements/gp.php?GROUP=amateur&FORMAT=csv",
@@ -49,4 +48,7 @@ object Sources {
         "R4UAB" to "https://r4uab.ru/satonline.txt",
         "Other" to "" // key for sats filter
     )
+    val transceiversDataUrls = mapOf(
+        "SatNOGS" to "https://db.satnogs.org/api/transmitters/?format=json&status=active"
+    )
 }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/sstv/SstvDecoder.kt

@@ -0,0 +1,816 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.sstv
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.channels.BufferOverflow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.SharedFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.withContext
+import kotlin.math.PI
+import kotlin.math.abs
+import kotlin.math.round
+import kotlin.math.sqrt
+
+class SstvFrame(
+    val scopePixels: IntArray?,
+    val scopeWidth: Int,
+    val scopeHeight: Int,
+    val imagePixels: IntArray?,
+    val imageWidth: Int,
+    val imageHeight: Int,
+    val modeName: String,
+    val imageComplete: Boolean,
+    val inputRms: Float,
+    val appliedGain: Float,
+    val syncHitRate: Float,
+    val predictedLineBursts: Int,
+    val maxPredictedStreak: Int,
+    val timingErrorSamples: Int
+)
+
+/**
+ * Decoder quality metrics for diagnostics and logging. Useful for profiling decode
+ * performance on noisy recordings.
+ */
+data class SstvQualityMetrics(
+    val syncHitRate: Float,
+    val predictedLineBursts: Int,
+    val maxPredictedStreak: Int,
+    val timingErrorSamples: Int
+)
+
+enum class LineRecoveryStrategy {
+    Look4SatLimited,
+    Robot36Compatible
+}
+
+class SstvDiagnosticsHandle internal constructor(
+    val enabled: Boolean,
+    val metrics: StateFlow<SstvQualityMetrics?>
+)
+
+class SstvDecoder(
+    sampleRate: Int = 44100,
+    scopeWidth: Int = 320,
+    scopeHeight: Int = 256,
+    private val channelSelect: Int = 0,
+    targetRmsLevel: Float = 0.25f,
+    private val includeScopeData: Boolean = false,
+    private val enableRmsNormalization: Boolean = true,
+    preFilterCutoffHz: Double = 500.0,
+    enablePreFilter: Boolean = true,
+    private val enableDiagnosticsHandle: Boolean = false,
+    lineRecoveryStrategy: LineRecoveryStrategy = LineRecoveryStrategy.Look4SatLimited
+) {
+    private val scopeBuffer = PixelBuffer(scopeWidth, scopeHeight * 2)
+    private val imageBuffer = PixelBuffer(scopeWidth, scopeHeight)
+    private val decoder = DecoderEngine(scopeBuffer, imageBuffer, "Raw", sampleRate, lineRecoveryStrategy)
+    private val _frames = MutableSharedFlow<SstvFrame>(
+        replay = 1,
+        onBufferOverflow = BufferOverflow.DROP_OLDEST
+    )
+    private var lastInputRms = 0f
+    private var lastAppliedGain = 1f
+    private val _qualityMetrics = MutableStateFlow<SstvQualityMetrics?>(null)
+    private val preFilter = if (enablePreFilter) HighPassFilter(preFilterCutoffHz, sampleRate.toDouble()) else null
+    private val diagnosticsHandle = SstvDiagnosticsHandle(enableDiagnosticsHandle, _qualityMetrics)
+    val frames: SharedFlow<SstvFrame> = _frames
+    val supportedModes: List<String> = decoder.allModes.map { it.name }
+
+    suspend fun feedSamples(samples: FloatArray) = withContext(Dispatchers.Default) {
+        // Optional pre-filtering: remove DC offset and subsonic noise that can mask
+        // weak signals and corrupt the RMS normalization baseline.
+        preFilter?.apply(samples)
+
+        // Optional RMS normalization: bring input to a consistent level so the
+        // FM demodulator operates in a predictable region. However, this amplifies
+        // noise proportionally. Aggressive RMS targets (e.g., 0.25) can hurt weak
+        // signals by boosting noise floor. Safer defaults: 0.35-0.50 for noisy inputs.
+        // Disable entirely for direct line-level inputs (e.g., receiver discriminator).
+        val gain = if (enableRmsNormalization) normalise(samples) else GainInfo(0f, 1f)
+        lastInputRms = gain.inputRms
+        lastAppliedGain = gain.appliedGain
+        val hasNewLines = decoder.process(samples, channelSelect)
+        if (hasNewLines) emitFrame()
+    }
+
+    fun lockMode(modeName: String) = decoder.setMode(modeName)
+
+    fun clearPixels() {
+        imageBuffer.line = -1
+        imageBuffer.pixels.fill(0)
+        decoder.resetQuality()
+        if (enableDiagnosticsHandle) _qualityMetrics.value = null
+    }
+
+    fun getDiagnosticsHandle(): SstvDiagnosticsHandle? = diagnosticsHandle.takeIf { it.enabled }
+
+    /**
+     * Export quality metrics for logging/diagnostics. Useful for profiling decode
+     * performance on noisy recordings. Returns null before first frame is emitted.
+     */
+    @Suppress("unused")
+    fun getQualityMetrics(): SstvQualityMetrics? {
+        if (enableDiagnosticsHandle) return _qualityMetrics.value
+        val q = decoder.quality()
+        return SstvQualityMetrics(
+            syncHitRate = q.syncHitRate,
+            predictedLineBursts = q.predictedLineBursts,
+            maxPredictedStreak = q.maxPredictedStreak,
+            timingErrorSamples = q.timingErrorSamples
+        )
+    }
+
+    private fun emitFrame() {
+        val imageWidth = imageBuffer.width
+        val imageHeight = imageBuffer.height
+        val quality = decoder.quality()
+        if (enableDiagnosticsHandle) {
+            _qualityMetrics.value = SstvQualityMetrics(
+                syncHitRate = quality.syncHitRate,
+                predictedLineBursts = quality.predictedLineBursts,
+                maxPredictedStreak = quality.maxPredictedStreak,
+                timingErrorSamples = quality.timingErrorSamples
+            )
+        }
+        val imageComplete = imageBuffer.line >= imageHeight && imageBuffer.line > 0
+        // Copy only the active image region — imageBuffer.pixels is pre-allocated
+        // at the maximum possible size (PD-290: 800×616), so we must not copyOf()
+        // the entire array and send padding pixels to the observer.
+        val imagePixels = if (imageBuffer.line > 0) imageBuffer.pixels.copyOf(imageWidth * imageHeight) else null
+        val modeName = decoder.currentMode.name
+        val scopePixels = if (includeScopeData) scopeBuffer.pixels.copyOf() else null
+        val scopeWidth = if (includeScopeData) scopeBuffer.width else 0
+        val scopeHeight = if (includeScopeData) scopeBuffer.height else 0
+        _frames.tryEmit(
+            SstvFrame(
+                scopePixels = scopePixels,
+                scopeWidth = scopeWidth,
+                scopeHeight = scopeHeight,
+                imagePixels = imagePixels,
+                imageWidth = imageWidth,
+                imageHeight = imageHeight,
+                modeName = modeName,
+                imageComplete = imageComplete,
+                inputRms = lastInputRms,
+                appliedGain = lastAppliedGain,
+                syncHitRate = quality.syncHitRate,
+                predictedLineBursts = quality.predictedLineBursts,
+                maxPredictedStreak = quality.maxPredictedStreak,
+                timingErrorSamples = quality.timingErrorSamples
+            )
+        )
+    }
+
+    // Target RMS level for the normalizer. 0.25 leaves headroom while keeping the
+    // FM demodulator well above its noise floor regardless of input gain.
+    // TUNING GUIDE:
+    //   - 0.20-0.25: Aggressive, best for clean direct-coupled inputs, worst for mic noise
+    //   - 0.35-0.40: Moderate, good balance for typical phone/mic inputs (RECOMMENDED)
+    //   - 0.50-0.60: Conservative, best for noisy environments, reduces amplitude resolution
+    // Disable RMS normalization entirely if using a professional receiver discriminator output.
+    private val targetRms = targetRmsLevel.coerceIn(0.05f, 0.8f)
+
+    private class GainInfo(
+        val inputRms: Float,
+        val appliedGain: Float
+    )
+
+    // Bring the buffer to a fixed RMS so that microphone and direct-coupled inputs
+    // both decode reliably. The guard prevents amplifying pure silence into noise.
+    private fun normalise(buffer: FloatArray): GainInfo {
+        var sumSq = 0f
+        for (s in buffer) sumSq += s * s
+        val rms = sqrt(sumSq / buffer.size)
+        if (rms > 1e-6f) {
+            val gain = targetRms / rms
+            for (i in buffer.indices) buffer[i] *= gain
+            return GainInfo(rms, gain)
+        }
+        return GainInfo(rms, 1f)
+    }
+}
+
+/**
+ * Simple high-pass filter to remove DC offset and subsonic interference before RMS
+ * normalization. Improves noise floor estimation and prevents low-freq noise from
+ * corrupting the gain calculation.
+ *
+ * Design: First-order butterworth (pole at cutoff frequency). Fast, minimal latency,
+ * suitable for real-time preprocessing.
+ */
+internal class HighPassFilter(cutoffHz: Double, sampleRateHz: Double) {
+    private val alpha: Float
+    private var prevInput = 0f
+    private var prevOutput = 0f
+
+    init {
+        // First-order pole placement: alpha = wc / (wc + ws) where wc = 2*pi*fc, ws = 2*pi*fs
+        val omega = 2f * PI.toFloat() * (cutoffHz / sampleRateHz).toFloat()
+        alpha = omega / (omega + 1f)
+    }
+
+    fun apply(buffer: FloatArray) {
+        for (i in buffer.indices) {
+            val input = buffer[i]
+            prevOutput = alpha * (prevOutput + input - prevInput)
+            buffer[i] = prevOutput
+            prevInput = input
+        }
+    }
+}
+
+internal class DecoderQuality(
+    val syncHitRate: Float,
+    val predictedLineBursts: Int,
+    val maxPredictedStreak: Int,
+    val timingErrorSamples: Int
+)
+
+internal enum class SyncPulseWidth { FiveMs, NineMs, TwentyMs }
+
+internal class SyncPulseDetector(sampleRate: Int) {
+
+    companion object {
+        const val SYNC_FREQ = 1200.0
+        const val BLACK_FREQ = 1500.0
+        const val WHITE_FREQ = 2300.0
+    }
+
+    var detectedWidth: SyncPulseWidth = SyncPulseWidth.NineMs; private set
+    var pulseOffset: Int = 0; private set
+    var freqOffset: Float = 0f; private set
+
+    private val bandwidth = WHITE_FREQ - BLACK_FREQ
+    private val fm = FmDemodulator(bandwidth, sampleRate.toDouble())
+    private val min5ms: Int = round(0.0025 * sampleRate).toInt()
+    private val max5ms: Int = round(0.007 * sampleRate).toInt()
+    private val max9ms: Int = round(0.0145 * sampleRate).toInt()
+    private val max20ms: Int = round(0.025 * sampleRate).toInt()
+    private val filterDelay: Int
+    private val avgFilter: MovingAverage
+    private val delayLine: Delay
+    private val lowPass: ComplexFirFilter
+    private val oscillator: Phasor
+    private val syncFreqValue: Float
+    private val syncFreqTolerance: Float
+    private val trigger: SchmittTrigger
+    private var counter = 0
+    private var baseBand = Complex()
+
+    init {
+        val filterLen = round(0.0025 * sampleRate).toInt() or 1
+        filterDelay = (filterLen - 1) / 2
+        avgFilter = MovingAverage(filterLen)
+        delayLine = Delay(filterLen)
+        val loFreq = 1000.0
+        val hiFreq = 2800.0
+        val cutoff = (hiFreq - loFreq) / 2
+        val lpLen = round(0.002 * sampleRate).toInt() or 1
+        lowPass = ComplexFirFilter(lpLen)
+        for (i in 0 until lpLen)
+            lowPass.taps[i] = (WindowFunctions.kaiser(2.0, i, lpLen) * WindowFunctions.sinc(
+                cutoff,
+                sampleRate.toDouble(),
+                i,
+                lpLen
+            )).toFloat()
+        val center = (loFreq + hiFreq) / 2
+        oscillator = Phasor(-center, sampleRate.toDouble())
+        syncFreqValue = ((SYNC_FREQ - center) * 2 / bandwidth).toFloat()
+        syncFreqTolerance = (50 * 2 / bandwidth).toFloat()
+        val porchFreq = 1500.0
+        val hiThresh = (SYNC_FREQ + porchFreq) / 2
+        val loThresh = (SYNC_FREQ + hiThresh) / 2
+        trigger = SchmittTrigger(
+            ((loThresh - center) * 2 / bandwidth).toFloat(),
+            ((hiThresh - center) * 2 / bandwidth).toFloat()
+        )
+    }
+
+    fun process(buffer: FloatArray, channelSelect: Int): Boolean {
+        var detected = false
+        val channels = if (channelSelect > 0) 2 else 1
+        // NOTE: buffer[i] is overwritten in-place with the FM-demodulated frequency
+        // value for every mono sample (channelSelect == 0). DecoderEngine.process()
+        // reads back these values to populate scanLineBuffer. Callers must not reuse
+        // the buffer after this call.
+        for (i in 0 until buffer.size / channels) {
+            when (channelSelect) {
+                1 -> baseBand.set(buffer[2 * i])
+                2 -> baseBand.set(buffer[2 * i + 1])
+                3 -> baseBand.set(buffer[2 * i] + buffer[2 * i + 1])
+                4 -> baseBand.set(buffer[2 * i], buffer[2 * i + 1])
+                else -> baseBand.set(buffer[i])
+            }
+            baseBand = lowPass.filter(baseBand.mul(oscillator.rotate()))
+            val freq = fm.demodulate(baseBand)
+            val avg = avgFilter.avg(freq)
+            val delayed = delayLine.push(avg)
+            buffer[i] = freq
+            if (!trigger.process(avg)) {
+                ++counter
+            } else if (counter !in min5ms..max20ms || abs(delayed - syncFreqValue) > syncFreqTolerance) {
+                counter = 0
+            } else {
+                detectedWidth = when {
+                    counter < max5ms -> SyncPulseWidth.FiveMs
+                    counter < max9ms -> SyncPulseWidth.NineMs
+                    else -> SyncPulseWidth.TwentyMs
+                }
+                pulseOffset = i - filterDelay
+                freqOffset = delayed - syncFreqValue
+                detected = true
+                counter = 0
+            }
+        }
+        return detected
+    }
+}
+
+internal class DecoderEngine(
+    private val scopeBuffer: PixelBuffer,
+    private val imageBuffer: PixelBuffer,
+    rawName: String,
+    sampleRate: Int,
+    lineRecoveryStrategy: LineRecoveryStrategy
+) {
+    private val pixelBuffer = PixelBuffer(800, 2)
+    private val detector = SyncPulseDetector(sampleRate)
+    private val pulseFilter: MovingAverage
+    private val pulseFilterDelay: Int
+    private val scanLineBuffer: FloatArray
+    private val scratch: FloatArray
+    private val sync5ms = IntArray(5)
+    private val sync9ms = IntArray(5)
+    private val sync20ms = IntArray(5)
+    private val lines5ms = IntArray(4)
+    private val lines9ms = IntArray(4)
+    private val lines20ms = IntArray(4)
+    private val offsets5ms = FloatArray(5)
+    private val offsets9ms = FloatArray(5)
+    private val offsets20ms = FloatArray(5)
+    private val visFreqs = FloatArray(10)
+    private val scanLineMin: Int
+    private val syncTolerance: Int
+    private val lineTolerance: Int
+    private val leaderLen: Int
+    private val leaderTol: Int
+    private val transition: Int
+    private val visBitLen: Int
+    private val visLen: Int
+    private val rawMode: SstvMode
+    private val modes5ms: ArrayList<SstvMode>
+    private val modes9ms: ArrayList<SstvMode>
+    private val modes20ms: ArrayList<SstvMode>
+
+    var currentMode: SstvMode; private set
+    val allModes: List<SstvMode> get() = modes5ms + modes9ms + modes20ms
+
+    private var lockMode = false
+    private var sample = 0
+    private var leaderBreak = 0
+    private var lastSync = 0
+    private var curLineSamples: Int
+    private var lastOffset = 0f
+    private var syncChecks = 0
+    private var syncHits = 0
+    private var predictedLineBursts = 0
+    private var predictedStreak = 0
+    private var maxPredictedStreak = 0
+    private var timingErrorSamples = 0
+
+    // Look4Sat strategy limits synthetic lines to avoid visible vertical collapse.
+    // Robot36 strategy preserves legacy behavior by allowing unlimited synthesis.
+    private val maxConsecutivePredictedLines = when (lineRecoveryStrategy) {
+        LineRecoveryStrategy.Look4SatLimited -> 2
+        LineRecoveryStrategy.Robot36Compatible -> Int.MAX_VALUE
+    }
+
+    init {
+        imageBuffer.line = -1
+        // Pre-allocate for the largest possible mode (PD-290: 800×616 = 492 800 ints)
+        // so that handleHeader/processPulse can reuse the array with a fill(0) instead
+        // of allocating a fresh IntArray on every new image, reducing GC pressure.
+        imageBuffer.pixels = IntArray(800 * 616)
+        val pfLen = round(0.0025 * sampleRate).toInt() or 1
+        pulseFilterDelay = (pfLen - 1) / 2
+        pulseFilter = MovingAverage(pfLen)
+        scanLineBuffer = FloatArray(round(7.0 * sampleRate).toInt())
+        scratch = FloatArray(round(1.1 * sampleRate).toInt())
+        leaderLen = round(0.3 * sampleRate).toInt()
+        leaderTol = round(0.06 * sampleRate).toInt()
+        transition = round(0.0005 * sampleRate).toInt()
+        visBitLen = round(0.03 * sampleRate).toInt()
+        visLen = round(0.3 * sampleRate).toInt()
+        scanLineMin = round(0.05 * sampleRate).toInt()
+        syncTolerance = round(0.03 * sampleRate).toInt()
+        lineTolerance = round(0.001 * sampleRate).toInt()
+        rawMode = RawMode(rawName, sampleRate)
+        val robot36 = Robot36Mode(sampleRate)
+        currentMode = robot36
+        curLineSamples = robot36.scanLineSamples
+        modes5ms = arrayListOf(
+            RgbMode.wraaseSc2180(sampleRate),
+            RgbMode.martin("1", 44, 0.146432, sampleRate),
+            RgbMode.martin("2", 40, 0.073216, sampleRate)
+        )
+        modes9ms = arrayListOf(
+            robot36, Robot72Mode(sampleRate),
+            RgbMode.scottie("1", 60, 0.138240, sampleRate),
+            RgbMode.scottie("2", 56, 0.088064, sampleRate),
+            RgbMode.scottie("DX", 76, 0.3456, sampleRate)
+        )
+        modes20ms = arrayListOf(
+            PdMode("50", 93, 320, 256, 0.09152, sampleRate),
+            PdMode("90", 99, 320, 256, 0.17024, sampleRate),
+            PdMode("120", 95, 640, 496, 0.1216, sampleRate),
+            PdMode("160", 98, 512, 400, 0.195584, sampleRate),
+            PdMode("180", 96, 640, 496, 0.18304, sampleRate),
+            PdMode("240", 97, 640, 496, 0.24448, sampleRate),
+            PdMode("290", 94, 800, 616, 0.2288, sampleRate)
+        )
+    }
+
+    fun process(recordBuffer: FloatArray, channelSelect: Int): Boolean {
+        var newLines = false
+        val detected = detector.process(recordBuffer, channelSelect)
+        syncChecks++
+        if (detected) {
+            syncHits++
+            predictedStreak = 0
+        }
+        var syncIdx = sample + detector.pulseOffset
+        val channels = if (channelSelect > 0) 2 else 1
+        for (j in 0 until recordBuffer.size / channels) {
+            if (sample >= scanLineBuffer.size) {
+                shift(curLineSamples)
+                syncIdx -= curLineSamples
+                if (sample >= scanLineBuffer.size) sample = scanLineBuffer.size - 1
+            }
+            scanLineBuffer[sample++] = recordBuffer[j]
+        }
+        if (detected) {
+            when (detector.detectedWidth) {
+                SyncPulseWidth.FiveMs -> newLines = processPulse(modes5ms, offsets5ms, sync5ms, lines5ms, syncIdx)
+                SyncPulseWidth.NineMs -> {
+                    leaderBreak = syncIdx; newLines = processPulse(modes9ms, offsets9ms, sync9ms, lines9ms, syncIdx)
+                }
+
+                SyncPulseWidth.TwentyMs -> {
+                    leaderBreak = syncIdx; newLines = processPulse(modes20ms, offsets20ms, sync20ms, lines20ms, syncIdx)
+                }
+            }
+        } else if (handleHeader()) {
+            predictedStreak = 0
+            newLines = true
+        } else if (sample > lastSync + (curLineSamples * 5) / 4) {
+            newLines = decodePredictedLine()
+        }
+        return newLines
+    }
+
+    fun setMode(name: String) {
+        val mode = allModes.firstOrNull { it.name == name }
+        if (mode == currentMode) {
+            lockMode = true; return
+        }
+        if (mode != null) {
+            lockMode = true; imageBuffer.line = -1; currentMode = mode; curLineSamples = mode.scanLineSamples; return
+        }
+        lockMode = false
+    }
+
+    fun quality(): DecoderQuality {
+        val hitRate = if (syncChecks > 0) syncHits.toFloat() / syncChecks else 0f
+        return DecoderQuality(
+            syncHitRate = hitRate,
+            predictedLineBursts = predictedLineBursts,
+            maxPredictedStreak = maxPredictedStreak,
+            timingErrorSamples = timingErrorSamples
+        )
+    }
+
+    fun resetQuality() {
+        syncChecks = 0
+        syncHits = 0
+        predictedLineBursts = 0
+        predictedStreak = 0
+        maxPredictedStreak = 0
+        timingErrorSamples = 0
+    }
+
+    private fun mean(a: IntArray): Double = a.sumOf { it.toDouble() } / a.size
+    private fun stdDev(a: IntArray, m: Double): Double {
+        var s = 0.0; for (v in a) s += (v - m) * (v - m); return sqrt(s / a.size)
+    }
+
+    private fun meanF(a: FloatArray): Float {
+        var s = 0f; for (v in a) s += v; return s / a.size
+    }
+
+    private fun detectMode(modes: ArrayList<SstvMode>, samples: Int): SstvMode {
+        var best: SstvMode = rawMode
+        var bestD = Int.MAX_VALUE
+        for (m in modes) {
+            val d = abs(samples - m.scanLineSamples); if (d <= lineTolerance && d < bestD) {
+                bestD = d; best = m
+            }
+        }
+        return best
+    }
+
+    // scopeBuffer is twice the display height. Each decoded scan line is written
+    // to both the current rolling position (top half, wraps at height/2) and the
+    // same row offset in the bottom half. The UI displays a window that always
+    // spans the half-height boundary, giving a seamless non-wrapping scroll effect.
+    private fun copyUnscaled() {
+        val w = minOf(scopeBuffer.width, pixelBuffer.width)
+        for (row in 0 until pixelBuffer.height) {
+            val line = scopeBuffer.width * scopeBuffer.line
+            pixelBuffer.pixels.copyInto(scopeBuffer.pixels, line, row * pixelBuffer.width, row * pixelBuffer.width + w)
+            scopeBuffer.pixels.fill(0, line + w, line + scopeBuffer.width)
+
+            scopeBuffer.pixels.copyInto(
+                scopeBuffer.pixels,
+                scopeBuffer.width * (scopeBuffer.line + scopeBuffer.height / 2),
+                line,
+                line + scopeBuffer.width
+            )
+            scopeBuffer.line = (scopeBuffer.line + 1) % (scopeBuffer.height / 2)
+        }
+    }
+
+    private fun copyScaled(scale: Int) {
+        for (row in 0 until pixelBuffer.height) {
+            val line = scopeBuffer.width * scopeBuffer.line
+            for (col in 0 until pixelBuffer.width) for (i in 0 until scale) scopeBuffer.pixels[line + col * scale + i] =
+                pixelBuffer.pixels[pixelBuffer.width * row + col]
+            scopeBuffer.pixels.fill(0, line + pixelBuffer.width * scale, line + scopeBuffer.width)
+
+            scopeBuffer.pixels.copyInto(
+                scopeBuffer.pixels,
+                scopeBuffer.width * (scopeBuffer.line + scopeBuffer.height / 2),
+                line,
+                line + scopeBuffer.width
+            )
+            scopeBuffer.line = (scopeBuffer.line + 1) % (scopeBuffer.height / 2)
+            repeat(scale - 1) {
+
+                scopeBuffer.pixels.copyInto(
+                    scopeBuffer.pixels, scopeBuffer.width * scopeBuffer.line, line, line + scopeBuffer.width
+                )
+
+                scopeBuffer.pixels.copyInto(
+                    scopeBuffer.pixels,
+                    scopeBuffer.width * (scopeBuffer.line + scopeBuffer.height / 2),
+                    line,
+                    line + scopeBuffer.width
+                )
+                scopeBuffer.line = (scopeBuffer.line + 1) % (scopeBuffer.height / 2)
+            }
+        }
+    }
+
+    private fun copyLines(ok: Boolean) {
+        if (!ok) return
+        var finish = false
+        if (imageBuffer.line in 0 until imageBuffer.height && imageBuffer.width == pixelBuffer.width) {
+            val w = imageBuffer.width
+            for (row in 0 until pixelBuffer.height) {
+                if (imageBuffer.line >= imageBuffer.height) break
+                pixelBuffer.pixels.copyInto(imageBuffer.pixels, imageBuffer.line * w, row * w, row * w + w)
+                imageBuffer.line++
+            }
+            finish = imageBuffer.line == imageBuffer.height
+        }
+        val scale = scopeBuffer.width / pixelBuffer.width
+        if (scale <= 1) copyUnscaled() else copyScaled(scale)
+        if (finish) drawLines(0xff000000.toInt(), 10)
+    }
+
+    private fun decodePredictedLine(): Boolean {
+        // Avoid long streaks of synthetic lines; once we exceed the cap we wait for
+        // real sync to reduce visible vertical compression on weak/noisy signals.
+        if (predictedStreak >= maxConsecutivePredictedLines) return false
+        val expectedSync = lastSync + curLineSamples
+        timingErrorSamples = sample - expectedSync
+        val decoded = currentMode.decodeScanLine(
+            pixelBuffer,
+            scratch,
+            scanLineBuffer,
+            scopeBuffer.width,
+            lastSync,
+            curLineSamples,
+            lastOffset
+        )
+        copyLines(decoded)
+        lastSync = expectedSync
+        predictedLineBursts++
+        predictedStreak++
+        if (predictedStreak > maxPredictedStreak) maxPredictedStreak = predictedStreak
+        return decoded
+    }
+
+    private fun drawLines(color: Int, count: Int) {
+        repeat(count) {
+            scopeBuffer.pixels.fill(
+                color,
+                scopeBuffer.line * scopeBuffer.width,
+                (scopeBuffer.line + 1) * scopeBuffer.width
+            )
+            scopeBuffer.pixels.fill(
+                color,
+                (scopeBuffer.line + scopeBuffer.height / 2) * scopeBuffer.width,
+                (scopeBuffer.line + 1 + scopeBuffer.height / 2) * scopeBuffer.width
+            )
+            scopeBuffer.line = (scopeBuffer.line + 1) % (scopeBuffer.height / 2)
+        }
+    }
+
+    private fun adjust(pulses: IntArray, shift: Int) {
+        for (i in pulses.indices) pulses[i] -= shift
+    }
+
+    private fun shift(amount: Int) {
+        if ((amount <= 0) || (amount > sample)) return
+        sample -= amount; leaderBreak -= amount; lastSync -= amount
+        adjust(sync5ms, amount); adjust(sync9ms, amount); adjust(sync20ms, amount)
+        // Discard already-decoded samples by sliding the live region back to index 0.
+        // System.arraycopy handles the overlapping regions correctly and is a native
+        // memcpy on JVM, so this is fast despite moving the full remaining window.
+        scanLineBuffer.copyInto(scanLineBuffer, 0, amount, amount + sample)
+    }
+
+    private fun handleHeader(): Boolean {
+        if (leaderBreak < visBitLen + leaderTol || sample < leaderBreak + leaderLen + leaderTol + visLen + visBitLen) return false
+        val bp = leaderBreak; leaderBreak = 0
+        var preFreq = 0f
+        for (i in 0 until leaderTol) preFreq += scanLineBuffer[bp - visBitLen - leaderTol + i]
+        val toneFreq = 1900f
+        val center = 1900f
+        val tol = 50f
+        val halfBw = 400f
+        preFreq = preFreq * halfBw / leaderTol + center
+        if (abs(preFreq - toneFreq) > tol) return false
+        var ldrFreq = 0f
+        for (i in transition until leaderLen - leaderTol) ldrFreq += scanLineBuffer[bp + i]
+        val ldrOffset = ldrFreq / (leaderLen - transition - leaderTol)
+        ldrFreq = ldrOffset * halfBw + center
+        if (abs(ldrFreq - toneFreq) > tol) return false
+        val stopFreq = 1200f
+        val pulseThr = ((stopFreq + toneFreq) / 2 - center) / halfBw
+        var vBegin = bp + leaderLen - leaderTol
+        val vEnd = bp + leaderLen + leaderTol + visBitLen
+        repeat(pulseFilter.length) { pulseFilter.avg(scanLineBuffer[vBegin++] - ldrOffset) }
+        while (++vBegin < vEnd) if (pulseFilter.avg(scanLineBuffer[vBegin] - ldrOffset) < pulseThr) break
+        if (vBegin >= vEnd) return false
+        vBegin -= pulseFilterDelay
+        val visEnd = vBegin + visLen
+        visFreqs.fill(0f)
+        for (j in 0 until 10) for (i in transition until visBitLen - transition) visFreqs[j] += scanLineBuffer[vBegin + visBitLen * j + i] - ldrOffset
+        for (i in 0 until 10) visFreqs[i] = visFreqs[i] * halfBw / (visBitLen - 2 * transition) + center
+        if (abs(visFreqs[0] - stopFreq) > tol || abs(visFreqs[9] - stopFreq) > tol) return false
+        for (i in 1 until 9) if (abs(visFreqs[i] - 1100f) > tol && abs(visFreqs[i] - 1300f) > tol) return false
+        var vis = 0
+        for (i in 0 until 8) vis = vis or ((if (visFreqs[i + 1] < stopFreq) 1 else 0) shl i)
+        var chk = true; for (i in 0 until 8) chk = chk xor ((vis and (1 shl i)) != 0)
+        vis = vis and 127; if (!chk) return false
+        val syncThr = ((1200f + 1500f) / 2 - center) / halfBw
+        var sIdx = visEnd - visBitLen
+        val sMax = visEnd + visBitLen
+        repeat(pulseFilter.length) { pulseFilter.avg(scanLineBuffer[sIdx++] - ldrOffset) }
+        while (++sIdx < sMax) if (pulseFilter.avg(scanLineBuffer[sIdx] - ldrOffset) > syncThr) break
+        if (sIdx >= sMax) return false
+        sIdx -= pulseFilterDelay
+        val mode: SstvMode
+        val pulses: IntArray
+        val lines: IntArray
+        val f5 = modes5ms.firstOrNull { it.visCode == vis }
+        val f9 = modes9ms.firstOrNull { it.visCode == vis }
+        val f20 = modes20ms.firstOrNull { it.visCode == vis }
+        when {
+            f5 != null -> {
+                mode = f5; pulses = sync5ms; lines = lines5ms
+            }
+
+            f9 != null -> {
+                mode = f9; pulses = sync9ms; lines = lines9ms
+            }
+
+            f20 != null -> {
+                mode = f20; pulses = sync20ms; lines = lines20ms
+            }
+
+            else -> {
+                if (!lockMode) drawLines(0xffff0000.toInt(), 8); return false
+            }
+        }
+        if (lockMode && mode != currentMode) return false
+        mode.resetState()
+        imageBuffer.width = mode.width; imageBuffer.height = mode.height
+        imageBuffer.pixels.fill(0, 0, mode.width * mode.height); imageBuffer.line = 0
+        currentMode = mode
+        lastSync = sIdx + mode.firstSyncPulseIndex; curLineSamples = mode.scanLineSamples; lastOffset = ldrOffset
+        var oldest = lastSync - (pulses.size - 1) * curLineSamples
+        if (mode.firstSyncPulseIndex > 0) oldest -= curLineSamples
+        for (i in pulses.indices) pulses[i] = oldest + i * curLineSamples
+        lines.fill(curLineSamples)
+        shift(lastSync + mode.firstPixelSampleIndex)
+        drawLines(0xff00ff00.toInt(), 8); drawLines(0xff000000.toInt(), 10)
+        return true
+    }
+
+    private fun processPulse(
+        modes: ArrayList<SstvMode>,
+        freqOffs: FloatArray,
+        syncPulses: IntArray,
+        lineLen: IntArray,
+        latest: Int
+    ): Boolean {
+        predictedStreak = 0
+        for (i in 1 until syncPulses.size) syncPulses[i - 1] = syncPulses[i]
+        syncPulses[syncPulses.size - 1] = latest
+        for (i in 1 until lineLen.size) lineLen[i - 1] = lineLen[i]
+        lineLen[lineLen.size - 1] = syncPulses.last() - syncPulses[syncPulses.size - 2]
+        for (i in 1 until freqOffs.size) freqOffs[i - 1] = freqOffs[i]
+        freqOffs[freqOffs.size - 1] = detector.freqOffset
+        if (lineLen[0] == 0) return false
+        val m = mean(lineLen)
+        val lineSamples = round(m).toInt()
+        if (lineSamples < scanLineMin || lineSamples > scratch.size) return false
+        if (stdDev(lineLen, m) > lineTolerance) return false
+        var changed = false
+        if (lockMode || imageBuffer.line in 0 until imageBuffer.height) {
+            if (currentMode != rawMode && abs(lineSamples - currentMode.scanLineSamples) > lineTolerance) return false
+            // Try continuous decoding
+            if (lockMode && imageBuffer.line == -1 && currentMode != rawMode) {
+                currentMode.resetState()
+                imageBuffer.width = currentMode.width
+                imageBuffer.height = currentMode.height
+                imageBuffer.pixels.fill(0, 0, currentMode.width * currentMode.height)
+                imageBuffer.line = 0
+                drawLines(0xff000000.toInt(), 10); drawLines(0xffffff00.toInt(), 8); drawLines(0xff000000.toInt(), 10)
+            }
+        } else {
+            val prev = currentMode; currentMode = detectMode(modes, lineSamples)
+            changed =
+                currentMode != prev || abs(curLineSamples - lineSamples) > lineTolerance || abs(lastSync + lineSamples - syncPulses.last()) > syncTolerance
+        }
+        if (changed) {
+            drawLines(0xff000000.toInt(), 10); drawLines(0xff00ffff.toInt(), 8); drawLines(0xff000000.toInt(), 10)
+        }
+        val offset = meanF(freqOffs)
+        if (syncPulses[0] >= lineSamples && changed) {
+            val end = syncPulses[0]
+            val extra = end / lineSamples
+            val first = end - extra * lineSamples
+            var p = first; while (p < end) {
+                copyLines(
+                    currentMode.decodeScanLine(
+                        pixelBuffer,
+                        scratch,
+                        scanLineBuffer,
+                        scopeBuffer.width,
+                        p,
+                        lineSamples,
+                        offset
+                    )
+                ); p += lineSamples
+            }
+        }
+        val start = if (changed) 0 else lineLen.size - 1
+        for (i in start until lineLen.size) copyLines(
+            currentMode.decodeScanLine(
+                pixelBuffer,
+                scratch,
+                scanLineBuffer,
+                scopeBuffer.width,
+                syncPulses[i],
+                lineLen[i],
+                offset
+            )
+        )
+        lastSync = syncPulses.last(); curLineSamples = lineSamples; lastOffset = offset
+        shift(lastSync + currentMode.firstPixelSampleIndex)
+        return true
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/sstv/SstvDsp.kt

@@ -0,0 +1,240 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.sstv
+
+import kotlin.math.PI
+import kotlin.math.cos
+import kotlin.math.pow
+import kotlin.math.round
+import kotlin.math.sin
+import kotlin.math.sqrt
+
+internal class Complex(var real: Float = 0f, var imag: Float = 0f) {
+
+    fun set(real: Float, imag: Float): Complex {
+        this.real = real; this.imag = imag; return this
+    }
+
+    fun set(real: Float): Complex = set(real, 0f)
+
+    fun abs(): Float = sqrt(real * real + imag * imag)
+
+    fun mul(other: Complex): Complex {
+        val tmp = real * other.real - imag * other.imag
+        imag = real * other.imag + imag * other.real
+        real = tmp
+        return this
+    }
+
+    fun div(value: Float): Complex {
+        real /= value; imag /= value; return this
+    }
+}
+
+internal object WindowFunctions {
+
+    fun sinc(cutoff: Double, rate: Double, n: Int, nN: Int): Double {
+        val f = 2 * cutoff / rate
+        val x = n - (nN - 1) / 2.0
+        val fx = f * x
+        return if (fx == 0.0) f else f * sin(PI * fx) / (PI * fx)
+    }
+
+    fun kaiser(a: Double, n: Int, nN: Int): Double {
+        fun square(v: Double) = v * v
+        fun i0(x: Double): Double {
+            val terms = DoubleArray(35)
+            terms[0] = 1.0
+            var v = 1.0
+            for (m in 1 until 35) {
+                v *= x / (2 * m); terms[m] = square(v)
+            }
+            terms.sort()
+            var sum = 0.0; for (m in 34 downTo 0) sum += terms[m]
+            return sum
+        }
+        return i0(PI * a * sqrt(1 - square((2.0 * n) / (nN - 1) - 1))) / i0(PI * a)
+    }
+}
+
+// O(1) ring buffer — simpler and faster than a segment tree for the short window
+// lengths used here (≤512 samples). Float32 accumulated drift over such windows
+// is ~6e-5, negligible for audio-frequency processing.
+internal open class MovingSum(val length: Int) {
+    private val buf = FloatArray(length)
+    private var pos = 0
+    private var runningSum = 0f
+
+    fun add(input: Float) {
+        runningSum += input - buf[pos]
+        buf[pos] = input
+        if (++pos >= length) pos = 0
+    }
+
+    fun sum(): Float = runningSum
+    fun sum(input: Float): Float {
+        add(input); return sum()
+    }
+}
+
+internal class MovingAverage(length: Int) : MovingSum(length) {
+    fun avg(input: Float): Float = sum(input) / length
+}
+
+internal class Ema {
+    private var alpha: Float = 1f
+    private var prev: Float = 0f
+
+    fun process(input: Float): Float {
+        prev = prev * (1 - alpha) + alpha * input; return prev
+    }
+
+    fun setCutoff(freq: Double, rate: Double, order: Int = 1) {
+        alpha = computeAlpha(freq, rate, order)
+    }
+
+    fun reset() {
+        prev = 0f
+    }
+
+    companion object {
+
+        fun computeAlpha(freq: Double, rate: Double, order: Int = 1): Float {
+            val x = cos(2 * PI * (freq.coerceAtMost(rate * 0.499)) / rate)
+            val discriminant = (x * (x - 4) + 3).coerceAtLeast(0.0)
+            return (x - 1 + sqrt(discriminant)).coerceIn(0.0, 1.0).pow(1.0 / order).toFloat()
+        }
+
+        fun withCutoff(freq: Double, rate: Double, order: Int = 1): Ema {
+            return Ema().also { it.setCutoff(freq, rate, order) }
+        }
+    }
+}
+
+internal class Phasor(freq: Double, rate: Double) {
+    private val value = Complex(1f, 0f)
+    private val delta: Complex = run {
+        val omega = 2 * PI * freq / rate
+        Complex(cos(omega).toFloat(), sin(omega).toFloat())
+    }
+    private var count = 0
+
+    // Renormalize every 512 rotations to prevent magnitude drift accumulation,
+    // eliminating the per-sample sqrt without sacrificing demodulation accuracy.
+    fun rotate(): Complex {
+        value.mul(delta)
+        if (++count == 512) { value.div(value.abs()); count = 0 }
+        return value
+    }
+}
+
+internal class FmDemodulator(bandwidth: Double, sampleRate: Double) {
+    private val scale = (sampleRate / (bandwidth * PI)).toFloat()
+    private val pi = PI.toFloat()
+    private val twoPi = (2 * PI).toFloat()
+    private var prev = 0f
+
+    fun demodulate(input: Complex): Float {
+        // Use fast polynomial atan2 instead of the exact trigonometric call.
+        // Max error ~0.005 rad translates to <1 Hz frequency error at 44100 Hz,
+        // well within the 50 Hz sync tolerance.
+        val phase = fastAtan2(input.imag, input.real)
+        var delta = phase - prev; prev = phase
+        if (delta < -pi) delta += twoPi else if (delta > pi) delta -= twoPi
+        return scale * delta
+    }
+
+    // Rajan's polynomial approximation of atan2 — avoids a transcendental call
+    // in the per-sample hot path (~44 k calls/s at 44100 Hz sample rate).
+    private fun fastAtan2(y: Float, x: Float): Float {
+        val absY = kotlin.math.abs(y) + 1e-10f
+        val r: Float
+        val angle: Float
+        if (x >= 0f) {
+            r = (x - absY) / (x + absY)
+            angle = 0.1963f * r * r * r - 0.9817f * r + pi / 4f
+        } else {
+            r = (x + absY) / (absY - x)
+            angle = 0.1963f * r * r * r - 0.9817f * r + 3f * pi / 4f
+        }
+        return if (y < 0f) -angle else angle
+    }
+}
+
+internal class ComplexFirFilter(val length: Int) {
+    private val real = FloatArray(length)
+    private val imag = FloatArray(length)
+    private val sum = Complex()
+    private var pos = 0
+
+    val taps = FloatArray(length)
+
+    fun filter(input: Complex): Complex {
+        real[pos] = input.real; imag[pos] = input.imag
+        if (++pos >= length) pos = 0
+        sum.real = 0f; sum.imag = 0f
+        for (tap in taps) {
+            sum.real += tap * real[pos]; sum.imag += tap * imag[pos]; if (++pos >= length) pos = 0
+        }
+        return sum
+    }
+}
+
+internal class Delay(val length: Int) {
+    private val buf = FloatArray(length)
+    private var pos = 0
+
+    fun push(input: Float): Float {
+        val tmp = buf[pos]; buf[pos] = input; if (++pos >= length) pos = 0; return tmp
+    }
+}
+
+internal class SchmittTrigger(private val low: Float, private val high: Float) {
+    private var state = false
+
+    fun process(input: Float): Boolean {
+        if (state) {
+            if (input < low) state = false
+        } else {
+            if (input > high) state = true
+        }
+        return state
+    }
+}
+
+internal object ColorConverter {
+
+    private fun clamp(v: Int) = v.coerceIn(0, 255)
+    private fun toInt(level: Float) = clamp(round(255 * level).toInt())
+    private fun compress(level: Float) = toInt(sqrt(level.coerceIn(0f, 1f)))
+
+    private fun yuv2rgb(yY: Int, uU: Int, vV: Int): Int {
+        val y = yY - 16
+        val u = uU - 128
+        val v = vV - 128
+        val r = clamp((298 * y + 409 * v + 128) shr 8)
+        val g = clamp((298 * y - 100 * u - 208 * v + 128) shr 8)
+        val b = clamp((298 * y + 516 * u + 128) shr 8)
+        return 0xff000000.toInt() or (r shl 16) or (g shl 8) or b
+    }
+
+    fun gray(level: Float): Int = 0xff000000.toInt() or (0x00010101 * compress(level))
+    fun rgb(r: Float, g: Float, b: Float): Int = 0xff000000.toInt() or (toInt(r) shl 16) or (toInt(g) shl 8) or toInt(b)
+    fun yuv2rgb(yY: Float, uU: Float, vV: Float): Int = yuv2rgb(toInt(yY), toInt(uU), toInt(vV))
+    fun yuv2rgb(packed: Int): Int = yuv2rgb((packed shr 16) and 0xff, (packed shr 8) and 0xff, packed and 0xff)
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/sstv/SstvModes.kt

@@ -0,0 +1,434 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.sstv
+
+import kotlin.math.round
+
+internal class PixelBuffer(var width: Int, var height: Int) {
+    var pixels = IntArray(width * height)
+    var line = 0
+}
+
+internal sealed interface SstvMode {
+    val name: String
+    val visCode: Int
+    val width: Int
+    val height: Int
+    val firstPixelSampleIndex: Int
+    val firstSyncPulseIndex: Int
+    val scanLineSamples: Int
+
+    fun resetState() {}
+
+    fun decodeScanLine(
+        pixelBuffer: PixelBuffer,
+        scratch: FloatArray,
+        scanLine: FloatArray,
+        scopeWidth: Int,
+        syncPulseIndex: Int,
+        lineSamples: Int,
+        freqOffset: Float
+    ): Boolean
+}
+
+internal class RgbMode(
+    override val name: String,
+    override val visCode: Int,
+    private val hPixels: Int,
+    private val vPixels: Int,
+    override val firstSyncPulseIndex: Int,
+    override val scanLineSamples: Int,
+    override val firstPixelSampleIndex: Int,
+    private val redBegin: Int,
+    private val redLen: Int,
+    private val greenBegin: Int,
+    private val greenLen: Int,
+    private val blueBegin: Int,
+    private val blueLen: Int,
+    private val endSamples: Int,
+) : SstvMode {
+    override val width get() = hPixels
+    override val height get() = vPixels
+    private val ema = Ema.withCutoff(hPixels.toDouble(), (2 * greenLen).toDouble(), 2)
+
+    override fun decodeScanLine(
+        pixelBuffer: PixelBuffer,
+        scratch: FloatArray,
+        scanLine: FloatArray,
+        scopeWidth: Int,
+        syncPulseIndex: Int,
+        lineSamples: Int,
+        freqOffset: Float
+    ): Boolean {
+        val begin = firstPixelSampleIndex
+        if (syncPulseIndex + begin < 0 || syncPulseIndex + endSamples > scanLine.size) return false
+        ema.reset()
+        for (i in 0 until endSamples - begin) scratch[i] = ema.process(scanLine[syncPulseIndex + begin + i])
+        ema.reset()
+        for (i in endSamples - begin - 1 downTo 0) scratch[i] = freqToLevel(ema.process(scratch[i]), freqOffset)
+        for (i in 0 until hPixels) {
+            val r = redBegin + (i * redLen) / hPixels
+            val g = greenBegin + (i * greenLen) / hPixels
+            val b = blueBegin + (i * blueLen) / hPixels
+            pixelBuffer.pixels[i] = ColorConverter.rgb(scratch[r], scratch[g], scratch[b])
+        }
+        pixelBuffer.width = hPixels; pixelBuffer.height = 1
+        return true
+    }
+
+    companion object {
+        fun martin(variant: String, code: Int, channelSec: Double, sampleRate: Int): RgbMode {
+            val sync = 0.004862
+            val sep = 0.000572
+            val scanLine = sync + sep + 3 * (channelSec + sep)
+            val gEnd = sep + channelSec
+            val bBegin = gEnd + sep
+            val bEnd = bBegin + channelSec
+            val rBegin = bEnd + sep
+            val rEnd = rBegin + channelSec
+            return fromSeconds(
+                name = "Martin $variant",
+                code = code,
+                firstSyncSec = 0.0,
+                scanLineSec = scanLine,
+                beginSec = sep,
+                rBeginSec = rBegin,
+                rEndSec = rEnd,
+                gBeginSec = sep,
+                gEndSec = gEnd,
+                bBeginSec = bBegin,
+                bEndSec = bEnd,
+                endSec = rEnd,
+                sr = sampleRate
+            )
+        }
+
+        fun scottie(variant: String, code: Int, channelSec: Double, sampleRate: Int): RgbMode {
+            val sync = 0.009
+            val sep = 0.0015
+            val firstSync = sync + 2 * (sep + channelSec)
+            val scanLine = sync + 3 * (channelSec + sep)
+            val bEnd = -sync
+            val bBegin = bEnd - channelSec
+            val gEnd = bBegin - sep
+            val gBegin = gEnd - channelSec
+            val rEnd = sep + channelSec
+            return fromSeconds(
+                name = "Scottie $variant",
+                code = code,
+                firstSyncSec = firstSync,
+                scanLineSec = scanLine,
+                beginSec = gBegin,
+                rBeginSec = sep,
+                rEndSec = rEnd,
+                gBeginSec = gBegin,
+                gEndSec = gEnd,
+                bBeginSec = bBegin,
+                bEndSec = bEnd,
+                endSec = rEnd,
+                sr = sampleRate
+            )
+        }
+
+        fun wraaseSc2180(sampleRate: Int): RgbMode {
+            val sync = 0.0055225
+            val porch = 0.0005
+            val ch = 0.235
+            val scanLine = sync + porch + 3 * ch
+            val rEnd = porch + ch
+            val gEnd = rEnd + ch
+            val bEnd = gEnd + ch
+            return fromSeconds(
+                name = "Wraase SC2-180",
+                code = 55,
+                firstSyncSec = 0.0,
+                scanLineSec = scanLine,
+                beginSec = porch,
+                rBeginSec = porch,
+                rEndSec = rEnd,
+                gBeginSec = rEnd,
+                gEndSec = gEnd,
+                bBeginSec = gEnd,
+                bEndSec = bEnd,
+                endSec = bEnd,
+                sr = sampleRate
+            )
+        }
+
+        private fun fromSeconds(
+            name: String, code: Int, w: Int = 320, h: Int = 256,
+            firstSyncSec: Double, scanLineSec: Double, beginSec: Double,
+            rBeginSec: Double, rEndSec: Double, gBeginSec: Double, gEndSec: Double,
+            bBeginSec: Double, bEndSec: Double, endSec: Double, sr: Int
+        ): RgbMode {
+            val begin = round(beginSec * sr).toInt()
+            return RgbMode(
+                name = name, visCode = code, hPixels = w, vPixels = h,
+                firstSyncPulseIndex = round(firstSyncSec * sr).toInt(),
+                scanLineSamples = round(scanLineSec * sr).toInt(),
+                firstPixelSampleIndex = begin,
+                redBegin = round(rBeginSec * sr).toInt() - begin,
+                redLen = round((rEndSec - rBeginSec) * sr).toInt(),
+                greenBegin = round(gBeginSec * sr).toInt() - begin,
+                greenLen = round((gEndSec - gBeginSec) * sr).toInt(),
+                blueBegin = round(bBeginSec * sr).toInt() - begin,
+                blueLen = round((bEndSec - bBeginSec) * sr).toInt(),
+                endSamples = round(endSec * sr).toInt()
+            )
+        }
+    }
+}
+
+internal class Robot36Mode(sampleRate: Int) : SstvMode {
+    override val name = "Robot 36 Color"
+    override val visCode = 8
+    override val width = 320
+    override val height = 240
+    override val firstSyncPulseIndex = 0
+    override val scanLineSamples: Int
+    override val firstPixelSampleIndex: Int
+
+    private val lumSamples: Int
+    private val sepSamples: Int
+    private val chromSamples: Int
+    private val lumBegin: Int
+    private val sepBegin: Int
+    private val chromBegin: Int
+    private val end: Int
+    private val ema: Ema
+    private var lastEven = false
+
+    init {
+        val syncPorch = 0.003
+        val lum = 0.088
+        val sep = 0.0045
+        val porch = 0.0015
+        val chrom = 0.044
+        scanLineSamples = round((0.009 + syncPorch + lum + sep + porch + chrom) * sampleRate).toInt()
+        lumSamples = round(lum * sampleRate).toInt(); sepSamples = round(sep * sampleRate).toInt()
+        chromSamples = round(chrom * sampleRate).toInt()
+        lumBegin = round(syncPorch * sampleRate).toInt(); firstPixelSampleIndex = lumBegin
+        sepBegin = round((syncPorch + lum) * sampleRate).toInt()
+        chromBegin = round((syncPorch + lum + sep + porch) * sampleRate).toInt()
+        end = round((syncPorch + lum + sep + porch + chrom) * sampleRate).toInt()
+        ema = Ema.withCutoff(width.toDouble(), (2 * lumSamples).toDouble(), 2)
+    }
+
+    override fun resetState() {
+        lastEven = false
+    }
+
+    override fun decodeScanLine(
+        pixelBuffer: PixelBuffer,
+        scratch: FloatArray,
+        scanLine: FloatArray,
+        scopeWidth: Int,
+        syncPulseIndex: Int,
+        lineSamples: Int,
+        freqOffset: Float
+    ): Boolean {
+        if (syncPulseIndex + firstPixelSampleIndex < 0 || syncPulseIndex + end > scanLine.size) return false
+        var sep = 0f
+        for (i in 0 until sepSamples) sep += scanLine[syncPulseIndex + sepBegin + i]
+        sep = sep / sepSamples - freqOffset
+        var even = sep < 0
+        if (sep < -1.1f || (sep > -0.9f && sep < 0.9f) || sep > 1.1f) even = !lastEven
+        lastEven = even
+        ema.reset()
+        for (i in firstPixelSampleIndex until end) scratch[i] = ema.process(scanLine[syncPulseIndex + i])
+        ema.reset()
+        for (i in end - 1 downTo firstPixelSampleIndex) scratch[i] = freqToLevel(ema.process(scratch[i]), freqOffset)
+        for (i in 0 until width) {
+            val lPos = lumBegin + (i * lumSamples) / width
+            val cPos = chromBegin + (i * chromSamples) / width
+            if (even) {
+                // Even line: store Y in the red channel slot and Cr in the blue slot,
+                // using ColorConverter.rgb() as a convenient 3×byte packer (not RGB).
+                // The odd line will read these back and combine with its own Cb to
+                // produce the final YUV→RGB conversion for both rows.
+                pixelBuffer.pixels[i] = ColorConverter.rgb(scratch[lPos], 0f, scratch[cPos])
+            } else {
+                val evenYuv = pixelBuffer.pixels[i]
+                // Even pixel packing: 0xAARRGGBB → Y=RR, Cb=GG(unused), Cr=BB
+                // Odd pixel:  Y=lPos, Cb=cPos, Cr=(borrowed from even's BB slot)
+                // Merge: take Y+Cr from even row (bits 0x00ff00ff) and Cb from odd (0x0000ff00).
+                val oddYuv = ColorConverter.rgb(scratch[lPos], scratch[cPos], 0f)
+                pixelBuffer.pixels[i] = ColorConverter.yuv2rgb((evenYuv and 0x00ff00ff) or (oddYuv and 0x0000ff00))
+                pixelBuffer.pixels[i + width] =
+                    ColorConverter.yuv2rgb((oddYuv and 0x00ffff00) or (evenYuv and 0x000000ff))
+            }
+        }
+        pixelBuffer.width = width; pixelBuffer.height = 2
+        return !even
+    }
+}
+
+internal class Robot72Mode(sampleRate: Int) : SstvMode {
+    override val name = "Robot 72 Color"
+    override val visCode = 12
+    override val width = 320
+    override val height = 240
+    override val firstSyncPulseIndex = 0
+    override val scanLineSamples: Int
+    override val firstPixelSampleIndex: Int
+
+    private val lumSamples: Int
+    private val chromSamples: Int
+    private val yBegin: Int
+    private val vBegin: Int
+    private val uBegin: Int
+    private val end: Int
+    private val ema: Ema
+
+    init {
+        val syncPorch = 0.003
+        val lum = 0.138
+        val sep = 0.0045
+        val porch = 0.0015
+        val chrom = 0.069
+        scanLineSamples = round((0.009 + syncPorch + lum + 2 * (sep + porch + chrom)) * sampleRate).toInt()
+        lumSamples = round(lum * sampleRate).toInt(); chromSamples = round(chrom * sampleRate).toInt()
+        yBegin = round(syncPorch * sampleRate).toInt(); firstPixelSampleIndex = yBegin
+        vBegin = round((syncPorch + lum + sep + porch) * sampleRate).toInt()
+        uBegin = round((syncPorch + lum + sep + porch + chrom + sep + porch) * sampleRate).toInt()
+        end = round((syncPorch + lum + 2 * (sep + porch + chrom)) * sampleRate).toInt()
+        ema = Ema.withCutoff(width.toDouble(), (2 * lumSamples).toDouble(), 2)
+    }
+
+    override fun decodeScanLine(
+        pixelBuffer: PixelBuffer,
+        scratch: FloatArray,
+        scanLine: FloatArray,
+        scopeWidth: Int,
+        syncPulseIndex: Int,
+        lineSamples: Int,
+        freqOffset: Float
+    ): Boolean {
+        if (syncPulseIndex + firstPixelSampleIndex < 0 || syncPulseIndex + end > scanLine.size) return false
+        ema.reset()
+        for (i in firstPixelSampleIndex until end) scratch[i] = ema.process(scanLine[syncPulseIndex + i])
+        ema.reset()
+        for (i in end - 1 downTo firstPixelSampleIndex) scratch[i] = freqToLevel(ema.process(scratch[i]), freqOffset)
+        for (i in 0 until width) {
+            val yP = yBegin + (i * lumSamples) / width
+            val uP = uBegin + (i * chromSamples) / width
+            val vP = vBegin + (i * chromSamples) / width
+            pixelBuffer.pixels[i] = ColorConverter.yuv2rgb(scratch[yP], scratch[uP], scratch[vP])
+        }
+        pixelBuffer.width = width; pixelBuffer.height = 1
+        return true
+    }
+}
+
+internal class PdMode(
+    variant: String,
+    override val visCode: Int,
+    private val hPixels: Int,
+    private val vPixels: Int,
+    channelSec: Double,
+    sampleRate: Int
+) : SstvMode {
+    override val name = "PD $variant"
+    override val width get() = hPixels
+    override val height get() = vPixels
+    override val firstSyncPulseIndex = 0
+    override val scanLineSamples: Int
+    override val firstPixelSampleIndex: Int
+
+    private val chSamples: Int
+    private val yEvenBegin: Int
+    private val vAvgBegin: Int
+    private val uAvgBegin: Int
+    private val yOddBegin: Int
+    private val end: Int
+    private val ema: Ema
+
+    init {
+        val syncPorch = 0.00208
+        scanLineSamples = round((0.02 + syncPorch + 4 * channelSec) * sampleRate).toInt()
+        chSamples = round(channelSec * sampleRate).toInt()
+        yEvenBegin = round(syncPorch * sampleRate).toInt(); firstPixelSampleIndex = yEvenBegin
+        vAvgBegin = round((syncPorch + channelSec) * sampleRate).toInt()
+        uAvgBegin = round((syncPorch + 2 * channelSec) * sampleRate).toInt()
+        yOddBegin = round((syncPorch + 3 * channelSec) * sampleRate).toInt()
+        end = round((syncPorch + 4 * channelSec) * sampleRate).toInt()
+        ema = Ema.withCutoff(hPixels.toDouble(), (2 * chSamples).toDouble(), 2)
+    }
+
+    override fun decodeScanLine(
+        pixelBuffer: PixelBuffer,
+        scratch: FloatArray,
+        scanLine: FloatArray,
+        scopeWidth: Int,
+        syncPulseIndex: Int,
+        lineSamples: Int,
+        freqOffset: Float
+    ): Boolean {
+        if (syncPulseIndex + firstPixelSampleIndex < 0 || syncPulseIndex + end > scanLine.size) return false
+        ema.reset()
+        for (i in firstPixelSampleIndex until end) scratch[i] = ema.process(scanLine[syncPulseIndex + i])
+        ema.reset()
+        for (i in end - 1 downTo firstPixelSampleIndex) scratch[i] = freqToLevel(ema.process(scratch[i]), freqOffset)
+        for (i in 0 until hPixels) {
+            val pos = (i * chSamples) / hPixels
+            pixelBuffer.pixels[i] =
+                ColorConverter.yuv2rgb(scratch[pos + yEvenBegin], scratch[pos + uAvgBegin], scratch[pos + vAvgBegin])
+            pixelBuffer.pixels[i + hPixels] =
+                ColorConverter.yuv2rgb(scratch[pos + yOddBegin], scratch[pos + uAvgBegin], scratch[pos + vAvgBegin])
+        }
+        pixelBuffer.width = hPixels; pixelBuffer.height = 2
+        return true
+    }
+}
+
+internal class RawMode(override val name: String, sampleRate: Int) : SstvMode {
+    override val visCode = -1
+    override val width = -1
+    override val height = -1
+    override val firstPixelSampleIndex = 0
+    override val firstSyncPulseIndex = -1
+    override val scanLineSamples = -1
+
+    private val smallMax = round(0.125 * sampleRate).toInt()
+    private val medMax = round(0.175 * sampleRate).toInt()
+    private val ema = Ema()
+
+    override fun decodeScanLine(
+        pixelBuffer: PixelBuffer,
+        scratch: FloatArray,
+        scanLine: FloatArray,
+        scopeWidth: Int,
+        syncPulseIndex: Int,
+        lineSamples: Int,
+        freqOffset: Float
+    ): Boolean {
+        if (syncPulseIndex < 0 || syncPulseIndex + lineSamples > scanLine.size) return false
+        var px = scopeWidth
+        if (lineSamples < smallMax) px /= 2
+        if (lineSamples < medMax) px /= 2
+        ema.setCutoff(px.toDouble(), (2 * lineSamples).toDouble(), 2); ema.reset()
+        for (i in 0 until lineSamples) scratch[i] = ema.process(scanLine[syncPulseIndex + i])
+        ema.reset()
+        for (i in lineSamples - 1 downTo 0) scratch[i] = freqToLevel(ema.process(scratch[i]), freqOffset)
+        for (i in 0 until px) pixelBuffer.pixels[i] = ColorConverter.gray(scratch[(i * lineSamples) / px])
+        pixelBuffer.width = px; pixelBuffer.height = 1
+        return true
+    }
+}
+
+private fun freqToLevel(frequency: Float, offset: Float): Float = 0.5f * (frequency - offset + 1f)

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/usecase/IAudioCapture.kt

@@ -0,0 +1,34 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.usecase
+
+import kotlinx.coroutines.flow.Flow
+
+/**
+ * Platform abstraction for microphone audio capture.
+ * Produces a flow of mono Float PCM buffers at the configured sample rate.
+ */
+interface IAudioCapture {
+    val sampleRate: Int
+
+    /**
+     * Start capturing audio. Emits FloatArray buffers continuously until the flow is canceled.
+     * Caller is responsible for holding RECORD_AUDIO permission before calling this.
+     */
+    fun audioFlow(): Flow<FloatArray>
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/usecase/ISaveImage.kt

@@ -0,0 +1,26 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.usecase
+
+/**
+ * Saves a decoded SSTV image to the device gallery.
+ * @return true if the image was saved successfully
+ */
+interface ISaveImage {
+    suspend operator fun invoke(pixels: IntArray, width: Int, height: Int, modeName: String): Boolean
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/utility/DataParser.kt

@@ -58,8 +58,6 @@ class DataParser(private val dispatcher: CoroutineDispatcher) {
         }.getOrDefault(emptyList())
     }
 
-    fun isLeapYear(year: Int): Boolean = (year % 4 == 0 && year % 100 != 0) || year % 400 == 0
-
     private fun parseCSV(values: List<String>): OrbitalData? = runCatching {
         val name = values[0]
         val timestamp = values[2]
@@ -84,7 +82,8 @@ class DataParser(private val dispatcher: CoroutineDispatcher) {
             argper = values[7].toDouble(),
             meanan = values[8].toDouble(),
             catnum = values[11].toInt(),
-            bstar = values[14].toDouble()
+            bstar = values[14].toDouble(),
+            ndot = values[15].toDouble()
         )
     }.onFailure { println("CSV parsing exception: $it") }.getOrNull()
 
@@ -101,11 +100,14 @@ class DataParser(private val dispatcher: CoroutineDispatcher) {
             argper = line2.substring(34, 42).toDouble(),
             meanan = line2.substring(43, 51).toDouble(),
             catnum = line1.substring(2, 7).trim().toInt(),
-            bstar = 1e-5 * line1.substring(53, 59).toDouble() / 10.0.pow(line1.substring(60, 61).toDouble())
+            bstar = 1e-5 * line1.substring(53, 59).toDouble() / 10.0.pow(line1.substring(60, 61).toDouble()),
+            ndot = line1.substring(33, 43).trim().toDouble()
         )
     }.onFailure { println("TLE parsing exception: $it") }.getOrNull()
 
-    private fun getDayOfYear(year: Int, month: Int, dayOfMonth: Int): Int {
+    fun isLeapYear(year: Int): Boolean = (year % 4 == 0 && year % 100 != 0) || year % 400 == 0
+
+    fun getDayOfYear(year: Int, month: Int, dayOfMonth: Int): Int {
         val daysInMonth = intArrayOf(31, if (isLeapYear(year)) 29 else 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31)
         return daysInMonth.take(month - 1).sum() + dayOfMonth
     }

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/utility/DopplerFrequencyCalculator.kt

@@ -0,0 +1,98 @@
+/* 
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ */
+package com.rtbishop.look4sat.core.domain.utility
+
+import com.rtbishop.look4sat.core.domain.model.SatRadio
+import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
+
+/**
+ * Computes Doppler-corrected reciprocal frequencies for linear transponders.
+ *
+ * For a linear (passband) transponder, uplink and downlink frequencies are
+ * related by a fixed passband offset. When the satellite moves, both are
+ * Doppler-shifted. Given one, we compute the other:
+ *
+ *   downlink → uplink: mapDownlinkToUplink (passband) → getUplinkFreq (Doppler)
+ *   uplink → downlink: mapUplinkToDownlink (passband) → getDownlinkFreq (Doppler)
+ *
+ * Addresses GitHub issue #91 (Custom frequency Doppler correction).
+ */
+object DopplerFrequencyCalculator {
+
+    /**
+     * Given a downlink frequency, compute the Doppler-corrected uplink frequency.
+     * Returns null if the transponder is not a linear passband type.
+     */
+    fun computeUplinkFromDownlink(
+        downlinkHz: Long,
+        transponder: SatRadio,
+        orbitalPos: OrbitalPos
+    ): Long? {
+        if (!isLinearTransponder(transponder)) return null
+        val baseUplink = TransponderMapper.mapDownlinkToUplink(downlinkHz, transponder) ?: return null
+        return orbitalPos.getUplinkFreq(baseUplink)
+    }
+
+    /**
+     * Given a downlink frequency, compute the Doppler-corrected uplink frequency
+     * with an offset applied to the downlink (in Hz).
+     * Returns null if the transponder is not a linear passband type.
+     */
+    fun computeUplinkFromDownlinkWithOffset(
+        downlinkHz: Long,
+        transponder: SatRadio,
+        orbitalPos: OrbitalPos,
+        offsetHz: Long
+    ): Long? {
+        if (!isLinearTransponder(transponder)) return null
+        val baseUplink = TransponderMapper.mapDownlinkToUplink(downlinkHz + offsetHz, transponder) ?: return null
+        return orbitalPos.getUplinkFreq(baseUplink)
+    }
+
+    /**
+     * Given an uplink frequency, compute the Doppler-corrected downlink frequency.
+     * Returns null if the transponder is not a linear passband type.
+     */
+    fun computeDownlinkFromUplink(
+        uplinkHz: Long,
+        transponder: SatRadio,
+        orbitalPos: OrbitalPos
+    ): Long? {
+        if (!isLinearTransponder(transponder)) return null
+        val baseDownlink = TransponderMapper.mapUplinkToDownlink(uplinkHz, transponder) ?: return null
+        return orbitalPos.getDownlinkFreq(baseDownlink)
+    }
+
+    /**
+     * Given an uplink frequency, compute the Doppler-corrected downlink frequency
+     * with an offset applied to the downlink (in Hz).
+     * Returns null if the transponder is not a linear passband type.
+     */
+    fun computeDownlinkFromUplinkWithOffset(
+        uplinkHz: Long,
+        transponder: SatRadio,
+        orbitalPos: OrbitalPos,
+        offsetHz: Long
+    ): Long? {
+        if (!isLinearTransponder(transponder)) return null
+        val baseDownlink = TransponderMapper.mapUplinkToDownlink(uplinkHz, transponder) ?: return null
+        return orbitalPos.getDownlinkFreq(baseDownlink + offsetHz)
+    }
+
+    /** True if this transponder supports linear passband mapping. */
+    fun isLinearTransponder(transponder: SatRadio): Boolean {
+        val upLow = transponder.uplinkLow
+        val upHigh = transponder.uplinkHigh
+        val downLow = transponder.downlinkLow
+        val downHigh = transponder.downlinkHigh
+        return upLow != null && upHigh != null && downLow != null && downHigh != null
+                && upLow != upHigh && downLow != downHigh
+    }
+}

core/domain/src/main/java/com/rtbishop/look4sat/core/domain/utility/GeoConverter.kt

@@ -17,11 +17,18 @@
  */
 package com.rtbishop.look4sat.core.domain.utility
 
+import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.DEG2RAD
+import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
 import com.rtbishop.look4sat.core.domain.predict.RAD2DEG
+import kotlin.math.acos
+import kotlin.math.atan2
+import kotlin.math.cos
 import kotlin.math.max
 import kotlin.math.min
+import kotlin.math.sin
 
+private const val AVG_EARTH_RADIUS_KM = 6371.009
 private const val MIN_LATITUDE = -85.05112877980658
 private const val MAX_LATITUDE = 85.05112877980658
 private const val MIN_LONGITUDE = -180.0
@@ -48,6 +55,27 @@ fun Double.toRadians(): Double = this * DEG2RAD
 //    return MIN_LONGITUDE + (MAX_LONGITUDE - MIN_LONGITUDE) * this
 //}
 
+// Great-circle distance between two positions in kilometers using the spherical law of cosines.
+fun greatCircleDistanceKm(lat1: Double, lon1: Double, lat2: Double, lon2: Double): Double {
+    val lat1R = lat1.toRadians()
+    val lat2R = lat2.toRadians()
+    val lon1R = lon1.toRadians()
+    val lon2R = lon2.toRadians()
+    return acos(
+        sin(lat1R) * sin(lat2R) + cos(lat1R) * cos(lat2R) * cos(lon2R - lon1R)
+    ) * AVG_EARTH_RADIUS_KM
+}
+
+// Initial bearing (azimuth) from position 1 to position 2, in degrees (0-360).
+fun bearingDeg(lat1: Double, lon1: Double, lat2: Double, lon2: Double): Double {
+    val lat1R = lat1.toRadians()
+    val lat2R = lat2.toRadians()
+    val dLon = (lon2 - lon1).toRadians()
+    val y = sin(dLon) * cos(lat2R)
+    val x = cos(lat1R) * sin(lat2R) - sin(lat1R) * cos(lat2R) * cos(dLon)
+    return (atan2(y, x).toDegrees() + 360) % 360
+}
+
 fun clipLat(latitude: Double): Double {
     return clip(latitude, MIN_LATITUDE, MAX_LATITUDE)
 }
@@ -59,6 +87,13 @@ fun clipLon(longitude: Double): Double {
     return clip(result, MIN_LONGITUDE, MAX_LONGITUDE)
 }
 
+fun OrbitalPos.toMapGeoPos(): GeoPos {
+    return GeoPos(
+        latitude = clipLat(latitude.toDegrees()),
+        longitude = clipLon(longitude.toDegrees())
+    )
+}
+
 private fun clip(currentValue: Double, minValue: Double, maxValue: Double): Double {
     return min(max(currentValue, minValue), maxValue)
 }

core/domain/src/test/java/com/rtbishop/look4sat/core/domain/DataParserTest.kt

@@ -59,10 +59,53 @@ class DataParserTest {
     @Test
     fun `Given valid CSV stream returns valid data`() = runTest(testDispatcher) {
         val parsedList = dataParser.parseCSVStream(validCSVStream)
+        assert(parsedList.size == 2)
         assert(parsedList[0].epoch == 21320.51955234)
         assert(parsedList[1].epoch == 24069.23963816)
     }
 
+    @Test
+    fun `Given valid CSV stream all orbital fields are parsed correctly`() = runTest(testDispatcher) {
+        val csvStream = """
+            OBJECT_NAME,OBJECT_ID,EPOCH,MEAN_MOTION,ECCENTRICITY,INCLINATION,RA_OF_ASC_NODE,ARG_OF_PERICENTER,MEAN_ANOMALY,EPHEMERIS_TYPE,CLASSIFICATION_TYPE,NORAD_CAT_ID,ELEMENT_SET_NO,REV_AT_EPOCH,BSTAR,MEAN_MOTION_DOT,MEAN_MOTION_DDOT
+            ISS (ZARYA),1998-067A,2021-11-16T12:28:09.322176,15.48582035,.0004694,51.6447,309.4881,203.6966,299.8876,0,U,25544,999,31220,.31985E-4,.1288E-4,0
+        """.trimIndent().byteInputStream()
+        val sat = dataParser.parseCSVStream(csvStream)[0]
+        assert(sat.name == "ISS (ZARYA)")
+        assert(sat.catnum == 25544)
+        assert(sat.meanmo == 15.48582035)
+        assert(sat.eccn == 0.0004694)
+        assert(sat.incl == 51.6447)
+        assert(sat.raan == 309.4881)
+        assert(sat.argper == 203.6966)
+        assert(sat.meanan == 299.8876)
+        assert(sat.bstar == 0.31985E-4)
+        assert(sat.ndot == 0.1288E-4)
+    }
+
+    @Test
+    fun `Given valid CSV stream ndot is parsed for decay detection`() = runTest(testDispatcher) {
+        val csvStream = """
+            OBJECT_NAME,OBJECT_ID,EPOCH,MEAN_MOTION,ECCENTRICITY,INCLINATION,RA_OF_ASC_NODE,ARG_OF_PERICENTER,MEAN_ANOMALY,EPHEMERIS_TYPE,CLASSIFICATION_TYPE,NORAD_CAT_ID,ELEMENT_SET_NO,REV_AT_EPOCH,BSTAR,MEAN_MOTION_DOT,MEAN_MOTION_DDOT
+            ISS (ZARYA),1998-067A,2021-11-16T12:28:09.322176,15.48582035,.0004694,51.6447,309.4881,203.6966,299.8876,0,U,25544,999,31220,.31985E-4,.1288E-4,0
+        """.trimIndent().byteInputStream()
+        val sat = dataParser.parseCSVStream(csvStream)[0]
+        // ISS is healthy, should not be decayed even years later
+        assert(!sat.hasDecayed(System.currentTimeMillis()))
+    }
+
+    @Test
+    fun `Given CSV with high drag satellite detects decay`() = runTest(testDispatcher) {
+        // Simulate a satellite with high drag and old epoch that should have decayed
+        val csvStream = """
+            OBJECT_NAME,OBJECT_ID,EPOCH,MEAN_MOTION,ECCENTRICITY,INCLINATION,RA_OF_ASC_NODE,ARG_OF_PERICENTER,MEAN_ANOMALY,EPHEMERIS_TYPE,CLASSIFICATION_TYPE,NORAD_CAT_ID,ELEMENT_SET_NO,REV_AT_EPOCH,BSTAR,MEAN_MOTION_DOT,MEAN_MOTION_DDOT
+            DEBRIS,2020-001A,2020-01-15T00:00:00.000000,15.9,.001,51.0,100.0,200.0,300.0,0,U,99999,1,100,.5E-3,.05,0
+        """.trimIndent().byteInputStream()
+        val sat = dataParser.parseCSVStream(csvStream)[0]
+        // High mean motion (15.9) + high drag (.05) + old epoch → should be decayed by now
+        assert(sat.hasDecayed(System.currentTimeMillis()))
+    }
+
     @Test
     fun `Given invalid CSV stream returns empty list`() = runTest(testDispatcher) {
         assert(dataParser.parseCSVStream(invalidCSVStream).isEmpty())
@@ -71,10 +114,41 @@ class DataParserTest {
     @Test
     fun `Given valid TLE stream returns valid data`() = runTest(testDispatcher) {
         val parsedList = dataParser.parseTLEStream(validTLEStream)
+        assert(parsedList.size == 2)
         assert(parsedList[0].epoch == 21320.51955234)
         assert(parsedList[1].epoch == 24069.23963816)
     }
 
+    @Test
+    fun `Given valid TLE stream all orbital fields are parsed correctly`() = runTest(testDispatcher) {
+        val tleStream = """
+            ISS (ZARYA)
+            1 25544U 98067A   21320.51955234  .00001288  00000+0  31985-4 0  9990
+            2 25544  51.6447 309.4881 0004694 203.6966 299.8876 15.48582035312205
+        """.trimIndent().byteInputStream()
+        val sat = dataParser.parseTLEStream(tleStream)[0]
+        assert(sat.name == "ISS (ZARYA)")
+        assert(sat.catnum == 25544)
+        assert(sat.meanmo == 15.48582035)
+        assert(sat.eccn == 0.0004694)
+        assert(sat.incl == 51.6447)
+        assert(sat.raan == 309.4881)
+        assert(sat.argper == 203.6966)
+        assert(sat.meanan == 299.8876)
+        assert(sat.ndot == 0.00001288)
+    }
+
+    @Test
+    fun `Given valid TLE stream ndot is parsed for decay detection`() = runTest(testDispatcher) {
+        val tleStream = """
+            ISS (ZARYA)
+            1 25544U 98067A   21320.51955234  .00001288  00000+0  31985-4 0  9990
+            2 25544  51.6447 309.4881 0004694 203.6966 299.8876 15.48582035312205
+        """.trimIndent().byteInputStream()
+        val sat = dataParser.parseTLEStream(tleStream)[0]
+        assert(!sat.hasDecayed(System.currentTimeMillis()))
+    }
+
     @Test
     fun `Given invalid TLE stream returns empty list`() = runTest(testDispatcher) {
         assert(dataParser.parseTLEStream(invalidTLEStream).isEmpty())
@@ -85,6 +159,43 @@ class DataParserTest {
         assert(dataParser.parseJSONStream(validJSONStream)[0].downlinkLow == 136658500L)
     }
 
+    @Test
+    fun `Given valid JSON stream all radio fields are parsed correctly`() = runTest(testDispatcher) {
+        val jsonStream = """
+            [{"uuid":"UzPz4gcsNBPKPKAFPmer7g","description":"Upper side band (drifting)","alive":true,"type":"Transmitter","uplink_low":145900000,"uplink_high":146000000,"uplink_drift":null,"downlink_low":136658500,"downlink_high":136700000,"downlink_drift":null,"mode":"USB","mode_id":9,"uplink_mode":"FM","invert":true,"baud":null,"sat_id":"SCHX-0895-2361-9925-0309","norad_cat_id":965,"status":"active","updated":"2019-04-18T05:39:53.343316Z","citation":"CITATION NEEDED","service":"Unknown","coordination":"","coordination_url":""}]
+        """.trimIndent().byteInputStream()
+        val radio = dataParser.parseJSONStream(jsonStream)[0]
+        assert(radio.uuid == "UzPz4gcsNBPKPKAFPmer7g")
+        assert(radio.info == "Upper side band (drifting)")
+        assert(radio.isAlive)
+        assert(radio.downlinkLow == 136658500L)
+        assert(radio.downlinkHigh == 136700000L)
+        assert(radio.downlinkMode == "USB")
+        assert(radio.uplinkLow == 145900000L)
+        assert(radio.uplinkHigh == 146000000L)
+        assert(radio.uplinkMode == "FM")
+        assert(radio.isInverted)
+        assert(radio.catnum == 965)
+    }
+
+    @Test
+    fun `Given JSON with null optional fields parses without error`() = runTest(testDispatcher) {
+        val jsonStream = """
+            [{"uuid":"abc123","description":"Beacon","alive":false,"type":"Transmitter","uplink_low":null,"uplink_high":null,"uplink_drift":null,"downlink_low":145800000,"downlink_high":null,"downlink_drift":null,"mode":null,"mode_id":null,"uplink_mode":null,"invert":false,"baud":null,"sat_id":"TEST","norad_cat_id":12345,"status":"active","updated":"2024-01-01T00:00:00Z","citation":"","service":"Unknown","coordination":"","coordination_url":""}]
+        """.trimIndent().byteInputStream()
+        val radio = dataParser.parseJSONStream(jsonStream)[0]
+        assert(radio.uuid == "abc123")
+        assert(!radio.isAlive)
+        assert(radio.downlinkLow == 145800000L)
+        assert(radio.downlinkHigh == null)
+        assert(radio.downlinkMode == null)
+        assert(radio.uplinkLow == null)
+        assert(radio.uplinkHigh == null)
+        assert(radio.uplinkMode == null)
+        assert(!radio.isInverted)
+        assert(radio.catnum == 12345)
+    }
+
     @Test
     fun `Given invalid JSON stream returns empty list`() = runTest(testDispatcher) {
         assert(dataParser.parseJSONStream(invalidJSONStream).isEmpty())
@@ -96,10 +207,36 @@ class DataParserTest {
     }
 
     @Test
-    fun `Function isLeapYear returns correct data`() = runTest(testDispatcher) {
+    fun `isLeapYear returns correct results`() {
-        val years = listOf(1900, 1984, 1994, 2016, 2022, 2024, 2042, 2048)
+        val years = listOf(1900, 1984, 1994, 2000, 2016, 2022, 2024, 2042, 2048, 2100)
-        val answers = listOf(false, true, false, true, false, true, false, true)
+        val expected = listOf(false, true, false, true, true, false, true, false, true, false)
         val results = years.map { dataParser.isLeapYear(it) }
-        assert(results == answers)
+        assert(results == expected)
+    }
+
+    @Test
+    fun `getDayOfYear returns correct day for January 1st`() {
+        assert(dataParser.getDayOfYear(2024, 1, 1) == 1)
+        assert(dataParser.getDayOfYear(2023, 1, 1) == 1)
+    }
+
+    @Test
+    fun `getDayOfYear returns correct day for March 1st in leap and non-leap years`() {
+        // 2024 is leap: Jan(31) + Feb(29) + 1 = 61
+        assert(dataParser.getDayOfYear(2024, 3, 1) == 61)
+        // 2023 is not leap: Jan(31) + Feb(28) + 1 = 60
+        assert(dataParser.getDayOfYear(2023, 3, 1) == 60)
+    }
+
+    @Test
+    fun `getDayOfYear returns correct day for December 31st`() {
+        assert(dataParser.getDayOfYear(2024, 12, 31) == 366) // leap year
+        assert(dataParser.getDayOfYear(2023, 12, 31) == 365) // non-leap year
+    }
+
+    @Test
+    fun `getDayOfYear returns correct day for November 16th`() {
+        // Matches the CSV test data epoch: 2021-11-16 → day 320
+        assert(dataParser.getDayOfYear(2021, 11, 16) == 320)
     }
 }

core/domain/src/test/java/com/rtbishop/look4sat/core/domain/DopplerFrequencyCalculatorTest.kt

@@ -0,0 +1,120 @@
+package com.rtbishop.look4sat.core.domain
+
+import com.rtbishop.look4sat.core.domain.model.SatRadio
+import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
+import com.rtbishop.look4sat.core.domain.utility.DopplerFrequencyCalculator
+import org.junit.Assert.*
+import org.junit.Test
+
+class DopplerFrequencyCalculatorTest {
+
+    private fun linearTransponder(
+        upLow: Long = 145_000_000L,
+        upHigh: Long = 145_500_000L,
+        downLow: Long = 435_000_000L,
+        downHigh: Long? = 435_500_000L,
+        inverted: Boolean = false
+    ) = SatRadio(
+        uuid = "linear", info = "Linear Transponder", isAlive = true,
+        downlinkLow = downLow, downlinkHigh = downHigh,
+        downlinkMode = "USB", uplinkLow = upLow, uplinkHigh = upHigh,
+        uplinkMode = "LSB", isInverted = inverted, catnum = 12345
+    )
+
+    private fun fmTransponder() = SatRadio(
+        uuid = "fm", info = "FM Repeater", isAlive = true,
+        downlinkLow = 435_600_000L, downlinkHigh = null,
+        downlinkMode = "FM", uplinkLow = 145_900_000L, uplinkHigh = null,
+        uplinkMode = "FM", isInverted = false, catnum = 99999
+    )
+
+    private fun pos(distanceRateKmS: Double = 0.0) = OrbitalPos().apply {
+        this.distanceRate = distanceRateKmS
+    }
+
+    @Test
+    fun isLinearTransponder_returnsTrueForLinear() {
+        assertTrue(DopplerFrequencyCalculator.isLinearTransponder(linearTransponder()))
+    }
+
+    @Test
+    fun isLinearTransponder_returnsFalseForFM() {
+        assertFalse(DopplerFrequencyCalculator.isLinearTransponder(fmTransponder()))
+    }
+
+    @Test
+    fun isLinearTransponder_returnsFalseForNullDownlinkHigh() {
+        val xpdr = linearTransponder(downHigh = null)
+        assertFalse(DopplerFrequencyCalculator.isLinearTransponder(xpdr))
+    }
+
+    @Test
+    fun computeUplinkFromDownlink_linear_noDoppler() {
+        val xpdr = linearTransponder()
+        val orbitalPos = pos(0.0)
+        val uplink = DopplerFrequencyCalculator.computeUplinkFromDownlink(435_200_000L, xpdr, orbitalPos)
+        assertNotNull(uplink)
+        assertTrue(uplink!! > 0)
+        // With zero Doppler, result equals mapDownlinkToUplink output
+        assertEquals(145_200_000L, uplink)
+    }
+
+    @Test
+    fun computeDownlinkFromUplink_linear_noDoppler() {
+        val xpdr = linearTransponder()
+        val orbitalPos = pos(0.0)
+        val downlink = DopplerFrequencyCalculator.computeDownlinkFromUplink(145_200_000L, xpdr, orbitalPos)
+        assertNotNull(downlink)
+        assertEquals(435_200_000L, downlink)
+    }
+
+    @Test
+    fun computeUplinkFromDownlink_withDoppler_positiveRangeRate() {
+        // Satellite receding (positive range rate) → ground must transmit higher freq to compensate
+        val xpdr = linearTransponder()
+        val orbitalPos = pos(7.0)  // ~7 km/s receding
+        val uplink = DopplerFrequencyCalculator.computeUplinkFromDownlink(435_200_000L, xpdr, orbitalPos)
+        assertNotNull(uplink)
+        // Uplink freq should be Doppler shifted UP (compensating for receding)
+        assertTrue(uplink!! > 145_200_000L)
+    }
+
+    @Test
+    fun computeUplinkFromDownlink_fm_transponder_returnsNull() {
+        val orbitalPos = pos()
+        val result = DopplerFrequencyCalculator.computeUplinkFromDownlink(435_600_000L, fmTransponder(), orbitalPos)
+        assertNull(result)
+    }
+
+    @Test
+    fun computeDownlinkFromUplink_fm_transponder_returnsNull() {
+        val orbitalPos = pos()
+        val result = DopplerFrequencyCalculator.computeDownlinkFromUplink(145_900_000L, fmTransponder(), orbitalPos)
+        assertNull(result)
+    }
+
+    @Test
+    fun computeUplinkFromDownlink_invertedTransponder() {
+        val xpdr = linearTransponder(inverted = true, downHigh = 435_500_000L)
+        val orbitalPos = pos(0.0)
+        val uplink = DopplerFrequencyCalculator.computeUplinkFromDownlink(435_200_000L, xpdr, orbitalPos)
+        assertNotNull(uplink)
+        // Inverted: offset from high end → maps to high end of uplink
+        assertEquals(145_300_000L, uplink)
+    }
+
+    @Test
+    fun computeUplinkFromDownlink_roundTrip() {
+        // downlink → uplink → downlink should round-trip
+        val xpdr = linearTransponder()
+        val orbitalPos = pos(3.5)
+        val originalDownlink = 435_250_000L
+        val uplink = DopplerFrequencyCalculator.computeUplinkFromDownlink(originalDownlink, xpdr, orbitalPos)
+        assertNotNull(uplink)
+        val roundTripDownlink = DopplerFrequencyCalculator.computeDownlinkFromUplink(uplink!!, xpdr, orbitalPos)
+        assertNotNull(roundTripDownlink)
+        // Doppler round-trip: small residual due to freq-dependent Doppler
+        val error = kotlin.math.abs(roundTripDownlink!! - originalDownlink)
+        assertTrue("Round-trip error too large: $error", error < 10000)
+    }
+}

core/domain/src/test/java/com/rtbishop/look4sat/core/domain/cw/CwDecoderTest.kt

@@ -0,0 +1,301 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.domain.cw
+
+import org.junit.Assert.*
+import org.junit.Test
+import kotlin.math.PI
+import kotlin.math.sin
+
+class CwDecoderTest {
+
+    // --- Morse table ---
+
+    @Test
+    fun morseToChar_basicLetters() {
+        assertEquals('A', CwBayesianDecoder.morseToChar("01"))
+        assertEquals('S', CwBayesianDecoder.morseToChar("000"))
+        assertEquals('O', CwBayesianDecoder.morseToChar("111"))
+    }
+
+    @Test
+    fun morseToChar_numbers() {
+        assertEquals('1', CwBayesianDecoder.morseToChar("01111"))
+        assertEquals('0', CwBayesianDecoder.morseToChar("11111"))
+    }
+
+    @Test
+    fun morseToChar_unknown_returnsNull() {
+        assertNull(CwBayesianDecoder.morseToChar("......."))
+        assertNull(CwBayesianDecoder.morseToChar(""))
+    }
+
+    // --- FFT ---
+
+    @Test
+    fun fft_magnitudeSpectrum_detectsTone() {
+        val fft = CwFFT(256)
+        val sampleRate = 8000f
+        val freq = 700f
+        val buffer = FloatArray(256) { (sin(2.0 * PI * freq * it / sampleRate)).toFloat() }
+        val mag = fft.magnitudeSpectrum(buffer)
+        // Peak should be at bin around 700 * 256 / 8000 ≈ 22.4
+        var maxBin = 0
+        var maxVal = 0f
+        for (i in mag.indices) {
+            if (mag[i] > maxVal) { maxVal = mag[i]; maxBin = i }
+        }
+        assertTrue("Peak bin $maxBin should be near 22", maxBin in 18..26)
+        assertTrue("Peak value $maxVal should be positive", maxVal > 0.01f)
+    }
+
+    @Test
+    fun fft_magnitudeSpectrum_silence_isFlat() {
+        val fft = CwFFT(256)
+        val buffer = FloatArray(256) { 0f }
+        val mag = fft.magnitudeSpectrum(buffer)
+        for (v in mag) assertEquals("Silence spectrum should be 0, got $v", 0f, v, 1e-6f)
+    }
+
+    @Test
+    fun fft_rejectsWrongSize() {
+        assertThrows(IllegalArgumentException::class.java) { CwFFT(100) }
+    }
+
+    // --- Spectrogram ---
+
+    @Test
+    fun spectrogram_addSamples_updatesEnergy() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        val freq = 700f
+        // Feed multiple frames to stabilize energy normalization
+        for (i in 0..5) {
+            val buffer = FloatArray(256) { (sin(2.0 * PI * freq * it / 8000.0)).toFloat() }
+            spec.addSamples(buffer)
+        }
+        val col = spec.getCurrentColumn()
+        val peakBin = spec.findPeakBin()
+        assertTrue("Peak bin $peakBin should be >= 0", peakBin >= 0)
+    }
+
+    @Test
+    fun spectrogram_findPeakBin_returnsValidBin() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        // Add multiple frames of 700 Hz tone
+        for (i in 0..5) {
+            val buffer = FloatArray(256) { (sin(2.0 * PI * 700.0 * it / 8000.0)).toFloat() }
+            spec.addSamples(buffer)
+        }
+        val peakBin = spec.findPeakBin()
+        assertTrue("Peak bin should be >= 0, got $peakBin", peakBin >= 0)
+    }
+
+    @Test
+    fun spectrogram_freqToBin_roundtrip() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        val freq = 700f
+        val bin = spec.freqToBin(freq)
+        val backFreq = spec.binToFreq(bin)
+        assertTrue("Freq $freq → bin $bin → freq $backFreq", backFreq > 600f && backFreq < 800f)
+    }
+
+    @Test
+    fun spectrogram_getBinEnergy_returnsCorrectLength() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        val energy = spec.getBinEnergy(0, 10)
+        assertEquals(10, energy.size)
+    }
+
+    @Test
+    fun spectrogram_reset() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        spec.addSamples(FloatArray(256) { 1f })
+        spec.reset()
+        assertEquals(-1, spec.findPeakBin())
+    }
+
+    // --- Bayesian decoder ---
+
+    @Test
+    fun bayesian_processTone_dit() {
+        val decoder = CwBayesianDecoder()
+        // At 20 WPM, dot = 60 ms
+        val result = decoder.processTone(60f)
+        assertEquals('0', result.symbol)
+        assertTrue("Dit probability should be positive", result.probability > 0.1f)
+    }
+
+    @Test
+    fun bayesian_processTone_dash() {
+        val decoder = CwBayesianDecoder()
+        // Dash = 3 * dot = 180 ms
+        val result = decoder.processTone(180f)
+        assertEquals('1', result.symbol)
+        assertTrue("Dash probability should be positive", result.probability > 0.1f)
+    }
+
+    @Test
+    fun bayesian_processTone_unknown_returnsNull() {
+        val decoder = CwBayesianDecoder()
+        // Very long tone — low probability for both dit and dash
+        val result = decoder.processTone(5000f)
+        assertNull(result.symbol)
+    }
+
+    @Test
+    fun bayesian_processGap_interChar_returnsChar() {
+        val decoder = CwBayesianDecoder()
+        decoder.processTone(60f) // dit
+        decoder.processTone(60f) // dit
+        decoder.processTone(60f) // dit
+        // 3 dots = "000" = 'S'
+        val char = decoder.processGap(180f) // 3 * dot = inter-char gap
+        assertEquals('S', char)
+    }
+
+    @Test
+    fun bayesian_processGap_wordGap_addsSpace() {
+        val decoder = CwBayesianDecoder()
+        decoder.processTone(60f) // dit = 'E'
+        decoder.processGap(180f) // inter-char gap
+        // Now word gap
+        val space = decoder.processGap(420f) // 7 * dot
+        assertEquals(' ', space)
+    }
+
+    @Test
+    fun bayesian_decodedText_accumulates() {
+        val decoder = CwBayesianDecoder()
+        decoder.processTone(60f) // dit = 'E'
+        decoder.processGap(180f) // inter-char
+        assertTrue(decoder.decodedText.isNotEmpty())
+    }
+
+    @Test
+    fun bayesian_reset() {
+        val decoder = CwBayesianDecoder()
+        decoder.processTone(60f)
+        decoder.reset()
+        assertEquals("", decoder.decodedText)
+    }
+
+    @Test
+    fun bayesian_getSpeed() {
+        val decoder = CwBayesianDecoder()
+        // Send 3 dits at 20 WPM (60 ms each)
+        decoder.processTone(60f)
+        decoder.processTone(60f)
+        decoder.processTone(60f)
+        val speed = decoder.getSpeed()
+        assertTrue("Speed should be ~20 WPM, got $speed", speed > 15f && speed < 30f)
+    }
+
+    // --- Channel tracker ---
+
+    @Test
+    fun channelTracker_initialState() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        val tracker = CwChannelTracker(spec)
+        val channels = tracker.update()
+        assertTrue("No channels should be active initially", channels.isEmpty())
+    }
+
+    @Test
+    fun channelTracker_detectsTone() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        // Feed a tone
+        for (i in 0..5) {
+            spec.addSamples(FloatArray(256) { (sin(2.0 * PI * 700.0 * it / 8000.0)).toFloat() })
+        }
+        val tracker = CwChannelTracker(spec)
+        val channels = tracker.update()
+        assertTrue("Should detect at least 1 channel", channels.isNotEmpty())
+    }
+
+    @Test
+    fun channelTracker_bestChannel() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        for (i in 0..5) {
+            spec.addSamples(FloatArray(256) { (sin(2.0 * PI * 700.0 * it / 8000.0)).toFloat() })
+        }
+        val tracker = CwChannelTracker(spec)
+        tracker.update()
+        val best = tracker.getBestChannel()
+        assertNotNull("Best channel should exist", best)
+        if (best != null) assertTrue(best.frequency in 600f..800f)
+    }
+
+    @Test
+    fun channelTracker_reset() {
+        val spec = CwSpectrogram(sampleRate = 8000)
+        for (i in 0..5) {
+            spec.addSamples(FloatArray(256) { (sin(2.0 * PI * 700.0 * it / 8000.0)).toFloat() })
+        }
+        val tracker = CwChannelTracker(spec)
+        tracker.update()
+        tracker.reset()
+        assertNull(tracker.getBestChannel())
+    }
+
+    // --- Full decoder ---
+
+    @Test
+    fun decoder_initialState() {
+        val decoder = CwDecoder()
+        assertEquals("", decoder.decodedTextFlow.value)
+        assertEquals(0f, decoder.signalStrength.value, 0.001f)
+    }
+
+    @Test
+    fun decoder_processSilence_doesNotCrash() {
+        val decoder = CwDecoder()
+        decoder.processBuffer(FloatArray(256) { 0f })
+        assertEquals("", decoder.decodedTextFlow.value)
+    }
+
+    @Test
+    fun decoder_processNoise_doesNotCrash() {
+        val decoder = CwDecoder()
+        decoder.processBuffer(FloatArray(256) { (Math.random() * 2 - 1).toFloat() * 0.1f })
+        assertNotNull(decoder.decodedTextFlow.value)
+    }
+
+    @Test
+    fun decoder_processTone_doesNotCrash() {
+        val decoder = CwDecoder()
+        for (i in 0..20) {
+            decoder.processBuffer(FloatArray(256) { (sin(2.0 * PI * 700.0 * it / 8000.0)).toFloat() })
+        }
+        assertNotNull(decoder.decodedTextFlow.value)
+    }
+
+    @Test
+    fun decoder_reset() {
+        val decoder = CwDecoder()
+        decoder.processBuffer(FloatArray(256) { 1f })
+        decoder.resetDecoder()
+        assertEquals("", decoder.decodedTextFlow.value)
+        assertEquals(0f, decoder.signalStrength.value, 0.001f)
+    }
+
+    @Test
+    fun decoder_withFixedPitch() {
+        val decoder = CwDecoder(sampleRate = 8000, cwToneFreq = 700f)
+        assertEquals(700f, decoder.estimatedPitch.value)
+    }
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/BubblesEffect.kt

@@ -0,0 +1,424 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.presentation
+
+import android.graphics.Paint
+import android.graphics.LinearGradient
+import android.graphics.RadialGradient
+import android.graphics.Shader
+import androidx.compose.foundation.Canvas
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.withFrameNanos
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.DrawScope
+import androidx.compose.ui.graphics.nativeCanvas
+import androidx.core.graphics.withRotation
+import kotlinx.coroutines.isActive
+import kotlin.math.atan2
+import kotlin.math.cos
+import kotlin.math.min
+import kotlin.math.sin
+import kotlin.math.sqrt
+import kotlin.random.Random
+
+@Immutable
+data class BubblesStyle(
+    val bgColor: Color = Color.Black,
+    val bubbleCount: Int = 16,
+    val minBubbleCount: Int = 8,
+    val maxBubbleCount: Int = 16,
+    val adaptiveBubbleCount: Boolean = true,
+    val spawnIntervalMs: Long = 800L,
+    val bubbleRadiusFraction: Float = 0.24f,
+    val adaptiveSizing: Boolean = true,
+    val referenceMinSizePx: Float = 360f,
+    val referenceAreaPx: Float = 360f * 800f,
+    val minBubbleRadiusPx: Float = 16f,
+    val maxBubbleRadiusPx: Float = 256f,
+    val speedScale: Float = 0.99f,
+    val minVelocity: Float = 0.8f,
+    val maxVelocity: Float = 3.2f,
+    val hueRotationSpeedDps: Float = 60f, // degrees per second
+)
+
+@Composable
+fun BubblesEffect(
+    modifier: Modifier = Modifier,
+    isRunning: Boolean = true,
+    style: BubblesStyle = BubblesStyle(),
+) {
+    val renderer = remember { BubblesRenderer() }
+    var frameSignal by remember { mutableIntStateOf(0) }
+
+    // Animation loop
+    LaunchedEffect(isRunning, style) {
+        if (!isRunning) return@LaunchedEffect
+        var previousNanos = 0L
+        while (isActive) {
+            withFrameNanos { now ->
+                if (previousNanos == 0L) previousNanos = now
+                val deltaSec = ((now - previousNanos).coerceAtMost(MAX_STEP_NANOS)).toFloat() / NANOS_TO_SECONDS
+                previousNanos = now
+                renderer.update(deltaSec, style)
+                frameSignal++
+            }
+        }
+    }
+    Canvas(modifier = modifier) {
+        frameSignal
+        renderer.ensureLayout(size)
+        renderer.draw(this, style)
+    }
+}
+
+private const val MAX_STEP_NANOS = 16_666_667L // ~60 FPS
+private const val NANOS_TO_SECONDS = 1_000_000_000f
+private val SHELL_GRADIENT_STOPS = floatArrayOf(0f, 0.52f, 0.66f, 0.79f, 0.90f, 0.968f, 0.993f, 1f)
+private val INNER_GRADIENT_STOPS = floatArrayOf(0f, 0.34f, 0.68f, 1f)
+
+private data class Velocity(var x: Float, var y: Float)
+
+private data class Bubble(
+    var x: Float,
+    var y: Float,
+    val radius: Float,
+    val velocity: Velocity,
+    val baseHue: Float, // 0-360, unique for each bubble
+)
+
+private class BubblesRenderer {
+    private var width = 0f
+    private var height = 0f
+    private val bubbles = mutableListOf<Bubble>()
+    private val random = Random(System.currentTimeMillis())
+    private var globalHueRotation = 0f // degrees, rotates all bubbles hues
+    private var spawnAccumulatorSec = 0f
+    private val paint = Paint(Paint.ANTI_ALIAS_FLAG)
+    private val shellColors = IntArray(8)
+    private val innerColors = IntArray(4)
+
+    fun ensureLayout(size: Size) {
+        val targetWidth = size.width
+        val targetHeight = size.height
+        if (targetWidth <= 0f || targetHeight <= 0f) return
+        val shouldRebuild = width != targetWidth || height != targetHeight
+        if (shouldRebuild) {
+            width = targetWidth
+            height = targetHeight
+            bubbles.clear()
+            spawnAccumulatorSec = 0f
+        }
+    }
+
+    fun spawnBubble(style: BubblesStyle): Boolean {
+        if (width <= 0f || height <= 0f) return false
+        val radius = resolveBubbleRadius(style)
+        val (velocityMin, velocityMax) = resolveVelocityRange(style)
+        val bubble = Bubble(
+            x = radius,
+            y = height - radius,
+            radius = radius,
+            velocity = Velocity(
+                x = randomInRange(velocityMin, velocityMax),
+                y = -randomInRange(velocityMin, velocityMax),
+            ),
+            baseHue = random.nextFloat() * 360f, // Random starting hue for this bubble
+        )
+        bubbles.add(bubble)
+        return true
+    }
+
+    fun update(deltaSeconds: Float, style: BubblesStyle) {
+        if (width <= 0f || height <= 0f) return
+
+        spawnMissingBubbles(deltaSeconds, style)
+
+        // Rotate hue for all bubbles
+        globalHueRotation += style.hueRotationSpeedDps * deltaSeconds
+        if (globalHueRotation >= 360f) globalHueRotation -= 360f
+        val frameScale = deltaSeconds * 60f
+        for (i in bubbles.indices) {
+            val bubble = bubbles[i]
+            // Update position
+            bubble.x += bubble.velocity.x * frameScale
+            bubble.y += bubble.velocity.y * frameScale
+            // Bounce off walls
+            if (bubble.x > width - bubble.radius) {
+                bubble.x = width - bubble.radius
+                bubble.velocity.x *= -1
+            }
+            if (bubble.x < bubble.radius) {
+                bubble.x = bubble.radius
+                bubble.velocity.x *= -1
+            }
+            if (bubble.y > height - bubble.radius) {
+                bubble.y = height - bubble.radius
+                bubble.velocity.y *= -1
+            }
+            if (bubble.y < bubble.radius) {
+                bubble.y = bubble.radius
+                bubble.velocity.y *= -1
+            }
+        }
+        // Collision detection and resolution
+        for (i in bubbles.indices) {
+            for (j in (i + 1) until bubbles.size) {
+                val b1 = bubbles[i]
+                val b2 = bubbles[j]
+                if (isCollided(b1, b2)) resolveCollision(b1, b2)
+            }
+        }
+    }
+
+    private fun spawnMissingBubbles(deltaSeconds: Float, style: BubblesStyle) {
+        val targetCount = resolveTargetBubbleCount(style)
+        if (bubbles.size >= targetCount) return
+
+        val spawnIntervalSec = style.spawnIntervalMs.coerceAtLeast(1L) / 1_000f
+        spawnAccumulatorSec += deltaSeconds
+
+        while (bubbles.size < targetCount && spawnAccumulatorSec >= spawnIntervalSec) {
+            if (!spawnBubble(style)) break
+            spawnAccumulatorSec -= spawnIntervalSec
+        }
+    }
+
+    fun draw(scope: DrawScope, style: BubblesStyle) {
+        if (width <= 0f || height <= 0f) return
+        scope.drawRect(style.bgColor)
+        val canvas = scope.drawContext.canvas.nativeCanvas
+        for (i in bubbles.indices) {
+            drawBubbleWithGradient(canvas, bubbles[i])
+        }
+    }
+
+    private fun drawBubbleWithGradient(canvas: android.graphics.Canvas, bubble: Bubble) {
+        val hue = (bubble.baseHue + globalHueRotation) % 360f
+        val lit = 53.33f + maxOf(0f, (70f - kotlin.math.abs(244f - hue)) / 4f)
+        val rgb = hueToRgb(hue, lit)
+        val shellColor = mixWithWhite(rgb, 0.04f)
+        val innerColor = mixWithWhite(rgb, 0.10f)
+        val shimmerColor = mixWithWhite(rgb, 0.35f)
+        // Outer shell
+        val shellGradient = RadialGradient(
+            bubble.x, bubble.y, bubble.radius,
+            buildShellColors(shellColor),
+            SHELL_GRADIENT_STOPS,
+            Shader.TileMode.CLAMP
+        )
+        paint.style = Paint.Style.FILL
+        paint.shader = shellGradient
+        canvas.drawCircle(bubble.x, bubble.y, bubble.radius, paint)
+        // Subtle thin rim
+        paint.shader = null
+        paint.style = Paint.Style.STROKE
+        paint.strokeWidth = maxOf(1f, bubble.radius * 0.024f)
+        paint.color = colorWithAlpha(mixWithWhite(shellColor, 0.08f), 0.30f)
+        canvas.drawCircle(bubble.x, bubble.y, bubble.radius - paint.strokeWidth * 0.5f, paint)
+        // Top internal bubble
+        val innerTop = bubble.y - bubble.radius * 0.96f
+        val innerBottom = bubble.y + bubble.radius * 0.48f
+        val innerLeft = bubble.x - bubble.radius * 0.84f
+        val innerRight = bubble.x + bubble.radius * 0.84f
+        val innerGradient = LinearGradient(
+            bubble.x,
+            innerTop,
+            bubble.x,
+            innerBottom,
+            buildInnerColors(innerColor),
+            INNER_GRADIENT_STOPS,
+            Shader.TileMode.CLAMP
+        )
+        paint.style = Paint.Style.FILL
+        paint.shader = innerGradient
+        canvas.drawOval(
+            innerLeft,
+            innerTop,
+            innerRight,
+            innerBottom,
+            paint
+        )
+        // Top-left shimmer
+        paint.shader = null
+        paint.style = Paint.Style.FILL
+        paint.color = colorWithAlpha(shimmerColor, 0.95f)
+        val shimmerCx = bubble.x - bubble.radius * 0.40f
+        val shimmerCy = bubble.y - bubble.radius * 0.72f
+        val shimmerHalfWidth = bubble.radius * 0.06f
+        val shimmerHalfHeight = bubble.radius * 0.21f
+        canvas.withRotation(60f, shimmerCx, shimmerCy) {
+            drawOval(
+                shimmerCx - shimmerHalfWidth,
+                shimmerCy - shimmerHalfHeight,
+                shimmerCx + shimmerHalfWidth,
+                shimmerCy + shimmerHalfHeight,
+                paint
+            )
+        }
+    }
+
+    private fun isCollided(bubble1: Bubble, bubble2: Bubble): Boolean {
+        val dx = bubble1.x - bubble2.x
+        val dy = bubble1.y - bubble2.y
+        val radius = (bubble1.radius + bubble2.radius) * 0.9f
+        return dx * dx + dy * dy < radius * radius
+    }
+
+    private fun resolveCollision(particle: Bubble, otherParticle: Bubble) {
+        val xVelocityDiff = particle.velocity.x - otherParticle.velocity.x
+        val yVelocityDiff = particle.velocity.y - otherParticle.velocity.y
+        val xDist = otherParticle.x - particle.x
+        val yDist = otherParticle.y - particle.y
+        // Prevent accidental overlap
+        if (xVelocityDiff * xDist + yVelocityDiff * yDist >= 0) {
+            val angle = -atan2(otherParticle.y - particle.y, otherParticle.x - particle.x)
+            val m1 = 1f
+            val m2 = 1f
+            val u1 = rotate(particle.velocity, angle)
+            val u2 = rotate(otherParticle.velocity, angle)
+            val v1 = Velocity(
+                x = (u1.x * (m1 - m2)) / (m1 + m2) + (u2.x * 2 * m2) / (m1 + m2),
+                y = u1.y,
+            )
+            val v2 = Velocity(
+                x = (u2.x * (m1 - m2)) / (m1 + m2) + (u1.x * 2 * m2) / (m1 + m2),
+                y = u2.y,
+            )
+            val vFinal1 = rotate(v1, -angle)
+            val vFinal2 = rotate(v2, -angle)
+            particle.velocity.x = vFinal1.x
+            particle.velocity.y = vFinal1.y
+            otherParticle.velocity.x = vFinal2.x
+            otherParticle.velocity.y = vFinal2.y
+        }
+    }
+
+    private fun rotate(velocity: Velocity, angle: Float): Velocity {
+        return Velocity(
+            x = velocity.x * cos(angle) - velocity.y * sin(angle),
+            y = velocity.x * sin(angle) + velocity.y * cos(angle),
+        )
+    }
+
+    private fun buildShellColors(shellColor: Int): IntArray {
+        shellColors[0] = colorWithAlpha(shellColor, 0f)
+        shellColors[1] = colorWithAlpha(shellColor, 0f)
+        shellColors[2] = colorWithAlpha(shellColor, 0.04f)
+        shellColors[3] = colorWithAlpha(shellColor, 0.12f)
+        shellColors[4] = colorWithAlpha(shellColor, 0.28f)
+        shellColors[5] = colorWithAlpha(shellColor, 0.44f)
+        shellColors[6] = colorWithAlpha(shellColor, 0.58f)
+        shellColors[7] = colorWithAlpha(shellColor, 0.64f)
+        return shellColors
+    }
+
+    private fun buildInnerColors(innerColor: Int): IntArray {
+        innerColors[0] = colorWithAlpha(innerColor, 0.48f)
+        innerColors[1] = colorWithAlpha(innerColor, 0.36f)
+        innerColors[2] = colorWithAlpha(innerColor, 0.08f)
+        innerColors[3] = colorWithAlpha(innerColor, 0f)
+        return innerColors
+    }
+
+    private fun resolveBubbleRadius(style: BubblesStyle): Float {
+        val minDimension = min(width, height)
+        val baseRadius = minDimension * style.bubbleRadiusFraction
+        val minRadius = style.minBubbleRadiusPx.coerceAtLeast(1f)
+        val maxRadius = maxOf(minRadius, style.maxBubbleRadiusPx)
+        if (!style.adaptiveSizing || minDimension <= 0f) {
+            return baseRadius.coerceIn(minRadius, maxRadius)
+        }
+
+        val reference = style.referenceMinSizePx.coerceAtLeast(1f)
+        val dampening = sqrt((reference / minDimension).coerceAtMost(1f))
+        return (baseRadius * dampening).coerceIn(minRadius, maxRadius)
+    }
+
+    private fun resolveTargetBubbleCount(style: BubblesStyle): Int {
+        val baseCount = style.bubbleCount.coerceAtLeast(1)
+        if (!style.adaptiveBubbleCount) return baseCount
+
+        val area = width * height
+        val referenceArea = style.referenceAreaPx.coerceAtLeast(1f)
+        val areaScale = sqrt((area / referenceArea).coerceAtLeast(0.25f))
+        val scaledCount = (baseCount * areaScale).toInt()
+        val minCount = style.minBubbleCount.coerceAtLeast(1)
+        val maxCount = maxOf(minCount, style.maxBubbleCount.coerceAtLeast(1))
+        return scaledCount.coerceIn(minCount, maxCount)
+    }
+
+    private fun resolveVelocityRange(style: BubblesStyle): Pair<Float, Float> {
+        val referenceMaxVelocity = maxOf(height / 300f, 1f)
+        val velocityMin = (style.minVelocity * style.speedScale).coerceAtLeast(0.05f)
+        val velocityMax = maxOf(velocityMin, min(style.maxVelocity, referenceMaxVelocity) * style.speedScale)
+        return velocityMin to velocityMax
+    }
+
+    private fun randomInRange(min: Float, max: Float): Float {
+        return random.nextFloat() * (max - min) + min
+    }
+}
+
+private fun hueToRgb(h: Float, l: Float): Int {
+    val hNorm = h / 360f
+    val lNorm = l / 100f
+    val sNorm = 1f
+    val c = (1f - kotlin.math.abs(2f * lNorm - 1f)) * sNorm
+    val hp = hNorm * 6f
+    val x = c * (1f - kotlin.math.abs((hp % 2f) - 1f))
+    val m = lNorm - c / 2f
+    val (r, g, b) = when {
+        hp < 1f -> Triple(c, x, 0f)
+        hp < 2f -> Triple(x, c, 0f)
+        hp < 3f -> Triple(0f, c, x)
+        hp < 4f -> Triple(0f, x, c)
+        hp < 5f -> Triple(x, 0f, c)
+        else -> Triple(c, 0f, x)
+    }
+    val r8 = ((r + m) * 255).toInt().coerceIn(0, 255)
+    val g8 = ((g + m) * 255).toInt().coerceIn(0, 255)
+    val b8 = ((b + m) * 255).toInt().coerceIn(0, 255)
+    return (0xFF shl 24) or (r8 shl 16) or (g8 shl 8) or b8
+}
+
+private fun colorWithAlpha(color: Int, alpha: Float): Int {
+    val a = (alpha * 255).toInt().coerceIn(0, 255)
+    val r = (color shr 16) and 0xFF
+    val g = (color shr 8) and 0xFF
+    val b = color and 0xFF
+    return (a shl 24) or (r shl 16) or (g shl 8) or b
+}
+
+private fun mixWithWhite(color: Int, amount: Float): Int {
+    val t = amount.coerceIn(0f, 1f)
+    val r = (color shr 16) and 0xFF
+    val g = (color shr 8) and 0xFF
+    val b = color and 0xFF
+    val mixedR = (r + (255 - r) * t).toInt().coerceIn(0, 255)
+    val mixedG = (g + (255 - g) * t).toInt().coerceIn(0, 255)
+    val mixedB = (b + (255 - b) * t).toInt().coerceIn(0, 255)
+    return (0xFF shl 24) or (mixedR shl 16) or (mixedG shl 8) or mixedB
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/Components.kt

@@ -39,24 +39,44 @@ import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.ElevatedButton
 import androidx.compose.material3.ElevatedCard
+import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
+import androidx.compose.material3.LocalTextStyle
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.ModalBottomSheet
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
+import androidx.compose.material3.rememberModalBottomSheetState
 import androidx.compose.material3.adaptive.currentWindowAdaptiveInfo
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.compositionLocalOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.drawscope.Stroke
+import androidx.compose.ui.input.nestedscroll.NestedScrollConnection
+import androidx.compose.ui.input.nestedscroll.NestedScrollSource
+import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.semantics.hideFromAccessibility
+import androidx.compose.ui.semantics.semantics
+import androidx.compose.ui.text.TextLayoutResult
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.font.FontFamily
+import androidx.compose.ui.text.font.FontStyle
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextDecoration
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.TextUnit
+import androidx.compose.ui.unit.Velocity
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
-import androidx.compose.ui.window.Dialog
 import com.rtbishop.look4sat.core.domain.predict.NearEarthObject
 import com.rtbishop.look4sat.core.domain.predict.OrbitalData
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
@@ -137,30 +157,28 @@ fun RowScope.NextPassRow(pass: OrbitalPass, modifier: Modifier = Modifier, isUtc
                 .padding(start = 6.dp, top = 1.dp, end = 6.dp, bottom = 0.dp)
         ) {
             Row(verticalAlignment = Alignment.CenterVertically) {
-                Text(
-                    text = "${stringResource(R.string.pass_satId, pass.catNum)} - ",
-                    color = MaterialTheme.colorScheme.primary
-                )
                 Text(
                     text = pass.name,
                     modifier = Modifier
                         .weight(1f)
                         .padding(end = 6.dp)
                         .infiniteMarquee(),
+                    color = MaterialTheme.colorScheme.primary,
                     fontWeight = FontWeight.Medium,
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis
                 )
+                val elevColor = elevationColor(pass.maxElevation)
                 Icon(
                     painter = painterResource(R.drawable.ic_elevation),
                     contentDescription = null,
-                    tint = MaterialTheme.colorScheme.primary,
+                    tint = elevColor,
                     modifier = Modifier.size(16.dp)
                 )
                 Spacer(modifier = Modifier.width(4.dp))
                 Text(
                     text = "${pass.maxElevation}°",
-                    color = MaterialTheme.colorScheme.primary
+                    color = elevColor
                 )
             }
             Row(
@@ -178,12 +196,6 @@ fun RowScope.NextPassRow(pass: OrbitalPass, modifier: Modifier = Modifier, isUtc
                     horizontalArrangement = Arrangement.Center,
                     verticalAlignment = Alignment.CenterVertically
                 ) {
-                    Icon(
-                        painter = painterResource(R.drawable.ic_altitude),
-                        contentDescription = null,
-                        modifier = Modifier.size(16.dp)
-                    )
-                    Spacer(modifier = Modifier.width(4.dp))
                     Text(text = "${pass.altitude} km", fontSize = 15.sp)
                 }
                 Text(
@@ -212,14 +224,11 @@ fun CardButton(onClick: () -> Unit, text: String, modifier: Modifier = Modifier)
 }
 
 @Composable
-fun IconCard(action: () -> Unit, resId: Int, modifier: Modifier = Modifier) {
+fun IconCard(action: () -> Unit, resId: Int, modifier: Modifier = Modifier, enabled: Boolean = true) {
-    ElevatedCard(modifier = Modifier.size(48.dp)) {
+    ElevatedCard(modifier = Modifier.size(48.dp), enabled = enabled, onClick = action) {
-        Box(
+        Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-            modifier = Modifier
+            Icon(painter = painterResource(resId), contentDescription = null, modifier = modifier)
-                .clickable(onClick = action)
+        }
-                .fillMaxSize(),
-            contentAlignment = Alignment.Center
-        ) { Icon(painter = painterResource(resId), contentDescription = null, modifier = modifier) }
     }
 }
 
@@ -275,55 +284,87 @@ fun getDefaultPass(): OrbitalPass = OrbitalPass(
 fun SharedDialog(
     title: String, onCancel: () -> Unit, onAccept: () -> Unit, content: @Composable () -> Unit
 ) {
-    DialogShell(title = title, titleFontSize = 16, onDismissRequest = onCancel) {
+    SharedDialog(title = title, onDismissRequest = onCancel, onCancel = onCancel, onAccept = onAccept) { _ ->
         content()
-        Row(modifier = Modifier.padding(start = it, bottom = it, end = it)) {
-            CardButton(onClick = onCancel, text = stringResource(R.string.btn_cancel))
-            Spacer(modifier = Modifier.weight(1f))
-            CardButton(onClick = onAccept, text = stringResource(R.string.btn_accept))
-        }
     }
 }
 
 @Composable
-fun InfoDialog(title: String, text: String, onDismiss: () -> Unit) {
+fun SharedDialog(
-    DialogShell(title = title, titleFontSize = 18, onDismissRequest = {}) {
+    title: String,
-        Text(
+    onDismissRequest: () -> Unit,
-            text = text,
+    onCancel: (() -> Unit)? = null,
-            fontSize = 16.sp,
+    onAccept: (() -> Unit)? = null,
-            color = MaterialTheme.colorScheme.onSurface,
+    titleFontSize: Int = 16,
-            modifier = Modifier.padding(horizontal = it)
+    titleTextAlign: TextAlign = if (onCancel != null && onAccept != null) TextAlign.Center else TextAlign.Start,
-        )
+    content: @Composable (padding: Dp) -> Unit
-        Row(modifier = Modifier.padding(start = it, bottom = it, end = it)) {
+) {
-            Spacer(modifier = Modifier.weight(1f))
+    DialogShell(onDismissRequest = onDismissRequest) { padding ->
-            CardButton(onClick = onDismiss, text = stringResource(R.string.btn_accept))
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(start = padding, top = padding, end = padding)
+        ) {
+            if (onCancel != null) {
+                CardButton(onClick = onCancel, text = stringResource(R.string.btn_cancel))
+            }
+            Text(
+                text = title,
+                fontSize = titleFontSize.sp,
+                fontWeight = FontWeight.Medium,
+                color = MaterialTheme.colorScheme.primary,
+                textAlign = titleTextAlign,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+                modifier = Modifier
+                    .weight(1f)
+                    .padding(horizontal = if (onCancel != null && onAccept != null) padding else 0.dp)
+            )
+            if (onAccept != null) {
+                CardButton(onClick = onAccept, text = stringResource(R.string.btn_accept))
+            }
         }
+        content(padding)
     }
 }
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Composable
 private fun DialogShell(
-    title: String,
-    titleFontSize: Int,
     onDismissRequest: () -> Unit,
-    content: @Composable (padding: androidx.compose.ui.unit.Dp) -> Unit
+    content: @Composable (padding: Dp) -> Unit
 ) {
     val padding = LocalSpacing.current.large
-    Dialog(onDismissRequest = onDismissRequest) {
+    val sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = true)
-        ElevatedCard {
+    val stopSheetFling = remember {
-            Column(
+        object : NestedScrollConnection {
-                horizontalAlignment = Alignment.CenterHorizontally,
+            override suspend fun onPostFling(consumed: Velocity, available: Velocity): Velocity {
-                verticalArrangement = Arrangement.spacedBy(padding)
+                return available
-            ) {
-                Text(
-                    text = title,
-                    fontSize = titleFontSize.sp,
-                    fontWeight = FontWeight.Medium,
-                    color = MaterialTheme.colorScheme.primary,
-                    modifier = Modifier.padding(start = padding, top = padding, end = padding)
-                )
-                content(padding)
             }
+
+            override fun onPostScroll(
+                consumed: Offset,
+                available: Offset,
+                source: NestedScrollSource
+            ): Offset = Offset.Zero
+        }
+    }
+    ModalBottomSheet(
+        onDismissRequest = onDismissRequest,
+        sheetState = sheetState,
+        dragHandle = null,
+        shape = MaterialTheme.shapes.medium,
+        scrimColor = Color.Black.copy(alpha = 0.64f)
+    ) {
+        Column(
+            horizontalAlignment = Alignment.CenterHorizontally,
+            verticalArrangement = Arrangement.spacedBy(padding),
+            modifier = Modifier
+                .fillMaxWidth()
+                .nestedScroll(stopSheetFling)
+        ) {
+            content(padding)
         }
     }
 }
@@ -385,3 +426,98 @@ fun TopBar(
         TopBar { startAction(); topInfo(); bottomInfo(); endAction() }
     }
 }
+
+@Composable
+fun elevationColor(elevation: Double): Color {
+    val thresholds = LocalElevationThresholds.current
+    return when {
+        elevation < thresholds.low -> ElevationLowColor // soft red for low elevation
+        elevation < thresholds.high -> MaterialTheme.colorScheme.primary // accent yellow for normal
+        else -> ElevationHighColor // soft green for high elevation
+    }
+}
+
+/** User-configurable elevation highlight thresholds (in degrees). */
+data class ElevationThresholds(val low: Double = 15.0, val high: Double = 45.0)
+
+/** Provided at the app root from settings; defaults keep the original 15°/45° behavior. */
+val LocalElevationThresholds = compositionLocalOf { ElevationThresholds() }
+
+/** Soft red used for elevations below the low threshold. */
+val ElevationLowColor = Color(0xFFEF5350)
+
+/** Soft green used for elevations above the high threshold. */
+val ElevationHighColor = Color(0xFF66BB6A)
+
+@Composable
+fun OutlinedText(
+    text: String,
+    modifier: Modifier = Modifier,
+    fillColor: Color = Color.Unspecified,
+    outlineColor: Color,
+    fontSize: TextUnit = TextUnit.Unspecified,
+    fontStyle: FontStyle? = null,
+    fontWeight: FontWeight? = null,
+    fontFamily: FontFamily? = null,
+    letterSpacing: TextUnit = TextUnit.Unspecified,
+    textDecoration: TextDecoration? = null,
+    textAlign: TextAlign? = null,
+    lineHeight: TextUnit = TextUnit.Unspecified,
+    overflow: TextOverflow = TextOverflow.Clip,
+    softWrap: Boolean = true,
+    maxLines: Int = Int.MAX_VALUE,
+    minLines: Int = 1,
+    onTextLayout: (TextLayoutResult) -> Unit = {},
+    style: TextStyle = LocalTextStyle.current,
+    outlineDrawStyle: Stroke = Stroke(width = 8f),
+) {
+    Box(modifier = modifier) {
+        Text(
+            text = text,
+            modifier = Modifier.semantics { hideFromAccessibility() },
+            color = outlineColor,
+            fontSize = fontSize,
+            fontStyle = fontStyle,
+            fontWeight = fontWeight,
+            fontFamily = fontFamily,
+            letterSpacing = letterSpacing,
+            textDecoration = null,
+            textAlign = textAlign,
+            lineHeight = lineHeight,
+            overflow = overflow,
+            softWrap = softWrap,
+            maxLines = maxLines,
+            minLines = minLines,
+            onTextLayout = onTextLayout,
+            style = style.copy(shadow = null, drawStyle = outlineDrawStyle),
+        )
+
+        Text(
+            text = text,
+            color = fillColor,
+            fontSize = fontSize,
+            fontStyle = fontStyle,
+            fontWeight = fontWeight,
+            fontFamily = fontFamily,
+            letterSpacing = letterSpacing,
+            textDecoration = textDecoration,
+            textAlign = textAlign,
+            lineHeight = lineHeight,
+            overflow = overflow,
+            softWrap = softWrap,
+            maxLines = maxLines,
+            minLines = minLines,
+            onTextLayout = onTextLayout,
+            style = style,
+        )
+    }
+}
+
+// Formats a frequency in Hz as "MMM.KKK.HHH" (e.g. 145.825.000) or "---"
+fun formatFrequency(frequencyHz: Long): String {
+    if (frequencyHz <= 0) return "---"
+    val mhz = frequencyHz / 1_000_000
+    val khz = (frequencyHz % 1_000_000) / 1_000
+    val hz = frequencyHz % 1_000
+    return String.format(Locale.ENGLISH, "%d.%03d.%03d", mhz, khz, hz)
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/MatrixEffect.kt

@@ -0,0 +1,260 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.presentation
+
+import android.graphics.Paint
+import android.graphics.Typeface
+import androidx.compose.foundation.Canvas
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.Immutable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableIntStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.runtime.withFrameNanos
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.nativeCanvas
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.unit.TextUnit
+import androidx.compose.ui.unit.sp
+import kotlinx.coroutines.isActive
+import kotlin.math.floor
+import kotlin.math.max
+import kotlin.math.min
+import kotlin.random.Random
+
+@Immutable
+data class MatrixStyle(
+    val bgColor: Color = Color.Black,
+    val bodyColor: Color = Color(0xFF29C94A),
+    val headColor: Color = Color(0xFFC2FFC6),
+    val tailAlphaFloor: Float = 0.14f, // 0.14f - 0.18f,
+    val fontSize: TextUnit = 14.sp, // 11.sp - 14.sp
+    val minStreamLength: Int = 8, // 6 - 8
+    val maxStreamLength: Int = 28,  // 20 - 28
+    val minSpeedRps: Float = 10f, // 10f - 15f
+    val maxSpeedRps: Float = 38f, // 38f - 45f
+    val resetPauseSec: ClosedFloatingPointRange<Float> = 0.1f..1.0f,
+)
+
+@Composable
+fun MatrixEffect(
+    modifier: Modifier = Modifier,
+    isRunning: Boolean = true,
+    style: MatrixStyle = MatrixStyle(),
+    symbols: String = DEFAULT_SYMBOLS,
+) {
+    val density = LocalDensity.current
+    val renderer = remember { MatrixRenderer() }
+    var frameSignal by remember { mutableIntStateOf(0) }
+
+    LaunchedEffect(isRunning, style, symbols) {
+        if (!isRunning) return@LaunchedEffect
+
+        var previousNanos = 0L
+        while (isActive) {
+            withFrameNanos { now ->
+                if (previousNanos == 0L) previousNanos = now
+                val deltaSec = ((now - previousNanos).coerceAtMost(MAX_STEP_NANOS)).toFloat() / NANOS_TO_SECONDS
+                previousNanos = now
+                renderer.update(deltaSec, style)
+                frameSignal++
+            }
+        }
+    }
+
+    Canvas(modifier = modifier) {
+        frameSignal
+        renderer.ensureLayout(size, density.density, style, symbols)
+        renderer.draw(this, style)
+    }
+}
+
+private const val MAX_STEP_NANOS = 33_333_333L
+private const val NANOS_TO_SECONDS = 1_000_000_000f
+private const val DEFAULT_SYMBOLS = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789<>=*+-~:;/[]{}()"
+
+private fun Color.toArgb(): Int {
+    val a = (alpha.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    val r = (red.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    val g = (green.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    val b = (blue.coerceIn(0f, 1f) * 255f + 0.5f).toInt()
+    return (a shl 24) or (r shl 16) or (g shl 8) or b
+}
+
+private class MatrixRenderer {
+    private var columns = 0
+    private var rows = 0
+    private var width = 0f
+    private var height = 0f
+    private var fontSizePx = 0f
+    private var charWidth = 0f
+    private var charHeight = 0f
+    private var baselineOffset = 0f
+    private var symbolSet = ""
+    private var symbols = charArrayOf()
+
+    private var glyphs = charArrayOf()
+    private var streams = emptyArray<StreamState>()
+
+    private val bodyPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply { typeface = Typeface.MONOSPACE }
+    private val headPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply { typeface = Typeface.MONOSPACE }
+    private val charBuffer = CharArray(1)
+    private val random = Random(System.currentTimeMillis())
+
+    fun ensureLayout(size: Size, density: Float, style: MatrixStyle, symbols: String) {
+        val targetFontPx = style.fontSize.value * density
+        val targetWidth = size.width
+        val targetHeight = size.height
+        val targetSymbols = symbols.ifBlank { DEFAULT_SYMBOLS }
+
+        if (targetWidth <= 0f || targetHeight <= 0f) return
+
+        val shouldRebuild = width != targetWidth ||
+            height != targetHeight ||
+            fontSizePx != targetFontPx ||
+            symbolSet != targetSymbols
+
+        if (!shouldRebuild) return
+
+        width = targetWidth
+        height = targetHeight
+        fontSizePx = targetFontPx
+        symbolSet = targetSymbols
+        this.symbols = targetSymbols.toCharArray()
+
+        bodyPaint.textSize = targetFontPx
+        headPaint.textSize = targetFontPx
+        charWidth = max(bodyPaint.measureText("W"), 1f)
+        val metrics = bodyPaint.fontMetrics
+        charHeight = max(metrics.descent - metrics.ascent, 1f)
+        baselineOffset = -metrics.ascent
+
+        columns = max((width / charWidth).toInt(), 1)
+        rows = max((height / charHeight).toInt() + 2, 1)
+
+        glyphs = CharArray(columns * rows) { randomGlyph() }
+        streams = Array(columns) { StreamState.random(rows, style, random) }
+    }
+
+    fun update(deltaSeconds: Float, style: MatrixStyle) {
+        if (columns == 0 || rows == 0 || deltaSeconds <= 0f) return
+
+        for (column in streams.indices) {
+            val stream = streams[column]
+            stream.pauseSec -= deltaSeconds
+            if (stream.pauseSec > 0f) continue
+
+            val previousHead = floor(stream.headRow).toInt()
+            stream.headRow += stream.speedRps * deltaSeconds
+            val newHead = floor(stream.headRow).toInt()
+
+            if (newHead > previousHead) {
+                for (row in (previousHead + 1)..newHead) {
+                    if (row in 0 until rows) {
+                        glyphs[row * columns + column] = randomGlyph()
+                    }
+                }
+            }
+
+            if (newHead - stream.length > rows) {
+                stream.reset(rows, style, random)
+            }
+        }
+    }
+
+    fun draw(scope: androidx.compose.ui.graphics.drawscope.DrawScope, style: MatrixStyle) {
+        if (columns == 0 || rows == 0) return
+
+        scope.drawRect(style.bgColor)
+
+        bodyPaint.color = style.bodyColor.toArgb()
+        headPaint.color = style.headColor.toArgb()
+        val tailAlphaFloor = style.tailAlphaFloor.coerceIn(0f, 1f)
+
+        val canvas = scope.drawContext.canvas.nativeCanvas
+        for (column in streams.indices) {
+            val stream = streams[column]
+            if (stream.pauseSec > 0f) continue
+
+            val head = floor(stream.headRow).toInt()
+            val startRow = max(0, head - stream.length + 1)
+            val endRow = min(rows - 1, head)
+            if (startRow > endRow) continue
+
+            for (row in endRow downTo startRow) {
+                val tailIndex = head - row
+
+                val paint = if (tailIndex == 0) headPaint else bodyPaint
+                if (tailIndex != 0) {
+                    val normalized = ((stream.length - tailIndex).toFloat() / stream.length).coerceIn(0f, 1f)
+                    val alpha = tailAlphaFloor + (1f - tailAlphaFloor) * normalized
+                    paint.alpha = (alpha * 255).toInt()
+                } else {
+                    paint.alpha = 255
+                }
+
+                val glyph = glyphs[row * columns + column]
+                charBuffer[0] = glyph
+                val x = column * charWidth
+                val y = row * charHeight + baselineOffset
+                canvas.drawText(charBuffer, 0, 1, x, y, paint)
+            }
+        }
+    }
+
+    private fun randomGlyph(): Char = symbols[random.nextInt(symbols.size)]
+}
+
+private data class StreamState(
+    var headRow: Float,
+    var length: Int,
+    var speedRps: Float,
+    var pauseSec: Float,
+) {
+    fun reset(rows: Int, style: MatrixStyle, random: Random) {
+        val randomOffset = random.nextFloat() * rows
+        headRow = -randomOffset
+        length = random.nextInt(
+            from = style.minStreamLength.coerceAtLeast(2),
+            until = (style.maxStreamLength.coerceAtLeast(style.minStreamLength + 1) + 1),
+        )
+        speedRps = random.nextFloat() * (style.maxSpeedRps - style.minSpeedRps) + style.minSpeedRps
+        pauseSec = random.nextFloat() * (style.resetPauseSec.endInclusive - style.resetPauseSec.start) +
+            style.resetPauseSec.start
+    }
+
+    companion object {
+        fun random(rows: Int, style: MatrixStyle, random: Random): StreamState {
+            val length = random.nextInt(
+                from = style.minStreamLength.coerceAtLeast(2),
+                until = (style.maxStreamLength.coerceAtLeast(style.minStreamLength + 1) + 1),
+            )
+            return StreamState(
+                headRow = -random.nextFloat() * rows,
+                length = length,
+                speedRps = random.nextFloat() * (style.maxSpeedRps - style.minSpeedRps) + style.minSpeedRps,
+                pauseSec = random.nextFloat() * (style.resetPauseSec.endInclusive - style.resetPauseSec.start) +
+                    style.resetPauseSec.start,
+            )
+        }
+    }
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/Navigation.kt

@@ -30,14 +30,44 @@ sealed class Screen(val iconResId: Int, val titleResId: Int) : NavKey {
     data object Passes : Screen(R.drawable.ic_passes, R.string.nav_pass)
 
     @Serializable
-    data class Radar(val catNum: Int = 0, val aosTime: Long = 0L) : Screen(R.drawable.ic_radar, R.string.nav_radar)
+    data object Radar : Screen(R.drawable.ic_radar, R.string.nav_radar)
-
-    @Serializable
-    data class RadioControl(val catNum: Int = 0, val aosTime: Long = 0L) : Screen(0, 0)
 
     @Serializable
     data object Map : Screen(R.drawable.ic_map, R.string.nav_map)
 
+    @Serializable
+    data object Mutual : Screen(R.drawable.ic_match, R.string.nav_mutual)
+
     @Serializable
     data object Settings : Screen(R.drawable.ic_settings, R.string.nav_prefs)
 }
+
+@Serializable
+data object RadarDestination : NavKey
+
+interface IDeeplinkMatcher {
+    fun match(deeplink: String): NavKey?
+}
+
+object PassDetailsMatcher : IDeeplinkMatcher {
+    val passDetailsRegex = """https://github.com/rt-bishop/Look4Sat/passes/(.*)""".toRegex()
+
+    override fun match(deeplink: String): NavKey? {
+        val passMatch = passDetailsRegex.find(deeplink)
+        passMatch?.let { match ->
+            val passId = match.groupValues[1]
+            if (passId.isNotEmpty()) return RadarDestination
+        }
+        return null
+    }
+}
+
+class DeeplinkResolver(private val fallbackDestination: NavKey = Screen.Passes) {
+
+    private val matchers: List<IDeeplinkMatcher> = listOf(PassDetailsMatcher)
+
+    fun resolve(deeplink: String): NavKey {
+        matchers.forEach { it.match(deeplink)?.let { match -> return match } }
+        return fallbackDestination
+    }
+}

core/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/SwipeableItem.kt

@@ -0,0 +1,105 @@
+package com.rtbishop.look4sat.core.presentation
+
+import androidx.compose.animation.core.animateDpAsState
+import androidx.compose.animation.core.animateFloatAsState
+import androidx.compose.foundation.border
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.size
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.SwipeToDismissBox
+import androidx.compose.material3.SwipeToDismissBoxValue
+import androidx.compose.material3.rememberSwipeToDismissBoxState
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.derivedStateOf
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.dropShadow
+import androidx.compose.ui.draw.innerShadow
+import androidx.compose.ui.draw.rotate
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.RectangleShape
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.hapticfeedback.HapticFeedbackType
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.platform.LocalHapticFeedback
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.unit.dp
+import kotlinx.coroutines.launch
+
+@Composable
+fun SwipeableItem(onSwipeRight: () -> Unit, onSwipeLeft: () -> Unit, content: @Composable () -> Unit) {
+    val coroutineScope = rememberCoroutineScope()
+    val dismissThresholdPx = with(LocalDensity.current) { 120.dp.toPx() }
+    val dismissState = rememberSwipeToDismissBoxState { dismissThresholdPx }
+    val willTrigger by remember { derivedStateOf { dismissState.targetValue != SwipeToDismissBoxValue.Settled } }
+    val hapticFeedback = LocalHapticFeedback.current
+    LaunchedEffect(willTrigger) {
+        val feedbackType = if (willTrigger) HapticFeedbackType.LongPress else HapticFeedbackType.SegmentTick
+        if (willTrigger) hapticFeedback.performHapticFeedback(feedbackType)
+    }
+    SwipeToDismissBox(
+        state = dismissState,
+        enableDismissFromStartToEnd = true,
+        enableDismissFromEndToStart = true,
+        backgroundContent = {
+            val isSwipeRight = dismissState.dismissDirection == SwipeToDismissBoxValue.StartToEnd
+            SwipeBackground(isSwipeRight, willTrigger, MaterialTheme.colorScheme.primary)
+        },
+        content = { content() },
+        onDismiss = {
+            val targetValue = dismissState.targetValue
+            when (targetValue) {
+                SwipeToDismissBoxValue.StartToEnd -> onSwipeRight()
+                SwipeToDismissBoxValue.EndToStart -> onSwipeLeft()
+                SwipeToDismissBoxValue.Settled -> {}
+            }
+            if (targetValue != SwipeToDismissBoxValue.Settled) {
+                coroutineScope.launch { dismissState.snapTo(SwipeToDismissBoxValue.Settled) }
+            }
+        }
+    )
+}
+
+@Composable
+fun SwipeBackground(isSwipeRight: Boolean, willTrigger: Boolean, bgColor: Color = Color(0x00000000)) {
+    val shape = RectangleShape
+    Box(
+        contentAlignment = if (isSwipeRight) Alignment.CenterStart else Alignment.CenterEnd,
+        modifier = Modifier
+            .fillMaxSize()
+            .border(width = 1.dp, shape = shape, color = bgColor)
+            .dropShadow(shape = shape) {
+                color = bgColor
+                radius = 40f
+                alpha = if (willTrigger) .2f else 0f
+            }
+            .innerShadow(shape = shape) {
+                color = bgColor
+                radius = 40f
+                alpha = if (willTrigger) 1f else .2f
+            }
+    ) {
+        val iconScale by animateFloatAsState(targetValue = if (willTrigger) 1f else .8f)
+        val slide by animateDpAsState(targetValue = if (willTrigger) 32.dp else (12).dp)
+        Icon(
+            painter = painterResource(R.drawable.ic_filter),
+            contentDescription = null,
+            modifier = Modifier
+                .size(32.dp)
+                .fillMaxHeight()
+                .rotate(if (isSwipeRight) 0f else 180f)
+                .graphicsLayer {
+                    scaleX = iconScale
+                    scaleY = iconScale
+                    translationX = slide.toPx()
+                }
+        )
+    }
+}

core/presentation/src/main/res/drawable/ic_delete.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2V7H6v12zM19,4h-3.5l-1,-1h-5l-1,1H5v2h14V4z" />
+</vector>

core/presentation/src/main/res/drawable/ic_match.xml

@@ -0,0 +1,22 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="96"
+    android:viewportHeight="96">
+
+    <path
+        android:fillColor="@android:color/transparent"
+        android:strokeColor="@android:color/white"
+        android:strokeWidth="6"
+        android:strokeLineCap="round"
+        android:strokeLineJoin="round"
+        android:pathData="M 8 76 C 8 44, 21 24, 39 24 C 57 24, 70 44, 70 76" />
+
+    <path
+        android:fillColor="@android:color/transparent"
+        android:strokeColor="@android:color/white"
+        android:strokeWidth="6"
+        android:strokeLineCap="round"
+        android:strokeLineJoin="round"
+        android:pathData="M 30 76 C 30 54, 44 42, 62 42 C 80 42, 94 54, 94 76" />
+</vector>

core/presentation/src/main/res/drawable/ic_moon.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M12.34,2.02C6.59,1.82 2,6.42 2,12c0,5.52 4.48,10 10,10c3.71,0 6.93,-2.02 8.66,-5.02C13.15,16.73 8.57,8.55 12.34,2.02z" />
+</vector>

core/presentation/src/main/res/drawable/ic_pause.xml

@@ -5,5 +5,5 @@
     android:viewportHeight="24">
     <path
         android:fillColor="@android:color/white"
-        android:pathData="M4,20h16v2L4,22zM4,2h16v2L4,4zM13,9h3l-4,-4 -4,4h3v6L8,15l4,4 4,-4h-3z" />
+        android:pathData="M6,19h4L10,5L6,5v14zM14,5v14h4L18,5h-4z" />
 </vector>

core/presentation/src/main/res/drawable/ic_play.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M8,5v14l11,-7z" />
+</vector>

core/presentation/src/main/res/drawable/ic_save.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M17,3L5,3c-1.11,0 -2,0.9 -2,2v14c0,1.1 0.89,2 2,2h14c1.1,0 2,-0.9 2,-2L21,7l-4,-4zM12,19c-1.66,0 -3,-1.34 -3,-3s1.34,-3 3,-3 3,1.34 3,3 -1.34,3 -3,3zM15,9L5,9L5,5h10v4z" />
+</vector>

core/presentation/src/main/res/drawable/ic_sun.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M11,4V2c0,-0.55 0.45,-1 1,-1s1,0.45 1,1v2c0,0.55 -0.45,1 -1,1S11,4.55 11,4zM18.36,7.05l1.41,-1.42c0.39,-0.39 0.39,-1.02 0,-1.41c-0.39,-0.39 -1.02,-0.39 -1.41,0l-1.41,1.42c-0.39,0.39 -0.39,1.02 0,1.41C17.34,7.44 17.97,7.44 18.36,7.05zM22,11h-2c-0.55,0 -1,0.45 -1,1s0.45,1 1,1h2c0.55,0 1,-0.45 1,-1S22.55,11 22,11zM12,19c-0.55,0 -1,0.45 -1,1v2c0,0.55 0.45,1 1,1s1,-0.45 1,-1v-2C13,19.45 12.55,19 12,19zM5.64,7.05L4.22,5.64c-0.39,-0.39 -0.39,-1.03 0,-1.41s1.03,-0.39 1.41,0l1.41,1.41c0.39,0.39 0.39,1.03 0,1.41S6.02,7.44 5.64,7.05zM16.95,16.95c-0.39,0.39 -0.39,1.03 0,1.41l1.41,1.41c0.39,0.39 1.03,0.39 1.41,0c0.39,-0.39 0.39,-1.03 0,-1.41l-1.41,-1.41C17.98,16.56 17.34,16.56 16.95,16.95zM2,13h2c0.55,0 1,-0.45 1,-1s-0.45,-1 -1,-1H2c-0.55,0 -1,0.45 -1,1S1.45,13 2,13zM5.64,19.78l1.41,-1.41c0.39,-0.39 0.39,-1.03 0,-1.41s-1.03,-0.39 -1.41,0l-1.41,1.41c-0.39,0.39 -0.39,1.03 0,1.41C4.61,20.17 5.25,20.17 5.64,19.78zM12,6c-3.31,0 -6,2.69 -6,6s2.69,6 6,6s6,-2.69 6,-6S15.31,6 12,6z" />
+</vector>

core/presentation/src/main/res/values-es/strings.xml

@@ -31,7 +31,10 @@
     <!-- Passes screen -->
     <string name="pass_filter_title">Filtrar pases</string>
     <string name="pass_filter_elev">Elevación mínima</string>
-    <string name="pass_filter_hours">Horas por delante</string>
+    <string name="pass_filter_hours">Tiempo por delante</string>
+    <string name="pass_filter_aos_time">Ventana AOS</string>
+    <string name="pass_filter_invert_time">Invertir ventana AOS</string>
+    <string name="pass_filter_deep_space">DeepSpace (período &gt;225min)</string>
     <string name="pass_modes_title">Tipo de modulación</string>
     <string name="pass_elevation">Elevación: %.1f°</string>
     <string name="pass_altitude">Altitud: %.0f km</string>
@@ -132,12 +135,19 @@
     <string name="prefs_bt_frequency_device_hint">Id dispositivo</string>
     <string name="prefs_bt_frequency_output_hint">Formato de datos</string>
     <string name="prefs_bt_perm_error">Revisa los permisos de Bluetooth</string>
+    <string name="prefs_net_perm_error">Revisa los permisos de red</string>
 
     <string name="prefs_other_title">Otros ajustes</string>
     <string name="prefs_other_switch_utc">Mostrar tiempos de pase en UTC</string>
     <string name="prefs_other_switch_update">Habilitar auto actualización de datos</string>
     <string name="prefs_other_switch_sweep">Habilitar animaciones radar</string>
     <string name="prefs_other_switch_sensors">Usar sensores para rotar vista de radar</string>
+    <string name="prefs_other_switch_night_mode">Activar filtro nocturno rojo</string>
+
+    <string name="prefs_highlight_title">Resaltado de elevación</string>
+    <string name="prefs_highlight_low">Baja &lt; %1$d°</string>
+    <string name="prefs_highlight_mid">Media %1$d-%2$d°</string>
+    <string name="prefs_highlight_high">Alta &gt; %1$d°</string>
 
     <string name="prefs_outro_title">Me gustaría dar las gracias a:</string>
     <string name="prefs_outro_license">La app viene sin garantías de ningún tipo.</string>

core/presentation/src/main/res/values-ru/strings.xml

@@ -30,7 +30,10 @@
     <!-- Passes screen -->
     <string name="pass_filter_title">Фильтровать пролеты</string>
     <string name="pass_filter_elev">Минимальная элевация</string>
-    <string name="pass_filter_hours">Количество часов</string>
+    <string name="pass_filter_hours">Период расчёта</string>
+    <string name="pass_filter_aos_time">Окно AOS</string>
+    <string name="pass_filter_invert_time">Инвертировать окно AOS</string>
+    <string name="pass_filter_deep_space">DeepSpace (период &gt;225мин)</string>
     <string name="pass_modes_title">Выберите тип модуляции</string>
     <string name="pass_elevation">Элевация: %.1f°</string>
     <string name="pass_altitude">Высота: %d км</string>
@@ -131,12 +134,19 @@
     <string name="prefs_bt_frequency_device_hint">Id устройства</string>
     <string name="prefs_bt_frequency_output_hint">Формат</string>
     <string name="prefs_bt_perm_error">Нет разрешения использовать bluetooth</string>
+    <string name="prefs_net_perm_error">Нет разрешения использовать сеть</string>
 
     <string name="prefs_other_title">Другие настройки</string>
     <string name="prefs_other_switch_utc">Показывать время по UTC</string>
     <string name="prefs_other_switch_update">Обновлять данные автоматически</string>
     <string name="prefs_other_switch_sweep">Показывать анимацию радара</string>
     <string name="prefs_other_switch_sensors">Использовать сенсоры устройства</string>
+    <string name="prefs_other_switch_night_mode">Включить красный ночной фильтр</string>
+
+    <string name="prefs_highlight_title">Подсветка высоты</string>
+    <string name="prefs_highlight_low">Низко &lt; %1$d°</string>
+    <string name="prefs_highlight_mid">Средне %1$d-%2$d°</string>
+    <string name="prefs_highlight_high">Высоко &gt; %1$d°</string>
 
     <string name="prefs_outro_title">Я хотел бы сказать спасибо:</string>
     <string name="prefs_outro_license">Это ПО поставляется без гарантий.</string>

core/presentation/src/main/res/values-si/strings.xml

@@ -31,7 +31,10 @@
     <!-- Passes screen -->
     <string name="pass_filter_title">පසුකිරිම් පිරිපහදුව</string>
     <string name="pass_filter_elev">අවම උත්තෝලනය</string>
-    <string name="pass_filter_hours">ඉදිරි පැය</string>
+    <string name="pass_filter_hours">ඉදිරි කාලය</string>
+    <string name="pass_filter_aos_time">AOS කවුළුව</string>
+    <string name="pass_filter_invert_time">AOS කවුළුව ප්‍රතිවිරුද්ධ කරන්න</string>
+    <string name="pass_filter_deep_space">DeepSpace (කාලය &gt;225min)</string>
     <string name="pass_modes_title">මූර්ජන ආකාරය තෝරන්න</string>
     <string name="pass_elevation">උත්තෝලනය: %.1f°</string>
     <string name="pass_altitude">උන්නතාශය: %d km</string>
@@ -132,12 +135,19 @@
     <string name="prefs_bt_frequency_device_hint">උපාංග id</string>
     <string name="prefs_bt_frequency_output_hint">දත්ත අකාරය</string>
     <string name="prefs_bt_perm_error">Bluetooth අවසර පරික්‍ෂා ක°</string>
+    <string name="prefs_net_perm_error">Network අවසර පරික්‍ෂා කරන්න</string>
 
     <string name="prefs_other_title">වෙනත් සැකසුම්</string>
     <string name="prefs_other_switch_utc">පසුකර වේලාවන් UTC මගින්</string>
     <string name="prefs_other_switch_update">ස්වයං දත්ත යාවත්කාලීනය</string>
     <string name="prefs_other_switch_sweep">radar sweep සජීවිකරණය සබල කරන්න</string>
     <string name="prefs_other_switch_sensors">Radar දර්ශනය කරකැවීමට සංවේදක භාවිතා කරන්න </string>
+    <string name="prefs_other_switch_night_mode">රතු රාත්‍රී පෙරහන සබල කරන්න</string>
+
+    <string name="prefs_highlight_title">උස් උද්දීපනය</string>
+    <string name="prefs_highlight_low">අඩු &lt; %1$d°</string>
+    <string name="prefs_highlight_mid">මධ්‍ය %1$d-%2$d°</string>
+    <string name="prefs_highlight_high">ඉහළ &gt; %1$d°</string>
 
     <string name="prefs_outro_title">මම ස්තුති කිරීමට කැමති:</string>
     <string name="prefs_outro_license">මෘදුකාංගය වගකීමක් සමග නොලැබේ</string>

core/presentation/src/main/res/values-tr/strings.xml

@@ -31,7 +31,10 @@
     <!-- Passes screen -->
     <string name="pass_filter_title">Geçişleri filtrele</string>
     <string name="pass_filter_elev">Minimum yükseklik açısı</string>
-    <string name="pass_filter_hours">İlerideki saatler</string>
+    <string name="pass_filter_hours">Gösterilecek zaman</string>
+    <string name="pass_filter_aos_time">AOS aralığı</string>
+    <string name="pass_filter_invert_time">AOS aralığını tersine çevir</string>
+    <string name="pass_filter_deep_space">DeepSpace (periyot &gt;225dk)</string>
     <string name="pass_time_placeholder" translatable="false"> -- : -- : -- </string>
     <string name="pass_modes_title">Modulasyon türü seçin</string>
     <string name="pass_satId" translatable="false">%05d</string>
@@ -66,7 +69,7 @@
     <string name="radar_alt_value" translatable="false">%.0f km</string>
     <string name="radar_dist_text">Mesafe</string>
     <string name="radar_dist_value" translatable="false">%.0f km</string>
-    <string name="radar_eclipsed">Tutulumda</string>
+    <string name="radar_eclipsed">Gölgede</string>
     <string name="radar_downlink">Downlink</string>
     <string name="radar_uplink">Uplink</string>
     <string name="radar_link_low" translatable="false">%.4f</string>
@@ -93,7 +96,7 @@
     <string name="map_longitude">Boylam: %.1f°</string>
     <string name="map_qth" translatable="false">QTH: %s</string>
     <string name="map_phase">Faz: %.1f°</string>
-    <string name="map_eclipsed">Tutulumda</string>
+    <string name="map_eclipsed">Gölgede</string>
     <string name="map_period">Periyot: %.0f dk</string>
     <string name="map_velocity">Hız: %.2f km/s</string>
     <string name="map_visibility">Görünürlük: %s</string>
@@ -175,14 +178,21 @@
     <string name="prefs_bt_frequency_device_hint">Cihaz kimliği</string>
     <string name="prefs_bt_frequency_output_hint">Veri biçimi</string>
     <string name="prefs_bt_perm_error">Bluetooth izninizi kontrol edin</string>
+    <string name="prefs_net_perm_error">Ağ izninizi kontrol edin</string>
 
     <string name="prefs_other_title">Diğer ayarlar</string>
     <string name="prefs_other_switch_utc">Geçiş saatini UTC olarak göster</string>
     <string name="prefs_other_switch_update">Otomatik veri güncellemeyi etkinleştir</string>
     <string name="prefs_other_switch_sweep">Radar taramasını etkinleştir</string>
     <string name="prefs_other_switch_sensors">Radar görünümünü döndürmek için sensörleri kullan</string>
+    <string name="prefs_other_switch_night_mode">Kırmızı gece filtresini etkinleştir</string>
 
-    <string name="prefs_outro_title">Teşekkür etmek istiyorum</string>
+    <string name="prefs_highlight_title">Elevasyon vurgusu</string>
+    <string name="prefs_highlight_low">Düşük &lt; %1$d°</string>
+    <string name="prefs_highlight_mid">Orta %1$d-%2$d°</string>
+    <string name="prefs_highlight_high">Yüksek &gt; %1$d°</string>
+
+    <string name="prefs_outro_title">Teşekkürler</string>
     <string name="prefs_outro_thanks" translatable="false">
         • Look4Sat users and contributors!
         \n• David A. B. Johnson (predict4java)

core/presentation/src/main/res/values-uk/strings.xml

@@ -30,8 +30,11 @@
 
     <!-- Passes screen -->
     <string name="pass_filter_title">Фільтр прольотів</string>
-    <string name="pass_filter_elev">Мінімальне піднесення</string>
+    <string name="pass_filter_elev">Мінімальне піднесень</string>
-    <string name="pass_filter_hours">Кількість годин</string>
+    <string name="pass_filter_hours">Час вперед</string>
+    <string name="pass_filter_aos_time">Вікно AOS</string>
+    <string name="pass_filter_invert_time">Інвертувати вікно AOS</string>
+    <string name="pass_filter_deep_space">DeepSpace (період &gt;225хв)</string>
     <string name="pass_modes_title">Виберіть тип модуляції</string>
     <string name="pass_elevation">Піднес.: %.1f°</string>
     <string name="pass_altitude">Висота: %.0f км</string>
@@ -66,7 +69,7 @@
     <string name="map_prev">Попередній</string>
     <string name="map_next">Наступний</string>
     <string name="map_azimuth">Азимут: %.1f°</string>
-    <string name="map_elevation">Піднесення: %.1f°</string>
+    <string name="map_elevation">Піднесень: %.1f°</string>
     <string name="map_altitude">Висота: %.0f км</string>
     <string name="map_distance">Дистанція: %.0f км</string>
     <string name="map_latitude">Широта: %.1f°</string>
@@ -132,12 +135,19 @@
     <string name="prefs_bt_frequency_device_hint">Id пристрою</string>
     <string name="prefs_bt_frequency_output_hint">Формат даних</string>
     <string name="prefs_bt_perm_error">Перевірте дозвіл Bluetooth</string>
+    <string name="prefs_net_perm_error">Перевірте дозвіл мережі</string>
 
     <string name="prefs_other_title">Інші налаштування</string>
     <string name="prefs_other_switch_utc">Показувати час в UTC</string>
     <string name="prefs_other_switch_update">Автоматичне оновлення даних</string>
     <string name="prefs_other_switch_sweep">Показувати анімацію радара</string>
     <string name="prefs_other_switch_sensors">Використовувати сенсори пристрою</string>
+    <string name="prefs_other_switch_night_mode">Увімкнути червоний нічний фільтр</string>
+
+    <string name="prefs_highlight_title">Підсвічування висоти</string>
+    <string name="prefs_highlight_low">Низько &lt; %1$d°</string>
+    <string name="prefs_highlight_mid">Середньо %1$d-%2$d°</string>
+    <string name="prefs_highlight_high">Високо &gt; %1$d°</string>
 
     <string name="prefs_outro_title">Я хотів би подякувати:</string>
     <string name="prefs_outro_license">Ця програма поставляється без жодних гарантій</string>

core/presentation/src/main/res/values-zh/strings.xml

@@ -9,6 +9,7 @@
     <string name="nav_sat">卫星</string>
     <string name="nav_pass">过境</string>
     <string name="nav_radar">雷达</string>
+    <string name="nav_mutual">匹配</string>
     <string name="nav_map">地图</string>
     <string name="nav_prefs">设置</string>
 
@@ -26,7 +27,10 @@
     <!-- Passes screen -->
     <string name="pass_filter_title">筛选过境</string>
     <string name="pass_filter_elev">仰角值</string>
-    <string name="pass_filter_hours">小时数</string>
+    <string name="pass_filter_hours">提前时间</string>
+    <string name="pass_filter_aos_time">AOS 时间段</string>
+    <string name="pass_filter_invert_time">反选 AOS 时间段</string>
+    <string name="pass_filter_deep_space">DeepSpace（周期 &gt;225分钟）</string>
     <string name="pass_modes_title">选择调制类型</string>
     <string name="pass_elevation">仰角：%.1f°</string>
     <string name="pass_altitude">高度：%d km</string>
@@ -54,6 +58,17 @@
     <string name="radar_string_yes">是</string>
     <string name="radar_visible">日照中</string>
 
+    <string name="radar_doppler_calc">多普勒频率计算器</string>
+    <string name="radar_doppler_tx_hint">输入上行频率 (MHz)</string>
+    <string name="radar_doppler_rx_hint">输入下行频率 (MHz)</string>
+    <string name="radar_doppler_offset_hint">偏移 (kHz)</string>
+    <string name="radar_doppler_info">线性转发器：输入一个频率即可算出另一个</string>
+
+    <string name="radar_cw_decoder">CW 解码器</string>
+    <string name="radar_cw_start">开始</string>
+    <string name="radar_cw_stop">停止</string>
+    <string name="radar_cw_reset">清空</string>
+
     <!-- Map screen -->
     <string name="map_prev">上一个</string>
     <string name="map_next">下一个</string>
@@ -100,6 +115,9 @@
     <string name="prefs_data_clear_success">数据清空成功</string>
     <string name="prefs_data_update_success">更新成功</string>
 
+    <string name="prefs_data_import_satellites_error">未导入卫星。请选择有效的 TLE/3LE (.txt) 或 OMM (.csv) 文件。</string>
+    <string name="prefs_data_import_transceivers_error">未导入收发器。请选择有效的 SatNOGS (.json) 文件。</string>
+
     <string name="prefs_data_sources_title">自定义数据源</string>
     <string name="prefs_data_sources_tle_switch">自定义TLE URL</string>
     <string name="prefs_data_sources_transceivers_switch">自定义收发器URL</string>
@@ -107,6 +125,7 @@
     <string name="prefs_data_output_title">数据输出</string>
     <string name="prefs_net_output">网络</string>
     <string name="prefs_bt_output">蓝牙</string>
+    <string name="prefs_cat_output">CAT</string>
 
     <string name="prefs_net_title">网络数据输出</string>
     <string name="prefs_net_rotator_switch">启用方位俯仰角输出</string>
@@ -124,14 +143,39 @@
     <string name="prefs_bt_frequency_device_hint">蓝牙设备 ID</string>
     <string name="prefs_bt_frequency_output_hint">数据格式</string>
     <string name="prefs_bt_perm_error">请检查蓝牙权限</string>
+    <string name="prefs_net_perm_error">请检查网络权限</string>
+
+    <!-- Radio Control -->
+    <string name="nav_radiocontrol">电台控制</string>
+    <string name="rc_settings_title">CAT 电台控制</string>
+    <string name="rc_radio_model">电台型号</string>
+    <string name="rc_tx_device_hint">发射电台蓝牙地址</string>
+    <string name="rc_rx_device_hint">接收电台蓝牙地址</string>
+    <string name="rc_tx_name_hint">发射电台名称</string>
+    <string name="rc_rx_name_hint">接收电台名称</string>
+    <string name="rc_enable_switch">启用 CAT 控制</string>
 
     <string name="prefs_other_title">其他设置</string>
     <string name="prefs_other_switch_utc">以 UTC 时间显示</string>
     <string name="prefs_other_switch_update">启用卫星数据自动更新</string>
     <string name="prefs_other_switch_sweep">启用雷达扫描动画</string>
     <string name="prefs_other_switch_sensors">使用传感器旋转雷达视图</string>
+    <string name="prefs_other_switch_night_mode">启用红色夜间模式</string>
+
+    <string name="prefs_highlight_title">仰角高亮</string>
+    <string name="prefs_highlight_low">低 &lt; %1$d°</string>
+    <string name="prefs_highlight_mid">中 %1$d-%2$d°</string>
+    <string name="prefs_highlight_high">高 &gt; %1$d°</string>
 
     <string name="prefs_outro_title">我要感谢：</string>
+    <string name="prefs_outro_thanks" translatable="false">
+        • Look4Sat 所有用户及贡献者!
+        \n• David A. B. Johnson (predict4java)
+        \n• Dave Moten (predict4java)
+        \n• Alexandru Csete (Gpredict)
+        \n• Dr T.S. Kelso (Celestrak)
+        \n• Libre Space Foundation (SatNOGS)
+        \n• xdsopl 和 Robot36 贡献者!</string>
     <string name="prefs_outro_license">该应用程序不提供任何保修.</string>
 
 </resources>

core/presentation/src/main/res/values/strings.xml

@@ -10,6 +10,7 @@
     <string name="nav_sat">Satellites</string>
     <string name="nav_pass">Passes</string>
     <string name="nav_radar">Radar</string>
+    <string name="nav_mutual">Match</string>
     <string name="nav_map">Map</string>
     <string name="nav_prefs">Settings</string>
 
@@ -31,7 +32,9 @@
     <!-- Passes screen -->
     <string name="pass_filter_title">Filter passes</string>
     <string name="pass_filter_elev">Minimal elevation</string>
-    <string name="pass_filter_hours">Hours ahead</string>
+    <string name="pass_filter_hours">Time ahead</string>
+    <string name="pass_filter_aos_time">AOS window</string>
+    <string name="pass_filter_invert_time">Invert AOS window</string>
     <string name="pass_filter_deep_space">DeepSpace (period >225min)</string>
     <string name="pass_time_placeholder" translatable="false"> -- : -- : -- </string>
     <string name="pass_modes_title">Select modulation type</string>
@@ -49,10 +52,8 @@
         \n\nPlease update the database at least weekly to get accurate predictions.</string>
     <string name="pass_whatsnew_title" translatable="false">What\'s new in Look4Sat</string>
     <string name="pass_whatsnew_message" translatable="false">
-        * Added Turkish translation, by Emre Can Akdaş (TA3ECR)
+        * Added required tweaks to support Android 17 (API 37)
-        \n* Added DeepSpace passes filter option to the dialog
+        \n\n* Added ACCESS_LOCAL_NETWORK permission check to support network data output
-        \n* Fixed the radar blip disappearing while eclipsed
-        \n* Fixed (hopefully) the refresh indicator being stuck
     </string>
 
     <!-- Radar screen -->
@@ -80,6 +81,16 @@
     <string name="radar_string_no">No</string>
     <string name="radar_string_yes">Yes</string>
     <string name="radar_visible">Visible</string>
+    <string name="radar_doppler_calc">Doppler Frequency Calculator</string>
+    <string name="radar_doppler_tx_hint">Enter TX freq (MHz)</string>
+    <string name="radar_doppler_rx_hint">Enter RX freq (MHz)</string>
+    <string name="radar_doppler_offset_hint">Offset (kHz)</string>
+    <string name="radar_doppler_info">For linear transponders, type one frequency to see the other</string>
+
+    <string name="radar_cw_decoder">CW Decoder</string>
+    <string name="radar_cw_start">Start</string>
+    <string name="radar_cw_stop">Stop</string>
+    <string name="radar_cw_reset">Clear</string>
 
     <!-- Map screen -->
     <string name="map_prev">Prev</string>
@@ -138,6 +149,8 @@
     <string name="prefs_data_clear">Clear</string>
     <string name="prefs_data_clear_success">Data was cleared successfully</string>
     <string name="prefs_data_update_success">Update completed successfully</string>
+    <string name="prefs_data_import_satellites_error">No satellites imported. Select a valid TLE/3LE (.txt) or OMM (.csv) file.</string>
+    <string name="prefs_data_import_transceivers_error">No transceivers imported. Select a valid SatNOGS (.json) file.</string>
 
     <string name="prefs_data_sources_title">Custom data sources</string>
     <string name="prefs_data_sources_tle_switch">Custom TLE URL</string>
@@ -175,21 +188,30 @@
     <string name="prefs_bt_frequency_device_hint">Device id</string>
     <string name="prefs_bt_frequency_output_hint">Data format</string>
     <string name="prefs_bt_perm_error">Check your bluetooth permission</string>
+    <string name="prefs_net_perm_error">Check your network permission</string>
 
     <string name="prefs_other_title">Other settings</string>
     <string name="prefs_other_switch_utc">Show pass time in UTC</string>
     <string name="prefs_other_switch_update">Enable automatic data update</string>
     <string name="prefs_other_switch_sweep">Enable radar sweep animation</string>
     <string name="prefs_other_switch_sensors">Use sensors to rotate radar view</string>
+    <string name="prefs_other_switch_night_mode">Enable red night mode filter</string>
+
+    <string name="prefs_highlight_title">Elevation highlight</string>
+    <string name="prefs_highlight_low">Low &lt; %1$d°</string>
+    <string name="prefs_highlight_mid">Mid %1$d–%2$d°</string>
+    <string name="prefs_highlight_high">High &gt; %1$d°</string>
 
     <string name="prefs_outro_title">I would like to say thanks to</string>
     <string name="prefs_outro_thanks" translatable="false">
-        • Look4Sat users and contributors!
+        * Look4Sat users and contributors!
-        \n• David A. B. Johnson (predict4java)
+        \n* David A. B. Johnson (predict4java)
-        \n• Dave Moten (predict4java)
+        \n* Dave Moten (predict4java)
-        \n• Alexandru Csete (Gpredict)
+        \n* Alexandru Csete (Gpredict)
-        \n• Dr T.S. Kelso (Celestrak)
+        \n* Dr T.S. Kelso (Celestrak)
-        \n• Libre Space Foundation (SatNOGS)</string>
+        \n* Libre Space Foundation (SatNOGS)
+        \n* xdsopl and Robot36 contributors!
+    </string>
     <string name="prefs_outro_license">The app comes with no warranty</string>
 
 </resources>

core/presentation/src/test/java/com/rtbishop/look4sat/core/presentation/DeeplinkResolverTest.kt

@@ -0,0 +1,39 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.core.presentation
+
+import org.junit.Test
+
+class DeeplinkResolverTest {
+
+    @Test
+    fun returnsDefaultDestination() {
+        val deeplinkResolver = DeeplinkResolver()
+        val result = deeplinkResolver.resolve("/deeplink")
+        assert(result == Screen.Passes)
+    }
+
+    @Test
+    fun returnsRadarDestination() {
+        val passId = "some-pass-id"
+        val passDeeplink = "https://github.com/rt-bishop/Look4Sat/passes/$passId"
+        val deeplinkResolver = DeeplinkResolver()
+        val result = deeplinkResolver.resolve(passDeeplink)
+        assert(result == RadarDestination)
+    }
+}

fastlane/metadata/android/en-US/changelogs/default.txt

@@ -1,4 +1,2 @@
-* Added Turkish translation, by Emre Can Akdaş (TA3ECR)
+* Added required tweaks to support Android 17 (API 37)
-* Added DeepSpace passes filter option to the dialog
+* Added ACCESS_LOCAL_NETWORK permission check to support network data output
-* Fixed the radar blip disappearing while eclipsed
-* Fixed (hopefully) the refresh indicator being stuck

fastlane/metadata/android/en-US/whatsnew/whatsnew-en-US

@@ -1,4 +0,0 @@
-* Added Turkish translation, by Emre Can Akdaş (TA3ECR)
-* Added DeepSpace passes filter option to the dialog
-* Fixed the radar blip disappearing while eclipsed
-* Fixed (hopefully) the refresh indicator being stuck

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapNightOverlay.kt

@@ -0,0 +1,152 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.feature.map
+
+import android.graphics.Canvas
+import android.graphics.Color
+import android.graphics.Paint
+import android.graphics.RectF
+import org.osmdroid.views.MapView
+import org.osmdroid.views.overlay.Overlay
+import kotlin.math.cos
+import kotlin.math.sin
+
+/**
+ * Custom osmdroid overlay that shades the night side of the globe.
+ *
+ * Works entirely in screen-pixel space: for each vertical strip on screen it
+ * asks osmdroid for the geographic coordinate, then tests whether that point is
+ * in the night half-sphere relative to the sub-solar point.  Because the
+ * computation happens during draw() the result is always correct regardless
+ * of zoom level or map scroll position — no polygon winding issues possible.
+ *
+ * A point (latRad, lonRad) is in night when the angle to the sub-solar point
+ * exceeds 90°, i.e. the dot product of the two unit vectors is negative:
+ *   dot = sin(lat)*sin(sunLat) + cos(lat)*cos(sunLat)*cos(lon - sunLon) < 0
+ *
+ * Performance: we sample one column per [stepPx] pixels (default 4) and draw
+ * filled vertical rectangles.  On a 1080-wide screen this means ~270 trig
+ * evaluations per row, which is imperceptible.
+ */
+class MapNightOverlay : Overlay() {
+
+    /** Sub-solar latitude in degrees. */
+    var sunLatDeg: Double = 0.0
+
+    /** Sub-solar longitude in degrees. */
+    var sunLonDeg: Double = 0.0
+
+    private val nightPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+        style = Paint.Style.FILL
+        color = Color.argb(75, 0, 0, 0)
+    }
+
+    private val rect = RectF()
+
+    override fun draw(canvas: Canvas, mapView: MapView, shadow: Boolean) {
+        if (shadow) return
+
+        val proj = mapView.projection
+        val sunLatRad = Math.toRadians(sunLatDeg)
+        val sunLonRad = Math.toRadians(sunLonDeg)
+        val sinSunLat = sin(sunLatRad)
+        val cosSunLat = cos(sunLatRad)
+
+        val w = mapView.width
+        val h = mapView.height
+        val stepPx = 4 // sample every N pixels — balance quality vs CPU
+
+        // We scan column by column. For each column we determine the longitude,
+        // then find the latitude range that is in night and shade it.
+        // Since longitude is constant along a vertical strip and the day/night
+        // boundary at a given longitude is at most two latitudes, we can do a
+        // scan-line fill efficiently.
+
+        var x = 0
+        while (x < w) {
+            // Get the geographic coordinate at the top and bottom of this column.
+            val geoTop = proj.fromPixels(x, 0) ?: run { x += stepPx; continue }
+            val geoBot = proj.fromPixels(x, h - 1) ?: run { x += stepPx; continue }
+
+            val lonRad = Math.toRadians(geoTop.longitude)
+            val cosLonDiff = cos(lonRad - sunLonRad)
+
+            // Top pixel geographic lat
+            val latTopRad = Math.toRadians(geoTop.latitude)
+            // Bottom pixel geographic lat (osmdroid: y=0 is top of screen, higher y = lower lat)
+            val latBotRad = Math.toRadians(geoBot.latitude)
+
+            // dot(sunVec, pointVec) < 0 → night
+            // dot = sin(lat)*sinSunLat + cos(lat)*cosSunLat*cosLonDiff
+            val dotTop = sin(latTopRad) * sinSunLat + cos(latTopRad) * cosSunLat * cosLonDiff
+            val dotBot = sin(latBotRad) * sinSunLat + cos(latBotRad) * cosSunLat * cosLonDiff
+
+            when {
+                dotTop < 0 && dotBot < 0 -> {
+                    // Entire column is night — shade from top to bottom
+                    rect.set(x.toFloat(), 0f, (x + stepPx).toFloat(), h.toFloat())
+                    canvas.drawRect(rect, nightPaint)
+                }
+
+                dotTop >= 0 && dotBot >= 0 -> {
+                    // Entire column is day — nothing to draw
+                }
+
+                else -> {
+                    // Terminator crosses this column — find the crossing pixel by binary search
+                    val crossY = findCrossingY(proj, x, 0, h - 1, sinSunLat, cosSunLat, cosLonDiff)
+                    if (dotTop < 0) {
+                        // Night at top, day at bottom
+                        rect.set(x.toFloat(), 0f, (x + stepPx).toFloat(), crossY.toFloat())
+                        canvas.drawRect(rect, nightPaint)
+                    } else {
+                        // Day at top, night at bottom
+                        rect.set(x.toFloat(), crossY.toFloat(), (x + stepPx).toFloat(), h.toFloat())
+                        canvas.drawRect(rect, nightPaint)
+                    }
+                }
+            }
+            x += stepPx
+        }
+    }
+
+    /**
+     * Binary-search for the pixel row where the day/night boundary crosses column [x].
+     * [yTop] is in day, [yBot] is in night (or vice versa).
+     */
+    private fun findCrossingY(
+        proj: org.osmdroid.views.Projection,
+        x: Int,
+        yTop: Int,
+        yBot: Int,
+        sinSunLat: Double,
+        cosSunLat: Double,
+        cosLonDiff: Double
+    ): Int {
+        var lo = yTop
+        var hi = yBot
+        while (hi - lo > 1) {
+            val mid = (lo + hi) / 2
+            val geo = proj.fromPixels(x, mid) ?: return mid
+            val latRad = Math.toRadians(geo.latitude)
+            val dot = sin(latRad) * sinSunLat + cos(latRad) * cosSunLat * cosLonDiff
+            if (dot < 0) hi = mid else lo = mid
+        }
+        return (lo + hi) / 2
+    }
+}

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapScreen.kt

@@ -63,6 +63,7 @@ import androidx.lifecycle.viewmodel.compose.viewModel
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.OrbitalObject
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
+import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
 import com.rtbishop.look4sat.core.presentation.IconCard
 import com.rtbishop.look4sat.core.presentation.NextPassRow
 import com.rtbishop.look4sat.core.presentation.R
@@ -83,7 +84,10 @@ private const val OVERLAY_STATION = 0
 private const val OVERLAY_TRACK = 1
 private const val OVERLAY_FOOTPRINT = 2
 private const val OVERLAY_POSITIONS = 3
-private const val OVERLAY_COUNT = 4
+private const val OVERLAY_TERMINATOR = 4
+private const val OVERLAY_SUN = 5
+private const val OVERLAY_MOON = 6
+private const val OVERLAY_COUNT = 7
 
 private val minLat = MapView.getTileSystem().minLatitude
 private val maxLat = MapView.getTileSystem().maxLatitude
@@ -106,13 +110,20 @@ private val textPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
     setShadowLayer(3f, 3f, 3f, Color.BLACK)
 }
 private val iconCache = LruCache<String, Drawable>(128)
+private val sunIconPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+    colorFilter =
+        android.graphics.PorterDuffColorFilter("#FFE082".toColorInt(), android.graphics.PorterDuff.Mode.SRC_IN)
+}
+private val moonIconPaint = Paint(Paint.ANTI_ALIAS_FLAG).apply {
+    colorFilter =
+        android.graphics.PorterDuffColorFilter("#E0E0E0".toColorInt(), android.graphics.PorterDuff.Mode.SRC_IN)
+}
 
 @Composable
 fun MapDestination() {
-    val viewModel = viewModel(
+    val context = LocalContext.current
-        modelClass = MapViewModel::class.java,
+    val container = (context.applicationContext as IContainerProvider).getMainContainer()
-        factory = MapViewModel.Factory
+    val viewModel: MapViewModel = viewModel(factory = MapViewModel.factory(container))
-    )
     val uiState by viewModel.uiState.collectAsStateWithLifecycle()
     val mapView = rememberMapViewWithLifecycle()
     MapScreen(uiState, viewModel::onAction, mapView)
@@ -152,6 +163,9 @@ private fun MapScreen(uiState: MapState, onAction: (MapAction) -> Unit, mapView:
                     uiState.track?.let { setSatelliteTrack(it, view) }
                     uiState.footprint?.let { setFootprint(it, view) }
                     uiState.positions?.let { setPositions(it, view) { item -> onAction(MapAction.SelectItem(item)) } }
+                    setTerminator(uiState.sunLatDeg, uiState.sunLonDeg, view)
+                    setSubSolarPoint(uiState.sunLatDeg, uiState.sunLonDeg, view)
+                    setMoonPosition(uiState.moonLatDeg, uiState.moonLonDeg, view)
                     view.invalidate()
                 }
                 uiState.mapData?.let { mapData ->
@@ -365,14 +379,12 @@ private var footprintPoints: ArrayList<GeoPoint>? = null
 private fun setFootprint(orbitalPos: OrbitalPos, mapView: MapView) {
     try {
         val rangeCircle = orbitalPos.getRangeCircle()
-        // Lazily initialize the reusable point list and polyline
         var pts = footprintPoints
         if (pts == null || pts.size != rangeCircle.size) {
             pts = ArrayList(rangeCircle.size)
             for (gp in rangeCircle) pts.add(GeoPoint(gp.latitude, gp.longitude))
             footprintPoints = pts
         } else {
-            // Update coordinates in-place — zero allocations
             for (i in rangeCircle.indices) {
                 pts[i].latitude = rangeCircle[i].latitude
                 pts[i].longitude = rangeCircle[i].longitude
@@ -388,6 +400,83 @@ private fun setFootprint(orbitalPos: OrbitalPos, mapView: MapView) {
         println(e)
     }
 }
+
+/**
+ * Update the NightOverlay with the current sub-solar position.
+ * The overlay is created once and kept in OVERLAY_TERMINATOR; only its
+ * sunLatDeg/sunLonDeg fields are updated each tick so osmdroid redraws it.
+ */
+private fun setTerminator(sunLatDeg: Double, sunLonDeg: Double, mapView: MapView) {
+    try {
+        val overlay = mapView.overlays[OVERLAY_TERMINATOR]
+        if (overlay is MapNightOverlay) {
+            overlay.sunLatDeg = sunLatDeg
+            overlay.sunLonDeg = sunLonDeg
+        } else {
+            mapView.overlays[OVERLAY_TERMINATOR] = MapNightOverlay().apply {
+                this.sunLatDeg = sunLatDeg
+                this.sunLonDeg = sunLonDeg
+            }
+        }
+    } catch (e: Exception) {
+        println(e)
+    }
+}
+
+/** Place an ic_sun icon marker at the sub-solar point. */
+private fun setSubSolarPoint(sunLatDeg: Double, sunLonDeg: Double, mapView: MapView) {
+    try {
+        val overlay = mapView.overlays[OVERLAY_SUN]
+        val sunPos = GeoPoint(sunLatDeg, sunLonDeg)
+        if (overlay is Marker) {
+            overlay.position = sunPos
+        } else {
+            val iconSize = 48
+            val bmp = createBitmap(iconSize, iconSize)
+            ContextCompat.getDrawable(mapView.context, R.drawable.ic_sun)?.apply {
+                setBounds(0, 0, iconSize, iconSize)
+                colorFilter = sunIconPaint.colorFilter
+                draw(Canvas(bmp))
+            }
+            mapView.overlays[OVERLAY_SUN] = Marker(mapView).apply {
+                setInfoWindow(null)
+                setAnchor(Marker.ANCHOR_CENTER, Marker.ANCHOR_CENTER)
+                icon = bmp.toDrawable(mapView.context.resources)
+                position = sunPos
+            }
+        }
+    } catch (e: Exception) {
+        println(e)
+    }
+}
+
+/** Place an ic_moon icon marker at the sub-lunar point. */
+private fun setMoonPosition(moonLatDeg: Double, moonLonDeg: Double, mapView: MapView) {
+    try {
+        val overlay = mapView.overlays[OVERLAY_MOON]
+        val moonPos = GeoPoint(moonLatDeg, moonLonDeg)
+        if (overlay is Marker) {
+            overlay.position = moonPos
+        } else {
+            val iconSize = 48
+            val bmp = createBitmap(iconSize, iconSize)
+            val c = Canvas(bmp)
+            ContextCompat.getDrawable(mapView.context, R.drawable.ic_moon)?.apply {
+                setBounds(0, 0, iconSize, iconSize)
+                colorFilter = moonIconPaint.colorFilter
+                draw(c)
+            }
+            mapView.overlays[OVERLAY_MOON] = Marker(mapView).apply {
+                setInfoWindow(null)
+                setAnchor(Marker.ANCHOR_CENTER, Marker.ANCHOR_CENTER)
+                icon = bmp.toDrawable(mapView.context.resources)
+                position = moonPos
+            }
+        }
+    } catch (e: Exception) {
+        println(e)
+    }
+}
 // endregion
 
 // region MapView lifecycle

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapState.kt

@@ -30,7 +30,11 @@ data class MapState(
     val orbitalPass: OrbitalPass,
     val track: List<List<GeoPos>>? = null,
     val footprint: OrbitalPos? = null,
-    val positions: Map<OrbitalObject, GeoPos>? = null
+    val positions: Map<OrbitalObject, GeoPos>? = null,
+    val sunLatDeg: Double = 0.0,
+    val sunLonDeg: Double = 0.0,
+    val moonLatDeg: Double = 0.0,
+    val moonLonDeg: Double = 0.0
 )
 
 sealed interface MapAction {

feature/map/src/main/java/com/rtbishop/look4sat/feature/map/MapViewModel.kt

@@ -18,20 +18,21 @@
 package com.rtbishop.look4sat.feature.map
 
 import androidx.lifecycle.ViewModel
-import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewModelScope
 import androidx.lifecycle.viewmodel.initializer
 import androidx.lifecycle.viewmodel.viewModelFactory
+import com.rtbishop.look4sat.core.domain.predict.CelestialComputer
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.OrbitalObject
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
-import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
+import com.rtbishop.look4sat.core.domain.repository.IMainContainer
 import com.rtbishop.look4sat.core.domain.repository.ISatelliteRepo
 import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
 import com.rtbishop.look4sat.core.domain.utility.clipLat
 import com.rtbishop.look4sat.core.domain.utility.clipLon
 import com.rtbishop.look4sat.core.domain.utility.positionToQth
+import com.rtbishop.look4sat.core.domain.utility.toMapGeoPos
 import com.rtbishop.look4sat.core.domain.utility.toDegrees
 import com.rtbishop.look4sat.core.domain.utility.toTimerString
 import com.rtbishop.look4sat.core.presentation.getDefaultPass
@@ -49,8 +50,10 @@ import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import java.util.Date
 
-class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settingsRepo: ISettingsRepo) :
+class MapViewModel(
-    ViewModel() {
+    private val satelliteRepo: ISatelliteRepo,
+    private val settingsRepo: ISettingsRepo
+) : ViewModel() {
 
     private val stationPos = settingsRepo.stationPosition.value
     private val defaultPass = getDefaultPass()
@@ -74,7 +77,8 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
                 _uiState.update { it.copy(isUtc = settings.stateOfUtc) }
             }
         }
-        selectDefaultSatellite(-1)
+        val (selectedCatNum, _) = satelliteRepo.selectedPass.value
+        selectDefaultSatellite(if (selectedCatNum != 0) selectedCatNum else -1)
     }
 
     fun onAction(action: MapAction) {
@@ -124,10 +128,16 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
                 val dateNow = Date()
                 getStationPosition()
                 getSatTrack(orbitalObject, stationPos, dateNow)
+                // Scale update interval based on satellite count to avoid excessive CPU usage
+                val effectiveRate = when {
+                    allSatellites.size > 5000 -> maxOf(updateFreq, 3000L)
+                    allSatellites.size > 1000 -> maxOf(updateFreq, 2000L)
+                    else -> updateFreq
+                }
                 while (isActive) {
                     dateNow.time = System.currentTimeMillis()
                     updateMapState(orbitalObject, allSatellites, stationPos, dateNow)
-                    delay(updateFreq)
+                    delay(effectiveRate)
                 }
             }
         }
@@ -157,9 +167,7 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
                     var localSelectedPos: OrbitalPos? = null
                     for (satellite in chunk) {
                         val satPos = satelliteRepo.getPosition(satellite, pos, date.time)
-                        val osmLat = clipLat(satPos.latitude.toDegrees())
+                        localPositions.add(satellite to satPos.toMapGeoPos())
-                        val osmLon = clipLon(satPos.longitude.toDegrees())
-                        localPositions.add(satellite to GeoPos(osmLat, osmLon))
                         if (satellite === selected) {
                             localSelectedPos = satPos
                         }
@@ -177,10 +185,12 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
             }
         }
 
-        // 2. Derive footprint and info data from the already-computed selected position
+        // 2. Derive footprint, info data, sun and moon position from already-computed state
         val satPos = selectedSatPos ?: satelliteRepo.getPosition(selected, pos, date.time)
         val footprint = satPos
         val mapData = buildMapData(selected, satPos, date)
+        val sunPos = CelestialComputer.getSunPosition(stationPos, date.time)
+        val moonPos = CelestialComputer.getMoonPosition(stationPos, date.time)
 
         // 3. Single atomic state update — one recomposition per cycle
         _uiState.update {
@@ -188,7 +198,11 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
                 positions = positionsMap,
                 footprint = footprint,
                 mapData = mapData.first,
-                orbitalPass = mapData.second
+                orbitalPass = mapData.second,
+                sunLatDeg = sunPos.latitude,
+                sunLonDeg = sunPos.longitude,
+                moonLatDeg = moonPos.declination, // sub-lunar latitude = declination
+                moonLonDeg = if (moonPos.gha <= 180.0) -moonPos.gha else 360.0 - moonPos.gha
             )
         }
     }
@@ -227,9 +241,7 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
             }
         val azimuth = satPos.azimuth.toDegrees()
         val elevation = satPos.elevation.toDegrees()
-        val osmLat = clipLat(satPos.latitude.toDegrees())
+        val osmPos = satPos.toMapGeoPos()
-        val osmLon = clipLon(satPos.longitude.toDegrees())
-        val osmPos = GeoPos(osmLat, osmLon)
         val qthLoc = positionToQth(osmPos.latitude, osmPos.longitude) ?: "-- --"
         val velocity = satPos.getOrbitalVelocity()
         val phase = satPos.phase.toDegrees()
@@ -259,18 +271,16 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
         val endDate = Date(date.time + (orbitalObject.data.orbitalPeriod * 2.4 * 60000L).toLong())
         var oldLongitude = 0.0
         satelliteRepo.getTrack(orbitalObject, pos, date.time, endDate.time).forEach { satPos ->
-            val osmLat = clipLat(satPos.latitude.toDegrees())
+            val currentPosition = satPos.toMapGeoPos()
-            val osmLon = clipLon(satPos.longitude.toDegrees())
-            val currentPosition = GeoPos(osmLat, osmLon)
             if (oldLongitude < -170.0 && currentPosition.longitude > 170.0) {
                 // adding left terminal position
-                currentTrack.add(GeoPos(osmLat, -180.0))
+                currentTrack.add(GeoPos(currentPosition.latitude, -180.0))
                 val finishedTrack = mutableListOf<GeoPos>().apply { addAll(currentTrack) }
                 satTracks.add(finishedTrack)
                 currentTrack.clear()
             } else if (oldLongitude > 170.0 && currentPosition.longitude < -170.0) {
                 // adding right terminal position
-                currentTrack.add(GeoPos(osmLat, 180.0))
+                currentTrack.add(GeoPos(currentPosition.latitude, 180.0))
                 val finishedTrack = mutableListOf<GeoPos>().apply { addAll(currentTrack) }
                 satTracks.add(finishedTrack)
                 currentTrack.clear()
@@ -286,11 +296,12 @@ class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settin
         /** Number of parallel chunks for satellite position computation */
         private const val PARALLEL_CHUNKS = 4
 
-        val Factory: ViewModelProvider.Factory = viewModelFactory {
+        fun factory(container: IMainContainer) = viewModelFactory {
-            val applicationKey = ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY
             initializer {
-                val container = (this[applicationKey] as IContainerProvider).getMainContainer()
+                MapViewModel(
-                MapViewModel(container.satelliteRepo, container.settingsRepo)
+                    satelliteRepo = container.satelliteRepo,
+                    settingsRepo = container.settingsRepo
+                )
             }
         }
     }

feature/mutual/build.gradle.kts

@@ -3,5 +3,5 @@ plugins {
 }
 
 android {
-    namespace = "com.rtbishop.look4sat.feature.radiocontrol"
+    namespace = "com.rtbishop.look4sat.feature.mutual"
-}
+}

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/ElevationCurveChart.kt

@@ -0,0 +1,262 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.feature.mutual
+
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.background
+import androidx.compose.foundation.gestures.detectDragGestures
+import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.toArgb
+import androidx.compose.ui.graphics.Path
+import androidx.compose.ui.graphics.drawscope.Stroke
+import androidx.compose.ui.graphics.nativeCanvas
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+import kotlin.math.roundToInt
+
+/**
+ * Draggable dual-station elevation curve chart.
+ * Controlled component: [progress] (0..1) and [onProgressChange] are owned by the parent,
+ * so the same time cursor can be shared with the radar track view.
+ */
+@Composable
+fun ElevationCurveChart(
+    samples: List<Pair<Long, Pair<Double, Double>>>,
+    startTime: Long,
+    endTime: Long,
+    maxElev: Double,
+    progress: Float = 0.5f,
+    onProgressChange: (Float) -> Unit = {},
+    modifier: Modifier = Modifier
+) {
+    if (samples.isEmpty()) return
+
+    val colorA = MaterialTheme.colorScheme.primary
+    val colorB = MaterialTheme.colorScheme.tertiary
+    val gridColor = MaterialTheme.colorScheme.outlineVariant
+    val textColor = MaterialTheme.colorScheme.onSurfaceVariant
+    val onSurfaceColor = MaterialTheme.colorScheme.onSurface
+    val colorAArgb = colorA.toArgb()
+    val colorBArgb = colorB.toArgb()
+    val textColorArgb = textColor.toArgb()
+    val onSurfaceArgb = onSurfaceColor.toArgb()
+    val gridColorArgb = gridColor.toArgb()
+    val timeFormat = remember { SimpleDateFormat("HH:mm", Locale.getDefault()) }
+
+    Column(modifier = modifier.fillMaxWidth()) {
+        Canvas(
+            modifier = Modifier
+                .fillMaxWidth()
+                .height(200.dp)
+                .background(MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.3f))
+                .pointerInput(Unit) {
+                    detectTapGestures { offset ->
+                        onProgressChange((offset.x / size.width.toFloat()).coerceIn(0f, 1f))
+                    }
+                }
+                .pointerInput(Unit) {
+                    detectDragGestures { change, _ ->
+                        onProgressChange((change.position.x / size.width.toFloat()).coerceIn(0f, 1f))
+                    }
+                }
+        ) {
+            val chartWidth = size.width
+            val chartHeight = size.height
+            val padding = 40f
+            val plotLeft = padding
+            val plotRight = chartWidth - 10f
+            val plotTop = 10f
+            val plotBottom = chartHeight - padding
+            val plotWidth = plotRight - plotLeft
+            val plotHeight = plotBottom - plotTop
+
+            if (plotWidth <= 0f || plotHeight <= 0f) return@Canvas
+
+            val minTime = startTime
+            val maxTime = endTime
+            val timeRange = (maxTime - minTime).toFloat()
+            if (timeRange <= 0f) return@Canvas
+
+            // Grid lines
+            val gridSteps = 4
+            for (i in 0..gridSteps) {
+                val y = plotBottom - (plotHeight * i / gridSteps)
+                drawLine(gridColor, Offset(plotLeft, y), Offset(plotRight, y), strokeWidth = 1f)
+                val elev = (maxElev * i / gridSteps).roundToInt()
+                drawContext.canvas.nativeCanvas.drawText(
+                    "$elev°", 2f, y + 4f,
+                    android.graphics.Paint().apply {
+                        color = textColorArgb
+                        textSize = 24f
+                        textAlign = android.graphics.Paint.Align.LEFT
+                    }
+                )
+            }
+
+            // Time axis
+            val timeSteps = 4
+            for (i in 0..timeSteps) {
+                val x = plotLeft + (plotWidth * i / timeSteps)
+                val t = startTime + ((endTime - startTime) * i / timeSteps)
+                drawContext.canvas.nativeCanvas.drawText(
+                    timeFormat.format(Date(t)), x - 20f, chartHeight - 2f,
+                    android.graphics.Paint().apply {
+                        color = textColorArgb
+                        textSize = 22f
+                        textAlign = android.graphics.Paint.Align.LEFT
+                    }
+                )
+            }
+
+            // Elevation curves (smooth cubic Bezier)
+            val pathA = Path()
+            val pathB = Path()
+            val ptsA = mutableListOf<Offset>()
+            val ptsB = mutableListOf<Offset>()
+
+            for ((time, elev) in samples) {
+                val x = plotLeft + ((time - minTime).toFloat() / timeRange) * plotWidth
+                val yA = plotBottom - ((elev.first.toFloat() / maxElev.toFloat()) * plotHeight).coerceIn(0f, plotHeight)
+                val yB = plotBottom - ((elev.second.toFloat() / maxElev.toFloat()) * plotHeight).coerceIn(0f, plotHeight)
+                ptsA.add(Offset(x, yA))
+                ptsB.add(Offset(x, yB))
+            }
+
+            if (ptsA.size >= 2) {
+                pathA.moveTo(ptsA[0].x, ptsA[0].y)
+                pathB.moveTo(ptsB[0].x, ptsB[0].y)
+                for (i in 1 until ptsA.size) {
+                    val p0a = ptsA.getOrNull(i - 2) ?: ptsA[i - 1]
+                    val p1a = ptsA[i - 1]
+                    val p2a = ptsA[i]
+                    val p3a = ptsA.getOrNull(i + 1) ?: ptsA[i]
+                    val cp1a = Offset(p1a.x + (p2a.x - p0a.x) / 6f, p1a.y + (p2a.y - p0a.y) / 6f)
+                    val cp2a = Offset(p2a.x - (p3a.x - p1a.x) / 6f, p2a.y - (p3a.y - p1a.y) / 6f)
+                    pathA.cubicTo(cp1a.x, cp1a.y, cp2a.x, cp2a.y, p2a.x, p2a.y)
+
+                    val p0b = ptsB.getOrNull(i - 2) ?: ptsB[i - 1]
+                    val p1b = ptsB[i - 1]
+                    val p2b = ptsB[i]
+                    val p3b = ptsB.getOrNull(i + 1) ?: ptsB[i]
+                    val cp1b = Offset(p1b.x + (p2b.x - p0b.x) / 6f, p1b.y + (p2b.y - p0b.y) / 6f)
+                    val cp2b = Offset(p2b.x - (p3b.x - p1b.x) / 6f, p2b.y - (p3b.y - p1b.y) / 6f)
+                    pathB.cubicTo(cp1b.x, cp1b.y, cp2b.x, cp2b.y, p2b.x, p2b.y)
+                }
+            }
+
+            drawPath(pathA, colorA, style = Stroke(width = 2.5f))
+            drawPath(pathB, colorB, style = Stroke(width = 2.5f))
+
+            // Drag indicator
+            val dragX = plotLeft + progress * plotWidth
+            val dragTime = startTime + (progress * (endTime - startTime)).toLong()
+
+            drawLine(
+                onSurfaceColor,
+                Offset(dragX, plotTop), Offset(dragX, plotBottom),
+                strokeWidth = 2f
+            )
+
+            val dragElev = getElevationAtTime(samples, dragTime)
+            val dragElevA = (dragElev?.first?.let { (it * 10).roundToInt() / 10.0 } ?: 0.0)
+            val dragElevB = (dragElev?.second?.let { (it * 10).roundToInt() / 10.0 } ?: 0.0)
+
+            drawContext.canvas.nativeCanvas.drawText(
+                timeFormat.format(Date(dragTime)),
+                dragX - 24f, plotBottom + 16f,
+                android.graphics.Paint().apply {
+                    color = onSurfaceArgb
+                    textSize = 24f
+                    textAlign = android.graphics.Paint.Align.LEFT
+                }
+            )
+            drawContext.canvas.nativeCanvas.drawText(
+                "A:${dragElevA}°",
+                dragX + 6f, plotTop + 16f,
+                android.graphics.Paint().apply {
+                    color = colorAArgb
+                    textSize = 24f
+                    textAlign = android.graphics.Paint.Align.LEFT
+                }
+            )
+            drawContext.canvas.nativeCanvas.drawText(
+                "B:${dragElevB}°",
+                dragX + 6f, plotTop + 42f,
+                android.graphics.Paint().apply {
+                    color = colorBArgb
+                    textSize = 24f
+                    textAlign = android.graphics.Paint.Align.LEFT
+                }
+            )
+        }
+
+        // Legend
+        Row(
+            modifier = Modifier.fillMaxWidth().padding(horizontal = 8.dp, vertical = 4.dp),
+            horizontalArrangement = Arrangement.SpaceEvenly
+        ) {
+            Text("● 站点A", color = colorA, fontSize = 12.sp)
+            Text("● 站点B", color = colorB, fontSize = 12.sp)
+        }
+    }
+}
+
+private fun getElevationAtTime(
+    samples: List<Pair<Long, Pair<Double, Double>>>,
+    time: Long
+): Pair<Double, Double>? {
+    if (samples.isEmpty()) return null
+    if (samples.size == 1) return samples[0].second
+    if (time <= samples[0].first) return samples[0].second
+    if (time >= samples.last().first) return samples.last().second
+
+    var lo = 0
+    var hi = samples.size - 1
+    while (hi - lo > 1) {
+        val mid = (lo + hi) / 2
+        if (samples[mid].first <= time) lo = mid
+        else hi = mid
+    }
+
+    val t0 = samples[lo].first
+    val t1 = samples[hi].first
+    val frac = if (t1 > t0) (time - t0).toFloat() / (t1 - t0).toFloat() else 0f
+
+    val e0 = samples[lo].second
+    val e1 = samples[hi].second
+    return Pair(
+        e0.first + (e1.first - e0.first) * frac,
+        e0.second + (e1.second - e0.second) * frac
+    )
+}

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualPass.kt

@@ -0,0 +1,53 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.feature.mutual
+
+/**
+ * A mutual pass where a satellite is visible from two stations simultaneously.
+ *
+ * @param catNum Satellite catalog number
+ * @param name Satellite name
+ * @param startTime Common AOS time (millis)
+ * @param endTime Common LOS time (millis)
+ * @param maxElevationA Peak elevation for station A
+ * @param maxElevationB Peak elevation for station B
+ * @param elevationSamples List of (time, (elevationA, elevationB)) pairs
+ * @param trackSamples List of radar-track samples (azimuth/elevation for both stations, degrees)
+ */
+data class MutualPass(
+    val catNum: Int,
+    val name: String,
+    val startTime: Long,
+    val endTime: Long,
+    val maxElevationA: Double,
+    val maxElevationB: Double,
+    val elevationSamples: List<Pair<Long, Pair<Double, Double>>>,
+    val trackSamples: List<TrackSample> = emptyList()
+)
+
+/**
+ * One radar-track sample: satellite position as seen from both stations.
+ * All angles are in degrees.
+ */
+data class TrackSample(
+    val time: Long,
+    val azimuthA: Double,
+    val elevationA: Double,
+    val azimuthB: Double,
+    val elevationB: Double
+)

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualRadarView.kt

@@ -0,0 +1,223 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.feature.mutual
+
+import androidx.compose.foundation.Canvas
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.aspectRatio
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.Path
+import androidx.compose.ui.graphics.PathEffect
+import androidx.compose.ui.graphics.drawscope.DrawScope
+import androidx.compose.ui.graphics.drawscope.Stroke
+import androidx.compose.ui.text.TextMeasurer
+import androidx.compose.ui.text.TextStyle
+import androidx.compose.ui.text.drawText
+import androidx.compose.ui.text.rememberTextMeasurer
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import kotlin.math.PI
+import kotlin.math.cos
+import kotlin.math.sin
+
+private const val CIRCLES = 3 // 30°, 60°, 90° rings
+private const val STROKE_WIDTH = 2.5f
+
+/**
+ * Polar radar chart showing the satellite track as seen from both stations
+ * on one plot. Station A is drawn solid, station B dashed.
+ * Controlled: [progress] (0..1) and [onProgressChange] are owned by the parent
+ * so the time cursor can be shared with the elevation curve chart.
+ */
+@Composable
+fun MutualRadarView(
+    trackSamples: List<TrackSample>,
+    progress: Float = 0.5f,
+    labelA: String = "站点A",
+    labelB: String = "站点B",
+    modifier: Modifier = Modifier
+) {
+    if (trackSamples.isEmpty()) return
+
+    val colorA = MaterialTheme.colorScheme.primary
+    val colorB = MaterialTheme.colorScheme.tertiary
+    val gridColor = MaterialTheme.colorScheme.outlineVariant
+    val textColor = MaterialTheme.colorScheme.onSurfaceVariant
+    val measurer = rememberTextMeasurer()
+
+    // Current-time samples (both stations' position at the shared cursor)
+    val t0 = trackSamples.first().time
+    val t1 = trackSamples.last().time
+    val selectedTime = t0 + ((t1 - t0) * progress).toLong()
+    val visibleSamples = trackSamples.filter { it.time <= selectedTime }
+    val currentSample = visibleSamples.lastOrNull() ?: trackSamples.first()
+
+    Column(modifier = modifier.fillMaxWidth()) {
+        Canvas(
+            modifier = Modifier
+                .fillMaxWidth()
+                .aspectRatio(1f)
+                .padding(4.dp)
+        ) {
+            val radius = size.minDimension / 2f * 0.92f
+            val center = Offset(size.width / 2f, size.height / 2f)
+
+            // Grid: elevation rings + azimuth spokes + cardinal labels
+            drawRadarGrid(center, radius, gridColor, textColor, measurer)
+
+            // Track paths (only the above-horizon arc, split at the 0/360° azimuth wrap)
+            val pathA = Path()
+            val pathB = Path()
+            var firstVisibleA = true
+            var firstVisibleB = true
+            var lastAzimA: Double? = null
+            var lastAzimB: Double? = null
+            trackSamples.forEach { sample ->
+                if (sample.elevationA > 0f) {
+                    val p = sph2Cart(center, sample.azimuthA, sample.elevationA, radius)
+                    val wrapA = lastAzimA != null && kotlin.math.abs(azimuthDelta(sample.azimuthA - lastAzimA!!)) > 180.0
+                    if (firstVisibleA || wrapA) {
+                        pathA.moveTo(p.x, p.y)
+                        firstVisibleA = false
+                    } else {
+                        pathA.lineTo(p.x, p.y)
+                    }
+                    lastAzimA = sample.azimuthA
+                }
+                if (sample.elevationB > 0f) {
+                    val p = sph2Cart(center, sample.azimuthB, sample.elevationB, radius)
+                    val wrapB = lastAzimB != null && kotlin.math.abs(azimuthDelta(sample.azimuthB - lastAzimB!!)) > 180.0
+                    if (firstVisibleB || wrapB) {
+                        pathB.moveTo(p.x, p.y)
+                        firstVisibleB = false
+                    } else {
+                        pathB.lineTo(p.x, p.y)
+                    }
+                    lastAzimB = sample.azimuthB
+                }
+            }
+
+            // Solid line for station A, dashed for station B
+            drawPath(pathA, colorA, style = Stroke(STROKE_WIDTH))
+            drawPath(
+                pathB, colorB,
+                style = Stroke(STROKE_WIDTH, pathEffect = PathEffect.dashPathEffect(floatArrayOf(14f, 10f)))
+            )
+
+            // AOS / LOS markers on both tracks
+            val first = trackSamples.first()
+            val last = trackSamples.last()
+            val aosA = sph2Cart(center, first.azimuthA, first.elevationA, radius)
+            val aosB = sph2Cart(center, first.azimuthB, first.elevationB, radius)
+            val losA = sph2Cart(center, last.azimuthA, last.elevationA, radius)
+            val losB = sph2Cart(center, last.azimuthB, last.elevationB, radius)
+            // AOS: hollow circle, LOS: filled circle
+            if (first.elevationA > 0f) drawCircle(colorA, 7f, aosA, style = Stroke(2.5f))
+            if (first.elevationB > 0f) drawCircle(colorB, 7f, aosB, style = Stroke(2.5f))
+            if (last.elevationA > 0f) drawCircle(colorA, 5f, losA)
+            if (last.elevationB > 0f) drawCircle(colorB, 5f, losB)
+
+            // Shared time-cursor positions (both stations at selectedTime)
+            val cursorA = sph2Cart(center, currentSample.azimuthA, currentSample.elevationA, radius)
+            val cursorB = sph2Cart(center, currentSample.azimuthB, currentSample.elevationB, radius)
+            drawCircle(colorA, 14f, cursorA, style = Stroke(3f))
+            drawCircle(colorA, 6f, cursorA)
+            drawCircle(colorB, 14f, cursorB, style = Stroke(3f))
+            drawCircle(colorB, 6f, cursorB)
+
+            // Center dot
+            drawCircle(gridColor, 4f, center)
+        }
+
+        // Legend
+        Row(
+            modifier = Modifier.fillMaxWidth().padding(horizontal = 8.dp, vertical = 4.dp),
+            horizontalArrangement = Arrangement.SpaceEvenly
+        ) {
+            Text("● $labelA", color = colorA, fontSize = 12.sp)
+            Text("- - $labelB", color = colorB, fontSize = 12.sp)
+        }
+    }
+}
+
+private fun DrawScope.drawRadarGrid(
+    center: Offset,
+    radius: Float,
+    color: Color,
+    textColor: Color,
+    measurer: TextMeasurer
+) {
+    // Elevation rings: 30°, 60°, 90°(center) — outer edge is horizon (0°)
+    val step = radius / CIRCLES
+    for (i in 0 until CIRCLES) {
+        drawCircle(color, radius - step * i, center, style = Stroke(1.5f))
+    }
+    // Cardinal spokes
+    drawLine(color, Offset(center.x - radius, center.y), Offset(center.x + radius, center.y), 1.5f)
+    drawLine(color, Offset(center.x, center.y - radius), Offset(center.x, center.y + radius), 1.5f)
+    // Diagonal spokes (lighter)
+    val diag = radius * 0.7071f
+    drawLine(
+        color.copy(alpha = 0.5f),
+        Offset(center.x - diag, center.y - diag), Offset(center.x + diag, center.y + diag), 1f
+    )
+    drawLine(
+        color.copy(alpha = 0.5f),
+        Offset(center.x - diag, center.y + diag), Offset(center.x + diag, center.y - diag), 1f
+    )
+
+    // Elevation ring labels: 30° on the outer ring, 60° on the middle ring, 90° at center
+    // (outer edge is the 0° horizon). Labels sit just above their ring.
+    val style = TextStyle(color = textColor, fontSize = 11.sp)
+    drawText(measurer, "30°", Offset(center.x + 6f, (center.y - (radius - step)) - 24f), style = style)
+    drawText(measurer, "60°", Offset(center.x + 6f, (center.y - (radius - 2 * step)) - 24f), style = style)
+    drawText(measurer, "90°", Offset(center.x + 6f, center.y - 18f), style = style)
+    // Cardinal labels
+    drawText(measurer, "N", Offset(center.x - 8f, center.y - radius - 20f), style = style)
+    drawText(measurer, "E", Offset(center.x + radius + 4f, center.y - 10f), style = style)
+    drawText(measurer, "S", Offset(center.x - 6f, center.y + radius + 2f), style = style)
+    drawText(measurer, "W", Offset(center.x - radius - 24f, center.y - 10f), style = style)
+}
+
+/** Normalize an azimuth delta (degrees) into the [-180, 180] range. */
+private fun azimuthDelta(deltaDeg: Double): Double {
+    var d = deltaDeg % 360.0
+    if (d > 180.0) d -= 360.0
+    if (d < -180.0) d += 360.0
+    return d
+}
+
+/** Convert azimuth (deg, 0=N, clockwise) and elevation (deg) to canvas offset. */
+private fun sph2Cart(center: Offset, azimDeg: Double, elevDeg: Double, r: Float): Offset {
+    val azimRad = azimDeg * PI / 180.0
+    val elevRad = elevDeg * PI / 180.0
+    val radius = r * (PI / 2 - elevRad) / (PI / 2)
+    return Offset(
+        x = center.x + (radius * cos(PI / 2 - azimRad)).toFloat(),
+        y = center.y - (radius * sin(PI / 2 - azimRad)).toFloat()
+    )
+}

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualScreen.kt

@@ -0,0 +1,590 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.feature.mutual
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.expandVertically
+import androidx.compose.animation.shrinkVertically
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.material3.Button
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.CircularProgressIndicator
+import androidx.compose.material3.ElevatedCard
+import androidx.compose.material3.FilterChip
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.OutlinedTextField
+import androidx.compose.material3.Slider
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.rtbishop.look4sat.core.domain.repository.MutualPassData
+import com.rtbishop.look4sat.core.domain.repository.TrackSampleData
+import com.rtbishop.look4sat.core.presentation.IconCard
+import com.rtbishop.look4sat.core.presentation.R
+import com.rtbishop.look4sat.core.presentation.ScreenColumn
+import com.rtbishop.look4sat.core.presentation.TopBar
+import com.rtbishop.look4sat.core.presentation.isVerticalLayout
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+
+@Composable
+fun MutualScreen(
+    viewModel: MutualViewModel,
+    navigateUp: () -> Unit = {},
+    navigateToRadar: (Int, Long, MutualPassData?) -> Unit = { _, _, _ -> },
+    modifier: Modifier = Modifier
+) {
+    val state by viewModel.uiState.collectAsState()
+
+    ScreenColumn(
+        topBar = { isVertical ->
+            TopBar(
+                isVerticalLayout = isVertical,
+                startAction = {
+                    IconCard(action = navigateUp, resId = R.drawable.ic_back)
+                },
+                topInfo = {
+                    Text(
+                        text = "过境匹配",
+                        style = MaterialTheme.typography.titleMedium,
+                        fontWeight = FontWeight.Bold
+                    )
+                },
+                bottomInfo = {
+                    if (state.mutualPasses.isNotEmpty()) {
+                        Text(
+                            text = "找到 ${state.mutualPasses.size} 个匹配",
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
+                        )
+                    }
+                },
+                endAction = {
+                    if (state.isCalculating) {
+                        CircularProgressIndicator(
+                            modifier = Modifier
+                                .height(24.dp)
+                                .width(24.dp),
+                            strokeWidth = 2.dp
+                        )
+                    }
+                }
+            )
+        }
+    ) { isVertical ->
+        MutualContent(
+            state = state,
+            isVertical = isVertical,
+            onQuery = viewModel::queryMutualPasses,
+            onSelectPass = viewModel::onSelectPass,
+            onNavigateToRadar = navigateToRadar,
+            onStationALat = viewModel::onStationALat,
+            onStationALon = viewModel::onStationALon,
+            onStationAGrid = viewModel::onStationAGrid,
+            onStationAMinElev = viewModel::onStationAMinElev,
+            onStationBLat = viewModel::onStationBLat,
+            onStationBLon = viewModel::onStationBLon,
+            onStationBGrid = viewModel::onStationBGrid,
+            onStationBMinElev = viewModel::onStationBMinElev,
+            onUseCurrentPosition = viewModel::onUseCurrentPosition,
+            onHoursAhead = viewModel::onHoursAhead,
+            onClearError = viewModel::clearError
+        )
+    }
+}
+
+@Composable
+private fun MutualContent(
+    state: MutualUiState,
+    isVertical: Boolean,
+    onQuery: () -> Unit,
+    onSelectPass: (Int) -> Unit,
+    onNavigateToRadar: (Int, Long, MutualPassData?) -> Unit,
+    onStationALat: (String) -> Unit,
+    onStationALon: (String) -> Unit,
+    onStationAGrid: (String) -> Unit,
+    onStationAMinElev: (Double) -> Unit,
+    onStationBLat: (String) -> Unit,
+    onStationBLon: (String) -> Unit,
+    onStationBGrid: (String) -> Unit,
+    onStationBMinElev: (Double) -> Unit,
+    onUseCurrentPosition: () -> Unit,
+    onHoursAhead: (Int) -> Unit,
+    onClearError: () -> Unit
+) {
+    val timeFormat = remember { SimpleDateFormat("MM/dd HH:mm", Locale.getDefault()) }
+
+    LazyColumn(
+        modifier = Modifier.fillMaxSize(),
+        verticalArrangement = Arrangement.spacedBy(6.dp)
+    ) {
+        // Error message
+        val errorMsg = state.errorMessage
+        if (errorMsg != null) {
+            item {
+                ElevatedCard(
+                    modifier = Modifier.fillMaxWidth(),
+                    colors = CardDefaults.elevatedCardColors(
+                        containerColor = MaterialTheme.colorScheme.errorContainer
+                    )
+                ) {
+                    Text(
+                        text = errorMsg,
+                        color = MaterialTheme.colorScheme.onErrorContainer,
+                        modifier = Modifier.padding(12.dp),
+                        style = MaterialTheme.typography.bodyMedium
+                    )
+                }
+            }
+        }
+
+        // Input form
+        item {
+            Column(
+                modifier = Modifier.fillMaxWidth(),
+                verticalArrangement = Arrangement.spacedBy(6.dp)
+            ) {
+                MatchIntroCard()
+
+                if (isVertical) {
+                    StationInputCard(
+                        title = "你的位置",
+                        titleColor = MaterialTheme.colorScheme.primary,
+                        lat = state.stationALat,
+                        lon = state.stationALon,
+                        grid = state.stationAGrid,
+                        minElev = state.stationAMinElev,
+                        latPlaceholder = "39.9042",
+                        lonPlaceholder = "116.4074",
+                        gridPlaceholder = "ON79uj",
+                        onLatChange = onStationALat,
+                        onLonChange = onStationALon,
+                        onGridChange = onStationAGrid,
+                        onMinElevChange = onStationAMinElev,
+                        currentPositionAction = onUseCurrentPosition
+                    )
+                    StationInputCard(
+                        title = "友台位置",
+                        titleColor = MaterialTheme.colorScheme.tertiary,
+                        lat = state.stationBLat,
+                        lon = state.stationBLon,
+                        grid = state.stationBGrid,
+                        minElev = state.stationBMinElev,
+                        latPlaceholder = "34.0522",
+                        lonPlaceholder = "-118.2437",
+                        gridPlaceholder = "PM01tv",
+                        onLatChange = onStationBLat,
+                        onLonChange = onStationBLon,
+                        onGridChange = onStationBGrid,
+                        onMinElevChange = onStationBMinElev
+                    )
+                } else {
+                    Row(
+                        modifier = Modifier.fillMaxWidth(),
+                        horizontalArrangement = Arrangement.spacedBy(6.dp)
+                    ) {
+                        StationInputCard(
+                            title = "你的位置",
+                            titleColor = MaterialTheme.colorScheme.primary,
+                            lat = state.stationALat,
+                            lon = state.stationALon,
+                            grid = state.stationAGrid,
+                            minElev = state.stationAMinElev,
+                            latPlaceholder = "39.9042",
+                            lonPlaceholder = "116.4074",
+                            gridPlaceholder = "ON79uj",
+                            onLatChange = onStationALat,
+                            onLonChange = onStationALon,
+                            onGridChange = onStationAGrid,
+                            onMinElevChange = onStationAMinElev,
+                            currentPositionAction = onUseCurrentPosition,
+                            modifier = Modifier.weight(1f)
+                        )
+                        StationInputCard(
+                            title = "友台位置",
+                            titleColor = MaterialTheme.colorScheme.tertiary,
+                            lat = state.stationBLat,
+                            lon = state.stationBLon,
+                            grid = state.stationBGrid,
+                            minElev = state.stationBMinElev,
+                            latPlaceholder = "34.0522",
+                            lonPlaceholder = "-118.2437",
+                            gridPlaceholder = "PM01tv",
+                            onLatChange = onStationBLat,
+                            onLonChange = onStationBLon,
+                            onGridChange = onStationBGrid,
+                            onMinElevChange = onStationBMinElev,
+                            modifier = Modifier.weight(1f)
+                        )
+                    }
+                }
+
+                MatchSearchCard(
+                    hoursAhead = state.hoursAhead,
+                    isCalculating = state.isCalculating,
+                    onHoursAhead = onHoursAhead,
+                    onQuery = onQuery
+                )
+            }
+        }
+
+        // Results
+        itemsIndexed(state.mutualPasses) { index, pass ->
+            val mutualData = MutualPassData(
+                samples = pass.elevationSamples,
+                trackSamples = pass.trackSamples.map {
+                    TrackSampleData(
+                        time = it.time,
+                        azimuthA = it.azimuthA,
+                        elevationA = it.elevationA,
+                        azimuthB = it.azimuthB,
+                        elevationB = it.elevationB
+                    )
+                },
+                startTime = pass.startTime,
+                endTime = pass.endTime,
+                maxElev = maxOf(pass.maxElevationA, pass.maxElevationB, 10.0),
+                labelA = "你",
+                labelB = "友台"
+            )
+            MutualPassCard(
+                pass = pass,
+                isExpanded = state.selectedPassIndex == index,
+                timeFormat = timeFormat,
+                minElevA = state.stationAMinElev,
+                minElevB = state.stationBMinElev,
+                onClick = { onSelectPass(if (state.selectedPassIndex == index) -1 else index) },
+                onNavigateToRadar = { onNavigateToRadar(pass.catNum, pass.startTime, mutualData) }
+            )
+        }
+    }
+}
+
+@Composable
+private fun MatchIntroCard(modifier: Modifier = Modifier) {
+    ElevatedCard(modifier = modifier.fillMaxWidth()) {
+        Column(
+            modifier = Modifier.padding(12.dp),
+            verticalArrangement = Arrangement.spacedBy(4.dp)
+        ) {
+            Text(
+                text = "位置匹配",
+                style = MaterialTheme.typography.titleSmall,
+                fontWeight = FontWeight.Medium,
+                color = MaterialTheme.colorScheme.primary
+            )
+            Text(
+                text = "输入双方位置，查找共同可见的卫星过境窗口",
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant
+            )
+        }
+    }
+}
+
+@Composable
+private fun StationInputCard(
+    title: String,
+    titleColor: androidx.compose.ui.graphics.Color,
+    lat: String,
+    lon: String,
+    grid: String,
+    minElev: Double,
+    latPlaceholder: String,
+    lonPlaceholder: String,
+    gridPlaceholder: String,
+    onLatChange: (String) -> Unit,
+    onLonChange: (String) -> Unit,
+    onGridChange: (String) -> Unit,
+    onMinElevChange: (Double) -> Unit,
+    modifier: Modifier = Modifier,
+    currentPositionAction: (() -> Unit)? = null
+) {
+    ElevatedCard(modifier = modifier.fillMaxWidth()) {
+        Column(
+            modifier = Modifier.padding(12.dp),
+            verticalArrangement = Arrangement.spacedBy(8.dp)
+        ) {
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.SpaceBetween,
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Text(
+                    text = title,
+                    style = MaterialTheme.typography.titleSmall,
+                    fontWeight = FontWeight.Medium,
+                    color = titleColor
+                )
+                if (currentPositionAction != null) {
+                    OutlinedButton(onClick = currentPositionAction) {
+                        Text("填入当前位置", style = MaterialTheme.typography.bodySmall)
+                    }
+                }
+            }
+
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.spacedBy(8.dp)
+            ) {
+                OutlinedTextField(
+                    value = lat,
+                    onValueChange = onLatChange,
+                    label = { Text("纬度") },
+                    placeholder = { Text(latPlaceholder) },
+                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Decimal),
+                    singleLine = true,
+                    modifier = Modifier.weight(1f)
+                )
+                OutlinedTextField(
+                    value = lon,
+                    onValueChange = onLonChange,
+                    label = { Text("经度") },
+                    placeholder = { Text(lonPlaceholder) },
+                    keyboardOptions = KeyboardOptions(keyboardType = KeyboardType.Decimal),
+                    singleLine = true,
+                    modifier = Modifier.weight(1f)
+                )
+            }
+
+            OutlinedTextField(
+                value = grid,
+                onValueChange = onGridChange,
+                label = { Text("网格") },
+                placeholder = { Text(gridPlaceholder) },
+                supportingText = { Text("支持 4/6/8 位 Maidenhead 网格；也可直接输入经纬度") },
+                singleLine = true,
+                modifier = Modifier.fillMaxWidth()
+            )
+
+            Text(
+                text = "最小仰角：${minElev.toInt()}°",
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant
+            )
+            Slider(
+                value = minElev.toFloat(),
+                onValueChange = { onMinElevChange(it.toDouble()) },
+                valueRange = 0f..90f,
+                steps = 17
+            )
+        }
+    }
+}
+
+@Composable
+private fun MatchSearchCard(
+    hoursAhead: Int,
+    isCalculating: Boolean,
+    onHoursAhead: (Int) -> Unit,
+    onQuery: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    ElevatedCard(modifier = modifier.fillMaxWidth()) {
+        Column(
+            modifier = Modifier.padding(12.dp),
+            verticalArrangement = Arrangement.spacedBy(10.dp)
+        ) {
+            Text(
+                text = "时间范围",
+                style = MaterialTheme.typography.titleSmall,
+                fontWeight = FontWeight.Medium
+            )
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.spacedBy(8.dp)
+            ) {
+                listOf(6, 12, 24, 48, 72).forEach { hours ->
+                    FilterChip(
+                        selected = hoursAhead == hours,
+                        onClick = { onHoursAhead(hours) },
+                        label = { Text("${hours}h") }
+                    )
+                }
+            }
+            Button(
+                onClick = onQuery,
+                enabled = !isCalculating,
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                if (isCalculating) {
+                    CircularProgressIndicator(
+                        modifier = Modifier
+                            .height(18.dp)
+                            .width(18.dp),
+                        strokeWidth = 2.dp,
+                        color = MaterialTheme.colorScheme.onPrimary
+                    )
+                    Spacer(Modifier.width(8.dp))
+                }
+                Text(if (isCalculating) "计算中..." else "查询匹配")
+            }
+        }
+    }
+}
+
+@Composable
+private fun MutualPassCard(
+    pass: MutualPass,
+    isExpanded: Boolean,
+    timeFormat: SimpleDateFormat,
+    minElevA: Double,
+    minElevB: Double,
+    onClick: () -> Unit,
+    onNavigateToRadar: () -> Unit
+) {
+    // Shared time cursor: both the elevation curve and the radar track view
+    // are controlled by this single progress value for bidirectional drag sync.
+    var dragProgress by remember(pass) { mutableFloatStateOf(0.5f) }
+
+    // Filter to only show the portion where both stations are above their minElev
+    val visibleSamples = remember(pass, minElevA, minElevB) {
+        pass.elevationSamples.filter { (_, elev) ->
+            elev.first >= minElevA && elev.second >= minElevB
+        }
+    }
+    val visibleTracks = remember(pass, minElevA, minElevB) {
+        pass.trackSamples.filter { it.elevationA >= minElevA && it.elevationB >= minElevB }
+    }
+    val visibleStart = visibleSamples.firstOrNull()?.first ?: pass.startTime
+    val visibleEnd = visibleSamples.lastOrNull()?.first ?: pass.endTime
+    val adjustedMaxElev = maxOf(
+        visibleSamples.maxOfOrNull { (_, elev) -> elev.first } ?: 10.0,
+        visibleSamples.maxOfOrNull { (_, elev) -> elev.second } ?: 10.0,
+        10.0
+    )
+    ElevatedCard(
+        modifier = Modifier
+            .fillMaxWidth()
+            .clickable(onClick = onClick)
+    ) {
+        Column(modifier = Modifier.padding(12.dp)) {
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.SpaceBetween,
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Text(
+                    text = pass.name,
+                    style = MaterialTheme.typography.bodyLarge,
+                    fontWeight = FontWeight.Medium,
+                    color = MaterialTheme.colorScheme.primary,
+                    modifier = Modifier.weight(1f)
+                )
+                Text(
+                    text = "${timeFormat.format(Date(pass.startTime))} - ${timeFormat.format(Date(pass.endTime))}",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
+                )
+            }
+            Spacer(Modifier.height(4.dp))
+            Row(
+                modifier = Modifier.fillMaxWidth(),
+                horizontalArrangement = Arrangement.SpaceBetween
+            ) {
+                Text(
+                    text = "你: ${pass.maxElevationA}°",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.primary
+                )
+                Text(
+                    text = "友台: ${pass.maxElevationB}°",
+                    style = MaterialTheme.typography.bodySmall,
+                    color = MaterialTheme.colorScheme.tertiary
+                )
+            }
+
+            AnimatedVisibility(
+                visible = isExpanded,
+                enter = expandVertically(),
+                exit = shrinkVertically()
+            ) {
+                Column {
+                    HorizontalDivider(modifier = Modifier.padding(vertical = 8.dp))
+                    // Dual-station radar track (polar plot)
+                    if (visibleTracks.isNotEmpty()) {
+                        Text(
+                            text = "双方轨迹",
+                            style = MaterialTheme.typography.titleSmall,
+                            fontWeight = FontWeight.Medium,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
+                        )
+                        MutualRadarView(
+                            trackSamples = visibleTracks,
+                            progress = dragProgress,
+                            labelA = "你",
+                            labelB = "友台"
+                        )
+                        Spacer(Modifier.height(8.dp))
+                    }
+                    if (visibleSamples.isNotEmpty()) {
+                        ElevationCurveChart(
+                            samples = visibleSamples,
+                            startTime = visibleStart,
+                            endTime = visibleEnd,
+                            maxElev = adjustedMaxElev,
+                            progress = dragProgress,
+                            onProgressChange = { dragProgress = it }
+                        )
+                    }
+                    Spacer(Modifier.height(8.dp))
+                    OutlinedButton(
+                        onClick = onNavigateToRadar,
+                        modifier = Modifier.fillMaxWidth()
+                    ) {
+                        Icon(
+                            painter = painterResource(id = R.drawable.ic_radar),
+                            contentDescription = null,
+                            modifier = Modifier.height(16.dp).width(16.dp)
+                        )
+                        Spacer(Modifier.width(6.dp))
+                        Text("查看雷达")
+                    }
+                }
+            }
+        }
+    }
+}

feature/mutual/src/main/java/com/rtbishop/look4sat/feature/mutual/MutualViewModel.kt

@@ -0,0 +1,560 @@
+/*
+ * Look4Sat. Amateur radio satellite tracker and pass predictor.
+ * Copyright (C) 2019-2026 Arty Bishop and contributors.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.rtbishop.look4sat.feature.mutual
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewModelScope
+import com.rtbishop.look4sat.core.domain.predict.GeoPos
+import com.rtbishop.look4sat.core.domain.predict.OrbitalObject
+import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
+import com.rtbishop.look4sat.core.domain.repository.IMainContainer
+import com.rtbishop.look4sat.core.domain.repository.ISatelliteRepo
+import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import kotlin.math.PI
+import kotlin.math.floor
+import kotlin.math.roundToInt
+
+data class MutualUiState(
+    val stationALat: String = "",
+    val stationALon: String = "",
+    val stationAGrid: String = "",
+    val stationAMinElev: Double = 10.0,
+    val stationBLat: String = "",
+    val stationBLon: String = "",
+    val stationBGrid: String = "",
+    val stationBMinElev: Double = 10.0,
+    val hoursAhead: Int = 24,
+    val mutualPasses: List<MutualPass> = emptyList(),
+    val isCalculating: Boolean = false,
+    val selectedPassIndex: Int = -1,
+    val errorMessage: String? = null
+)
+
+class MutualViewModel(
+    private val satelliteRepo: ISatelliteRepo,
+    private val settingsRepo: ISettingsRepo
+) : ViewModel() {
+
+    private val _uiState = MutableStateFlow(MutualUiState())
+    val uiState: StateFlow<MutualUiState> = _uiState.asStateFlow()
+
+    init {
+        // Pre-fill station A with the user's current station position (as grid),
+        // and default min elevation to the same value used by the main radar passes
+        val pos = settingsRepo.stationPosition.value
+        val grid = latLonToGrid(pos.latitude, pos.longitude)
+        _uiState.update { it.copy(
+            stationAGrid = grid,
+            stationALat = "%.4f".format(pos.latitude),
+            stationALon = "%.4f".format(pos.longitude),
+            stationAMinElev = 0.0,
+            stationBMinElev = 0.0
+        ) }
+    }
+
+    fun onStationALat(value: String) {
+        _uiState.update { it.copy(stationALat = value) }
+        val lat = value.toDoubleOrNull()
+        val lon = _uiState.value.stationALon.toDoubleOrNull()
+        if (lat != null && lon != null) {
+            _uiState.update { it.copy(stationAGrid = latLonToGrid(lat, lon)) }
+        }
+    }
+
+    fun onStationALon(value: String) {
+        _uiState.update { it.copy(stationALon = value) }
+        val lat = _uiState.value.stationALat.toDoubleOrNull()
+        val lon = value.toDoubleOrNull()
+        if (lat != null && lon != null) {
+            _uiState.update { it.copy(stationAGrid = latLonToGrid(lat, lon)) }
+        }
+    }
+
+    fun onStationAGrid(value: String) {
+        val old = _uiState.value.stationAGrid
+        _uiState.update { it.copy(stationAGrid = value) }
+        if (value.trim().uppercase() == old.trim().uppercase()) return
+        val pos = gridToLatLon(value.trim().uppercase())
+        if (pos != null) {
+            _uiState.update { it.copy(
+                stationALat = "%.4f".format(pos.latitude),
+                stationALon = "%.4f".format(pos.longitude)
+            )}
+        }
+    }
+
+    fun onStationBLat(value: String) {
+        _uiState.update { it.copy(stationBLat = value) }
+        val lat = value.toDoubleOrNull()
+        val lon = _uiState.value.stationBLon.toDoubleOrNull()
+        if (lat != null && lon != null) {
+            _uiState.update { it.copy(stationBGrid = latLonToGrid(lat, lon)) }
+        }
+    }
+
+    fun onStationBLon(value: String) {
+        _uiState.update { it.copy(stationBLon = value) }
+        val lat = _uiState.value.stationBLat.toDoubleOrNull()
+        val lon = value.toDoubleOrNull()
+        if (lat != null && lon != null) {
+            _uiState.update { it.copy(stationBGrid = latLonToGrid(lat, lon)) }
+        }
+    }
+
+    fun onStationBGrid(value: String) {
+        val old = _uiState.value.stationBGrid
+        _uiState.update { it.copy(stationBGrid = value) }
+        if (value.trim().uppercase() == old.trim().uppercase()) return
+        val pos = gridToLatLon(value.trim().uppercase())
+        if (pos != null) {
+            _uiState.update { it.copy(
+                stationBLat = "%.4f".format(pos.latitude),
+                stationBLon = "%.4f".format(pos.longitude)
+            )}
+        }
+    }
+    fun onStationAMinElev(value: Double) = _uiState.update { it.copy(stationAMinElev = value) }
+    fun onStationBMinElev(value: Double) = _uiState.update { it.copy(stationBMinElev = value) }
+    fun onUseCurrentPosition() {
+        val pos = settingsRepo.stationPosition.value
+        _uiState.update { it.copy(
+            stationALat = "%.4f".format(pos.latitude),
+            stationALon = "%.4f".format(pos.longitude),
+            stationAGrid = latLonToGrid(pos.latitude, pos.longitude)
+        ) }
+    }
+    fun onHoursAhead(value: Int) = _uiState.update { it.copy(hoursAhead = value) }
+    fun onSelectPass(index: Int) = _uiState.update { it.copy(selectedPassIndex = index) }
+
+    fun queryMutualPasses() {
+        val state = _uiState.value
+
+        // Resolve positions from lat/lon or grid
+        var posA = resolvePosition(state.stationALat, state.stationALon, state.stationAGrid)
+        var posB = resolvePosition(state.stationBLat, state.stationBLon, state.stationBGrid)
+
+        if (posA == null || posB == null) {
+            _uiState.update { it.copy(errorMessage = "请输入有效的位置坐标或网格（4/6/8位）") }
+            return
+        }
+
+        val satellites = satelliteRepo.satellites.value
+        if (satellites.isEmpty()) {
+            _uiState.update { it.copy(errorMessage = "没有卫星数据，请先在卫星列表中选择卫星") }
+            return
+        }
+
+        _uiState.update { it.copy(isCalculating = true, errorMessage = null, mutualPasses = emptyList()) }
+
+        viewModelScope.launch {
+            val time = System.currentTimeMillis()
+            val minElevA = state.stationAMinElev
+            val minElevB = state.stationBMinElev
+            val hours = state.hoursAhead
+
+            val results = withContext(Dispatchers.Default) {
+                findMutualPasses(satellites, posA, posB, minElevA, minElevB, time, hours)
+            }
+
+            val errorMsg = if (results.isEmpty()) {
+                // Debug: check if the main pass list is the culprit
+                val passCount = satelliteRepo.passes.value.size
+                val satCount = satellites.size
+                when {
+                    passCount == 0 -> "过境列表为空，请先在卫星列表中选择卫星"
+                    satCount == 0 -> "没有已选中的卫星"
+                    else -> "未找到共同过境（${passCount}个过境，${satCount}颗卫星）"
+                }
+            } else null
+
+            _uiState.update {
+                it.copy(
+                    mutualPasses = results.sortedBy { mp -> mp.startTime },
+                    isCalculating = false,
+                    errorMessage = errorMsg
+                )
+            }
+        }
+    }
+
+    /** Resolve a position from lat/lon text or grid square text. */
+    private fun resolvePosition(latText: String, lonText: String, gridText: String): GeoPos? {
+        val trimmed = gridText.trim().uppercase()
+        if (trimmed.length in listOf(4, 6, 8) && trimmed.all { it.isLetterOrDigit() }) {
+            return gridToLatLon(trimmed)
+        }
+        val lat = latText.toDoubleOrNull()
+        val lon = lonText.toDoubleOrNull()
+        return if (lat != null && lon != null) GeoPos(lat, lon) else null
+    }
+
+    /** Convert lat/lon to Maidenhead grid (6-char). */
+    private fun latLonToGrid(lat: Double, lon: Double): String {
+        var adjLon = (lon + 180.0) % 360.0
+        var adjLat = (lat + 90.0) % 180.0
+
+        val fieldLon = (adjLon / 20.0).toInt()
+        val fieldLat = (adjLat / 10.0).toInt()
+        adjLon -= fieldLon * 20.0
+        adjLat -= fieldLat * 10.0
+
+        val squareLon = (adjLon / 2.0).toInt()
+        val squareLat = (adjLat / 1.0).toInt()
+        adjLon -= squareLon * 2.0
+        adjLat -= squareLat * 1.0
+
+        val subLon = (adjLon * 60.0 / 5.0).toInt()
+        val subLat = (adjLat * 60.0 / 2.5).toInt()
+
+        return buildString {
+            append('A' + fieldLon)
+            append('A' + fieldLat)
+            append('0' + squareLon)
+            append('0' + squareLat)
+            append('A' + subLon)
+            append('A' + subLat)
+        }
+    }
+
+    /** Convert Maidenhead grid (4, 6, or 8 chars) to lat/lon center of the square. */
+    private fun gridToLatLon(grid: String): GeoPos? {
+        val g = grid.uppercase()
+        if (g.length < 4) return null
+        val lonField = (g[0] - 'A').toDouble() * 20.0
+        val latField = (g[1] - 'A').toDouble() * 10.0
+        if (lonField < 0 || lonField > 340 || latField < 0 || latField > 170) return null
+
+        val lonSquare = (g[2] - '0').toDouble() * 2.0
+        val latSquare = (g[3] - '0').toDouble() * 1.0
+        if (lonSquare < 0 || lonSquare > 18 || latSquare < 0 || latSquare > 9) return null
+
+        var lon = lonField + lonSquare
+        var lat = latField + latSquare
+
+        if (g.length >= 6) {
+            val lonSub = (g[4] - 'A').toDouble() * 5.0 / 60.0
+            val latSub = (g[5] - 'A').toDouble() * 2.5 / 60.0
+            if (lonSub < 0 || lonSub > 115.0 / 60.0 || latSub < 0 || latSub > 57.5 / 60.0) return null
+            lon += lonSub
+            lat += latSub
+
+            if (g.length >= 8) {
+                val lonExt = (g[6] - '0').toDouble() * 30.0 / 3600.0
+                val latExt = (g[7] - '0').toDouble() * 15.0 / 3600.0
+                if (lonExt < 0 || lonExt > 270.0 / 3600.0 || latExt < 0 || latExt > 135.0 / 3600.0) return null
+                lon += lonExt + 15.0 / 3600.0
+                lat += latExt + 7.5 / 3600.0
+            } else {
+                lon += 2.5 / 60.0
+                lat += 1.25 / 60.0
+            }
+        } else {
+            lon += 1.0
+            lat += 0.5
+        }
+
+        lon = lon - 180.0
+        lat = lat - 90.0
+        return GeoPos(lat, lon)
+    }
+
+    private fun findMutualPasses(
+        satellites: List<OrbitalObject>,
+        posA: GeoPos, posB: GeoPos,
+        minElevADeg: Double, minElevBDeg: Double,
+        time: Long, hours: Int
+    ): List<MutualPass> {
+        val endTime = time + hours * 60L * 60L * 1000L
+        val sampleInterval = 5_000L
+
+        // Use the main page's pass list for AOS/LOS times, then sample the curves
+        // using the actual positions. The passes list is already computed by getLeoPass
+        // and its AOS/LOS times match the Passes page exactly.
+        val existingPasses = satelliteRepo.passes.value
+        val results = findMutualPassesFromList(existingPasses, satellites, posA, posB,
+            minElevADeg, minElevBDeg, time, endTime, sampleInterval)
+        if (results.isNotEmpty()) return results
+
+        // Fallback: try the independent search.
+        return findMutualPassesFallback(satellites, posA, posB,
+            minElevADeg, minElevBDeg, time, endTime, sampleInterval)
+    }
+
+    /** Reuse the main page's pass list. Uses AOS/LOS times directly (no refineEdge) */
+    private fun findMutualPassesFromList(
+        existingPasses: List<OrbitalPass>,
+        satellites: List<OrbitalObject>,
+        posA: GeoPos, posB: GeoPos,
+        minElevADeg: Double, minElevBDeg: Double,
+        time: Long, endTime: Long, sampleInterval: Long
+    ): List<MutualPass> {
+        val results = mutableListOf<MutualPass>()
+        for (pass in existingPasses) {
+            if (pass.losTime <= time || pass.aosTime >= endTime) continue
+            if (pass.isDeepSpace) continue
+            if (pass.orbitalObject.data.meanmo < 1e-8) continue
+
+            val sat = pass.orbitalObject
+            // Refine the AOS/LOS to the actual posA/posB (0° horizon).
+            // This ensures the elevation curve starts from ~0°.
+            val refinedAos = refineEdge(sat, posA, posB, pass.aosTime, 1_000L, goingUp = true)
+            val refinedLos = refineEdge(sat, posA, posB, pass.losTime, 1_000L, goingUp = false)
+            if (refinedLos <= refinedAos) continue
+
+            val samples = mutableListOf<Pair<Long, Pair<Double, Double>>>()
+            val tracks = mutableListOf<TrackSample>()
+            var maxElevA = 0.0
+            var maxElevB = 0.0
+
+            var tSample = refinedAos
+            while (tSample <= refinedLos) {
+                // Use getElevation (same function used by getLeoPass) for elevation,
+                // and getFullPosition only for azimuth.
+                val elevA = sat.getElevation(posA, tSample) * 180.0 / PI
+                val elevB = sat.getElevation(posB, tSample) * 180.0 / PI
+                val fullA = sat.getFullPosition(posA, tSample)
+                val fullB = sat.getFullPosition(posB, tSample)
+                if (elevA > maxElevA) maxElevA = elevA
+                if (elevB > maxElevB) maxElevB = elevB
+                samples.add(tSample to (elevA to elevB))
+                tracks.add(
+                    TrackSample(
+                        time = tSample,
+                        azimuthA = fullA.azimuth * 180.0 / PI,
+                        elevationA = elevA,
+                        azimuthB = fullB.azimuth * 180.0 / PI,
+                        elevationB = elevB
+                    )
+                )
+                tSample += sampleInterval
+            }
+
+            // Search uses the 0° horizon as the pass boundary, but the user sliders are
+            // a final visibility filter. Both stations must exceed their own threshold;
+            // otherwise the result would expand to an empty filtered chart.
+            if (maxElevA > minElevADeg && maxElevB > minElevBDeg) {
+                results.add(
+                    MutualPass(
+                        catNum = pass.catNum,
+                        name = pass.orbitalObject.data.name,
+                        startTime = refinedAos,
+                        endTime = refinedLos,
+                        maxElevationA = (maxElevA * 10).roundToInt() / 10.0,
+                        maxElevationB = (maxElevB * 10).roundToInt() / 10.0,
+                        elevationSamples = samples,
+                        trackSamples = tracks
+                    )
+                )
+            }
+        }
+        return results
+    }
+
+    /** Fallback: search passes independently (same logic as original findMutualPasses). */
+    private fun findMutualPassesFallback(
+        satellites: List<OrbitalObject>,
+        posA: GeoPos, posB: GeoPos,
+        minElevADeg: Double, minElevBDeg: Double,
+        time: Long, endTime: Long, sampleInterval: Long
+    ): List<MutualPass> {
+        val results = mutableListOf<MutualPass>()
+        for (sat in satellites) {
+            if (sat.data.meanmo < 1e-8) continue
+            var searchStart = time
+            while (true) {
+                val t = findNextMutualPass(sat, posA, posB, searchStart, endTime)
+                if (t == null) break
+                val (aos, los) = t
+
+                val refinedAos = refineEdge(sat, posA, posB, aos, 1_000L, true)
+                val refinedLos = refineEdge(sat, posA, posB, los, 1_000L, false)
+                if (refinedLos <= refinedAos) continue
+
+                val mutualPass = sampleMutualPass(sat, posA, posB, refinedAos, refinedLos,
+                    minElevADeg, minElevBDeg, sampleInterval)
+                if (mutualPass != null) results.add(mutualPass)
+                searchStart = refinedLos + 120_000L
+            }
+        }
+        return results
+    }
+
+    /** Sample elevation/azimuth data for one mutual pass window. */
+    private fun sampleMutualPass(
+        sat: OrbitalObject, posA: GeoPos, posB: GeoPos,
+        refinedAos: Long, refinedLos: Long,
+        minElevADeg: Double, minElevBDeg: Double,
+        sampleInterval: Long
+    ): MutualPass? {
+        val samples = mutableListOf<Pair<Long, Pair<Double, Double>>>()
+        val tracks = mutableListOf<TrackSample>()
+        var maxElevA = 0.0
+        var maxElevB = 0.0
+
+        var tSample = refinedAos
+        while (tSample <= refinedLos) {
+            // Use getElevation for elevation, matching the main pass predictor; use
+            // getFullPosition only for azimuth needed by the radar plot.
+            val elevA = elevationDeg(sat, posA, tSample)
+            val elevB = elevationDeg(sat, posB, tSample)
+            val fullA = sat.getFullPosition(posA, tSample)
+            val fullB = sat.getFullPosition(posB, tSample)
+            if (elevA > maxElevA) maxElevA = elevA
+            if (elevB > maxElevB) maxElevB = elevB
+            samples.add(tSample to (elevA to elevB))
+            tracks.add(
+                TrackSample(
+                    time = tSample,
+                    azimuthA = fullA.azimuth * 180.0 / PI,
+                    elevationA = elevA,
+                    azimuthB = fullB.azimuth * 180.0 / PI,
+                    elevationB = elevB
+                )
+            )
+            tSample += sampleInterval
+        }
+
+        if (maxElevA > minElevADeg && maxElevB > minElevBDeg) {
+            return MutualPass(
+                catNum = sat.data.catnum,
+                name = sat.data.name,
+                startTime = refinedAos,
+                endTime = refinedLos,
+                maxElevationA = (maxElevA * 10).roundToInt() / 10.0,
+                maxElevationB = (maxElevB * 10).roundToInt() / 10.0,
+                elevationSamples = samples,
+                trackSamples = tracks
+            )
+        }
+        return null
+    }
+
+    /** Refine the AOS (goingUp=true) or LOS (goingUp=false) to ~1s precision at the 0° horizon. */
+    private fun refineEdge(
+        sat: OrbitalObject, posA: GeoPos, posB: GeoPos,
+        approxTime: Long, step: Long, goingUp: Boolean
+    ): Long {
+        if (goingUp) {
+            // AOS: walk backward from approxTime to find the last sample where either is below
+            // the horizon, then AOS is the next step after that.
+            var t = approxTime
+            while (t > approxTime - 70_000L) {
+                val eA = elevationDeg(sat, posA, t)
+                val eB = elevationDeg(sat, posB, t)
+                if (eA > 0.0 && eB > 0.0) {
+                    t -= step
+                } else {
+                    return t + step
+                }
+            }
+            return approxTime - 70_000L + step
+        } else {
+            // LOS: walk forward from approxTime to find the first sample where either drops
+            // below the horizon, then LOS is the step before that.
+            var t = approxTime
+            while (t < approxTime + 70_000L) {
+                val eA = elevationDeg(sat, posA, t)
+                val eB = elevationDeg(sat, posB, t)
+                if (eA > 0.0 && eB > 0.0) {
+                    t += step
+                } else {
+                    return t - step
+                }
+            }
+            return approxTime + 70_000L - step
+        }
+    }
+
+    private fun elevationDeg(sat: OrbitalObject, pos: GeoPos, time: Long): Double {
+        return sat.getElevation(pos, time) * 180.0 / PI
+    }
+
+    private fun findNextMutualPass(
+        sat: OrbitalObject,
+        posA: GeoPos, posB: GeoPos,
+        startTime: Long, endTime: Long
+    ): Pair<Long, Long>? {
+        var t = startTime
+        val step = 60_000L
+
+        // Skip an in-progress mutual window at the search start (same as getLeoPass):
+        // walk forward until either station drops below the horizon, then keep searching.
+        if (elevationDeg(sat, posA, t) > 0.0 && elevationDeg(sat, posB, t) > 0.0) {
+            while (t < endTime) {
+                if (elevationDeg(sat, posA, t) <= 0.0 || elevationDeg(sat, posB, t) <= 0.0) break
+                t += step
+            }
+        }
+
+        while (t < endTime) {
+            val elevA = elevationDeg(sat, posA, t)
+            val elevB = elevationDeg(sat, posB, t)
+
+            if (elevA > 0.0 && elevB > 0.0) {
+                var aos = t
+                var rew = t
+                while (rew > startTime - 600_000L) {
+                    val eA = elevationDeg(sat, posA, rew)
+                    val eB = elevationDeg(sat, posB, rew)
+                    if (eA <= 0.0 || eB <= 0.0) {
+                        aos = rew + step
+                        break
+                    }
+                    rew -= step
+                }
+
+                var los = t
+                var fwd = t
+                while (fwd < endTime + 600_000L) {
+                    val eA = elevationDeg(sat, posA, fwd)
+                    val eB = elevationDeg(sat, posB, fwd)
+                    if (eA <= 0.0 || eB <= 0.0) {
+                        los = fwd
+                        break
+                    }
+                    fwd += step
+                }
+
+                if (los > aos) return Pair(aos, los)
+            }
+            t += step
+        }
+        return null
+    }
+
+    fun clearError() = _uiState.update { it.copy(errorMessage = null) }
+
+    companion object {
+        fun factory(container: IMainContainer) = object : ViewModelProvider.Factory {
+            @Suppress("UNCHECKED_CAST")
+            override fun <T : ViewModel> create(modelClass: Class<T>): T =
+                MutualViewModel(
+                    satelliteRepo = container.satelliteRepo,
+                    settingsRepo = container.settingsRepo
+                ) as T
+        }
+    }
+}

feature/passes/src/main/java/com/rtbishop/look4sat/feature/passes/PassesDialog.kt

@@ -21,8 +21,11 @@ import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxHeight
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.lazy.grid.GridCells
@@ -31,6 +34,7 @@ import androidx.compose.foundation.lazy.grid.itemsIndexed
 import androidx.compose.material3.Checkbox
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.RangeSlider
 import androidx.compose.material3.Slider
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
@@ -43,6 +47,7 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
@@ -54,6 +59,10 @@ import com.rtbishop.look4sat.core.presentation.LocalSpacing
 import com.rtbishop.look4sat.core.presentation.MainTheme
 import com.rtbishop.look4sat.core.presentation.R
 import com.rtbishop.look4sat.core.presentation.SharedDialog
+import com.rtbishop.look4sat.core.presentation.ElevationHighColor
+import com.rtbishop.look4sat.core.presentation.ElevationLowColor
+import com.rtbishop.look4sat.core.presentation.elevationColor
+import kotlin.math.roundToInt
 
 private val allModes = listOf(
     "AFSK", "AFSK S-Net", "AFSK SALSAT", "AHRPT", "AM", "APT", "BPSK", "BPSK PMT-A3",
@@ -64,60 +73,160 @@ private val allModes = listOf(
 )
 
 private val hourSteps = listOf(1, 2, 4, 8, 12, 24, 48, 72, 96, 120, 144, 168, 192, 216, 240)
+private const val dayMinutes = 24 * 60
+private const val minuteStep = 15
+private const val endOfDayMinute = dayMinutes - 1
+private const val quarterHourSlots = dayMinutes / minuteStep
+
+data class PassFilterParams(
+    val hours: Int,
+    val elevation: Double,
+    val lowElevation: Double,
+    val highElevation: Double,
+    val aosStartMinute: Int,
+    val aosEndMinute: Int,
+    val invertAosTimeWindow: Boolean,
+    val showDeepSpace: Boolean
+)
 
 @Preview
 @Composable
 private fun PassesDialogPreview() {
-    MainTheme { PassesDialog(24, 16.0, true, {}) { _, _, _ -> } }
+    MainTheme {
+        PassesFilterDialog(
+            hours = 24,
+            elevation = 16.0,
+            lowElevation = 16.0,
+            highElevation = 65.0,
+            aosStartMinute = 0,
+            aosEndMinute = 23 * 60 + 59,
+            invertAosTimeWindow = false,
+            showDeepSpace = true,
+            cancel = {},
+            accept = {}
+        )
+    }
 }
 
 @Composable
-internal fun PassesDialog(
+internal fun PassesFilterDialog(
     hours: Int,
     elevation: Double,
+    lowElevation: Double,
+    highElevation: Double,
+    aosStartMinute: Int,
+    aosEndMinute: Int,
+    invertAosTimeWindow: Boolean,
     showDeepSpace: Boolean,
     cancel: () -> Unit,
-    accept: (Int, Double, Boolean) -> Unit
+    accept: (PassFilterParams) -> Unit
 ) {
     val hoursIndex = remember { mutableIntStateOf(hourSteps.indexOfFirst { it >= hours }.coerceAtLeast(0)) }
     val elevationValueNew = remember { mutableDoubleStateOf(elevation) }
+    val highlightBounds = 0f..90f
+    var highlightRange by remember(lowElevation, highElevation) {
+        mutableStateOf(lowElevation.toFloat()..highElevation.toFloat())
+    }
+    var aosRangeValue by remember {
+        mutableStateOf(minuteToSlot(aosStartMinute).toFloat()..minuteToSlot(aosEndMinute).toFloat())
+    }
+    var invertedAosRange by remember { mutableStateOf(invertAosTimeWindow) }
     var deepSpaceEnabled by remember { mutableStateOf(showDeepSpace) }
     val onAccept = {
-        accept(hourSteps[hoursIndex.intValue], elevationValueNew.doubleValue, deepSpaceEnabled).also { cancel() }
+        accept(
+            PassFilterParams(
+                hours = hourSteps[hoursIndex.intValue],
+                elevation = elevationValueNew.doubleValue,
+                lowElevation = highlightRange.start.roundToInt().toDouble(),
+                highElevation = highlightRange.endInclusive.roundToInt().toDouble(),
+                aosStartMinute = slotToMinute(aosRangeValue.start),
+                aosEndMinute = slotToMinute(aosRangeValue.endInclusive),
+                invertAosTimeWindow = invertedAosRange,
+                showDeepSpace = deepSpaceEnabled
+            )
+        )
+        cancel()
     }
     SharedDialog(title = stringResource(R.string.pass_filter_title), onCancel = cancel, onAccept = onAccept) {
-        ToggleRow(
-            title = stringResource(R.string.pass_filter_deep_space),
-            checked = deepSpaceEnabled,
-            onCheckedChange = { deepSpaceEnabled = it }
-        )
         SliderRow(
             title = stringResource(R.string.pass_filter_elev),
             value = elevationValueNew.doubleValue,
             displayValue = "${elevationValueNew.doubleValue.toInt()}°",
             valueResId = R.drawable.ic_elevation,
-            valueRange = 0f..60f
+            valueRange = 0f..60f,
+            accentColor = elevationColor(elevationValueNew.doubleValue)
         ) { elevationValueNew.doubleValue = it.toDouble() }
         SliderRow(
             title = stringResource(R.string.pass_filter_hours),
             value = hoursIndex.intValue.toDouble(),
-            displayValue = "${hourSteps[hoursIndex.intValue]}h",
+            displayValue = formatHoursLabel(hourSteps[hoursIndex.intValue]),
             valueResId = R.drawable.ic_clock,
             valueRange = 0f..(hourSteps.size - 1).toFloat(),
             steps = hourSteps.size - 2
         ) { hoursIndex.intValue = it.toInt().coerceIn(0, hourSteps.size - 1) }
+        ToggleRow(
+            title = stringResource(R.string.pass_filter_deep_space),
+            checked = deepSpaceEnabled,
+            onCheckedChange = { deepSpaceEnabled = it }
+        )
+        ElevationColorsRangeSliderRow(
+            title = stringResource(R.string.prefs_highlight_title),
+            range = highlightRange,
+            valueRange = highlightBounds
+        ) { highlightRange = it }
+        TimeRangeSliderRow(
+            title = stringResource(R.string.pass_filter_aos_time),
+            range = aosRangeValue,
+            displayValue = formatTimeRange(aosRangeValue, invertedAosRange),
+            valueResId = R.drawable.ic_clock,
+            valueRange = 0f..quarterHourSlots.toFloat(),
+        ) { aosRangeValue = it }
+        ToggleRow(
+            title = stringResource(R.string.pass_filter_invert_time),
+            checked = invertedAosRange,
+            onCheckedChange = { invertedAosRange = it }
+        )
+        Spacer(modifier = Modifier.height(0.dp))
     }
 }
 
+private fun slotToMinute(value: Float): Int {
+    val slot = value.roundToInt().coerceIn(0, quarterHourSlots)
+    return if (slot == quarterHourSlots) endOfDayMinute else slot * minuteStep
+}
+
+private fun minuteToSlot(minute: Int): Int {
+    if (minute >= endOfDayMinute) return quarterHourSlots
+    return ((minute + minuteStep / 2) / minuteStep).coerceIn(0, quarterHourSlots)
+}
+
+private fun formatMinuteOfDay(minute: Int): String {
+    val hourPart = minute / 60
+    val minutePart = minute % 60
+    return "%02d:%02d".format(hourPart, minutePart)
+}
+
+private fun formatHoursLabel(hours: Int): String {
+    if (hours < 24) return "${hours}h"
+    val days = hours / 24
+    val remainder = hours % 24
+    return if (remainder == 0) "${days}d" else "${days}d ${remainder}h"
+}
+
+private fun formatTimeRange(
+    range: ClosedFloatingPointRange<Float>,
+    inverted: Boolean
+): String {
+    val start = formatMinuteOfDay(slotToMinute(range.start))
+    val end = formatMinuteOfDay(slotToMinute(range.endInclusive))
+    return if (inverted) "$end - $start" else "$start - $end"
+}
+
 @Composable
-private fun SliderRow(
+private fun SliderSection(
     title: String,
-    value: Double,
+    trailingContent: @Composable () -> Unit,
-    displayValue: String,
+    sliderContent: @Composable () -> Unit
-    valueResId: Int,
-    valueRange: ClosedFloatingPointRange<Float>,
-    steps: Int = 0,
-    onChange: (Float) -> Unit
 ) {
     Column(
         horizontalAlignment = Alignment.CenterHorizontally,
@@ -134,6 +243,56 @@ private fun SliderRow(
                 modifier = Modifier.weight(1f),
                 color = MaterialTheme.colorScheme.onSurface
             )
+            trailingContent()
+        }
+        sliderContent()
+    }
+}
+
+@Composable
+private fun SliderRow(
+    title: String,
+    value: Double,
+    displayValue: String,
+    valueResId: Int,
+    valueRange: ClosedFloatingPointRange<Float>,
+    steps: Int = 0,
+    accentColor: Color = MaterialTheme.colorScheme.primary,
+    onChange: (Float) -> Unit
+) {
+    SliderSection(
+        title = title,
+        trailingContent = {
+            Icon(
+                painter = painterResource(id = valueResId),
+                contentDescription = null,
+                tint = accentColor,
+                modifier = Modifier.size(20.dp)
+            )
+            Text(
+                text = displayValue,
+                fontSize = 18.sp,
+                fontWeight = FontWeight.Medium,
+                color = accentColor
+            )
+        }
+    ) {
+        Slider(value = value.toFloat(), onValueChange = onChange, valueRange = valueRange, steps = steps)
+    }
+}
+
+@Composable
+private fun TimeRangeSliderRow(
+    title: String,
+    range: ClosedFloatingPointRange<Float>,
+    displayValue: String,
+    valueResId: Int,
+    valueRange: ClosedFloatingPointRange<Float>,
+    onChange: (ClosedFloatingPointRange<Float>) -> Unit
+) {
+    SliderSection(
+        title = title,
+        trailingContent = {
             Icon(
                 painter = painterResource(id = valueResId),
                 contentDescription = null,
@@ -147,7 +306,56 @@ private fun SliderRow(
                 color = MaterialTheme.colorScheme.primary
             )
         }
-        Slider(value = value.toFloat(), onValueChange = onChange, valueRange = valueRange, steps = steps)
+    ) {
+        RangeSlider(
+            value = range,
+            onValueChange = { onChange(it.start..it.endInclusive) },
+            valueRange = valueRange,
+            steps = 0,
+            modifier = Modifier.fillMaxWidth()
+        )
+    }
+}
+
+@Composable
+private fun ElevationColorsRangeSliderRow(
+    title: String,
+    range: ClosedFloatingPointRange<Float>,
+    valueRange: ClosedFloatingPointRange<Float>,
+    onChange: (ClosedFloatingPointRange<Float>) -> Unit
+) {
+    val low = range.start.roundToInt()
+    val high = range.endInclusive.roundToInt()
+    SliderSection(
+        title = title,
+        trailingContent = {
+            Text(
+                text = "$low°",
+                fontSize = 18.sp,
+                fontWeight = FontWeight.Medium,
+                color = ElevationLowColor
+            )
+            Text(
+                text = "..",
+                fontSize = 18.sp,
+                fontWeight = FontWeight.Medium,
+                color = MaterialTheme.colorScheme.primary
+            )
+            Text(
+                text = "$high°",
+                fontSize = 18.sp,
+                fontWeight = FontWeight.Medium,
+                color = ElevationHighColor
+            )
+        }
+    ) {
+        RangeSlider(
+            value = range,
+            onValueChange = { onChange(it.start..it.endInclusive) },
+            valueRange = valueRange,
+            steps = 0,
+            modifier = Modifier.fillMaxWidth()
+        )
     }
 }
 

feature/passes/src/main/java/com/rtbishop/look4sat/feature/passes/PassesScreen.kt

@@ -17,6 +17,11 @@
  */
 package com.rtbishop.look4sat.feature.passes
 
+import androidx.compose.animation.AnimatedContent
+import androidx.compose.animation.core.tween
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.togetherWith
 import androidx.compose.foundation.background
 import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
@@ -29,10 +34,8 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.grid.GridCells
-import androidx.compose.foundation.lazy.grid.LazyGridState
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
-import androidx.compose.foundation.lazy.grid.rememberLazyGridState
 import androidx.compose.material3.ElevatedCard
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.HorizontalDivider
@@ -47,6 +50,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
@@ -60,15 +64,18 @@ import com.rtbishop.look4sat.core.domain.predict.DeepSpaceObject
 import com.rtbishop.look4sat.core.domain.predict.NearEarthObject
 import com.rtbishop.look4sat.core.domain.predict.OrbitalData
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
+import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
 import com.rtbishop.look4sat.core.presentation.EmptyListCard
 import com.rtbishop.look4sat.core.presentation.IconCard
-import com.rtbishop.look4sat.core.presentation.InfoDialog
 import com.rtbishop.look4sat.core.presentation.MainTheme
 import com.rtbishop.look4sat.core.presentation.NextPassRow
 import com.rtbishop.look4sat.core.presentation.R
 import com.rtbishop.look4sat.core.presentation.ScreenColumn
+import com.rtbishop.look4sat.core.presentation.SharedDialog
+import com.rtbishop.look4sat.core.presentation.SwipeableItem
 import com.rtbishop.look4sat.core.presentation.TimerRow
 import com.rtbishop.look4sat.core.presentation.TopBar
+import com.rtbishop.look4sat.core.presentation.elevationColor
 import com.rtbishop.look4sat.core.presentation.infiniteMarquee
 import com.rtbishop.look4sat.core.presentation.isVerticalLayout
 import java.text.SimpleDateFormat
@@ -78,10 +85,9 @@ import java.util.TimeZone
 
 @Composable
 fun PassesDestination(navigateToRadar: (Int, Long) -> Unit) {
-    val viewModel = viewModel(
+    val context = LocalContext.current
-        modelClass = PassesViewModel::class.java,
+    val container = (context.applicationContext as IContainerProvider).getMainContainer()
-        factory = PassesViewModel.Factory
+    val viewModel: PassesViewModel = viewModel(factory = PassesViewModel.factory(container))
-    )
     val uiState = viewModel.uiState.collectAsStateWithLifecycle().value
     PassesScreen(uiState, viewModel::onAction, navigateToRadar)
 }
@@ -93,14 +99,31 @@ private fun PassesScreen(
     navigateToRadar: (Int, Long) -> Unit
 ) {
     if (uiState.isPassesDialogShown) {
-        PassesDialog(
+        PassesFilterDialog(
             hours = uiState.hours,
             elevation = uiState.elevation,
+            lowElevation = uiState.lowElevation,
+            highElevation = uiState.highElevation,
+            aosStartMinute = uiState.aosStartMinute,
+            aosEndMinute = uiState.aosEndMinute,
+            invertAosTimeWindow = uiState.invertAosTimeWindow,
             showDeepSpace = uiState.showDeepSpace,
-            cancel = { onAction(PassesAction.TogglePassesDialog) }
+            cancel = { onAction(PassesAction.TogglePassesDialog) },
-        ) { hours, elevation, showDeepSpace ->
+            accept = { params ->
-            onAction(PassesAction.FilterPasses(hours, elevation, showDeepSpace))
+                onAction(
-        }
+                    PassesAction.FilterPasses(
+                        hoursAhead = params.hours,
+                        minElevation = params.elevation,
+                        lowElevation = params.lowElevation,
+                        highElevation = params.highElevation,
+                        aosStartMinute = params.aosStartMinute,
+                        aosEndMinute = params.aosEndMinute,
+                        invertAosTimeWindow = params.invertAosTimeWindow,
+                        showDeepSpace = params.showDeepSpace
+                    )
+                )
+            }
+        )
     }
     if (uiState.isRadiosDialogShown) {
         RadiosDialog(
@@ -111,14 +134,21 @@ private fun PassesScreen(
         }
     }
     if (uiState.shouldSeeWhatsNew) {
-        InfoDialog(
+        val dismiss = { onAction(PassesAction.DismissWhatsNew) }
+        SharedDialog(
             title = stringResource(R.string.pass_whatsnew_title),
-            text = stringResource(R.string.pass_whatsnew_message)
+            onDismissRequest = dismiss,
-        ) {
+            onAccept = dismiss,
-            onAction(PassesAction.DismissWhatsNew)
+            titleFontSize = 18
+        ) { padding ->
+            Text(
+                text = stringResource(R.string.pass_whatsnew_message),
+                fontSize = 16.sp,
+                color = MaterialTheme.colorScheme.onSurface,
+                modifier = Modifier.padding(horizontal = padding)
+            )
         }
     }
-    val gridState = rememberLazyGridState()
     ScreenColumn(
         topBar = { isVerticalLayout ->
             TopBar(
@@ -142,9 +172,11 @@ private fun PassesScreen(
             isRefreshing = uiState.isRefreshing,
             isUtc = uiState.isUtc,
             passes = uiState.itemsList,
+            groupedPasses = uiState.groupedPasses,
+            sunTimes = uiState.sunTimes,
+            focusedCatNum = uiState.focusedCatNum,
             navigateToRadar = navigateToRadar,
-            refreshPasses = { onAction(PassesAction.RefreshPasses) },
+            onAction = onAction
-            gridState = gridState
         )
     }
 }
@@ -155,9 +187,11 @@ private fun PassesList(
     isRefreshing: Boolean,
     isUtc: Boolean,
     passes: List<OrbitalPass>,
+    groupedPasses: Map<String, List<OrbitalPass>>,
+    sunTimes: Map<String, Pair<String, String>>,
+    focusedCatNum: Int?,
     navigateToRadar: (Int, Long) -> Unit,
-    refreshPasses: () -> Unit,
+    onAction: (PassesAction) -> Unit
-    gridState: LazyGridState
 ) {
     val isVerticalLayout = isVerticalLayout()
     val refreshState = rememberPullToRefreshState()
@@ -165,7 +199,7 @@ private fun PassesList(
         PullToRefreshBox(
             isRefreshing = isRefreshing,
             state = refreshState,
-            onRefresh = refreshPasses,
+            onRefresh = { onAction(PassesAction.RefreshPasses) },
             indicator = {
                 PullToRefreshDefaults.Indicator(
                     state = refreshState,
@@ -179,19 +213,37 @@ private fun PassesList(
             if (passes.isEmpty()) {
                 EmptyListCard(message = stringResource(R.string.pass_empty_list_message))
             } else {
-                LazyVerticalGrid(
+                AnimatedContent(
-                    state = gridState,
+                    targetState = focusedCatNum,
-                    columns = GridCells.Adaptive(320.dp),
+                    transitionSpec = { fadeIn(tween(200)) togetherWith fadeOut(tween(200)) },
-                    modifier = Modifier.fillMaxSize()
+                    label = "PassesFocusTransition"
-                ) {
+                ) { targetFocus ->
-                    items(items = passes, key = { item -> item.catNum + item.aosTime }) { pass ->
+                    LazyVerticalGrid(columns = GridCells.Adaptive(320.dp), modifier = Modifier.fillMaxSize()) {
-                        PassItem(
+                        for ((dateLabel, dayPasses) in groupedPasses) {
-                            pass = pass,
+                            val headerVisible = targetFocus == null || dayPasses.any { it.catNum == targetFocus }
-                            navigateToRadar = navigateToRadar,
+                            if (headerVisible) {
-                            modifier = Modifier.animateItem(),
+                                stickyHeader(key = "header_$dateLabel") {
-                            isVerticalLayout = isVerticalLayout,
+                                    val (rise, set) = sunTimes[dateLabel] ?: ("--:--" to "--:--")
-                            isUtc = isUtc
+                                    StickyDateHeader(label = dateLabel, sunriseTime = rise, sunsetTime = set)
-                        )
+                                }
+                            }
+                            val visiblePasses = if (targetFocus == null) dayPasses
+                            else dayPasses.filter { it.catNum == targetFocus }
+                            items(items = visiblePasses, key = { item -> item.catNum + item.aosTime }) { pass ->
+                                SwipeableItem(
+                                    onSwipeRight = { onAction(PassesAction.FocusCatNum(pass.catNum)) },
+                                    onSwipeLeft = { onAction(PassesAction.ClearFocus) }
+                                ) {
+                                    PassItem(
+                                        pass = pass,
+                                        navigateToRadar = navigateToRadar,
+                                        modifier = Modifier.animateItem(),
+                                        isVerticalLayout = isVerticalLayout,
+                                        isUtc = isUtc
+                                    )
+                                }
+                            }
+                        }
                     }
                 }
             }
@@ -199,6 +251,45 @@ private fun PassesList(
     }
 }
 
+@Composable
+private fun StickyDateHeader(label: String, sunriseTime: String, sunsetTime: String) {
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        horizontalArrangement = Arrangement.SpaceBetween,
+        modifier = Modifier
+            .fillMaxWidth()
+            .background(MaterialTheme.colorScheme.surfaceContainerHighest)
+            .padding(horizontal = 12.dp, vertical = 4.dp)
+    ) {
+        Text(
+            text = label,
+            fontSize = 14.sp,
+            fontWeight = FontWeight.Normal,
+            color = MaterialTheme.colorScheme.primary
+        )
+        Row(horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+            Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+                Icon(
+                    painter = painterResource(R.drawable.ic_sun),
+                    contentDescription = null,
+                    tint = MaterialTheme.colorScheme.primary,
+                    modifier = Modifier.size(16.dp)
+                )
+                Text(text = sunriseTime, fontSize = 14.sp, color = MaterialTheme.colorScheme.onSurface)
+            }
+            Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+                Icon(
+                    painter = painterResource(R.drawable.ic_moon),
+                    contentDescription = null,
+                    tint = MaterialTheme.colorScheme.onSurface,
+                    modifier = Modifier.size(16.dp)
+                )
+                Text(text = sunsetTime, fontSize = 14.sp, color = MaterialTheme.colorScheme.onSurface)
+            }
+        }
+    }
+}
+
 @Preview(showBackground = true)
 @Composable
 private fun DeepSpacePassPreview() {
@@ -225,20 +316,19 @@ private fun PassItem(
     isVerticalLayout: Boolean = true,
     isUtc: Boolean = false
 ) {
-    val passSatId = stringResource(id = R.string.pass_satId, pass.catNum)
     val horizontalPadding = if (isVerticalLayout) 6.dp else 10.dp
     val timeZone = remember(isUtc) {
         if (isUtc) TimeZone.getTimeZone("UTC") else TimeZone.getDefault()
     }
-    val sdfDate = remember(isUtc) {
-        SimpleDateFormat("EEE dd MMM", Locale.ENGLISH).also { it.timeZone = timeZone }
-    }
     val sdfTime = remember(isUtc) {
-        SimpleDateFormat("HH:mm:ss", Locale.ENGLISH).also { it.timeZone = timeZone }
+        SimpleDateFormat("HH:mm:ss", Locale.getDefault()).also { it.timeZone = timeZone }
     }
-    val aosDateStr = remember(pass.aosTime, isUtc) { sdfDate.format(Date(pass.aosTime)) }
     val aosTimeStr = remember(pass.aosTime, isUtc) { sdfTime.format(Date(pass.aosTime)) }
     val losTimeStr = remember(pass.losTime, isUtc) { sdfTime.format(Date(pass.losTime)) }
+    val durationStr = remember(pass.aosTime, pass.losTime) {
+        val seconds = (pass.losTime - pass.aosTime) / 1000
+        "${seconds / 60}m ${seconds % 60}s"
+    }
 
     Column(
         modifier = modifier.clickable { navigateToRadar(pass.catNum, pass.aosTime) }
@@ -251,10 +341,6 @@ private fun PassItem(
                 .padding(horizontal = horizontalPadding, vertical = 4.dp)
         ) {
             Row(verticalAlignment = Alignment.CenterVertically) {
-                Text(
-                    text = "$passSatId - ",
-                    color = MaterialTheme.colorScheme.primary
-                )
                 Text(
                     text = pass.name,
                     modifier = Modifier
@@ -264,18 +350,19 @@ private fun PassItem(
                     fontWeight = FontWeight.Medium,
                     maxLines = 1,
                     overflow = TextOverflow.Ellipsis,
-                    color = MaterialTheme.colorScheme.onSurface
+                    color = MaterialTheme.colorScheme.primary
                 )
+                val elevColor = elevationColor(pass.maxElevation)
                 Icon(
                     painter = painterResource(id = R.drawable.ic_elevation),
                     contentDescription = null,
-                    tint = MaterialTheme.colorScheme.primary,
+                    tint = elevColor,
                     modifier = Modifier.size(16.dp)
                 )
                 Spacer(modifier = Modifier.width(4.dp))
                 Text(
                     text = "${pass.maxElevation}°",
-                    color = MaterialTheme.colorScheme.primary
+                    color = elevColor
                 )
             }
             Row(
@@ -295,7 +382,7 @@ private fun PassItem(
                             color = MaterialTheme.colorScheme.onSurface
                         )
                     } else {
-                        Text(text = aosDateStr, fontSize = 15.sp, color = MaterialTheme.colorScheme.onSurface)
+                        Text(text = durationStr, fontSize = 15.sp, color = MaterialTheme.colorScheme.onSurface)
                     }
                 }
                 Row(
@@ -303,13 +390,6 @@ private fun PassItem(
                     horizontalArrangement = Arrangement.Center,
                     verticalAlignment = Alignment.CenterVertically
                 ) {
-                    Icon(
-                        painter = painterResource(id = R.drawable.ic_altitude),
-                        contentDescription = null,
-                        modifier = Modifier.size(16.dp),
-                        tint = MaterialTheme.colorScheme.onSurface
-                    )
-                    Spacer(modifier = Modifier.width(4.dp))
                     Text(text = "${pass.altitude} km", fontSize = 15.sp, color = MaterialTheme.colorScheme.onSurface)
                 }
                 Row(

feature/passes/src/main/java/com/rtbishop/look4sat/feature/passes/PassesState.kt

@@ -29,17 +29,36 @@ data class PassesState(
     val isNextTimeAos: Boolean = true,
     val hours: Int = 24,
     val elevation: Double = 16.0,
+    val lowElevation: Double = 16.0,
+    val highElevation: Double = 65.0,
+    val aosStartMinute: Int = 0,
+    val aosEndMinute: Int = 23 * 60 + 59,
+    val invertAosTimeWindow: Boolean = false,
     val showDeepSpace: Boolean = true,
     val modes: List<String> = emptyList(),
     val itemsList: List<OrbitalPass> = emptyList(),
-    val shouldSeeWhatsNew: Boolean = false
+    val groupedPasses: Map<String, List<OrbitalPass>> = emptyMap(),
+    val shouldSeeWhatsNew: Boolean = false,
+    val sunTimes: Map<String, Pair<String, String>> = emptyMap(),
+    val focusedCatNum: Int? = null
 )
 
 sealed interface PassesAction {
     data object DismissWhatsNew : PassesAction
-    data class FilterPasses(val hoursAhead: Int, val minElevation: Double, val showDeepSpace: Boolean) : PassesAction
+    data class FilterPasses(
+        val hoursAhead: Int,
+        val minElevation: Double,
+        val lowElevation: Double,
+        val highElevation: Double,
+        val aosStartMinute: Int,
+        val aosEndMinute: Int,
+        val invertAosTimeWindow: Boolean,
+        val showDeepSpace: Boolean
+    ) : PassesAction
     data class FilterRadios(val modes: List<String>) : PassesAction
     data object RefreshPasses : PassesAction
     data object TogglePassesDialog : PassesAction
     data object ToggleRadiosDialog : PassesAction
+    data class FocusCatNum(val catNum: Int) : PassesAction
+    data object ClearFocus : PassesAction
 }