v4.4.0 - Implemented CAT and SSTV support in RadarScreen

Co-authored-by: Arty Bishop <44072814+rt-bishop@users.noreply.github.com>

.github/dependabot.yml

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

.github/workflows/release.yml

@@ -25,50 +25,54 @@ jobs:
           java-version: '17'
 
       - name: Setup Gradle
-        uses: gradle/actions/setup-gradle@v5
+        uses: gradle/actions/setup-gradle@v6
 
       - name: Assemble Artifacts
-        run: |
-          ./gradlew assembleRelease
-          ./gradlew bundleRelease
+        run: ./gradlew assembleRelease bundleRelease
 
       - name: Sign APK
-        uses: r0adkll/sign-android-release@v1
-        id: sign_apk
-        with:
-          releaseDirectory: app/build/outputs/apk/release
-          signingKeyBase64: ${{ secrets.KEY_STORE }}
-          keyStorePassword: ${{ secrets.KEY_STORE_PASSWORD }}
-          alias: ${{ secrets.KEY_ALIAS }}
-          keyPassword: ${{ secrets.KEY_PASSWORD }}
-        env:
-          BUILD_TOOLS_VERSION: "36.0.0"
+        run: |
+          echo "${{ secrets.KEY_STORE }}" | base64 -d > keystore.jks
+          APK=$(find app/build/outputs/apk/release -name "*.apk" | head -1)
+          BUILD_TOOLS=$(ls -d ${ANDROID_HOME}/build-tools/*/ | sort -V | tail -1)
+          ${BUILD_TOOLS}apksigner sign \
+            --ks keystore.jks \
+            --ks-pass pass:${{ secrets.KEY_STORE_PASSWORD }} \
+            --ks-key-alias ${{ secrets.KEY_ALIAS }} \
+            --key-pass pass:${{ secrets.KEY_PASSWORD }} \
+            --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
-          mv ${{steps.sign_bundle.outputs.signedReleaseFile}} app/build/outputs/apk/release/look4sat.aab
+          echo "${{ secrets.KEY_STORE }}" | base64 -d > keystore.jks
+          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
-        uses: r0adkll/upload-google-play@v1
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@v1
         with:
-          serviceAccountJsonPlainText: ${{secrets.SERVICE_ACCOUNT_JSON}}
-          packageName: com.rtbishop.look4sat
-          releaseFiles: app/build/outputs/apk/release/look4sat.aab
-          track: production
-          whatsNewDirectory: fastlane/metadata/android/en-US/whatsnew
+          ruby-version: '3.3'
+
+      - name: Deploy Bundle to Google Play
+        run: |
+          gem install fastlane --no-document
+          AAB=$(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: |

CLAUDE.md

@@ -0,0 +1,110 @@
+# CLAUDE.md
+
+## 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.

app/src/main/AndroidManifest.xml

@@ -11,12 +11,15 @@
     <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:roundIcon="@mipmap/ic_launcher_round">
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:usesCleartextTraffic="true">
 
         <activity
             android:name=".MainActivity"

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

@@ -56,8 +56,10 @@ import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
+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.presentation.Screen
@@ -66,7 +68,6 @@ import com.rtbishop.look4sat.core.presentation.hasEnoughWidth
 import com.rtbishop.look4sat.feature.map.MapDestination
 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
 
@@ -74,9 +75,11 @@ import com.rtbishop.look4sat.feature.settings.SettingsDestination
 fun MainScreen() {
     val backStack = rememberNavBackStack(Screen.Passes)
     val currentKey = backStack.lastOrNull()
-    val navigateBack: () -> Unit = { backStack.removeAt(backStack.size - 1) }
+    val navigateBack: () -> Unit = { if (backStack.size > 1) backStack.removeAt(backStack.size - 1) }
     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 slideInTransition = slideInHorizontally(initialOffsetX = { it }) togetherWith scaleOut(targetScale = 0.9f)
+//    val slideOutTransition = scaleIn(initialScale = 0.9f) togetherWith slideOutHorizontally(targetOffsetX = { it })
+    val navItems = listOf(Screen.Satellites, Screen.Passes, Screen.Radar, Screen.Map, Screen.Settings)
 
     val context = LocalContext.current
     val container = (context.applicationContext as IContainerProvider).getMainContainer()
@@ -122,31 +125,24 @@ fun MainScreen() {
                 transitionSpec = { fadeTransition },
                 popTransitionSpec = { fadeTransition },
                 predictivePopTransitionSpec = { fadeTransition },
+                entryDecorators = listOf(
+                    // 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 ->
-                            backStack.add(Screen.Radar(catNum, aosTime))
+                            container.satelliteRepo.selectPass(catNum, aosTime)
+                            backStack.add(Screen.Radar)
                         }
                     }
-                    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.Radar> {
+                        RadarDestination(navigateUp = navigateBack)
                     }
                     entry<Screen.Map> {
                         MapDestination()
@@ -174,7 +170,8 @@ fun MainScreen() {
                         .clickable {
                             val pass = trackingState.currentPass
                             if (pass != null) {
-                                backStack.add(Screen.RadioControl(pass.catNum, pass.aosTime))
+                                container.satelliteRepo.selectPass(pass.catNum, pass.aosTime)
+                                backStack.add(Screen.Radar)
                             }
                         }
                         .padding(horizontal = 12.dp, vertical = 6.dp)

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

@@ -34,7 +34,6 @@ internal class ApplicationPlugin : Plugin<Project> {
             implementation(project(":feature:map"))
             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)

core/data/src/main/AndroidManifest.xml

@@ -11,5 +11,6 @@
     <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/RadioTrackingService.kt

@@ -64,7 +64,7 @@ class RadioTrackingService(
         Log.i(tag, "Connecting TX=$txAddr RX=$rxAddr")
 
         if (txAddr.isBlank() && rxAddr.isBlank()) {
-            _state.update { it.copy(errorMessage = "No radio addresses configured. Set them in Settings → FT-817.") }
+            _state.update { it.copy(errorMessage = "No radio addresses configured in Settings") }
             return
         }
 

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

@@ -1,3 +1,20 @@
+/*
+ * 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
@@ -20,6 +37,8 @@ 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.repository.IDatabaseRepo
 import com.rtbishop.look4sat.core.domain.repository.IMainContainer
@@ -33,6 +52,8 @@ 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.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
@@ -59,6 +80,10 @@ class MainContainer(private val context: Context) : IMainContainer {
 
     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

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

@@ -40,28 +40,22 @@ class DatabaseRepo(
     private val settingsRepo: ISettingsRepo
 ) : IDatabaseRepo {
 
-    private companion object {
-        val tleTypes = setOf("Amsat", "R4UAB", "Other")
-        val zippedTleTypes = setOf("McCants", "Classified")
-    }
+    private val customSourceType = "Other"
 
     override suspend fun updateTLEFromFile(uri: String) = withContext(dispatcher) {
         remoteSource.getFileStream(uri)?.let { stream ->
-            val entries = dataParser.parseTLEStream(stream)
+            val entries = dataParser.parseTLEStream(unwrapIfZipped(uri, stream))
             localSource.insertEntries(entries)
-            settingsRepo.setSatelliteTypeIds("Other", entries.map { it.catnum })
+            settingsRepo.setSatelliteTypeIds(customSourceType, entries.map { it.catnum })
         }
         setUpdateSuccessful(System.currentTimeMillis())
     }
 
     override suspend fun updateTransceiversFromFile(uri: String) = withContext(dispatcher) {
-        remoteSource.getFileStream(uri)
-            ?.let { dataParser.parseJSONStream(it) }
-            ?.takeIf { it.isNotEmpty() }
-            ?.let {
-                localSource.deleteRadios()
-                localSource.insertRadios(it)
-            }
+        remoteSource.getFileStream(uri)?.let { stream ->
+            val transceivers = dataParser.parseJSONStream(unwrapIfZipped(uri, stream))
+            localSource.insertRadios(transceivers)
+        }
         setUpdateSuccessful(System.currentTimeMillis())
     }
 
@@ -69,28 +63,26 @@ class DatabaseRepo(
         val dataSourcesSettings = settingsRepo.dataSourcesSettings.value
         val tleUrls = buildMap {
             putAll(Sources.satelliteDataUrls)
-            if (dataSourcesSettings.useCustomTLE) put("Other", dataSourcesSettings.tleUrl)
-        }.filterValues { it.isNotEmpty() }
-
-        val radioUrls = buildList {
-            add(Sources.RADIO_DATA_URL)
-            if (dataSourcesSettings.useCustomTransceivers) add(dataSourcesSettings.transceiversUrl)
-        }
-
+            if (dataSourcesSettings.useCustomTLE) put(customSourceType, dataSourcesSettings.tleUrl)
+        }.filterValues { it.isNotBlank() }
+        val radioUrls = buildMap {
+            putAll(Sources.transceiversDataUrls)
+            if (dataSourcesSettings.useCustomTransceivers) put(customSourceType, dataSourcesSettings.transceiversUrl)
+        }.filterValues { it.isNotBlank() }
         // launch all network requests concurrently
-        val tleJobs = tleUrls.map { (type, url) -> async { type to remoteSource.getNetworkStream(url) } }
-        val radioJobs = radioUrls.map { url -> async { remoteSource.getNetworkStream(url) } }
-
-        // parse satellite data
-        val importedEntries = tleJobs.awaitAll().flatMap { (type, stream) ->
-            stream?.let { parseSatelliteStream(type, it) }.orEmpty().also { satellites ->
-                settingsRepo.setSatelliteTypeIds(type, satellites.map { it.catnum })
+        val tleJobs = tleUrls.values.map { url -> async { url to remoteSource.getNetworkStream(url) } }
+        val radioJobs = radioUrls.values.map { url -> async { url to remoteSource.getNetworkStream(url) } }
+        // parse fetched data concurrently and associate with types
+        val importedEntries = tleJobs.awaitAll().flatMap { (url, stream) ->
+            val type = tleUrls.entries.find { it.value == url }?.key ?: customSourceType
+            stream?.let { parseSatelliteStream(url, unwrapIfZipped(url, it)) }.orEmpty().also { entries ->
+                settingsRepo.setSatelliteTypeIds(type, entries.map { it.catnum })
             }
         }
-
-        // parse radio data
-        val importedRadios = radioJobs.awaitAll().filterNotNull().flatMap { dataParser.parseJSONStream(it) }
-
+        val importedRadios = radioJobs.awaitAll().flatMap { (url, stream) ->
+            stream?.let { dataParser.parseJSONStream(unwrapIfZipped(url, it)) }.orEmpty()
+        }
+        // insert parsed data into the database
         localSource.insertEntries(importedEntries)
         localSource.insertRadios(importedRadios)
         setUpdateSuccessful(System.currentTimeMillis())
@@ -102,10 +94,9 @@ class DatabaseRepo(
         setUpdateSuccessful(0L)
     }
 
-    private suspend fun parseSatelliteStream(type: String, stream: InputStream): List<OrbitalData> = when (type) {
-        in tleTypes -> dataParser.parseTLEStream(stream)
-        in zippedTleTypes -> dataParser.parseTLEStream(ZipInputStream(stream).apply { nextEntry })
-        else -> dataParser.parseCSVStream(stream)
+    private suspend fun parseSatelliteStream(url: String, stream: InputStream): List<OrbitalData> = when {
+        url.contains("FORMAT=csv", ignoreCase = true) -> dataParser.parseCSVStream(stream)
+        else -> dataParser.parseTLEStream(stream)
     }
 
     private suspend fun setUpdateSuccessful(timestamp: Long) {
@@ -113,4 +104,7 @@ 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

@@ -52,6 +52,13 @@ 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) {
@@ -139,17 +146,18 @@ class SatelliteRepo(
         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 +168,17 @@ 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 +242,6 @@ 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/SettingsRepo.kt

@@ -72,6 +72,7 @@ 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 +81,7 @@ class SettingsRepo(
     private val keyUpdateTimestamp = "updateTimestamp"
     private val keyShouldSeeWarning = "shouldSeeWarning"
     private val keyShouldSeeWhatsNew = "shouldSeeWhatsNew_v$appVersionName"
+    private val keySstvMode = "sstvMode"
     private val keyUseCustomTle = "useCustomTle"
     private val keyUseCustomTransceivers = "useCustomTransceivers"
     private val keyTleUrl = "tleUrl"
@@ -329,8 +331,10 @@ 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)
             }
             new
         }
@@ -342,8 +346,10 @@ 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"
     )
     //endregion
 

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

@@ -54,8 +54,10 @@ 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"
 )
 
 data class DataSourcesSettings(

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
-    internal fun mod2PI(value: Double): Double {
-        var retVal = value
-        val i = (retVal / TWO_PI).toInt()
-        retVal -= i * TWO_PI
-        if (retVal < 0.0) retVal += TWO_PI
-        return retVal
-    }
+    // Delegates to package-level mod2PI in OrbitalMath.kt
+    internal fun mod2PI(value: Double): Double = com.rtbishop.look4sat.core.domain.predict.mod2PI(value)
 
     // 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))
     }
 
-    /**
-     * The function Delta_ET has been added to allow calculations on the
-     * 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))
-    }
+    // Delegates to package-level deltaET in OrbitalMath.kt
+    private fun deltaEt(year: Double): Double = deltaET(year)
 
     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 {
-        var returnValue = arg1
-        val i = floor(returnValue / arg2).toInt()
-        returnValue -= i * arg2
-        if (returnValue < 0.0) returnValue += arg2
-        return returnValue
-    }
+    private fun modulus(arg1: Double, arg2: Double = SEC_PER_DAY): Double =
+        com.rtbishop.look4sat.core.domain.predict.modulus(arg1, arg2)
 
     // 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 {
-        val earthRotPerSidDay = 1.00273790934
-        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
-    }
+    // Delegates to package-level thetaGJD in OrbitalMath.kt
+    private fun thetaGJD(theJD: Double): Double = com.rtbishop.look4sat.core.domain.predict.thetaGJD(theJD)
 }

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 cosRads = cos(rads)
-            val lat = asin(sinLat * cosBeta + cosLat * sinBeta * cosRads)
-            val lon = longitude + atan2(sinRads * sinBeta * cosLat, cosBeta - sinLat * sin(lat))
+            val lat = asin(sinLat * cosBeta + cosLat * sinBeta * cos(rads))
+            val lon = longitude + atan2(sin(rads) * 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/IMainContainer.kt

@@ -1,6 +1,25 @@
+/*
+ * 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.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
 
@@ -10,6 +29,7 @@ interface IMainContainer {
     val selectionRepo: ISelectionRepo
     val satelliteRepo: ISatelliteRepo
     val databaseRepo: IDatabaseRepo
+    val radioTrackingService: IRadioTrackingService
     fun provideAddToCalendar(): IAddToCalendar
     fun provideShowToast(): IShowToast
     fun provideBluetoothReporter(): IReporter
@@ -17,7 +37,8 @@ interface IMainContainer {
     fun provideSensorsRepo(): ISensorsRepo
     fun provideTxRadioController(): IRadioController
     fun provideRxRadioController(): IRadioController
-    val radioTrackingService: IRadioTrackingService
+    fun provideAudioCapture(): IAudioCapture
+    fun provideSaveImage(): ISaveImage
 }
 
 interface IContainerProvider {

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

@@ -34,6 +34,12 @@ 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()
 

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 +1,573 @@
+/*
+ * 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.SharedFlow
+import kotlinx.coroutines.withContext
+import kotlin.math.abs
+import kotlin.math.round
+import kotlin.math.sqrt
+
+class SstvFrame(
+    val imagePixels: IntArray?,
+    val imageWidth: Int,
+    val imageHeight: Int,
+    val modeName: String
+)
+
+class SstvDecoder(
+    sampleRate: Int = 44100,
+    scopeWidth: Int = 320,
+    scopeHeight: Int = 256,
+    private val channelSelect: Int = 0
+) {
+    private val scopeBuffer = PixelBuffer(scopeWidth, scopeHeight * 2)
+    private val imageBuffer = PixelBuffer(scopeWidth, scopeHeight)
+    private val decoder = DecoderEngine(scopeBuffer, imageBuffer, "Raw", sampleRate)
+    private val _frames = MutableSharedFlow<SstvFrame>(
+        replay = 1,
+        onBufferOverflow = BufferOverflow.DROP_OLDEST
+    )
+    val frames: SharedFlow<SstvFrame> = _frames
+    val supportedModes: List<String> = buildList {
+        add("Raw"); add("HF Fax"); decoder.allModes.mapTo(this) { it.name }
+    }
+
+    suspend fun feedSamples(samples: FloatArray) = withContext(Dispatchers.Default) {
+        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)
+    }
+
+    private fun emitFrame() {
+        val imagePixels = if (imageBuffer.line > 0) imageBuffer.pixels.copyOf() else null
+        val imageWidth = imageBuffer.width
+        val imageHeight = imageBuffer.height
+        val modeName = decoder.currentMode.name
+        _frames.tryEmit(SstvFrame(imagePixels, imageWidth, imageHeight, modeName))
+    }
+}
+
+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
+        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
+) {
+    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 hfFaxMode: 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
+
+    init {
+        imageBuffer.line = -1
+        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)
+        hfFaxMode = HfFaxMode(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)
+        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()) {
+            newLines = true
+        } else if (sample > lastSync + (curLineSamples * 5) / 4) {
+            copyLines(
+                currentMode.decodeScanLine(
+                    pixelBuffer,
+                    scratch,
+                    scanLineBuffer,
+                    scopeBuffer.width,
+                    lastSync,
+                    curLineSamples,
+                    lastOffset
+                )
+            )
+            lastSync += curLineSamples; newLines = true
+        }
+        return newLines
+    }
+
+    fun setMode(name: String) {
+        if (rawMode.name == name) {
+            lockMode = true; imageBuffer.line = -1; currentMode = rawMode; return
+        }
+        var mode = allModes.firstOrNull { it.name == name }
+        if (mode == null && hfFaxMode.name == name) mode = hfFaxMode
+        if (mode == currentMode) {
+            lockMode = true; return
+        }
+        if (mode != null) {
+            lockMode = true; imageBuffer.line = -1; currentMode = mode; curLineSamples = mode.scanLineSamples; return
+        }
+        lockMode = false
+    }
+
+    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
+    }
+
+    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 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)
+        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 = IntArray(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 {
+        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
+        } 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 +1,216 @@
+/*
+ * 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.atan2
+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 arg(): Float = atan2(imag, real)
+
+    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)
+    }
+}
+
+internal open class MovingSum(val length: Int) {
+    private val tree = FloatArray(2 * length)
+    private var leaf = length
+
+    fun add(input: Float) {
+        tree[leaf] = input
+        var child = leaf
+        var parent = leaf / 2
+        while (parent > 0) {
+            tree[parent] = tree[child] + tree[child xor 1]; child = parent; parent /= 2
+        }
+        if (++leaf >= tree.size) leaf = length
+    }
+
+    fun sum(): Float = tree[1]
+    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())
+    }
+
+    fun rotate(): Complex = value.div(value.mul(delta).abs())
+}
+
+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 {
+        val phase = input.arg()
+        var delta = phase - prev; prev = phase
+        if (delta < -pi) delta += twoPi else if (delta > pi) delta -= twoPi
+        return scale * delta
+    }
+}
+
+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 +1,474 @@
+/*
+ * 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) {
+                pixelBuffer.pixels[i] = ColorConverter.rgb(scratch[lPos], 0f, scratch[cPos])
+            } else {
+                val evenYuv = pixelBuffer.pixels[i]
+                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 HfFaxMode(private val sampleRate: Int) : SstvMode {
+    override val name = "HF Fax"
+    override val visCode = -1
+    override val width = 640
+    override val height = 1200
+    override val firstPixelSampleIndex = 0
+    override val firstSyncPulseIndex = -1
+    override val scanLineSamples get() = sampleRate / 2
+
+    private val ema = Ema()
+    private val cumulated = FloatArray(width)
+
+    var horizontalShift = 0; private set
+
+    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
+        ema.setCutoff(width.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)
+        var bestIdx = 0
+        var bestVal = 0f
+        for (i in 0 until width) {
+            val pos = (i * lineSamples) / width
+            val color = ColorConverter.gray(scratch[pos])
+            pixelBuffer.pixels[i] = color
+            // Grayscale: R==G==B, so luminance is simply the channel value normalized
+            val gray = (color and 0xFF) / 255f
+            cumulated[i] = cumulated[i] * 0.99f + gray * 0.01f
+            if (cumulated[i] > bestVal) {
+                bestIdx = i; bestVal = cumulated[i]
+            }
+        }
+        horizontalShift = bestIdx
+        pixelBuffer.width = width; pixelBuffer.height = 1
+        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/GeoConverter.kt

@@ -19,9 +19,14 @@ package com.rtbishop.look4sat.core.domain.utility
 
 import com.rtbishop.look4sat.core.domain.predict.DEG2RAD
 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 +53,27 @@ 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)
 }

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) {
-        val years = listOf(1900, 1984, 1994, 2016, 2022, 2024, 2042, 2048)
-        val answers = listOf(false, true, false, true, false, true, false, true)
+    fun `isLeapYear returns correct results`() {
+        val years = listOf(1900, 1984, 1994, 2000, 2016, 2022, 2024, 2042, 2048, 2100)
+        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/presentation/src/main/java/com/rtbishop/look4sat/core/presentation/Components.kt

@@ -48,6 +48,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.font.FontWeight
@@ -151,16 +152,17 @@ fun RowScope.NextPassRow(pass: OrbitalPass, modifier: Modifier = Modifier, isUtc
                     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 = "${pass.maxElevation}°",
-                    color = MaterialTheme.colorScheme.primary
+                    color = elevColor
                 )
             }
             Row(
@@ -178,12 +180,6 @@ fun RowScope.NextPassRow(pass: OrbitalPass, modifier: Modifier = Modifier, isUtc
                     horizontalArrangement = Arrangement.Center,
                     verticalAlignment = Alignment.CenterVertically
                 ) {
-                    Icon(
-                        painter = painterResource(R.drawable.ic_altitude),
-                        contentDescription = null,
-                        modifier = Modifier.size(16.dp)
-                    )
-                    Spacer(modifier = Modifier.width(4.dp))
                     Text(text = "${pass.altitude} km", fontSize = 15.sp)
                 }
                 Text(
@@ -212,14 +208,11 @@ fun CardButton(onClick: () -> Unit, text: String, modifier: Modifier = Modifier)
 }
 
 @Composable
-fun IconCard(action: () -> Unit, resId: Int, modifier: Modifier = Modifier) {
-    ElevatedCard(modifier = Modifier.size(48.dp)) {
-        Box(
-            modifier = Modifier
-                .clickable(onClick = action)
-                .fillMaxSize(),
-            contentAlignment = Alignment.Center
-        ) { Icon(painter = painterResource(resId), contentDescription = null, modifier = modifier) }
+fun IconCard(action: () -> Unit, resId: Int, modifier: Modifier = Modifier, enabled: Boolean = true) {
+    ElevatedCard(modifier = Modifier.size(48.dp), enabled = enabled, onClick = action) {
+        Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+            Icon(painter = painterResource(resId), contentDescription = null, modifier = modifier)
+        }
     }
 }
 
@@ -385,3 +378,12 @@ fun TopBar(
         TopBar { startAction(); topInfo(); bottomInfo(); endAction() }
     }
 }
+
+@Composable
+fun elevationColor(elevation: Double): Color {
+    return when {
+        elevation < 15.0 -> Color(0xFFEF5350) // soft red for low elevation
+        elevation < 45.0 -> MaterialTheme.colorScheme.primary // accent yellow for normal
+        else -> Color(0xFF66BB6A) // soft green for high elevation
+    }
+}

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

@@ -30,10 +30,7 @@ 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)
-
-    @Serializable
-    data class RadioControl(val catNum: Int = 0, val aosTime: Long = 0L) : Screen(0, 0)
+    data object Radar : Screen(R.drawable.ic_radar, R.string.nav_radar)
 
     @Serializable
     data object Map : Screen(R.drawable.ic_map, R.string.nav_map)

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_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-tr/strings.xml

@@ -31,7 +31,7 @@
     <!-- 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 saat aralığı</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 +66,7 @@
     <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 +93,7 @@
     <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>
@@ -182,7 +182,7 @@
     <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_outro_title">Teşekkür etmek istiyorum</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-zh/strings.xml

@@ -130,8 +130,16 @@
     <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_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)</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

@@ -49,10 +49,9 @@
         \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)
-        \n* Added DeepSpace passes filter option to the dialog
-        \n* Fixed the radar blip disappearing while eclipsed
-        \n* Fixed (hopefully) the refresh indicator being stuck
+        * Merged RadarScreen and RadioControlScreen functionality
+        \n\n* Added SSTV image decoding functionality to RadarScreen
+        \n\n* Added colored elevation and decay check to satellite passes
     </string>
 
     <!-- Radar screen -->
@@ -181,15 +180,18 @@
     <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_outro_title">I would like to say thanks to</string>
     <string name="prefs_outro_thanks" translatable="false">
-        • Look4Sat users and contributors!
-        \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)</string>
+        * Look4Sat users and contributors!
+        \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 and Robot36 contributors!
+    </string>
     <string name="prefs_outro_license">The app comes with no warranty</string>
 
 </resources>

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

@@ -1,4 +1,3 @@
-* 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
+* Merged RadarScreen and RadioControlScreen functionality
+* Added SSTV image decoding functionality to RadarScreen
+* Added colored elevation and decay check to satellite passes

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(
-        modelClass = MapViewModel::class.java,
-        factory = MapViewModel.Factory
-    )
+    val context = LocalContext.current
+    val container = (context.applicationContext as IContainerProvider).getMainContainer()
+    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

@@ -18,15 +18,15 @@
 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
@@ -49,8 +49,10 @@ import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
 import java.util.Date
 
-class MapViewModel(private val satelliteRepo: ISatelliteRepo, private val settingsRepo: ISettingsRepo) :
-    ViewModel() {
+class MapViewModel(
+    private val satelliteRepo: ISatelliteRepo,
+    private val settingsRepo: ISettingsRepo
+) : ViewModel() {
 
     private val stationPos = settingsRepo.stationPosition.value
     private val defaultPass = getDefaultPass()
@@ -74,7 +76,8 @@ 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 +127,16 @@ 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)
                 }
             }
         }
@@ -177,10 +186,12 @@ 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 +199,11 @@ 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
             )
         }
     }
@@ -286,11 +301,12 @@ 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 {
-            val applicationKey = ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY
+        fun factory(container: IMainContainer) = viewModelFactory {
             initializer {
-                val container = (this[applicationKey] as IContainerProvider).getMainContainer()
-                MapViewModel(container.satelliteRepo, container.settingsRepo)
+                MapViewModel(
+                    satelliteRepo = container.satelliteRepo,
+                    settingsRepo = container.settingsRepo
+                )
             }
         }
     }

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

@@ -43,6 +43,7 @@ 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 +55,7 @@ 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.elevationColor
 
 private val allModes = listOf(
     "AFSK", "AFSK S-Net", "AFSK SALSAT", "AHRPT", "AM", "APT", "BPSK", "BPSK PMT-A3",
@@ -96,7 +98,8 @@ internal fun PassesDialog(
             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),
@@ -117,6 +120,7 @@ private fun SliderRow(
     valueResId: Int,
     valueRange: ClosedFloatingPointRange<Float>,
     steps: Int = 0,
+    accentColor: Color = MaterialTheme.colorScheme.primary,
     onChange: (Float) -> Unit
 ) {
     Column(
@@ -137,14 +141,14 @@ private fun SliderRow(
             Icon(
                 painter = painterResource(id = valueResId),
                 contentDescription = null,
-                tint = MaterialTheme.colorScheme.primary,
+                tint = accentColor,
                 modifier = Modifier.size(20.dp)
             )
             Text(
                 text = displayValue,
                 fontSize = 18.sp,
                 fontWeight = FontWeight.Medium,
-                color = MaterialTheme.colorScheme.primary
+                color = accentColor
             )
         }
         Slider(value = value.toFloat(), onValueChange = onChange, valueRange = valueRange, steps = steps)

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
@@ -60,6 +64,7 @@ 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
@@ -67,8 +72,10 @@ 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.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(
-        modelClass = PassesViewModel::class.java,
-        factory = PassesViewModel.Factory
-    )
+    val context = LocalContext.current
+    val container = (context.applicationContext as IContainerProvider).getMainContainer()
+    val viewModel: PassesViewModel = viewModel(factory = PassesViewModel.factory(container))
     val uiState = viewModel.uiState.collectAsStateWithLifecycle().value
     PassesScreen(uiState, viewModel::onAction, navigateToRadar)
 }
@@ -118,7 +124,6 @@ private fun PassesScreen(
             onAction(PassesAction.DismissWhatsNew)
         }
     }
-    val gridState = rememberLazyGridState()
     ScreenColumn(
         topBar = { isVerticalLayout ->
             TopBar(
@@ -142,9 +147,11 @@ 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) },
-            gridState = gridState
+            onAction = onAction
         )
     }
 }
@@ -155,9 +162,11 @@ 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,
-    gridState: LazyGridState
+    onAction: (PassesAction) -> Unit
 ) {
     val isVerticalLayout = isVerticalLayout()
     val refreshState = rememberPullToRefreshState()
@@ -165,7 +174,7 @@ private fun PassesList(
         PullToRefreshBox(
             isRefreshing = isRefreshing,
             state = refreshState,
-            onRefresh = refreshPasses,
+            onRefresh = { onAction(PassesAction.RefreshPasses) },
             indicator = {
                 PullToRefreshDefaults.Indicator(
                     state = refreshState,
@@ -179,19 +188,37 @@ private fun PassesList(
             if (passes.isEmpty()) {
                 EmptyListCard(message = stringResource(R.string.pass_empty_list_message))
             } else {
-                LazyVerticalGrid(
-                    state = gridState,
-                    columns = GridCells.Adaptive(320.dp),
-                    modifier = Modifier.fillMaxSize()
-                ) {
-                    items(items = passes, key = { item -> item.catNum + item.aosTime }) { pass ->
-                        PassItem(
-                            pass = pass,
-                            navigateToRadar = navigateToRadar,
-                            modifier = Modifier.animateItem(),
-                            isVerticalLayout = isVerticalLayout,
-                            isUtc = isUtc
-                        )
+                AnimatedContent(
+                    targetState = focusedCatNum,
+                    transitionSpec = { fadeIn(tween(200)) togetherWith fadeOut(tween(200)) },
+                    label = "PassesFocusTransition"
+                ) { targetFocus ->
+                    LazyVerticalGrid(columns = GridCells.Adaptive(320.dp), modifier = Modifier.fillMaxSize()) {
+                        for ((dateLabel, dayPasses) in groupedPasses) {
+                            val headerVisible = targetFocus == null || dayPasses.any { it.catNum == targetFocus }
+                            if (headerVisible) {
+                                stickyHeader(key = "header_$dateLabel") {
+                                    val (rise, set) = sunTimes[dateLabel] ?: ("--:--" to "--:--")
+                                    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 +226,45 @@ 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() {
@@ -230,15 +296,15 @@ private fun PassItem(
     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 }
     }
-    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) }
@@ -266,16 +332,17 @@ private fun PassItem(
                     overflow = TextOverflow.Ellipsis,
                     color = MaterialTheme.colorScheme.onSurface
                 )
+                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 = "${pass.maxElevation}°",
-                    color = MaterialTheme.colorScheme.primary
+                    color = elevColor
                 )
             }
             Row(
@@ -295,7 +362,7 @@ private fun PassItem(
                             color = MaterialTheme.colorScheme.onSurface
                         )
                     } else {
-                        Text(text = aosDateStr, fontSize = 15.sp, color = MaterialTheme.colorScheme.onSurface)
+                        Text(text = durationStr, fontSize = 15.sp, color = MaterialTheme.colorScheme.onSurface)
                     }
                 }
                 Row(
@@ -303,13 +370,6 @@ private fun PassItem(
                     horizontalArrangement = Arrangement.Center,
                     verticalAlignment = Alignment.CenterVertically
                 ) {
-                    Icon(
-                        painter = painterResource(id = R.drawable.ic_altitude),
-                        contentDescription = null,
-                        modifier = Modifier.size(16.dp),
-                        tint = MaterialTheme.colorScheme.onSurface
-                    )
-                    Spacer(modifier = Modifier.width(4.dp))
                     Text(text = "${pass.altitude} km", fontSize = 15.sp, color = MaterialTheme.colorScheme.onSurface)
                 }
                 Row(

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

@@ -32,7 +32,10 @@ data class PassesState(
     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 {
@@ -42,4 +45,6 @@ sealed interface PassesAction {
     data object RefreshPasses : PassesAction
     data object TogglePassesDialog : PassesAction
     data object ToggleRadiosDialog : PassesAction
+    data class FocusCatNum(val catNum: Int) : PassesAction
+    data object ClearFocus : PassesAction
 }

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

@@ -18,13 +18,13 @@
 package com.rtbishop.look4sat.feature.passes
 
 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.model.PassesSettings
+import com.rtbishop.look4sat.core.domain.predict.CelestialComputer
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
-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.round
@@ -37,6 +37,10 @@ import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
+import java.text.SimpleDateFormat
+import java.util.Date
+import java.util.Locale
+import java.util.TimeZone
 
 class PassesViewModel(
     private val satelliteRepo: ISatelliteRepo,
@@ -64,33 +68,36 @@ class PassesViewModel(
                 _uiState.update { it.copy(isRefreshing = calculating) }
             }
         }
-        // Local tick loop — computes pass progress and countdown timer every second
-        viewModelScope.launch {
-            while (isActive) {
-                val timeNow = System.currentTimeMillis()
-                val showDeepSpace = _uiState.value.showDeepSpace
-                val allPasses = satelliteRepo.passes.value
-                val filtered = if (showDeepSpace) allPasses else allPasses.filter { !it.isDeepSpace }
-                val processed = computePassProgress(filtered, timeNow)
-                val (nextPass, nextTime, isAos) = resolveNextPass(processed, timeNow)
-                _uiState.update {
-                    it.copy(
-                        itemsList = processed,
-                        nextPass = nextPass,
-                        nextTime = nextTime,
-                        isNextTimeAos = isAos
-                    )
-                }
-                delay(1000)
-            }
-        }
+        // React to settings changes: update UTC flag and whatsNew
         viewModelScope.launch {
             settingsRepo.otherSettings.collectLatest { settings ->
-                _uiState.update {
-                    it.copy(
-                        isUtc = settings.stateOfUtc,
-                        shouldSeeWhatsNew = settings.shouldSeeWhatsNew
-                    )
+                _uiState.update { it.copy(isUtc = settings.stateOfUtc, shouldSeeWhatsNew = settings.shouldSeeWhatsNew) }
+            }
+        }
+        // Main tick loop: reacts to new passes, then ticks every second
+        viewModelScope.launch {
+            satelliteRepo.passes.collectLatest { allPasses ->
+                while (isActive) {
+                    val timeNow = System.currentTimeMillis()
+                    val isUtc = _uiState.value.isUtc
+                    val showDeepSpace = _uiState.value.showDeepSpace
+                    val filtered = allPasses
+                        .let { if (showDeepSpace) it else it.filter { pass -> !pass.isDeepSpace } }
+                    val processed = computePassProgress(filtered, timeNow)
+                    val (nextPass, nextTime, isAos) = resolveNextPass(processed, timeNow)
+                    val sunTimes = computeSunTimes(processed, isUtc)
+                    val grouped = groupPasses(processed, isUtc)
+                    _uiState.update {
+                        it.copy(
+                            itemsList = processed,
+                            groupedPasses = grouped,
+                            sunTimes = sunTimes,
+                            nextPass = nextPass,
+                            nextTime = nextTime,
+                            isNextTimeAos = isAos
+                        )
+                    }
+                    delay(1000)
                 }
             }
         }
@@ -101,18 +108,56 @@ class PassesViewModel(
             PassesAction.DismissWhatsNew -> settingsRepo.setWhatsNewDismissed()
             is PassesAction.FilterPasses ->
                 applyFilter(action.hoursAhead, action.minElevation, action.showDeepSpace, _uiState.value.modes)
-
             is PassesAction.FilterRadios ->
                 applyFilter(_uiState.value.hours, _uiState.value.elevation, _uiState.value.showDeepSpace, action.modes)
             PassesAction.RefreshPasses -> refreshPasses()
             PassesAction.TogglePassesDialog ->
                 _uiState.update { it.copy(isPassesDialogShown = !it.isPassesDialogShown) }
-
             PassesAction.ToggleRadiosDialog ->
                 _uiState.update { it.copy(isRadiosDialogShown = !it.isRadiosDialogShown) }
+            is PassesAction.FocusCatNum -> _uiState.update { it.copy(focusedCatNum = action.catNum) }
+            PassesAction.ClearFocus -> _uiState.update { it.copy(focusedCatNum = null) }
         }
     }
 
+    // Computes sunrise/sunset strings for each unique calendar day in the pass list, plus today for DeepSpace
+    private fun computeSunTimes(passes: List<OrbitalPass>, isUtc: Boolean): Map<String, Pair<String, String>> {
+        val stationPos = settingsRepo.stationPosition.value
+        val tz = if (isUtc) TimeZone.getTimeZone("UTC") else TimeZone.getDefault()
+        val sdfDate = SimpleDateFormat("EEE, dd MMM yyyy", Locale.ENGLISH).also { it.timeZone = tz }
+        val sdfTime = SimpleDateFormat("HH:mm", Locale.ENGLISH).also { it.timeZone = tz }
+        val result = LinkedHashMap<String, Pair<String, String>>()
+        // DeepSpace group always shows today's sun times
+        if (passes.any { it.isDeepSpace }) {
+            val riseSet = CelestialComputer.findSunRiseSet(stationPos, System.currentTimeMillis())
+            val rise = if (riseSet.riseTimeMillis > 0) sdfTime.format(Date(riseSet.riseTimeMillis)) else "--:--"
+            val set = if (riseSet.setTimeMillis > 0) sdfTime.format(Date(riseSet.setTimeMillis)) else "--:--"
+            result["DeepSpace (period >225min)"] = rise to set
+        }
+        for (pass in passes) {
+            if (pass.isDeepSpace) continue
+            val label = sdfDate.format(Date(pass.aosTime))
+            if (label in result) continue
+            val riseSet = CelestialComputer.findSunRiseSet(stationPos, pass.aosTime)
+            val rise = if (riseSet.riseTimeMillis > 0) sdfTime.format(Date(riseSet.riseTimeMillis)) else "--:--"
+            val set = if (riseSet.setTimeMillis > 0) sdfTime.format(Date(riseSet.setTimeMillis)) else "--:--"
+            result[label] = rise to set
+        }
+        return result
+    }
+
+    private fun groupPasses(passes: List<OrbitalPass>, isUtc: Boolean): Map<String, List<OrbitalPass>> {
+        val tz = if (isUtc) TimeZone.getTimeZone("UTC") else TimeZone.getDefault()
+        val sdfDate = SimpleDateFormat("EEE, dd MMM yyyy", Locale.ENGLISH).also { it.timeZone = tz }
+        val ordered = LinkedHashMap<String, List<OrbitalPass>>()
+        val deepSpace = passes.filter { it.isDeepSpace }
+        if (deepSpace.isNotEmpty()) ordered["DeepSpace (period >225min)"] = deepSpace
+        passes.filter { !it.isDeepSpace }
+            .groupByTo(LinkedHashMap()) { sdfDate.format(Date(it.aosTime)) }
+            .forEach { (k, v) -> ordered[k] = v }
+        return ordered
+    }
+
     /** Computes live progress for each pass, filtering out expired ones. */
     private fun computePassProgress(passList: List<OrbitalPass>, time: Long): List<OrbitalPass> {
         val result = ArrayList<OrbitalPass>(passList.size)
@@ -169,11 +214,12 @@ class PassesViewModel(
     }
 
     companion object {
-        val Factory: ViewModelProvider.Factory = viewModelFactory {
-            val applicationKey = ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY
+        fun factory(container: IMainContainer) = viewModelFactory {
             initializer {
-                val container = (this[applicationKey] as IContainerProvider).getMainContainer()
-                PassesViewModel(container.satelliteRepo, container.settingsRepo)
+                PassesViewModel(
+                    satelliteRepo = container.satelliteRepo,
+                    settingsRepo = container.settingsRepo
+                )
             }
         }
     }

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarScreen.kt

@@ -17,15 +17,17 @@
  */
 package com.rtbishop.look4sat.feature.radar
 
+import android.Manifest
+import android.content.pm.PackageManager
+import androidx.activity.compose.rememberLauncherForActivityResult
+import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.animation.core.LinearEasing
 import androidx.compose.animation.core.RepeatMode
 import androidx.compose.animation.core.animateFloat
 import androidx.compose.animation.core.infiniteRepeatable
 import androidx.compose.animation.core.rememberInfiniteTransition
 import androidx.compose.animation.core.tween
-import androidx.compose.foundation.background
 import androidx.compose.foundation.border
-import androidx.compose.foundation.clickable
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -33,61 +35,66 @@ import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.lazy.LazyColumn
-import androidx.compose.foundation.lazy.items
+import androidx.compose.foundation.pager.HorizontalPager
+import androidx.compose.foundation.pager.rememberPagerState
 import androidx.compose.material3.ElevatedCard
-import androidx.compose.material3.HorizontalDivider
-import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.PrimaryTabRow
+import androidx.compose.material3.Tab
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.draw.rotate
 import androidx.compose.ui.keepScreenOn
-import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
-import androidx.compose.ui.semantics.contentDescription
-import androidx.compose.ui.semantics.semantics
-import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.text.style.TextAlign
-import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
+import androidx.core.content.ContextCompat
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
-import com.rtbishop.look4sat.core.domain.model.SatRadio
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
+import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
 import com.rtbishop.look4sat.core.domain.utility.toDegrees
 import com.rtbishop.look4sat.core.presentation.EmptyListCard
 import com.rtbishop.look4sat.core.presentation.IconCard
-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.TimerRow
 import com.rtbishop.look4sat.core.presentation.TopBar
 import com.rtbishop.look4sat.core.presentation.getDefaultPass
-import com.rtbishop.look4sat.core.presentation.infiniteMarquee
 import com.rtbishop.look4sat.core.presentation.isVerticalLayout
 import com.rtbishop.look4sat.core.presentation.layoutPadding
+import kotlinx.coroutines.launch
+
+private enum class RadarPage(val title: String) {
+    Transceivers("Transceivers"),
+    Sstv("SSTV")
+}
 
 @Composable
-fun RadarDestination(
-    catNum: Int = 0,
-    aosTime: Long = 0L,
-    navigateUp: () -> Unit,
-    navigateToRadioControl: (Int, Long) -> Unit = { _, _ -> }
-) {
-    val viewModel = viewModel(
-        modelClass = RadarViewModel::class.java,
-        key = "$catNum-$aosTime",
-        factory = RadarViewModel.factory(catNum, aosTime)
-    )
+fun RadarDestination(navigateUp: () -> Unit) {
+    val context = LocalContext.current
+    val container = (context.applicationContext as IContainerProvider).getMainContainer()
+    val viewModel: RadarViewModel = viewModel(factory = RadarViewModel.factory(container))
     val uiState by viewModel.uiState.collectAsStateWithLifecycle()
-    RadarScreen(uiState, viewModel::onAction, navigateUp, navigateToRadioControl)
+    // Sync actual permission state on every recomposition so it survives screen re-entry
+    val hasPermission = ContextCompat.checkSelfPermission(
+        context, Manifest.permission.RECORD_AUDIO
+    ) == PackageManager.PERMISSION_GRANTED
+    LaunchedEffect(hasPermission) {
+        viewModel.onAction(RadarAction.SstvPermissionResult(hasPermission))
+    }
+    val permissionLauncher = rememberLauncherForActivityResult(
+        ActivityResultContracts.RequestPermission()
+    ) { granted -> viewModel.onAction(RadarAction.SstvPermissionResult(granted)) }
+    RadarScreen(uiState, viewModel::onAction, navigateUp, requestMicPermission = {
+        permissionLauncher.launch(Manifest.permission.RECORD_AUDIO)
+    })
 }
 
 @Composable
@@ -95,20 +102,11 @@ private fun RadarScreen(
     uiState: RadarState,
     onAction: (RadarAction) -> Unit,
     navigateUp: () -> Unit,
-    navigateToRadioControl: (Int, Long) -> Unit
+    requestMicPermission: () -> Unit
 ) {
     val upcomingPass = uiState.currentPass ?: getDefaultPass()
-    LaunchedEffect(uiState.isLos) { if (uiState.isLos) navigateUp() }
-
     val addToCalendar: () -> Unit = {
-        uiState.currentPass?.let { pass ->
-            onAction(RadarAction.AddToCalendar(pass.name, pass.aosTime, pass.losTime))
-        }
-    }
-    val openRadioControl: () -> Unit = {
-        uiState.currentPass?.let { pass ->
-            navigateToRadioControl(pass.catNum, pass.aosTime)
-        }
+        uiState.currentPass?.let { onAction(RadarAction.AddToCalendar(it.name, it.aosTime, it.losTime)) }
     }
     Column(
         modifier = Modifier
@@ -119,26 +117,70 @@ private fun RadarScreen(
         val isVertical = isVerticalLayout()
         if (isVertical) {
             TopBar {
-                IconCard(action = addToCalendar, resId = R.drawable.ic_calendar)
+                IconCard(action = navigateUp, resId = R.drawable.ic_back)
                 TimerRow(timeString = uiState.currentTime, isTimeAos = uiState.isTimeAos)
-                IconCard(action = openRadioControl, resId = R.drawable.ic_radios)
+                IconCard(action = addToCalendar, resId = R.drawable.ic_calendar)
             }
             TopBar { NextPassRow(pass = upcomingPass, isUtc = uiState.isUtc) }
         } else {
             TopBar {
-                IconCard(action = addToCalendar, resId = R.drawable.ic_calendar)
+                IconCard(action = navigateUp, resId = R.drawable.ic_back)
                 TimerRow(timeString = uiState.currentTime, isTimeAos = uiState.isTimeAos)
                 NextPassRow(pass = upcomingPass, modifier = Modifier.weight(1f), isUtc = uiState.isUtc)
-                IconCard(action = openRadioControl, resId = R.drawable.ic_radios)
+                IconCard(action = addToCalendar, resId = R.drawable.ic_calendar)
             }
         }
         if (isVertical) {
             RadarCard(uiState, Modifier.weight(1f))
-            TransmittersCard(uiState.transmitters, uiState.selectedTransmitterUuid, onAction, Modifier.weight(1f))
+            PagerCard(uiState, onAction, requestMicPermission, Modifier.weight(1f))
         } else {
             Row(horizontalArrangement = Arrangement.spacedBy(6.dp)) {
                 RadarCard(uiState, Modifier.weight(1f))
-                TransmittersCard(uiState.transmitters, uiState.selectedTransmitterUuid, onAction, Modifier.weight(1f))
+                PagerCard(uiState, onAction, requestMicPermission, Modifier.weight(1f))
+            }
+        }
+    }
+}
+
+@Composable
+private fun PagerCard(
+    uiState: RadarState,
+    onAction: (RadarAction) -> Unit,
+    requestMicPermission: () -> Unit,
+    modifier: Modifier = Modifier
+) {
+    val pages = RadarPage.entries
+    val pagerState = rememberPagerState(pageCount = { pages.size })
+    val coroutineScope = rememberCoroutineScope()
+
+    ElevatedCard(modifier = modifier) {
+        Column(modifier = Modifier.fillMaxSize()) {
+            PrimaryTabRow(selectedTabIndex = pagerState.currentPage) {
+                pages.forEachIndexed { index, page ->
+                    Tab(
+                        selected = pagerState.currentPage == index,
+                        onClick = { coroutineScope.launch { pagerState.animateScrollToPage(index) } },
+                        text = { Text(text = page.title, maxLines = 1, overflow = TextOverflow.Ellipsis) }
+                    )
+                }
+            }
+            HorizontalPager(
+                state = pagerState,
+                modifier = Modifier.fillMaxSize()
+            ) { pageIndex ->
+                when (pages[pageIndex]) {
+                    RadarPage.Transceivers -> TransceiversPage(
+                        transceivers = uiState.transmitters,
+                        selectedUuid = uiState.selectedTransmitterUuid,
+                        radioControl = uiState.radioControl,
+                        onAction = onAction
+                    )
+                    RadarPage.Sstv -> SstvPage(
+                        sstv = uiState.sstv,
+                        onAction = onAction,
+                        requestMicPermission = requestMicPermission
+                    )
+                }
             }
         }
     }
@@ -180,7 +222,9 @@ private fun RadarCard(uiState: RadarState, modifier: Modifier = Modifier) {
                     azimElev = uiState.orientationValues,
                     shouldShowSweep = uiState.shouldShowSweep,
                     shouldUseCompass = uiState.shouldUseCompass,
-                    modifier = Modifier.align(Alignment.Center)
+                    modifier = Modifier.align(Alignment.Center),
+                    sunPosition = uiState.sunPosition,
+                    moonPosition = uiState.moonPosition,
                 )
                 PositionOverlay(position)
             }
@@ -251,180 +295,3 @@ private fun RadarLabel(
     }
 }
 
-@Composable
-private fun TransmittersCard(
-    transmitters: List<SatRadio>,
-    selectedUuid: String?,
-    onAction: (RadarAction) -> Unit,
-    modifier: Modifier = Modifier
-) {
-    ElevatedCard(modifier = modifier) {
-        if (transmitters.isEmpty()) {
-            EmptyTransmittersContent()
-        } else {
-            TransmittersList(
-                transmitters = transmitters,
-                selectedUuid = selectedUuid,
-                onSelect = { uuid ->
-                    if (selectedUuid != null) {
-                        onAction(RadarAction.SelectTransmitter(uuid))
-                    }
-                }
-            )
-        }
-    }
-}
-
-@Composable
-private fun EmptyTransmittersContent() {
-    Box(contentAlignment = Alignment.Center, modifier = Modifier.fillMaxSize()) {
-        Column(
-            horizontalAlignment = Alignment.CenterHorizontally,
-            verticalArrangement = Arrangement.spacedBy(24.dp),
-            modifier = Modifier.padding(32.dp)
-        ) {
-            Text(text = """¯\_(ツ)_/¯""", fontSize = 32.sp)
-            Text(
-                text = stringResource(R.string.empty_list_message),
-                fontSize = 21.sp,
-                textAlign = TextAlign.Center
-            )
-            Text(
-                text = stringResource(R.string.radar_no_data),
-                fontSize = 18.sp,
-                textAlign = TextAlign.Center
-            )
-        }
-    }
-}
-
-@Composable
-private fun TransmittersList(
-    transmitters: List<SatRadio>,
-    selectedUuid: String?,
-    onSelect: (String) -> Unit
-) {
-    LazyColumn(modifier = Modifier.fillMaxSize()) {
-        items(items = transmitters, key = { it.uuid }) { radio ->
-            TransmitterItem(
-                radio = radio,
-                isClickable = selectedUuid != null,
-                isSelected = radio.uuid == selectedUuid,
-                onClick = { onSelect(radio.uuid) }
-            )
-        }
-    }
-}
-
-@Preview
-@Composable
-private fun TransmitterItemPreview() {
-    val transmitter = SatRadio(
-        "", "Extremely powerful transmitter", true, 10000000000L, 10000000000L,
-        null, 10000000000L, 10000000000L, "FSK AX.100 Mode 5", true, 0
-    )
-    MainTheme { TransmitterItem(transmitter, isClickable = true, isSelected = true, onClick = {}) }
-}
-
-@Composable
-private fun TransmitterItem(
-    radio: SatRadio,
-    isClickable: Boolean,
-    isSelected: Boolean,
-    onClick: () -> Unit
-) {
-    val title = if (radio.isInverted) "INVERTED: ${radio.info}" else radio.info
-    val fullTitle = "$title - (${radio.downlinkMode ?: "--"}/${radio.uplinkMode ?: "--"})"
-    Column(
-        modifier = Modifier
-            .fillMaxWidth()
-            .then(if (isClickable) Modifier.clickable { onClick() } else Modifier)
-    ) {
-        Column(
-            horizontalAlignment = Alignment.CenterHorizontally,
-            verticalArrangement = Arrangement.spacedBy(6.dp),
-            modifier = Modifier
-                .fillMaxWidth()
-                .background(MaterialTheme.colorScheme.surface)
-                .padding(horizontal = 8.dp, vertical = 6.dp)
-        ) {
-            Box {
-                Text(
-                    text = fullTitle,
-                    textAlign = TextAlign.Center,
-                    color = MaterialTheme.colorScheme.onSurface,
-                    modifier = Modifier
-                        .fillMaxWidth()
-                        .padding(horizontal = 6.dp)
-                        .infiniteMarquee()
-                )
-                if (isSelected) {
-                    Icon(
-                        painter = painterResource(id = R.drawable.ic_radios),
-                        contentDescription = null,
-                        tint = MaterialTheme.colorScheme.primary,
-                        modifier = Modifier.background(color = MaterialTheme.colorScheme.surface)
-                    )
-                }
-            }
-            FrequencyRow(radio = radio, isDownlink = true)
-            FrequencyRow(radio = radio, isDownlink = false)
-        }
-        HorizontalDivider(thickness = 2.dp, color = MaterialTheme.colorScheme.background)
-    }
-}
-
-@Composable
-private fun FrequencyRow(radio: SatRadio, isDownlink: Boolean) {
-    Row(verticalAlignment = Alignment.CenterVertically, modifier = Modifier.fillMaxWidth()) {
-        val desc = if (isDownlink) stringResource(R.string.radar_downlink)
-        else stringResource(R.string.radar_uplink)
-        Text(
-            text = if (isDownlink) "D:" else "U:",
-            textAlign = TextAlign.Center,
-            fontSize = 18.sp,
-            color = MaterialTheme.colorScheme.onSurface,
-            modifier = Modifier
-                .size(24.dp)
-                .semantics { contentDescription = desc }
-        )
-        FrequencyText(
-            frequency = if (isDownlink) radio.downlinkLow else radio.uplinkLow,
-            modifier = Modifier.weight(1f)
-        )
-        Text(
-            text = "-",
-            textAlign = TextAlign.Center,
-            fontSize = 21.sp,
-            fontWeight = FontWeight.Bold,
-            color = MaterialTheme.colorScheme.primary
-        )
-        FrequencyText(
-            frequency = if (isDownlink) radio.downlinkHigh else radio.uplinkHigh,
-            modifier = Modifier.weight(1f)
-        )
-        Icon(
-            painter = painterResource(id = R.drawable.ic_arrow),
-            tint = MaterialTheme.colorScheme.onSurface,
-            contentDescription = null,
-            modifier = Modifier
-                .rotate(if (isDownlink) 90f else -90f)
-                .size(24.dp)
-        )
-    }
-}
-
-@Composable
-private fun FrequencyText(frequency: Long?, modifier: Modifier = Modifier) {
-    val text = frequency?.let {
-        stringResource(id = R.string.radar_link_low, it / 1000000f)
-    } ?: stringResource(R.string.radar_no_link)
-    Text(
-        text = text,
-        textAlign = TextAlign.Center,
-        fontSize = 21.sp,
-        fontWeight = FontWeight.Bold,
-        color = MaterialTheme.colorScheme.primary,
-        modifier = modifier
-    )
-}

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarState.kt

@@ -18,8 +18,29 @@
 package com.rtbishop.look4sat.feature.radar
 
 import com.rtbishop.look4sat.core.domain.model.SatRadio
+import com.rtbishop.look4sat.core.domain.predict.CelestialComputer
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
+import com.rtbishop.look4sat.core.domain.sstv.SstvFrame
+
+data class RadioPanelState(
+    val label: String = "",
+    val isConnected: Boolean = false,
+    val frequencyHz: Long? = null,
+    val frequencyDisplay: String = "---",
+    val mode: String? = null
+)
+
+data class RadioControlSubState(
+    val txPanel: RadioPanelState = RadioPanelState("TX (Uplink)"),
+    val rxPanel: RadioPanelState = RadioPanelState("RX (Downlink)"),
+    val transponders: List<SatRadio> = emptyList(),
+    val selectedTransponderUuid: String? = null,
+    val txBaseFrequencyHz: Long? = null,
+    val ctcssTone: Double? = null,
+    val isTracking: Boolean = false,
+    val errorMessage: String? = null
+)
 
 data class RadarState(
     val currentPass: OrbitalPass? = null,
@@ -32,12 +53,43 @@ data class RadarState(
     val satTrack: List<OrbitalPos> = emptyList(),
     val shouldShowSweep: Boolean = false,
     val shouldUseCompass: Boolean = false,
+    val sunPosition: CelestialComputer.SunPosition? = null,
+    val moonPosition: CelestialComputer.MoonPosition? = null,
     val transmitters: List<SatRadio> = emptyList(),
     val selectedTransmitterUuid: String? = null,
-    val selectedFrequency: Long? = null
+    val selectedFrequency: Long? = null,
+    val radioControl: RadioControlSubState = RadioControlSubState(),
+    val sstv: SstvSubState = SstvSubState()
+)
+
+enum class SstvStatus { Idle, Recording, Saving }
+
+data class SstvSubState(
+    val status: SstvStatus = SstvStatus.Idle,
+    val hasPermission: Boolean = false,
+    val selectedMode: String = "Auto",
+    val supportedModes: List<String> = emptyList(),
+    val currentFrame: SstvFrame? = null
 )
 
 sealed interface RadarAction {
     data class AddToCalendar(val name: String, val aosTime: Long, val losTime: Long) : RadarAction
     data class SelectTransmitter(val uuid: String) : RadarAction
+
+    // Radio control actions
+    data class SelectTransponder(val uuid: String) : RadarAction
+    data class SetTxFrequency(val frequencyHz: Long) : RadarAction
+    data class AdjustTxFrequency(val deltaHz: Long) : RadarAction
+    data class SetCtcssTone(val toneHz: Double?) : RadarAction
+    data object ToggleTracking : RadarAction
+    data object ConnectRadios : RadarAction
+    data object DisconnectRadios : RadarAction
+
+    // SSTV actions
+    data object SstvStartRecording : RadarAction
+    data object SstvStopRecording : RadarAction
+    data object SstvSaveImage : RadarAction
+    data object SstvReset : RadarAction
+    data class SstvSelectMode(val modeName: String) : RadarAction
+    data class SstvPermissionResult(val granted: Boolean) : RadarAction
 }

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarView.kt

@@ -32,11 +32,13 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.Path
 import androidx.compose.ui.graphics.PathEffect
 import androidx.compose.ui.graphics.PathMeasure
 import androidx.compose.ui.graphics.ShaderBrush
+import androidx.compose.ui.graphics.ColorFilter
 import androidx.compose.ui.graphics.StampedPathEffectStyle
 import androidx.compose.ui.graphics.SweepGradientShader
 import androidx.compose.ui.graphics.drawscope.DrawScope
@@ -44,14 +46,19 @@ import androidx.compose.ui.graphics.drawscope.Fill
 import androidx.compose.ui.graphics.drawscope.Stroke
 import androidx.compose.ui.graphics.drawscope.rotate
 import androidx.compose.ui.graphics.drawscope.translate
+import androidx.compose.ui.graphics.drawscope.withTransform
+import androidx.compose.ui.graphics.painter.Painter
+import androidx.compose.ui.res.painterResource
 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.sp
+import com.rtbishop.look4sat.core.domain.predict.CelestialComputer
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPos
 import com.rtbishop.look4sat.core.domain.predict.PI_2
 import com.rtbishop.look4sat.core.domain.utility.toRadians
+import com.rtbishop.look4sat.core.presentation.R
 import kotlin.math.cos
 import kotlin.math.sin
 
@@ -66,11 +73,14 @@ fun RadarViewCompose(
     azimElev: Pair<Float, Float>,
     shouldShowSweep: Boolean,
     shouldUseCompass: Boolean,
-    modifier: Modifier = Modifier
+    modifier: Modifier = Modifier,
+    sunPosition: CelestialComputer.SunPosition? = null,
+    moonPosition: CelestialComputer.MoonPosition? = null,
 ) {
-    val radarColor = MaterialTheme.colorScheme.secondary
-    val trackColor = MaterialTheme.colorScheme.primary
     val aimColor = MaterialTheme.colorScheme.error
+    val primaryColor = MaterialTheme.colorScheme.primary
+    val radarColor = MaterialTheme.colorScheme.secondary
+    val sunColor = MaterialTheme.colorScheme.primary
     val animTransition = rememberInfiniteTransition(label = "animScale")
     val animScale by animTransition.animateFloat(
         initialValue = 16f,
@@ -79,6 +89,8 @@ fun RadarViewCompose(
         label = "animScale"
     )
     val measurer = rememberTextMeasurer()
+    val sunPainter = painterResource(R.drawable.ic_sun)
+    val moonPainter = painterResource(R.drawable.ic_moon)
     var sweepDegrees by remember { mutableFloatStateOf(0f) }
     var cachedRadius by remember { mutableFloatStateOf(0f) }
     var trackPath by remember { mutableStateOf(Path()) }
@@ -92,13 +104,26 @@ fun RadarViewCompose(
             cachedRadius = radius
         }
         rotate(if (shouldUseCompass) -azimElev.first else 0f) {
-            if (shouldShowSweep) drawSweep(center, sweepDegrees, radius, trackColor)
+            if (shouldShowSweep) drawSweep(center, sweepDegrees, radius, primaryColor)
             drawRadar(radius, radarColor)
-            drawElevationLabels(radius, trackColor, measurer)
+            drawElevationLabels(radius, primaryColor, measurer)
             translate(center.x, center.y) {
-                drawTrack(trackPath, trackEffect, aimColor, trackColor)
+                drawTrack(trackPath, trackEffect, aimColor, primaryColor)
                 if (item.elevation > 0) {
-                    drawPosition(item, radius, animScale, trackColor)
+                    drawPosition(item, radius, animScale, primaryColor)
+                }
+                sunPosition?.let { sun ->
+                    if (sun.elevation > 0) drawBodyIcon(sun.azimuth, sun.elevation, radius, sunColor, sunPainter, 52f)
+                }
+                moonPosition?.let { moon ->
+                    if (moon.elevation > 0) drawBodyIcon(
+                        moon.azimuth,
+                        moon.elevation,
+                        radius,
+                        radarColor,
+                        moonPainter,
+                        52f
+                    )
                 }
                 if (shouldUseCompass) drawAim(azimElev.first, azimElev.second, radius, aimColor)
             }
@@ -180,6 +205,27 @@ private fun createTrackEffect(trackPath: Path): PathEffect {
     return PathEffect.stampedPathEffect(shape, trackLength / 2f, trackLength / 4f, StampedPathEffectStyle.Rotate)
 }
 
+private fun DrawScope.drawBodyIcon(
+    azimDeg: Double,
+    elevDeg: Double,
+    radius: Float,
+    color: Color,
+    painter: Painter,
+    iconSize: Float
+) {
+    val azimRad = azimDeg.toRadians()
+    val elevRad = elevDeg.toRadians()
+    val pos = sph2Cart(azimRad, elevRad, radius.toDouble())
+    val half = iconSize / 2f
+    withTransform({
+        translate(pos.x - half, pos.y - half)
+    }) {
+        with(painter) {
+            draw(Size(iconSize, iconSize), colorFilter = ColorFilter.tint(color))
+        }
+    }
+}
+
 private fun sph2Cart(azim: Double, elev: Double, r: Double): Offset {
     val radius = r * (PI_2 - elev) / PI_2
     return Offset(

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/RadarViewModel.kt

@@ -18,22 +18,29 @@
 package com.rtbishop.look4sat.feature.radar
 
 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.model.SatRadio
+import com.rtbishop.look4sat.core.domain.predict.CelestialComputer
 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.IRadioTrackingService
 import com.rtbishop.look4sat.core.domain.repository.IReporter
 import com.rtbishop.look4sat.core.domain.repository.ISatelliteRepo
 import com.rtbishop.look4sat.core.domain.repository.ISensorsRepo
 import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
+import com.rtbishop.look4sat.core.domain.sstv.SstvDecoder
+import com.rtbishop.look4sat.core.domain.usecase.IAudioCapture
 import com.rtbishop.look4sat.core.domain.usecase.IAddToCalendar
+import com.rtbishop.look4sat.core.domain.usecase.ISaveImage
+import com.rtbishop.look4sat.core.domain.usecase.IShowToast
 import com.rtbishop.look4sat.core.domain.utility.round
 import com.rtbishop.look4sat.core.domain.utility.toDegrees
 import com.rtbishop.look4sat.core.domain.utility.toTimerString
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
@@ -41,72 +48,135 @@ import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
+import java.util.Locale
 
 class RadarViewModel(
-    private val catNum: Int,
-    private val aosTime: Long,
     private val bluetoothReporter: IReporter,
     private val networkReporter: IReporter,
     private val satelliteRepo: ISatelliteRepo,
     private val settingsRepo: ISettingsRepo,
     private val sensorsRepo: ISensorsRepo,
-    private val addToCalendar: IAddToCalendar
+    private val addToCalendar: IAddToCalendar,
+    private val trackingService: IRadioTrackingService,
+    private val audioCapture: IAudioCapture,
+    private val saveImage: ISaveImage,
+    private val showToast: IShowToast
 ) : ViewModel() {
 
     private val stationPos = settingsRepo.stationPosition.value
     private val magDeclination = sensorsRepo.getMagDeclination(stationPos)
+    private var transponders: List<SatRadio> = emptyList()
+    private var sstvDecoder: SstvDecoder? = null
+    private var sstvRecordingJob: Job? = null
+
     private val _uiState = MutableStateFlow(
         RadarState(
             isUtc = settingsRepo.otherSettings.value.stateOfUtc,
             orientationValues = sensorsRepo.orientation.value,
             shouldShowSweep = settingsRepo.otherSettings.value.stateOfSweep,
-            shouldUseCompass = settingsRepo.otherSettings.value.stateOfSensors
+            shouldUseCompass = settingsRepo.otherSettings.value.stateOfSensors,
+            sstv = SstvSubState(selectedMode = settingsRepo.otherSettings.value.sstvMode)
         )
     )
     val uiState: StateFlow<RadarState> = _uiState
 
     init {
-        // Compass sensor collection
-        if (settingsRepo.otherSettings.value.stateOfSensors) {
-            viewModelScope.launch {
-                sensorsRepo.enableSensor()
-                sensorsRepo.orientation.collect { data ->
-                    val orientationValues = (data.first + magDeclination) to data.second
-                    _uiState.update { it.copy(orientationValues = orientationValues) }
-                }
+        collectCompassSensor()
+        collectSettingsChanges()
+        collectPassAndStartTickLoop()
+        collectRadioTrackingState()
+    }
+
+    private fun collectCompassSensor() {
+        if (!settingsRepo.otherSettings.value.stateOfSensors) return
+        viewModelScope.launch {
+            sensorsRepo.enableSensor()
+            sensorsRepo.orientation.collect { data ->
+                val orientationValues = (data.first + magDeclination) to data.second
+                _uiState.update { it.copy(orientationValues = orientationValues) }
             }
         }
-        // React to UTC setting changes
+    }
+
+    private fun collectSettingsChanges() {
         viewModelScope.launch {
             settingsRepo.otherSettings.collectLatest { settings ->
                 _uiState.update { it.copy(isUtc = settings.stateOfUtc) }
             }
         }
-        // Resolve which pass we're tracking and start the tick loop
+    }
+
+    private fun collectPassAndStartTickLoop() {
         viewModelScope.launch {
             val passes = satelliteRepo.passes.value
-            val currentPass = passes.find { it.catNum == catNum && it.aosTime == aosTime }
-                ?: passes.firstOrNull()
-            currentPass?.let { satPass ->
-                _uiState.update { it.copy(currentPass = satPass) }
-                val transmitters = satelliteRepo.getRadiosWithId(satPass.catNum)
-                // Compute track once (it doesn't change for a given pass)
-                if (!satPass.isDeepSpace) {
-                    val track = satelliteRepo.getTrack(
-                        satPass.orbitalObject, stationPos, satPass.aosTime, satPass.losTime
+            val (catNum, aosTime) = satelliteRepo.selectedPass.value
+            val pass = passes.find { it.catNum == catNum && it.aosTime == aosTime } ?: passes.firstOrNull() ?: return@launch
+            _uiState.update { it.copy(currentPass = pass) }
+            val transmittersList = satelliteRepo.getRadiosWithId(pass.catNum)
+            transponders = transmittersList.filter { it.downlinkLow != null }
+            _uiState.update { state ->
+                state.copy(radioControl = state.radioControl.copy(transponders = transponders))
+            }
+            if (transmittersList.isNotEmpty()) {
+                val firstUuid = transmittersList.first().uuid
+                _uiState.update { it.copy(selectedTransmitterUuid = firstUuid) }
+                transponders.find { it.uuid == firstUuid }?.let { trackingService.setTransponder(it) }
+            }
+            if (!pass.isDeepSpace) {
+                val track = satelliteRepo.getTrack(pass.orbitalObject, stationPos, pass.aosTime, pass.losTime)
+                _uiState.update { it.copy(satTrack = track) }
+            }
+            while (isActive) {
+                tickPass(pass, transmittersList)
+                delay(1000)
+            }
+        }
+    }
+
+    private suspend fun tickPass(pass: OrbitalPass, transmittersList: List<SatRadio>) {
+        val timeNow = System.currentTimeMillis()
+        val pos = satelliteRepo.getPosition(pass.orbitalObject, stationPos, timeNow)
+        val sunPos = CelestialComputer.getSunPosition(stationPos, timeNow)
+        val moonPos = CelestialComputer.getMoonPosition(stationPos, timeNow)
+        val (time, isAos) = computeTimer(pass.isDeepSpace, pass.aosTime, pass.losTime, timeNow)
+        val isLos = !pass.isDeepSpace && timeNow > pass.losTime
+        _uiState.update {
+            it.copy(
+                currentTime = time, isTimeAos = isAos, isLos = isLos,
+                orbitalPos = pos, sunPosition = sunPos, moonPosition = moonPos
+            )
+        }
+        processRadios(transmittersList, pass.orbitalObject, timeNow)
+        sendPassData(pos)
+    }
+
+    private fun collectRadioTrackingState() {
+        viewModelScope.launch {
+            trackingService.state.collect { svc ->
+                _uiState.update { state ->
+                    state.copy(
+                        radioControl = state.radioControl.copy(
+                            txPanel = RadioPanelState(
+                                label = "TX (Uplink)",
+                                isConnected = svc.txConnected,
+                                frequencyHz = svc.txFrequencyHz,
+                                frequencyDisplay = svc.txFrequencyHz?.let { formatFrequency(it) } ?: "---",
+                                mode = svc.txMode
+                            ),
+                            rxPanel = RadioPanelState(
+                                label = "RX (Downlink)",
+                                isConnected = svc.rxConnected,
+                                frequencyHz = svc.rxFrequencyHz,
+                                frequencyDisplay = svc.rxFrequencyHz?.let { formatFrequency(it) } ?: "---",
+                                mode = svc.rxMode
+                            ),
+                            txBaseFrequencyHz = svc.txBaseFrequencyHz,
+                            ctcssTone = svc.ctcssTone,
+                            isTracking = svc.isActive,
+                            selectedTransponderUuid = svc.selectedTransponder?.uuid,
+                            errorMessage = svc.errorMessage
+                        )
                     )
-                    _uiState.update { it.copy(satTrack = track) }
-                }
-                // Tick loop — position, timer, and radio updates every second
-                while (isActive) {
-                    val timeNow = System.currentTimeMillis()
-                    val pos = satelliteRepo.getPosition(satPass.orbitalObject, stationPos, timeNow)
-                    val (time, isAos) = computeTimer(satPass.isDeepSpace, satPass.aosTime, satPass.losTime, timeNow)
-                    val isLos = !satPass.isDeepSpace && timeNow > satPass.losTime
-                    _uiState.update { it.copy(currentTime = time, isTimeAos = isAos, isLos = isLos, orbitalPos = pos) }
-                    processRadios(transmitters, satPass.orbitalObject, timeNow)
-                    sendPassData(pos)
-                    delay(1000)
                 }
             }
         }
@@ -120,7 +190,68 @@ class RadarViewModel(
     fun onAction(action: RadarAction) {
         when (action) {
             is RadarAction.AddToCalendar -> addToCalendar(action.name, action.aosTime, action.losTime)
-            is RadarAction.SelectTransmitter -> _uiState.update { it.copy(selectedTransmitterUuid = action.uuid) }
+            is RadarAction.SelectTransmitter -> {
+                val previousUuid = _uiState.value.selectedTransmitterUuid
+                _uiState.update {
+                    val newUuid = if (it.selectedTransmitterUuid == action.uuid) null else action.uuid
+                    it.copy(selectedTransmitterUuid = newUuid)
+                }
+                // Also set this as the active transponder for radio tracking.
+                // Always use the original (un-Dopplered) transponders list so that the
+                // TX base frequency is computed from the clean nominal values.
+                // Only update the service when selecting a *different* transponder to
+                // avoid resetting a user-adjusted TX base on re-expand.
+                val selected = transponders.find { it.uuid == action.uuid }
+                if (selected != null && _uiState.value.selectedTransmitterUuid != null && previousUuid != action.uuid) {
+                    trackingService.setTransponder(selected)
+                }
+            }
+            is RadarAction.SelectTransponder -> {
+                val transponder = transponders.find { it.uuid == action.uuid } ?: return
+                trackingService.setTransponder(transponder)
+            }
+            is RadarAction.SetTxFrequency -> trackingService.setTxBaseFrequency(action.frequencyHz)
+            is RadarAction.AdjustTxFrequency -> trackingService.adjustTxBaseFrequency(action.deltaHz)
+            is RadarAction.SetCtcssTone -> trackingService.setCtcssTone(action.toneHz)
+            RadarAction.ToggleTracking -> {
+                val svc = trackingService.state.value
+                if (svc.isActive) {
+                    trackingService.stopTracking()
+                } else {
+                    val pass = _uiState.value.currentPass ?: return
+                    val transponder = svc.selectedTransponder ?: return
+                    trackingService.startTracking(pass, transponder, svc.txBaseFrequencyHz)
+                }
+            }
+            RadarAction.ConnectRadios -> viewModelScope.launch { trackingService.connectRadios() }
+            RadarAction.DisconnectRadios -> viewModelScope.launch { trackingService.disconnectRadios() }
+
+            // SSTV actions
+            is RadarAction.SstvPermissionResult -> {
+                _uiState.update { it.copy(sstv = it.sstv.copy(hasPermission = action.granted)) }
+                if (action.granted) initSstvDecoder()
+            }
+            RadarAction.SstvStartRecording -> startSstvRecording()
+            RadarAction.SstvStopRecording -> stopSstvRecording()
+            RadarAction.SstvSaveImage -> {
+                val frame = _uiState.value.sstv.currentFrame ?: return
+                val pixels = frame.imagePixels ?: return
+                _uiState.update { it.copy(sstv = it.sstv.copy(status = SstvStatus.Saving)) }
+                viewModelScope.launch {
+                    saveImage(pixels, frame.imageWidth, frame.imageHeight, frame.modeName)
+                    _uiState.update { it.copy(sstv = it.sstv.copy(status = SstvStatus.Idle)) }
+                    showToast("Image saved")
+                }
+            }
+            is RadarAction.SstvSelectMode -> {
+                sstvDecoder?.lockMode(action.modeName)
+                _uiState.update { it.copy(sstv = it.sstv.copy(selectedMode = action.modeName)) }
+                settingsRepo.updateOtherSettings { it.copy(sstvMode = action.modeName) }
+            }
+            RadarAction.SstvReset -> {
+                sstvDecoder?.clearPixels() // Keep decoder alive, just reset pixels
+                _uiState.update { it.copy(sstv = it.sstv.copy(currentFrame = null)) }
+            }
         }
     }
 
@@ -171,50 +302,87 @@ class RadarViewModel(
         val isFreqEnabled =
             settingsRepo.rcSettings.value.frequencyState || settingsRepo.rcSettings.value.bluetoothFrequencyState
         _uiState.update { state ->
-            if (!isFreqEnabled) {
-                // Skip update if nothing changed
-                if (state.transmitters == transmitters && state.selectedTransmitterUuid == null && state.selectedFrequency == null) {
-                    return@update state
+            // Derive the frequency to report from the user's current selection (if any)
+            val freq = if (isFreqEnabled && state.selectedTransmitterUuid != null) {
+                val selectedRadio = transmitters.firstOrNull { it.uuid == state.selectedTransmitterUuid }
+                selectedRadio?.let { radio ->
+                    val low = radio.downlinkLow
+                    val high = radio.downlinkHigh
+                    when {
+                        low != null && high != null -> (low + high) / 2
+                        low != null -> low
+                        else -> null
+                    }
                 }
-                return@update state.copy(
-                    transmitters = transmitters,
-                    selectedTransmitterUuid = null,
-                    selectedFrequency = null
-                )
-            }
-            val selectedUuid = state.selectedTransmitterUuid ?: transmitters.firstOrNull()?.uuid
-            val selectedRadio = transmitters.firstOrNull { it.uuid == selectedUuid }
-            val freq = selectedRadio?.let { radio ->
-                val low = radio.downlinkLow
-                val high = radio.downlinkHigh
-                when {
-                    low != null && high != null -> (low + high) / 2
-                    low != null -> low
-                    else -> null
-                }
-            }
-            // Skip update if nothing changed
-            if (state.transmitters == transmitters && state.selectedTransmitterUuid == selectedUuid && state.selectedFrequency == freq) {
+            } else null
+
+            if (state.transmitters == transmitters && state.selectedFrequency == freq) {
                 return@update state
             }
-            state.copy(transmitters = transmitters, selectedTransmitterUuid = selectedUuid, selectedFrequency = freq)
+            state.copy(transmitters = transmitters, selectedFrequency = freq)
         }
     }
 
+    private fun initSstvDecoder() {
+        if (sstvDecoder == null) {
+            val decoder = SstvDecoder(sampleRate = audioCapture.sampleRate)
+            sstvDecoder = decoder
+            _uiState.update { it.copy(sstv = it.sstv.copy(supportedModes = decoder.supportedModes)) }
+            viewModelScope.launch {
+                decoder.frames.collect { frame ->
+                    _uiState.update { it.copy(sstv = it.sstv.copy(currentFrame = frame)) }
+                }
+            }
+        }
+    }
+
+    private fun startSstvRecording() {
+        if (sstvRecordingJob?.isActive == true) return
+        initSstvDecoder()
+        _uiState.update { it.copy(sstv = it.sstv.copy(status = SstvStatus.Recording)) }
+        sstvRecordingJob = viewModelScope.launch {
+            audioCapture.audioFlow().collect { buffer ->
+                sstvDecoder?.feedSamples(buffer)
+            }
+        }
+    }
+
+    private fun stopSstvRecording() {
+        sstvRecordingJob?.cancel()
+        sstvRecordingJob = null
+        _uiState.update { it.copy(sstv = it.sstv.copy(status = SstvStatus.Idle)) }
+    }
+
     companion object {
-        fun factory(catNum: Int, aosTime: Long): ViewModelProvider.Factory = viewModelFactory {
-            val applicationKey = ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY
+
+        val CTCSS_TONES = listOf(
+            67.0, 69.3, 71.9, 74.4, 77.0, 79.7, 82.5, 85.4, 88.5, 91.5,
+            94.8, 97.4, 100.0, 103.5, 107.2, 110.9, 114.8, 118.8, 123.0, 127.3, 131.8, 136.5,
+            141.3, 146.2, 151.4, 156.7, 162.2, 167.9, 173.8, 179.9, 186.2, 192.8, 203.5, 210.7,
+            218.1, 225.7, 233.6, 241.8, 250.3
+        )
+
+        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)
+        }
+
+        fun factory(container: IMainContainer) = viewModelFactory {
             initializer {
-                val container = (this[applicationKey] as IContainerProvider).getMainContainer()
                 RadarViewModel(
-                    catNum = catNum,
-                    aosTime = aosTime,
                     bluetoothReporter = container.provideBluetoothReporter(),
                     networkReporter = container.provideNetworkReporter(),
                     satelliteRepo = container.satelliteRepo,
                     settingsRepo = container.settingsRepo,
                     sensorsRepo = container.provideSensorsRepo(),
-                    addToCalendar = container.provideAddToCalendar()
+                    addToCalendar = container.provideAddToCalendar(),
+                    trackingService = container.radioTrackingService,
+                    audioCapture = container.provideAudioCapture(),
+                    saveImage = container.provideSaveImage(),
+                    showToast = container.provideShowToast()
                 )
             }
         }

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/SstvPage.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.feature.radar
+
+import android.graphics.Bitmap
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.fillMaxHeight
+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.size
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.items
+import androidx.compose.material3.Button
+import androidx.compose.material3.CardDefaults
+import androidx.compose.material3.ElevatedCard
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.RadioButton
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.asImageBitmap
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import androidx.compose.ui.window.Dialog
+import com.rtbishop.look4sat.core.presentation.IconCard
+import com.rtbishop.look4sat.core.presentation.R
+import com.rtbishop.look4sat.core.presentation.infiniteMarquee
+
+@Composable
+internal fun SstvPage(
+    sstv: SstvSubState,
+    onAction: (RadarAction) -> Unit,
+    requestMicPermission: () -> Unit
+) {
+    if (!sstv.hasPermission) {
+        Box(
+            contentAlignment = Alignment.Center,
+            modifier = Modifier.fillMaxSize()
+        ) {
+            Column(
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.spacedBy(16.dp)
+            ) {
+                Text(text = "🎙️", fontSize = 48.sp)
+                Text(
+                    text = "Microphone access needed",
+                    fontSize = 16.sp,
+                    color = MaterialTheme.colorScheme.onSurface
+                )
+                Button(onClick = requestMicPermission) {
+                    Text("Grant permission")
+                }
+            }
+        }
+        return
+    }
+
+    // Mode selection dialog
+    val showModeDialog = remember { mutableStateOf(false) }
+
+    if (showModeDialog.value) {
+        val allModes = remember(sstv.supportedModes) { listOf("Auto") + sstv.supportedModes }
+        Dialog(onDismissRequest = { showModeDialog.value = false }) {
+            ElevatedCard {
+                Column(
+                    horizontalAlignment = Alignment.CenterHorizontally,
+                    modifier = Modifier.padding(vertical = 16.dp)
+                ) {
+                    Text(
+                        text = "SSTV Mode",
+                        fontSize = 16.sp,
+                        fontWeight = FontWeight.Medium,
+                        color = MaterialTheme.colorScheme.primary,
+                        modifier = Modifier.padding(bottom = 12.dp)
+                    )
+                    LazyColumn(
+                        modifier = Modifier
+                            .fillMaxHeight(0.5f)
+                            .background(MaterialTheme.colorScheme.background),
+                        verticalArrangement = Arrangement.spacedBy(1.dp)
+                    ) {
+                        items(allModes) { mode ->
+                            Row(
+                                verticalAlignment = Alignment.CenterVertically,
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .background(MaterialTheme.colorScheme.surface)
+                                    .clickable {
+                                        onAction(RadarAction.SstvSelectMode(mode))
+                                        showModeDialog.value = false
+                                    }
+                            ) {
+                                Text(
+                                    text = mode,
+                                    fontSize = 16.sp,
+                                    fontWeight = FontWeight.Medium,
+                                    maxLines = 1,
+                                    overflow = TextOverflow.Ellipsis,
+                                    modifier = Modifier
+                                        .weight(1f)
+                                        .padding(start = 16.dp)
+                                )
+                                RadioButton(
+                                    selected = mode == sstv.selectedMode,
+                                    onClick = null,
+                                    modifier = Modifier.padding(horizontal = 16.dp, vertical = 12.dp)
+                                )
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    // Main SSTV view — image fills entire area, controls overlay at bottom
+    Box(
+        modifier = Modifier
+            .fillMaxSize()
+            .background(Color.Black)
+    ) {
+        // Decoded image or placeholder — centered in available space
+        val frame = sstv.currentFrame
+        val pixels = frame?.imagePixels
+        if (pixels != null && frame.imageWidth > 0 && frame.imageHeight > 0) {
+            val bitmap = remember(pixels, frame.imageWidth, frame.imageHeight) {
+                Bitmap.createBitmap(
+                    pixels,
+                    frame.imageWidth,
+                    frame.imageHeight,
+                    Bitmap.Config.ARGB_8888
+                ).asImageBitmap()
+            }
+            Image(
+                bitmap = bitmap,
+                contentDescription = "Decoded SSTV image",
+                contentScale = ContentScale.Fit,
+                modifier = Modifier
+                    .fillMaxSize()
+                    .align(Alignment.Center)
+            )
+        } else {
+            Text(
+                text = if (sstv.status == SstvStatus.Recording) "Listening…" else "No signal",
+                color = MaterialTheme.colorScheme.onSurface,
+                fontSize = 16.sp,
+                modifier = Modifier.align(Alignment.Center)
+            )
+        }
+        // Bottom control bar — dark, blends with the black canvas
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            horizontalArrangement = Arrangement.spacedBy(8.dp),
+            modifier = Modifier
+                .align(Alignment.BottomCenter)
+                .fillMaxWidth()
+                .padding(horizontal = 8.dp, vertical = 8.dp)
+        ) {
+            // Mode button — opens dialog
+            ElevatedCard(
+                modifier = Modifier.weight(1f).height(48.dp),
+                onClick = { showModeDialog.value = true },
+                colors = CardDefaults.elevatedCardColors(
+                    containerColor = MaterialTheme.colorScheme.surface
+                )
+            ) {
+                Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+                    Text(
+                        text = "Mode: ${sstv.selectedMode}",
+                        fontSize = 14.sp,
+                        maxLines = 1,
+                        color = MaterialTheme.colorScheme.onSurface,
+                        modifier = Modifier.infiniteMarquee()
+                    )
+                }
+            }
+            // Reset button — clears decoder state and image
+            IconCard(
+                action = { onAction(RadarAction.SstvReset) },
+                resId = R.drawable.ic_delete
+            )
+            // Save button — always visible, enabled when there are pixels
+            IconCard(
+                action = { onAction(RadarAction.SstvSaveImage) },
+                resId = R.drawable.ic_save,
+                enabled = sstv.currentFrame?.imagePixels != null
+            )
+            // Record / Stop button
+            val playAction = {
+                when (sstv.status) {
+                    SstvStatus.Idle -> onAction(RadarAction.SstvStartRecording)
+                    SstvStatus.Recording -> onAction(RadarAction.SstvStopRecording)
+                    SstvStatus.Saving -> {}
+                }
+            }
+            val playColors = CardDefaults.elevatedCardColors(
+                containerColor = if (sstv.status == SstvStatus.Recording) MaterialTheme.colorScheme.primary
+                else MaterialTheme.colorScheme.surface
+            )
+            val playIcon = if (sstv.status == SstvStatus.Recording) R.drawable.ic_pause else R.drawable.ic_play
+            ElevatedCard(modifier = Modifier.size(48.dp), onClick = playAction, colors = playColors) {
+                Box(modifier = Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
+                    Icon(painter = painterResource(playIcon), contentDescription = null)
+                }
+            }
+        }
+    }
+}

feature/radar/src/main/java/com/rtbishop/look4sat/feature/radar/TransceiversPage.kt

@@ -0,0 +1,453 @@
+/*
+ * 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.radar
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.animation.expandVertically
+import androidx.compose.animation.shrinkVertically
+import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
+import androidx.compose.foundation.interaction.MutableInteractionSource
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.FlowRow
+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.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.lazy.LazyColumn
+import androidx.compose.foundation.lazy.itemsIndexed
+import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material3.FilterChip
+import androidx.compose.material3.HorizontalDivider
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.draw.rotate
+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
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.unit.sp
+import com.rtbishop.look4sat.core.domain.model.SatRadio
+import com.rtbishop.look4sat.core.presentation.CardButton
+import com.rtbishop.look4sat.core.presentation.R
+import com.rtbishop.look4sat.core.presentation.infiniteMarquee
+import java.util.Locale
+
+@Composable
+fun TransceiversPage(
+    transceivers: List<SatRadio>,
+    selectedUuid: String?,
+    radioControl: RadioControlSubState,
+    onAction: (RadarAction) -> Unit,
+    modifier: Modifier = Modifier
+) {
+    if (transceivers.isEmpty()) {
+        EmptyTransceiversContent(modifier)
+    } else {
+        val listState = rememberLazyListState()
+        // Snap the expanded item to the top of the visible area
+        LaunchedEffect(selectedUuid) {
+            if (selectedUuid != null) {
+                val index = transceivers.indexOfFirst { it.uuid == selectedUuid }
+                if (index >= 0) {
+                    kotlinx.coroutines.delay(300)
+                    listState.animateScrollToItem(index)
+                }
+            }
+        }
+        LazyColumn(modifier = modifier.fillMaxSize(), state = listState) {
+            itemsIndexed(items = transceivers, key = { _, radio -> radio.uuid }) { _, radio ->
+                val isExpanded = radio.uuid == selectedUuid
+                TransceiverItem(
+                    radio = radio,
+                    isExpanded = isExpanded,
+                    radioControl = radioControl,
+                    onAction = onAction,
+                    onToggle = { onAction(RadarAction.SelectTransmitter(radio.uuid)) }
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun EmptyTransceiversContent(modifier: Modifier = Modifier) {
+    Box(contentAlignment = Alignment.Center, modifier = modifier.fillMaxSize()) {
+        Column(
+            horizontalAlignment = Alignment.CenterHorizontally,
+            verticalArrangement = Arrangement.spacedBy(24.dp),
+            modifier = Modifier.padding(32.dp)
+        ) {
+            Text(text = """¯\_(ツ)_/¯""", fontSize = 32.sp)
+            Text(
+                text = stringResource(R.string.empty_list_message),
+                fontSize = 21.sp,
+                textAlign = TextAlign.Center
+            )
+            Text(
+                text = stringResource(R.string.radar_no_data),
+                fontSize = 18.sp,
+                textAlign = TextAlign.Center
+            )
+        }
+    }
+}
+
+@Composable
+private fun TransceiverItem(
+    radio: SatRadio,
+    isExpanded: Boolean,
+    radioControl: RadioControlSubState,
+    onAction: (RadarAction) -> Unit,
+    onToggle: () -> Unit
+) {
+    val bgColor = if (isExpanded) MaterialTheme.colorScheme.surfaceContainerHighest
+    else MaterialTheme.colorScheme.surface
+
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .background(bgColor)
+            .clickable(
+                interactionSource = remember { MutableInteractionSource() },
+                indication = null
+            ) { onToggle() }
+    ) {
+        Column(
+            verticalArrangement = Arrangement.spacedBy(4.dp),
+            modifier = Modifier
+                .fillMaxWidth()
+                .padding(horizontal = 8.dp, vertical = 6.dp)
+        ) {
+            // Header: [arrow slot] [name - (mode)] [icon slot]
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                // Left icon slot — always reserved
+                Box(
+                    contentAlignment = Alignment.Center,
+                    modifier = Modifier.size(20.dp)
+                ) {
+                    Icon(
+                        painter = painterResource(id = R.drawable.ic_arrow),
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                        contentDescription = null,
+                        modifier = Modifier
+                            .size(20.dp)
+                            .rotate(if (isExpanded) 270f else 90f)
+                    )
+                }
+                // Title with mode
+                val title = if (radio.isInverted) "INV: ${radio.info}" else radio.info
+                val mode = "${radio.downlinkMode ?: "--"}/${radio.uplinkMode ?: "--"}"
+                val fullTitle = "$title ($mode)"
+                Text(
+                    text = fullTitle,
+                    textAlign = TextAlign.Center,
+                    color = MaterialTheme.colorScheme.onSurface,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier
+                        .weight(1f)
+                        .infiniteMarquee()
+                )
+                // Right arrow slot — always reserved
+                val iconTint = if (isExpanded) MaterialTheme.colorScheme.primary
+                else MaterialTheme.colorScheme.outlineVariant
+                Box(
+                    contentAlignment = Alignment.Center,
+                    modifier = Modifier.size(24.dp)
+                ) {
+                    Icon(
+                        painter = painterResource(id = R.drawable.ic_radios),
+                        contentDescription = null,
+                        tint = iconTint,
+                        modifier = Modifier.size(20.dp)
+                    )
+                }
+            }
+
+            // Frequency rows
+            UnifiedFrequencyRow(
+                label = "TX",
+                frequencyLow = radio.uplinkLow,
+                frequencyHigh = radio.uplinkHigh,
+                isConnected = if (isExpanded) radioControl.txPanel.isConnected else null
+            )
+            UnifiedFrequencyRow(
+                label = "RX",
+                frequencyLow = radio.downlinkLow,
+                frequencyHigh = radio.downlinkHigh,
+                isConnected = if (isExpanded) radioControl.rxPanel.isConnected else null
+            )
+        }
+
+        // Expanded CAT control area
+        AnimatedVisibility(
+            visible = isExpanded,
+            enter = expandVertically(),
+            exit = shrinkVertically()
+        ) {
+            ExpandedRadioControl(
+                radio = radio,
+                radioControl = radioControl,
+                onAction = onAction
+            )
+        }
+
+        HorizontalDivider(thickness = 2.dp, color = MaterialTheme.colorScheme.background)
+    }
+}
+
+@Composable
+private fun UnifiedFrequencyRow(
+    label: String,
+    frequencyLow: Long?,
+    frequencyHigh: Long?,
+    isConnected: Boolean?
+) {
+    Row(
+        verticalAlignment = Alignment.CenterVertically,
+        modifier = Modifier.fillMaxWidth()
+    ) {
+        // TX:/RX: label
+        Text(
+            text = "$label:",
+            fontSize = 14.sp,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
+            modifier = Modifier.width(24.dp)
+        )
+        // Low frequency
+        FrequencyText(
+            frequency = frequencyLow,
+            modifier = Modifier.weight(1f)
+        )
+        // Dash — always centered
+        Text(
+            text = "–",
+            textAlign = TextAlign.Center,
+            fontSize = 18.sp,
+            fontWeight = FontWeight.Bold,
+            color = MaterialTheme.colorScheme.primary,
+            modifier = Modifier.width(16.dp)
+        )
+        // High frequency
+        FrequencyText(
+            frequency = frequencyHigh,
+            modifier = Modifier.weight(1f)
+        )
+        // Connection dot on the right
+        Box(
+            contentAlignment = Alignment.Center,
+            modifier = Modifier.width(24.dp)
+        ) {
+            Box(
+                modifier = Modifier
+                    .size(8.dp)
+                    .clip(CircleShape)
+                    .background(
+                        when (isConnected) {
+                            true -> Color(0xFF4CAF50)
+                            false -> Color(0xFFE57373)
+                            null -> MaterialTheme.colorScheme.outlineVariant
+                        }
+                    )
+            )
+        }
+    }
+}
+
+@Composable
+private fun ExpandedRadioControl(
+    radio: SatRadio,
+    radioControl: RadioControlSubState,
+    onAction: (RadarAction) -> Unit
+) {
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(horizontal = 8.dp)
+            .padding(bottom = 8.dp),
+        verticalArrangement = Arrangement.spacedBy(6.dp)
+    ) {
+        HorizontalDivider(
+            thickness = 1.dp,
+            color = MaterialTheme.colorScheme.outline.copy(alpha = 0.3f)
+        )
+
+        // Frequency tuner
+        if (radioControl.txBaseFrequencyHz != null) {
+            Column(
+                horizontalAlignment = Alignment.CenterHorizontally,
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                Row(
+                    verticalAlignment = Alignment.CenterVertically,
+                    horizontalArrangement = Arrangement.Center,
+                    modifier = Modifier.fillMaxWidth()
+                ) {
+                    Text(
+                        text = "TX Base: ",
+                        fontSize = 14.sp,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
+                    )
+                    Text(
+                        text = "${RadarViewModel.formatFrequency(radioControl.txBaseFrequencyHz)} MHz",
+                        fontSize = 18.sp,
+                        fontWeight = FontWeight.Bold,
+                        color = MaterialTheme.colorScheme.primary
+                    )
+                }
+                val upLow = radio.uplinkLow
+                val upHigh = radio.uplinkHigh
+                if (upLow != null && upHigh != null && upLow != upHigh) {
+                    Text(
+                        text = "(${RadarViewModel.formatFrequency(upLow)} – ${RadarViewModel.formatFrequency(upHigh)})",
+                        fontSize = 12.sp,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
+                    )
+                }
+                Spacer(modifier = Modifier.height(4.dp))
+                Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+                    FREQ_ADJUSTMENTS.forEach { (delta, label) ->
+                        CardButton(
+                            onClick = { onAction(RadarAction.AdjustTxFrequency(delta)) },
+                            text = label,
+                            modifier = Modifier.weight(1f)
+                        )
+                    }
+                }
+            }
+        }
+
+        // CTCSS (only for FM uplink)
+        if (radio.uplinkMode?.uppercase() == "FM") {
+            Column(
+                horizontalAlignment = Alignment.CenterHorizontally,
+                modifier = Modifier.fillMaxWidth()
+            ) {
+                Text(
+                    text = "CTCSS",
+                    fontSize = 14.sp,
+                    fontWeight = FontWeight.Medium,
+                    color = MaterialTheme.colorScheme.primary
+                )
+                Spacer(modifier = Modifier.height(4.dp))
+                FlowRow(
+                    horizontalArrangement = Arrangement.spacedBy(4.dp),
+                    modifier = Modifier.fillMaxWidth()
+                ) {
+                    val chipModifier = Modifier.width(64.dp)
+                    FilterChip(
+                        selected = radioControl.ctcssTone == null,
+                        onClick = { onAction(RadarAction.SetCtcssTone(null)) },
+                        label = {
+                            Text(
+                                text = "Off",
+                                fontSize = 12.sp,
+                                textAlign = TextAlign.Center,
+                                modifier = Modifier.fillMaxWidth()
+                            )
+                        },
+                        modifier = chipModifier
+                    )
+                    RadarViewModel.CTCSS_TONES.forEach { tone ->
+                        FilterChip(
+                            selected = radioControl.ctcssTone == tone,
+                            onClick = { onAction(RadarAction.SetCtcssTone(tone)) },
+                            label = {
+                                Text(
+                                    text = String.format(Locale.ENGLISH, "%.1f", tone),
+                                    fontSize = 12.sp,
+                                    textAlign = TextAlign.Center,
+                                    modifier = Modifier.fillMaxWidth()
+                                )
+                            },
+                            modifier = chipModifier
+                        )
+                    }
+                }
+            }
+        }
+
+        // Control buttons
+        Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
+            if (!radioControl.txPanel.isConnected && !radioControl.rxPanel.isConnected) {
+                CardButton(
+                    onClick = { onAction(RadarAction.ConnectRadios) },
+                    text = "Connect",
+                    modifier = Modifier.weight(1f)
+                )
+            } else {
+                CardButton(
+                    onClick = { onAction(RadarAction.DisconnectRadios) },
+                    text = "Disconnect",
+                    modifier = Modifier.weight(1f)
+                )
+            }
+            CardButton(
+                onClick = { onAction(RadarAction.ToggleTracking) },
+                text = if (radioControl.isTracking) "Stop" else "Track",
+                modifier = Modifier.weight(1f)
+            )
+        }
+
+        // Error
+        radioControl.errorMessage?.let { msg ->
+            Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.Center) {
+                Text(text = msg, color = MaterialTheme.colorScheme.error, fontSize = 14.sp)
+            }
+        }
+    }
+}
+
+@Composable
+private fun FrequencyText(frequency: Long?, modifier: Modifier = Modifier) {
+    val text = frequency?.let {
+        stringResource(id = R.string.radar_link_low, it / 1000000f)
+    } ?: stringResource(R.string.radar_no_link)
+    Text(
+        text = text,
+        textAlign = TextAlign.Center,
+        fontSize = 18.sp,
+        fontWeight = FontWeight.Bold,
+        color = MaterialTheme.colorScheme.primary,
+        modifier = modifier
+    )
+}
+
+private val FREQ_ADJUSTMENTS =
+    listOf(-10_000L to "-10k", -1_000L to "-1k", -100L to "-100", 100L to "+100", 1_000L to "+1k", 10_000L to "+10k")

feature/radiocontrol/build.gradle.kts

@@ -1,7 +0,0 @@
-plugins {
-    alias(libs.plugins.convention.featurePlugin)
-}
-
-android {
-    namespace = "com.rtbishop.look4sat.feature.radiocontrol"
-}

feature/radiocontrol/src/main/AndroidManifest.xml

@@ -1,4 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<manifest>
-
-</manifest>

feature/radiocontrol/src/main/java/com/rtbishop/look4sat/feature/radiocontrol/RadioControlScreen.kt

@@ -1,392 +0,0 @@
-/*
- * 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.radiocontrol
-
-import androidx.compose.foundation.background
-import androidx.compose.foundation.clickable
-import androidx.compose.foundation.layout.Arrangement
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.ExperimentalLayoutApi
-import androidx.compose.foundation.layout.FlowRow
-import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.Spacer
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.foundation.layout.height
-import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.size
-import androidx.compose.foundation.layout.width
-import androidx.compose.foundation.lazy.LazyColumn
-import androidx.compose.foundation.shape.CircleShape
-import androidx.compose.material3.ElevatedCard
-import androidx.compose.material3.FilterChip
-import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Surface
-import androidx.compose.material3.Text
-import androidx.compose.runtime.Composable
-import androidx.compose.runtime.getValue
-import androidx.compose.ui.Alignment
-import androidx.compose.ui.Modifier
-import androidx.compose.ui.draw.clip
-import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.keepScreenOn
-import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.text.style.TextAlign
-import androidx.compose.ui.unit.dp
-import androidx.compose.ui.unit.sp
-import androidx.lifecycle.compose.collectAsStateWithLifecycle
-import androidx.lifecycle.viewmodel.compose.viewModel
-import com.rtbishop.look4sat.core.domain.model.SatRadio
-import com.rtbishop.look4sat.core.presentation.CardButton
-import com.rtbishop.look4sat.core.presentation.IconCard
-import com.rtbishop.look4sat.core.presentation.NextPassRow
-import com.rtbishop.look4sat.core.presentation.R
-import com.rtbishop.look4sat.core.presentation.TimerRow
-import com.rtbishop.look4sat.core.presentation.TopBar
-import com.rtbishop.look4sat.core.presentation.getDefaultPass
-import com.rtbishop.look4sat.core.presentation.isVerticalLayout
-import com.rtbishop.look4sat.core.presentation.layoutPadding
-import java.util.Locale
-
-@Composable
-fun RadioControlDestination(catNum: Int = 0, aosTime: Long = 0L, navigateUp: () -> Unit) {
-    val viewModel = viewModel(
-        modelClass = RadioControlViewModel::class.java,
-        key = "$catNum-$aosTime",
-        factory = RadioControlViewModel.factory(catNum, aosTime)
-    )
-    val uiState by viewModel.uiState.collectAsStateWithLifecycle()
-    RadioControlScreen(uiState, viewModel::onAction, navigateUp)
-}
-
-@Composable
-private fun RadioControlScreen(
-    uiState: RadioControlState,
-    onAction: (RadioControlAction) -> Unit,
-    navigateUp: () -> Unit
-) {
-    Column(
-        modifier = Modifier
-            .layoutPadding()
-            .keepScreenOn(),
-        verticalArrangement = Arrangement.spacedBy(6.dp)
-    ) {
-        val currentPass = uiState.currentPass ?: getDefaultPass()
-        val isVertical = isVerticalLayout()
-        if (isVertical) {
-            TopBar {
-                IconCard(action = navigateUp, resId = R.drawable.ic_back)
-                TimerRow(timeString = uiState.currentTime, isTimeAos = uiState.isCurrentTimeAos)
-                IconCard(action = navigateUp, resId = R.drawable.ic_back)
-            }
-            TopBar { NextPassRow(pass = currentPass) }
-        } else {
-            TopBar {
-                IconCard(action = navigateUp, resId = R.drawable.ic_back)
-                TimerRow(timeString = uiState.currentTime, isTimeAos = uiState.isCurrentTimeAos)
-                NextPassRow(pass = currentPass, modifier = Modifier.weight(1f))
-                IconCard(action = navigateUp, resId = R.drawable.ic_back)
-            }
-        }
-
-        RadioPanel(panel = uiState.txPanel)
-        RadioPanel(panel = uiState.rxPanel)
-
-        PositionRow(
-            azimuth = uiState.azimuth,
-            elevation = uiState.elevation,
-            distance = uiState.distance
-        )
-
-        val selectedTransponder = uiState.transponders.find {
-            it.uuid == uiState.selectedTransponderUuid
-        }
-
-        LazyColumn(
-            modifier = Modifier.weight(1f),
-            verticalArrangement = Arrangement.spacedBy(4.dp)
-        ) {
-            item {
-                TransponderSelector(
-                    transponders = uiState.transponders,
-                    selectedUuid = uiState.selectedTransponderUuid,
-                    onAction = onAction
-                )
-            }
-
-            if (selectedTransponder?.uplinkMode?.uppercase() == "FM") {
-                item {
-                    CtcssSelector(
-                        ctcssTone = uiState.ctcssTone,
-                        onAction = onAction
-                    )
-                }
-            }
-
-            if (uiState.txBaseFrequencyHz != null) {
-                item {
-                    FrequencyTuner(
-                        txBaseFrequencyHz = uiState.txBaseFrequencyHz,
-                        selectedTransponder = selectedTransponder,
-                        onAction = onAction
-                    )
-                }
-            }
-
-            uiState.errorMessage?.let { msg ->
-                item {
-                    Text(
-                        text = msg,
-                        color = MaterialTheme.colorScheme.error,
-                        modifier = Modifier.padding(8.dp)
-                    )
-                }
-            }
-        }
-
-        ControlButtons(
-            isConnected = uiState.txPanel.isConnected || uiState.rxPanel.isConnected,
-            isTracking = uiState.isTracking,
-            onAction = onAction
-        )
-    }
-}
-
-@Composable
-private fun RadioPanel(panel: RadioPanelState) {
-    ElevatedCard(modifier = Modifier.fillMaxWidth()) {
-        Row(
-            verticalAlignment = Alignment.CenterVertically,
-            horizontalArrangement = Arrangement.SpaceBetween,
-            modifier = Modifier
-                .fillMaxWidth()
-                .padding(horizontal = 12.dp, vertical = 8.dp)
-        ) {
-            Row(verticalAlignment = Alignment.CenterVertically) {
-                Box(
-                    modifier = Modifier
-                        .size(10.dp)
-                        .clip(CircleShape)
-                        .background(if (panel.isConnected) Color(0xFF4CAF50) else Color(0xFFE57373))
-                )
-                Spacer(modifier = Modifier.width(8.dp))
-                Text(text = panel.label, fontSize = 14.sp)
-            }
-            Text(
-                text = panel.frequencyDisplay,
-                fontSize = 24.sp,
-                fontWeight = FontWeight.Bold,
-                color = MaterialTheme.colorScheme.primary
-            )
-            Text(
-                text = panel.mode ?: "--",
-                fontSize = 16.sp,
-                fontWeight = FontWeight.Medium
-            )
-        }
-    }
-}
-
-@Composable
-private fun PositionRow(azimuth: String, elevation: String, distance: String) {
-    ElevatedCard(modifier = Modifier.fillMaxWidth()) {
-        Row(
-            horizontalArrangement = Arrangement.SpaceEvenly,
-            modifier = Modifier
-                .fillMaxWidth()
-                .padding(vertical = 6.dp)
-        ) {
-            Column(horizontalAlignment = Alignment.CenterHorizontally) {
-                Text(text = "Az", fontSize = 12.sp)
-                Text(text = "$azimuth°", fontSize = 16.sp, fontWeight = FontWeight.Medium)
-            }
-            Column(horizontalAlignment = Alignment.CenterHorizontally) {
-                Text(text = "El", fontSize = 12.sp)
-                Text(text = "$elevation°", fontSize = 16.sp, fontWeight = FontWeight.Medium)
-            }
-            Column(horizontalAlignment = Alignment.CenterHorizontally) {
-                Text(text = "Dist", fontSize = 12.sp)
-                Text(text = "$distance km", fontSize = 16.sp, fontWeight = FontWeight.Medium)
-            }
-        }
-    }
-}
-
-@Composable
-private fun TransponderSelector(
-    transponders: List<SatRadio>,
-    selectedUuid: String?,
-    onAction: (RadioControlAction) -> Unit
-) {
-    if (transponders.isEmpty()) {
-        ElevatedCard(modifier = Modifier.fillMaxWidth()) {
-            Text(
-                text = "No transponders with uplink+downlink available",
-                textAlign = TextAlign.Center,
-                modifier = Modifier
-                    .fillMaxWidth()
-                    .padding(16.dp)
-            )
-        }
-        return
-    }
-    Column(verticalArrangement = Arrangement.spacedBy(2.dp)) {
-        transponders.forEach { radio ->
-            TransponderItem(
-                radio = radio,
-                isSelected = radio.uuid == selectedUuid,
-                onSelect = { onAction(RadioControlAction.SelectTransponder(radio.uuid)) }
-            )
-        }
-    }
-}
-
-@Composable
-private fun TransponderItem(radio: SatRadio, isSelected: Boolean, onSelect: () -> Unit) {
-    val invLabel = if (radio.isInverted) " INV" else ""
-    val modeLabel = "${radio.uplinkMode ?: "--"}/${radio.downlinkMode ?: "--"}$invLabel"
-    Surface(
-        color = if (isSelected) MaterialTheme.colorScheme.primaryContainer
-        else MaterialTheme.colorScheme.surface,
-        shape = MaterialTheme.shapes.small,
-        modifier = Modifier
-            .fillMaxWidth()
-            .clickable { onSelect() }
-    ) {
-        Row(
-            horizontalArrangement = Arrangement.SpaceBetween,
-            verticalAlignment = Alignment.CenterVertically,
-            modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp)
-        ) {
-            Text(text = radio.info, modifier = Modifier.weight(1f))
-            Text(text = modeLabel, fontSize = 13.sp, fontWeight = FontWeight.Medium)
-        }
-    }
-}
-
-@OptIn(ExperimentalLayoutApi::class)
-@Composable
-private fun CtcssSelector(
-    ctcssTone: Double?,
-    onAction: (RadioControlAction) -> Unit
-) {
-    ElevatedCard(modifier = Modifier.fillMaxWidth()) {
-        Column(modifier = Modifier.padding(horizontal = 8.dp, vertical = 6.dp)) {
-            Text(text = "CTCSS Tone", color = MaterialTheme.colorScheme.primary)
-            Spacer(modifier = Modifier.height(4.dp))
-            FlowRow(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
-                FilterChip(
-                    selected = ctcssTone == null,
-                    onClick = { onAction(RadioControlAction.SetCtcssTone(null)) },
-                    label = { Text("Off") }
-                )
-                RadioControlViewModel.CTCSS_TONES.forEach { tone ->
-                    FilterChip(
-                        selected = ctcssTone == tone,
-                        onClick = { onAction(RadioControlAction.SetCtcssTone(tone)) },
-                        label = { Text(String.format(Locale.ENGLISH, "%.1f", tone)) }
-                    )
-                }
-            }
-        }
-    }
-}
-
-private val FREQ_ADJUSTMENTS =
-    listOf(-10_000L to "-10k", -1_000L to "-1k", -100L to "-100", 100L to "+100", 1_000L to "+1k", 10_000L to "+10k")
-
-@Composable
-private fun FrequencyTuner(
-    txBaseFrequencyHz: Long,
-    selectedTransponder: SatRadio?,
-    onAction: (RadioControlAction) -> Unit
-) {
-    ElevatedCard(modifier = Modifier.fillMaxWidth()) {
-        Column(
-            horizontalAlignment = Alignment.CenterHorizontally,
-            modifier = Modifier.padding(horizontal = 8.dp, vertical = 6.dp)
-        ) {
-            Text(text = "TX Base Frequency", color = MaterialTheme.colorScheme.primary)
-            if (selectedTransponder != null) {
-                val upLow = selectedTransponder.uplinkLow
-                val upHigh = selectedTransponder.uplinkHigh
-                val dnLow = selectedTransponder.downlinkLow
-                val dnHigh = selectedTransponder.downlinkHigh
-                if (upLow != null && upHigh != null && upLow != upHigh) {
-                    Text(
-                        text = "UP: ${RadioControlViewModel.formatFrequency(upLow)} - ${RadioControlViewModel.formatFrequency(upHigh)}",
-                        fontSize = 11.sp,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant
-                    )
-                }
-                if (dnLow != null && dnHigh != null && dnLow != dnHigh) {
-                    Text(
-                        text = "DN: ${RadioControlViewModel.formatFrequency(dnLow)} - ${RadioControlViewModel.formatFrequency(dnHigh)}",
-                        fontSize = 11.sp,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant
-                    )
-                }
-            }
-            Spacer(modifier = Modifier.height(4.dp))
-            Text(
-                text = "${RadioControlViewModel.formatFrequency(txBaseFrequencyHz)} MHz",
-                fontSize = 20.sp,
-                fontWeight = FontWeight.Bold,
-                color = MaterialTheme.colorScheme.primary
-            )
-            Spacer(modifier = Modifier.height(4.dp))
-            Row(horizontalArrangement = Arrangement.spacedBy(4.dp)) {
-                FREQ_ADJUSTMENTS.forEach { (delta, label) ->
-                    CardButton(
-                        onClick = { onAction(RadioControlAction.AdjustTxFrequency(delta)) },
-                        text = label,
-                        modifier = Modifier.weight(1f)
-                    )
-                }
-            }
-        }
-    }
-}
-
-@Composable
-private fun ControlButtons(
-    isConnected: Boolean,
-    isTracking: Boolean,
-    onAction: (RadioControlAction) -> Unit
-) {
-    Row(horizontalArrangement = Arrangement.spacedBy(6.dp)) {
-        if (!isConnected) {
-            CardButton(
-                onClick = { onAction(RadioControlAction.ConnectRadios) },
-                text = "Connect",
-                modifier = Modifier.weight(1f)
-            )
-        } else {
-            CardButton(
-                onClick = { onAction(RadioControlAction.DisconnectRadios) },
-                text = "Disconnect",
-                modifier = Modifier.weight(1f)
-            )
-        }
-        CardButton(
-            onClick = { onAction(RadioControlAction.ToggleTracking) },
-            text = if (isTracking) "Stop Tracking" else "Start Tracking",
-            modifier = Modifier.weight(1f)
-        )
-    }
-}

feature/radiocontrol/src/main/java/com/rtbishop/look4sat/feature/radiocontrol/RadioControlState.kt

@@ -1,56 +0,0 @@
-/*
- * 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.radiocontrol
-
-import com.rtbishop.look4sat.core.domain.model.SatRadio
-import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
-
-data class RadioPanelState(
-    val label: String,
-    val isConnected: Boolean,
-    val frequencyHz: Long?,
-    val frequencyDisplay: String,
-    val mode: String?
-)
-
-data class RadioControlState(
-    val currentPass: OrbitalPass?,
-    val currentTime: String,
-    val isCurrentTimeAos: Boolean,
-    val azimuth: String,
-    val elevation: String,
-    val distance: String,
-    val txPanel: RadioPanelState,
-    val rxPanel: RadioPanelState,
-    val transponders: List<SatRadio>,
-    val selectedTransponderUuid: String?,
-    val txBaseFrequencyHz: Long?,
-    val ctcssTone: Double?,
-    val isTracking: Boolean,
-    val errorMessage: String?
-)
-
-sealed interface RadioControlAction {
-    data class SelectTransponder(val uuid: String) : RadioControlAction
-    data class SetTxFrequency(val frequencyHz: Long) : RadioControlAction
-    data class AdjustTxFrequency(val deltaHz: Long) : RadioControlAction
-    data class SetCtcssTone(val toneHz: Double?) : RadioControlAction
-    data object ToggleTracking : RadioControlAction
-    data object ConnectRadios : RadioControlAction
-    data object DisconnectRadios : RadioControlAction
-}

feature/radiocontrol/src/main/java/com/rtbishop/look4sat/feature/radiocontrol/RadioControlViewModel.kt

@@ -1,203 +0,0 @@
-/*
- * 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.radiocontrol
-
-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.model.SatRadio
-import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
-import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
-import com.rtbishop.look4sat.core.domain.repository.IRadioTrackingService
-import com.rtbishop.look4sat.core.domain.repository.ISatelliteRepo
-import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
-import com.rtbishop.look4sat.core.domain.utility.toDegrees
-import com.rtbishop.look4sat.core.domain.utility.toTimerString
-import kotlinx.coroutines.delay
-import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.update
-import kotlinx.coroutines.isActive
-import kotlinx.coroutines.launch
-import java.util.Locale
-
-class RadioControlViewModel(
-    private val catNum: Int,
-    private val aosTime: Long,
-    private val trackingService: IRadioTrackingService,
-    private val satelliteRepo: ISatelliteRepo,
-    settingsRepo: ISettingsRepo
-) : ViewModel() {
-
-    private val stationPos = settingsRepo.stationPosition.value
-    private var currentPass: OrbitalPass? = null
-    private var transponders: List<SatRadio> = emptyList()
-
-    private val _uiState = MutableStateFlow(
-        RadioControlState(
-            currentPass = null,
-            currentTime = "00:00:00",
-            isCurrentTimeAos = true,
-            azimuth = "0.0",
-            elevation = "0.0",
-            distance = "0.0",
-            txPanel = RadioPanelState("TX (Uplink)", false, null, "---", null),
-            rxPanel = RadioPanelState("RX (Downlink)", false, null, "---", null),
-            transponders = emptyList(),
-            selectedTransponderUuid = null,
-            txBaseFrequencyHz = null,
-            ctcssTone = null,
-            isTracking = false,
-            errorMessage = null
-        )
-    )
-    val uiState: StateFlow<RadioControlState> = _uiState
-
-    init {
-        // Resolve pass and load transponders
-        viewModelScope.launch {
-            val passes = satelliteRepo.passes.value
-            val pass = passes.find { it.catNum == catNum && it.aosTime == aosTime }
-                ?: passes.firstOrNull()
-            currentPass = pass
-            pass?.let { satPass ->
-                val allRadios = satelliteRepo.getRadiosWithId(satPass.catNum)
-                transponders = allRadios.filter { it.downlinkLow != null }
-                _uiState.update {
-                    it.copy(currentPass = satPass, transponders = transponders)
-                }
-                // If service is already tracking this pass, sync the selected transponder
-                val svcState = trackingService.state.value
-                if (svcState.isActive && svcState.currentPass?.catNum == satPass.catNum) {
-                    _uiState.update {
-                        it.copy(selectedTransponderUuid = svcState.selectedTransponder?.uuid)
-                    }
-                }
-                // Tick loop — timer and satellite position updates every second
-                while (isActive) {
-                    val timeNow = System.currentTimeMillis()
-                    val pos = satelliteRepo.getPosition(satPass.orbitalObject, stationPos, timeNow)
-                    val (timeStr, isAos) = computeTimer(satPass.isDeepSpace, satPass.aosTime, satPass.losTime, timeNow)
-                    _uiState.update { state ->
-                        state.copy(
-                            currentTime = timeStr,
-                            isCurrentTimeAos = isAos,
-                            azimuth = String.format(Locale.ENGLISH, "%.1f", pos.azimuth.toDegrees()),
-                            elevation = String.format(Locale.ENGLISH, "%.1f", pos.elevation.toDegrees()),
-                            distance = String.format(Locale.ENGLISH, "%.0f", pos.distance)
-                        )
-                    }
-                    delay(1000)
-                }
-            }
-        }
-
-        // Observe service state for radio-specific updates (panels, frequencies, tracking status)
-        viewModelScope.launch {
-            trackingService.state.collect { svc ->
-                _uiState.update { state ->
-                    state.copy(
-                        txPanel = RadioPanelState(
-                            label = "TX (Uplink)",
-                            isConnected = svc.txConnected,
-                            frequencyHz = svc.txFrequencyHz,
-                            frequencyDisplay = svc.txFrequencyHz?.let { formatFrequency(it) } ?: "---",
-                            mode = svc.txMode
-                        ),
-                        rxPanel = RadioPanelState(
-                            label = "RX (Downlink)",
-                            isConnected = svc.rxConnected,
-                            frequencyHz = svc.rxFrequencyHz,
-                            frequencyDisplay = svc.rxFrequencyHz?.let { formatFrequency(it) } ?: "---",
-                            mode = svc.rxMode
-                        ),
-                        txBaseFrequencyHz = svc.txBaseFrequencyHz,
-                        ctcssTone = svc.ctcssTone,
-                        isTracking = svc.isActive,
-                        selectedTransponderUuid = svc.selectedTransponder?.uuid,
-                        errorMessage = svc.errorMessage
-                    )
-                }
-            }
-        }
-    }
-
-    private fun computeTimer(isDeepSpace: Boolean, aosTime: Long, losTime: Long, timeNow: Long): Pair<String, Boolean> {
-        return when {
-            isDeepSpace -> 0L.toTimerString() to false
-            aosTime > timeNow -> (aosTime - timeNow).toTimerString() to true
-            else -> (losTime - timeNow).toTimerString() to false
-        }
-    }
-
-    fun onAction(action: RadioControlAction) {
-        when (action) {
-            is RadioControlAction.SelectTransponder -> {
-                val transponder = transponders.find { it.uuid == action.uuid } ?: return
-                trackingService.setTransponder(transponder)
-            }
-            is RadioControlAction.SetTxFrequency -> trackingService.setTxBaseFrequency(action.frequencyHz)
-            is RadioControlAction.AdjustTxFrequency -> trackingService.adjustTxBaseFrequency(action.deltaHz)
-            is RadioControlAction.SetCtcssTone -> trackingService.setCtcssTone(action.toneHz)
-            RadioControlAction.ToggleTracking -> {
-                val svc = trackingService.state.value
-                if (svc.isActive) {
-                    trackingService.stopTracking()
-                } else {
-                    val pass = currentPass ?: return
-                    val transponder = svc.selectedTransponder ?: return
-                    trackingService.startTracking(pass, transponder, svc.txBaseFrequencyHz)
-                }
-            }
-            RadioControlAction.ConnectRadios -> viewModelScope.launch { trackingService.connectRadios() }
-            RadioControlAction.DisconnectRadios -> viewModelScope.launch { trackingService.disconnectRadios() }
-        }
-    }
-
-    companion object {
-
-        val CTCSS_TONES = listOf(67.0, 69.3, 71.9, 74.4, 77.0, 79.7, 82.5, 85.4, 88.5, 91.5,
-            94.8, 97.4, 100.0, 103.5, 107.2, 110.9, 114.8, 118.8, 123.0, 127.3, 131.8, 136.5,
-            141.3, 146.2, 151.4, 156.7, 162.2, 167.9, 173.8, 179.9, 186.2, 192.8, 203.5, 210.7,
-            218.1, 225.7, 233.6, 241.8, 250.3)
-
-        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)
-        }
-
-        fun factory(catNum: Int, aosTime: Long): ViewModelProvider.Factory = viewModelFactory {
-            val applicationKey = ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY
-            initializer {
-                val container = (this[applicationKey] as IContainerProvider).getMainContainer()
-                RadioControlViewModel(
-                    catNum = catNum,
-                    aosTime = aosTime,
-                    trackingService = container.radioTrackingService,
-                    satelliteRepo = container.satelliteRepo,
-                    settingsRepo = container.settingsRepo
-                )
-            }
-        }
-    }
-}

feature/satellites/src/main/java/com/rtbishop/look4sat/feature/satellites/SatellitesScreen.kt

@@ -44,6 +44,7 @@ import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.contentDescription
@@ -57,6 +58,7 @@ import androidx.compose.ui.unit.sp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.rtbishop.look4sat.core.domain.model.SatItem
+import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
 import com.rtbishop.look4sat.core.presentation.CardLoadingIndicator
 import com.rtbishop.look4sat.core.presentation.EmptyListCard
 import com.rtbishop.look4sat.core.presentation.IconCard
@@ -71,10 +73,9 @@ import com.rtbishop.look4sat.core.presentation.layoutPadding
 
 @Composable
 fun SatellitesDestination(navigateUp: () -> Unit) {
-    val viewModel = viewModel(
-        modelClass = SatellitesViewModel::class.java,
-        factory = SatellitesViewModel.Factory
-    )
+    val context = LocalContext.current
+    val container = (context.applicationContext as IContainerProvider).getMainContainer()
+    val viewModel: SatellitesViewModel = viewModel(factory = SatellitesViewModel.factory(container))
     val uiState = viewModel.uiState.collectAsStateWithLifecycle().value
     SatellitesScreen(uiState, viewModel::onAction, navigateUp)
 }

feature/satellites/src/main/java/com/rtbishop/look4sat/feature/satellites/SatellitesViewModel.kt

@@ -18,11 +18,10 @@
 package com.rtbishop.look4sat.feature.satellites
 
 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.repository.IContainerProvider
+import com.rtbishop.look4sat.core.domain.repository.IMainContainer
 import com.rtbishop.look4sat.core.domain.repository.ISelectionRepo
 import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -97,11 +96,12 @@ class SatellitesViewModel(
     }
 
     companion object {
-        val Factory: ViewModelProvider.Factory = viewModelFactory {
-            val applicationKey = ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY
+        fun factory(container: IMainContainer) = viewModelFactory {
             initializer {
-                val container = (this[applicationKey] as IContainerProvider).getMainContainer()
-                SatellitesViewModel(container.selectionRepo, container.settingsRepo)
+                SatellitesViewModel(
+                    selectionRepo = container.selectionRepo,
+                    settingsRepo = container.settingsRepo
+                )
             }
         }
     }

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsScreen.kt

@@ -51,6 +51,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalUriHandler
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
@@ -62,6 +63,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.rtbishop.look4sat.core.domain.model.OtherSettings
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
+import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
 import com.rtbishop.look4sat.core.presentation.CardButton
 import com.rtbishop.look4sat.core.presentation.IconCard
 import com.rtbishop.look4sat.core.presentation.MainTheme
@@ -77,10 +79,9 @@ import java.util.Locale
 
 @Composable
 fun SettingsDestination() {
-    val viewModel = viewModel(
-        modelClass = SettingsViewModel::class.java,
-        factory = SettingsViewModel.Factory
-    )
+    val context = LocalContext.current
+    val container = (context.applicationContext as IContainerProvider).getMainContainer()
+    val viewModel: SettingsViewModel = viewModel(factory = SettingsViewModel.factory(container))
     val uiState by viewModel.uiState.collectAsStateWithLifecycle()
     SettingsScreen(uiState, viewModel::onAction)
 }
@@ -184,32 +185,63 @@ private fun SettingsScreen(uiState: SettingsState, onAction: (SettingsAction) ->
     val gitHubUrl = stringResource(R.string.prefs_github_url)
     val licenseUrl = stringResource(R.string.prefs_license_url)
     val privacyUrl = stringResource(R.string.prefs_privacy_url)
+    val safeOpenUri: (String) -> Unit = { url ->
+        try { uriHandler.openUri(url) } catch (_: Exception) {}
+    }
 
     ScreenColumn(
         topBar = { isVerticalLayout ->
             if (isVerticalLayout) {
                 TopBar {
-                    TopCard(onClick = { uriHandler.openUri(appUrl) }, version = uiState.appVersionName, modifier = Modifier.weight(1f))
-                    PrimaryIconCard(onClick = { uriHandler.openUri(donateUrl) }, resId = R.drawable.ic_pound)
+                    TopCard(
+                        onClick = { safeOpenUri(appUrl) },
+                        version = uiState.appVersionName,
+                        modifier = Modifier.weight(1f)
+                    )
+                    PrimaryIconCard(onClick = { safeOpenUri(donateUrl) }, resId = R.drawable.ic_pound)
                 }
                 TopBar {
                     Row(modifier = Modifier.weight(1f), horizontalArrangement = Arrangement.spacedBy(6.dp)) {
-                        BotCard(onClick = { uriHandler.openUri(fdroidUrl) }, R.drawable.ic_fdroid, fdroidTitle, modifier = Modifier.weight(1f))
-                        BotCard(onClick = { uriHandler.openUri(gitHubUrl) }, R.drawable.ic_github, gitHubTitle, modifier = Modifier.weight(1f))
+                        BotCard(
+                            onClick = { safeOpenUri(fdroidUrl) },
+                            resId = R.drawable.ic_fdroid,
+                            text = fdroidTitle,
+                            modifier = Modifier.weight(1f)
+                        )
+                        BotCard(
+                            onClick = { safeOpenUri(gitHubUrl) },
+                            resId = R.drawable.ic_github,
+                            text = gitHubTitle,
+                            modifier = Modifier.weight(1f)
+                        )
                     }
-                    IconCard(action = { uriHandler.openUri(licenseUrl) }, resId = R.drawable.ic_license)
-                    IconCard(action = { uriHandler.openUri(privacyUrl) }, resId = R.drawable.ic_policy)
+                    IconCard(action = { safeOpenUri(licenseUrl) }, resId = R.drawable.ic_license)
+                    IconCard(action = { safeOpenUri(privacyUrl) }, resId = R.drawable.ic_policy)
                 }
             } else {
                 TopBar {
-                    PrimaryIconCard(onClick = { uriHandler.openUri(donateUrl) }, resId = R.drawable.ic_pound)
-                    TopCard(onClick = { uriHandler.openUri(appUrl) }, version = uiState.appVersionName, modifier = Modifier.weight(1f))
+                    PrimaryIconCard(onClick = { safeOpenUri(donateUrl) }, resId = R.drawable.ic_pound)
+                    TopCard(
+                        onClick = { safeOpenUri(appUrl) },
+                        version = uiState.appVersionName,
+                        modifier = Modifier.weight(1f)
+                    )
                     Row(modifier = Modifier.weight(1f), horizontalArrangement = Arrangement.spacedBy(6.dp)) {
-                        BotCard(onClick = { uriHandler.openUri(fdroidUrl) }, R.drawable.ic_fdroid, fdroidTitle, modifier = Modifier.weight(1f))
-                        BotCard(onClick = { uriHandler.openUri(gitHubUrl) }, R.drawable.ic_github, gitHubTitle, modifier = Modifier.weight(1f))
+                        BotCard(
+                            onClick = { safeOpenUri(fdroidUrl) },
+                            resId = R.drawable.ic_fdroid,
+                            text = fdroidTitle,
+                            modifier = Modifier.weight(1f)
+                        )
+                        BotCard(
+                            onClick = { safeOpenUri(gitHubUrl) },
+                            resId = R.drawable.ic_github,
+                            text = gitHubTitle,
+                            modifier = Modifier.weight(1f)
+                        )
                     }
-                    IconCard(action = { uriHandler.openUri(licenseUrl) }, resId = R.drawable.ic_license)
-                    IconCard(action = { uriHandler.openUri(privacyUrl) }, resId = R.drawable.ic_policy)
+                    IconCard(action = { safeOpenUri(licenseUrl) }, resId = R.drawable.ic_license)
+                    IconCard(action = { safeOpenUri(privacyUrl) }, resId = R.drawable.ic_policy)
                 }
             }
         }
@@ -422,6 +454,7 @@ private fun OtherCardPreview() = MainTheme {
         stateOfSweep = true,
         stateOfUtc = false,
         stateOfLightTheme = false,
+        stateOfNightMode = false,
         shouldSeeWarning = false,
         shouldSeeWhatsNew = false
     )
@@ -433,7 +466,7 @@ private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Uni
     ElevatedCard(
         modifier = Modifier
             .fillMaxWidth()
-            .height(220.dp)
+            .height(268.dp)
     ) {
         Column(modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)) {
             Text(
@@ -452,6 +485,9 @@ private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Uni
             SwitchRow(R.string.prefs_other_switch_sensors, settings.stateOfSensors) {
                 onAction(SettingsAction.ToggleSensor(it))
             }
+            SwitchRow(R.string.prefs_other_switch_night_mode, settings.stateOfNightMode) {
+                onAction(SettingsAction.ToggleNightMode(it))
+            }
         }
     }
 }
@@ -502,7 +538,7 @@ private fun CardCredits(modifier: Modifier = Modifier) {
     ElevatedCard(
         modifier = modifier
             .fillMaxWidth()
-            .height(220.dp)
+            .height(268.dp)
     ) {
         Column(
             verticalArrangement = Arrangement.SpaceBetween,

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsState.kt

@@ -60,6 +60,7 @@ sealed interface SettingsAction {
     data class ToggleSweep(val value: Boolean) : SettingsAction
     data class ToggleSensor(val value: Boolean) : SettingsAction
     data class ToggleLightTheme(val value: Boolean) : SettingsAction
+    data class ToggleNightMode(val value: Boolean) : SettingsAction
 
     // Remote control
     data class UpdateRC(val settings: RCSettings) : SettingsAction

feature/settings/src/main/java/com/rtbishop/look4sat/feature/settings/SettingsViewModel.kt

@@ -18,12 +18,11 @@
 package com.rtbishop.look4sat.feature.settings
 
 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.repository.IContainerProvider
 import com.rtbishop.look4sat.core.domain.repository.IDatabaseRepo
+import com.rtbishop.look4sat.core.domain.repository.IMainContainer
 import com.rtbishop.look4sat.core.domain.repository.ISettingsRepo
 import com.rtbishop.look4sat.core.domain.usecase.IShowToast
 import com.rtbishop.look4sat.core.presentation.R
@@ -121,6 +120,7 @@ class SettingsViewModel(
             is SettingsAction.ToggleSweep -> settingsRepo.updateOtherSettings { it.copy(stateOfSweep = action.value) }
             is SettingsAction.ToggleSensor -> settingsRepo.updateOtherSettings { it.copy(stateOfSensors = action.value) }
             is SettingsAction.ToggleLightTheme -> settingsRepo.updateOtherSettings { it.copy(stateOfLightTheme = action.value) }
+            is SettingsAction.ToggleNightMode -> settingsRepo.updateOtherSettings { it.copy(stateOfNightMode = action.value) }
             // Remote control & data sources
             is SettingsAction.UpdateRC -> settingsRepo.updateRCSettings(action.settings)
             is SettingsAction.UpdateRadioControl -> settingsRepo.updateRadioControlSettings(action.settings)
@@ -187,14 +187,12 @@ class SettingsViewModel(
     // endregion
 
     companion object {
-        val Factory: ViewModelProvider.Factory = viewModelFactory {
-            val applicationKey = ViewModelProvider.AndroidViewModelFactory.APPLICATION_KEY
+        fun factory(container: IMainContainer) = viewModelFactory {
             initializer {
-                val container = (this[applicationKey] as IContainerProvider).getMainContainer()
                 SettingsViewModel(
-                    container.databaseRepo,
-                    container.settingsRepo,
-                    container.provideShowToast()
+                    databaseRepo = container.databaseRepo,
+                    settingsRepo = container.settingsRepo,
+                    showToast = container.provideShowToast()
                 )
             }
         }

gradle/libs.versions.toml

@@ -1,8 +1,8 @@
 [versions]
 #noinspection UnusedVersionCatalogEntry
-appVersionCode = "422"
+appVersionCode = "440"
 #noinspection UnusedVersionCatalogEntry
-appVersionName = "4.2.2"
+appVersionName = "4.4.0"
 #noinspection GradleDependency,UnusedVersionCatalogEntry
 compileSdk = "36"
 #noinspection UnusedVersionCatalogEntry
@@ -12,21 +12,21 @@ jdkVersion = "17"
 #noinspection UnusedVersionCatalogEntry
 packageName = "com.rtbishop.look4sat"
 
-android-gradle-plugin = "9.2.0"
+android-gradle-plugin = "9.2.1"
 
 androidx-core-ktx = "1.18.0"
 androidx-core-splashscreen = "1.2.0"
 androidx-room = "2.8.4"
 
-compose-bom = "2026.04.01"
+compose-bom = "2026.05.01"
 compose-activity = "1.13.0"
 compose-lifecycle = "2.10.0"
-compose-navigation3 = "1.1.1"
+compose-navigation3 = "1.1.2"
 
-google-ksp = "2.3.6"
+google-ksp = "2.3.7"
 
-kotlin = "2.3.20"
-kotlin-coroutines = "1.10.2"
+kotlin = "2.3.21"
+kotlin-coroutines = "1.11.0"
 kotlin-serialization = "1.11.0"
 
 other-okhttp = "5.3.2"

gradle/wrapper/gradle-wrapper.properties

@@ -1,7 +1,7 @@
-#Sun Mar 22 10:09:53 GMT 2026
+#Mon May 25 11:20:48 BST 2026
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.5.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME

settings.gradle.kts

@@ -24,7 +24,6 @@ include(
     ":feature:map",
     ":feature:passes",
     ":feature:radar",
-    ":feature:radiocontrol",
     ":feature:satellites",
     ":feature:settings"
 )