feat(lotw): cancel in-flight sync, honest progress bar, drop stale hint

- Cancel: the dialog's cancel/back while syncing now aborts the download job
  (cooperative cancellation in the stream reader, CancellationException
  propagated, nothing written to storage). An accidental full sync can be
  stopped immediately.
- Progress: the size estimate is conservative (900 B/record vs measured 720)
  so the bar never hits 100% before the download truly ends; storage writes
  moved to the IO dispatcher (multi-MB per-grid QSO JSON used to freeze the
  main thread after download); when the bar caps, the UI switches to
  'Processing downloaded data…' instead of looking stuck.
- Removed the outdated '3-10 seconds' hint (misleading for large accounts).

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

@@ -18,9 +18,13 @@
 package com.rtbishop.look4sat.core.data.repository
 
 import com.rtbishop.look4sat.core.domain.repository.ILoTWRepository
+import com.rtbishop.look4sat.core.domain.repository.LoTWPhase
+import com.rtbishop.look4sat.core.domain.repository.LoTWProgress
 import com.rtbishop.look4sat.core.domain.repository.LoTWResult
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ensureActive
 import kotlinx.coroutines.withContext
+import kotlin.coroutines.coroutineContext
 import java.net.HttpURLConnection
 import java.net.SocketTimeoutException
 import java.net.URL
@@ -46,7 +50,7 @@ class LoTWRepository : ILoTWRepository {
 
     override suspend fun fetchConfirmedGrids(callsign: String, password: String): LoTWResult =
         withContext(Dispatchers.IO) {
-            fetchReportBody(callsign, password).fold(
+            fetchReportBody(callsign, password, since = "", onProgress = {}).fold(
                 onSuccess = { body ->
                     parseBoth(body)?.let { (grids, _, roamed) ->
                         LoTWResult.Success(grids, emptyMap(), roamed)
@@ -58,9 +62,11 @@ class LoTWRepository : ILoTWRepository {
 
     override suspend fun fetchConfirmedGridQsos(
         callsign: String,
-        password: String
+        password: String,
+        since: String,
+        onProgress: (LoTWProgress) -> Unit
     ): LoTWResult = withContext(Dispatchers.IO) {
-        fetchReportBody(callsign, password).fold(
+        fetchReportBody(callsign, password, since, onProgress).fold(
             onSuccess = { body ->
                 parseBoth(body)?.let { (grids, qsos, roamed) ->
                     LoTWResult.Success(grids, qsos, roamed)
@@ -87,33 +93,46 @@ class LoTWRepository : ILoTWRepository {
         return Triple(grids, qsos, roamed)
     }
 
-    private fun fetchReportBody(callsign: String, password: String): Result<String> {
+    private suspend fun fetchReportBody(
+        callsign: String,
+        password: String,
+        since: String,
+        onProgress: (LoTWProgress) -> Unit
+    ): Result<String> {
         val call = callsign.trim().uppercase()
         val pwd = password.trim()
         if (call.isBlank() || pwd.isBlank()) return Result.failure(IOException("empty credentials"))
-        // qso_qslsince with an early date forces a FULL confirmed-QSL report.
-        // Without it, LoTW applies a "system supplied default" since-date and
-        // only returns confirmations newer than the account's last query —
-        // subsequent syncs would return an empty/incremental report.
-        val since = "2000-01-01"
+        // Empty since -> full report. qso_qslsince with an early date forces a
+        // FULL confirmed-QSL report; without it LoTW applies a "system supplied
+        // default" since-date and only returns confirmations newer than the
+        // account's last query — subsequent syncs would be incremental/empty.
+        val effectiveSince = since.ifBlank { "2000-01-01" }
         val query = buildString {
             append("login=").append(URLEncoder.encode(call, "UTF-8"))
             append("&password=").append(URLEncoder.encode(pwd, "UTF-8"))
             append("&qso_query=1&qso_qsl=yes&qso_qsldetail=yes&qso_mydetail=yes")
-            append("&qso_qslsince=").append(URLEncoder.encode(since, "UTF-8"))
+            append("&qso_qslsince=").append(URLEncoder.encode(effectiveSince, "UTF-8"))
         }
         return try {
             val connection = URL("$BASE_URL?$query").openConnection() as HttpURLConnection
             // ARRL can be slow to accept connections from mobile networks
             // (long TLS handshakes across the Pacific, occasional server-side
-            // queueing). 30s connect + 120s read gives the request enough
-            // headroom; the sync button stays disabled meanwhile so users
-            // see progress rather than a hung dialog.
-            connection.connectTimeout = 30_000
-            connection.readTimeout = 120_000
+            // queueing — a busy server took 36.5 s to accept a connection in
+            // testing, so 30 s connect would have killed it).
+            //
+            // NOTE: readTimeout is NOT a total-download cap. It is the longest
+            // wait for the NEXT chunk of data (a stall timeout). A full report
+            // for a huge account (tens of thousands of QSLs ≈ tens of MB at
+            // ARRL's ~10 KB/s stream rate) legitimately takes 30+ minutes;
+            // as long as chunks keep arriving it must never be cut off.
+            // 600 s tolerates long server-side pauses while it generates the
+            // report; a truly dead link (no data at all) still fails within it.
+            connection.connectTimeout = 60_000
+            connection.readTimeout = 600_000
             connection.requestMethod = "GET"
             connection.setRequestProperty("Accept-Encoding", "gzip")
             connection.instanceFollowRedirects = true
+            onProgress(LoTWProgress(LoTWPhase.Connecting))
             val code = connection.responseCode
             if (code !in 200..299) {
                 connection.disconnect()
@@ -123,9 +142,8 @@ class LoTWRepository : ILoTWRepository {
                 else Result.failure(IOException("HTTP $code"))
             }
             val stream = connection.inputStream
-            val body = ("gzip".equals(connection.contentEncoding, ignoreCase = true))
-                .let { gz -> if (gz) java.util.zip.GZIPInputStream(stream) else stream }
-                .bufferedReader().use { it.readText() }
+            val isGzip = "gzip".equals(connection.contentEncoding, ignoreCase = true)
+            val body = readBodyWithProgress(stream, isGzip, onProgress)
             connection.disconnect()
             when {
                 // Login failure: HTTP 200 + HTML login page with the error text.
@@ -135,6 +153,9 @@ class LoTWRepository : ILoTWRepository {
                 !body.contains("<eoh>", ignoreCase = true) -> Result.failure(RateLimitException())
                 else -> Result.success(body)
             }
+        } catch (e: java.util.concurrent.CancellationException) {
+            // Cancellation must propagate — it is not a network failure.
+            throw e
         } catch (e: SocketTimeoutException) {
             Result.failure(TimeoutException(e.message ?: "timed out"))
         } catch (e: SSLException) {
@@ -145,6 +166,68 @@ class LoTWRepository : ILoTWRepository {
         }
     }
 
+    /**
+     * Streams the report body into a string while reporting download progress.
+     * Once the header's record count (<APP_LoTW_NUMREC>) is seen, the total
+     * body size is estimated as NUMREC * AVG_RECORD_BYTES so the UI can show a
+     * meaningful progress bar and remaining-time estimate.
+     */
+    private suspend fun readBodyWithProgress(
+        stream: java.io.InputStream,
+        isGzip: Boolean,
+        onProgress: (LoTWProgress) -> Unit
+    ): String {
+        val input = if (isGzip) java.util.zip.GZIPInputStream(stream) else stream
+        val reader = java.io.InputStreamReader(input, Charsets.UTF_8)
+        val sb = StringBuilder()
+        val buf = CharArray(8192)
+        var bytesRead = 0L
+        var expected = 0L
+        var qsoCount = 0L
+        var speed = 0L
+        var headerSeen = false
+        var lastSampleMs = System.currentTimeMillis()
+        var lastSampleBytes = 0L
+        var lastEmitMs = 0L
+        while (true) {
+            // Cooperative cancellation: lets the user abort a full sync that
+            // was started by mistake. Throws CancellationException once the
+            // job is cancelled; the blocking read below is fast while chunks
+            // keep arriving, so the abort lands on the next chunk boundary.
+            coroutineContext.ensureActive()
+            val n = reader.read(buf)
+            if (n <= 0) break
+            sb.append(buf, 0, n)
+            bytesRead += n
+            // The record count sits in the report header, long before the data.
+            if (!headerSeen) {
+                NUMREC_REGEX.find(sb)?.let { m ->
+                    qsoCount = m.groupValues[1].toLongOrNull() ?: 0L
+                    expected = qsoCount * AVG_RECORD_BYTES
+                    headerSeen = true
+                }
+            }
+            // Sample speed every 500ms, EMA-smoothed.
+            val now = System.currentTimeMillis()
+            if (now - lastSampleMs >= 500) {
+                val elapsedS = (now - lastSampleMs) / 1000.0
+                if (elapsedS > 0) {
+                    val inst = ((bytesRead - lastSampleBytes) / elapsedS).toLong()
+                    speed = if (speed == 0L) inst else (speed * 7 + inst * 3) / 10
+                    lastSampleMs = now
+                    lastSampleBytes = bytesRead
+                }
+            }
+            // Throttle callbacks to ~4/s so StateFlow updates stay cheap.
+            if (now - lastEmitMs >= 250) {
+                onProgress(LoTWProgress(LoTWPhase.Downloading, bytesRead, expected, speed, qsoCount))
+                lastEmitMs = now
+            }
+        }
+        onProgress(LoTWProgress(LoTWPhase.Downloading, bytesRead, expected, speed, qsoCount))
+        return sb.toString()
+    }
+
     internal class CredentialsException : Exception("bad callsign/password")
     internal class RateLimitException : Exception("report refused (rate limit / server error)")
     internal class TimeoutException(message: String) : Exception(message)
@@ -362,5 +445,16 @@ class LoTWRepository : ILoTWRepository {
 
     private companion object {
         const val BASE_URL = "https://lotw.arrl.org/lotwuser/lotwreport.adi"
+
+        /** Record count in the report header: `<APP_LoTW_NUMREC:4>2367`. */
+        val NUMREC_REGEX = Regex("<APP_LoTW_NUMREC:\\d+>(\\d+)")
+        /**
+         * Measured 2026-09-16 (BH6RJD, 2367 QSLs): 1.7 MB body streamed at
+         * ~9.5 KB/s ≈ 180 s, i.e. ≈ 720 bytes per ADIF record. Use a
+         * CONSERVATIVE (larger) estimate so the progress bar never hits 100%
+         * before the download truly ends — an under-estimate made the bar sit
+         * at 100% while data was still flowing, read as "finished but stuck".
+         */
+        const val AVG_RECORD_BYTES = 900L
     }
 }

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

@@ -289,6 +289,24 @@ class SettingsRepo(
             callsign = preferences.getString(keyLoTWCall, null).orEmpty(),
             password = preferences.getString(keyLoTWPass, null).orEmpty()
         )
+
+    // Last successful sync bookkeeping: date ("yyyyMMdd") and callsign. Used to
+    // decide incremental (same callsign) vs full (first time / callsign change)
+    // report requests and to merge increments into the stored grid data.
+    private val keyLastLotwSyncDate = "lotwLastSyncDate"
+    private val keyLastLotwSyncCallsign = "lotwLastSyncCallsign"
+
+    override fun getLastLotwSyncDate(): String =
+        preferences.getString(keyLastLotwSyncDate, null).orEmpty()
+
+    override fun setLastLotwSyncDate(date: String) =
+        preferences.edit { putString(keyLastLotwSyncDate, date) }
+
+    override fun getLastLotwSyncCallsign(): String =
+        preferences.getString(keyLastLotwSyncCallsign, null).orEmpty()
+
+    override fun setLastLotwSyncCallsign(callsign: String) =
+        preferences.edit { putString(keyLastLotwSyncCallsign, callsign.trim().uppercase()) }
     //endregion
 
     //region # Transceivers settings

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

@@ -296,6 +296,10 @@ private class FakeSettingsRepo(dataSources: DataSourcesSettings = defaultDataSou
         MutableStateFlow(com.rtbishop.look4sat.core.domain.model.LoTWSettings())
 
     override fun updateLoTWSettings(settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings) = Unit
+    override fun getLastLotwSyncDate(): String = ""
+    override fun setLastLotwSyncDate(date: String) = Unit
+    override fun getLastLotwSyncCallsign(): String = ""
+    override fun setLastLotwSyncCallsign(callsign: String) = Unit
 
     override fun getWorkedGridQsos(): Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>> = emptyMap()
 

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

@@ -30,9 +30,43 @@ interface ILoTWRepository {
      * Same report, but keeps the per-QSO detail of every confirmed satellite
      * QSO (call / time / satellite / mode / bands), grouped by worked 4-char
      * gridsquare. Failure cause is kept explicit.
+     *
+     * @param since   QSL-since date ("yyyyMMdd" or "yyyy-MM-dd"); use an early
+     *                date for a full report, or the last sync date for an
+     *                incremental pull. Empty falls back to a full report.
+     * @param onProgress  streamed download progress (phase + bytes + estimate),
+     *                invoked from the IO dispatcher; may be called on every
+     *                read chunk.
      */
     suspend fun fetchConfirmedGridQsos(
         callsign: String,
-        password: String
+        password: String,
+        since: String = "",
+        onProgress: (LoTWProgress) -> Unit = {}
     ): LoTWResult
 }
+
+/** Streamed progress of a LoTW report download. */
+data class LoTWProgress(
+    val phase: LoTWPhase,
+    /** Bytes read so far (uncompressed body). */
+    val bytesRead: Long = 0,
+    /** Estimated total body bytes, derived from <APP_LoTW_NUMREC>; 0 before known. */
+    val expectedBytes: Long = 0,
+    /** Smoothed download speed in bytes/second; 0 while unknown. */
+    val speedBps: Long = 0,
+    /** Total QSL records reported in the header (<APP_LoTW_NUMREC>); 0 before known. */
+    val qsoCount: Long = 0
+) {
+    /** Fraction 0..1 of the estimated body already read; 0 while unknown. */
+    val fraction: Float
+        get() = if (expectedBytes > 0 && bytesRead > 0)
+            (bytesRead.toFloat() / expectedBytes).coerceIn(0f, 1f) else 0f
+
+    /** Estimated seconds remaining; 0 while size or speed is unknown. */
+    val remainingSeconds: Long
+        get() = if (expectedBytes > 0 && speedBps > 0)
+            ((expectedBytes - bytesRead) / speedBps).coerceAtLeast(0) else 0L
+}
+
+enum class LoTWPhase { Connecting, Downloading }

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

@@ -110,5 +110,11 @@ interface ISettingsRepo {
     //region # LoTW confirmed-grids settings
     val lotwSettings: StateFlow<com.rtbishop.look4sat.core.domain.model.LoTWSettings>
     fun updateLoTWSettings(settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings)
+    /** Last successful LoTW sync date ("yyyyMMdd", empty when never synced). */
+    fun getLastLotwSyncDate(): String
+    fun setLastLotwSyncDate(date: String)
+    /** Callsign of the last successful LoTW sync (empty when never synced). */
+    fun getLastLotwSyncCallsign(): String
+    fun setLastLotwSyncCallsign(callsign: String)
     //endregion
 }

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

@@ -375,7 +375,10 @@ fun SharedDialog(
                 overflow = TextOverflow.Ellipsis,
                 modifier = Modifier
                     .weight(1f)
-                    .padding(horizontal = if (onCancel != null && onAccept != null) padding else 0.dp)
+                    .padding(
+                        start = if (onCancel != null) padding else 0.dp,
+                        end = if (onAccept != null) padding else 0.dp
+                    )
             )
             if (onAccept != null) {
                 CardButton(

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

@@ -160,11 +160,23 @@
     <string name="prefs_lotw_callsign">LoTW 呼号</string>
     <string name="prefs_lotw_password">LoTW 密码</string>
     <string name="prefs_lotw_hint">直接从 ARRL LoTW 拉取该呼号已确认 QSO 的网格并覆盖本地已存集合（当前 %1$d 个）。密码仅保存在手机本地。点"同步"会自动保存凭据并拉取。</string>
-    <string name="prefs_lotw_sync_duration_hint">同步通常约需 3–10 秒；首次同步或 ARRL 服务器繁忙时可能更久。</string>
     <string name="prefs_lotw_sync">同步</string>
     <string name="prefs_lotw_syncing">同步中…</string>
     <string name="prefs_lotw_configured">已从 LoTW 同步 — 共 %1$d 个网格</string>
     <string name="prefs_lotw_not_configured">未配置 — 直接登录 ARRL LoTW 拉取已确认 QSO 的网格，无需自建服务器</string>
+    <string name="lotw_sync_error_not_configured">LoTW 呼号/密码未配置</string>
+    <string name="lotw_sync_error_credentials">LoTW 同步失败——呼号或密码错误</string>
+    <string name="lotw_sync_error_rate_limited">LoTW 同步失败——服务器限流，请等几分钟后再试</string>
+    <string name="lotw_sync_error_timeout">LoTW 同步失败——连接超时，请更换网络重试</string>
+    <string name="lotw_sync_error_network">LoTW 同步失败——网络错误（%1$s）</string>
+    <string name="lotw_sync_full">全量同步</string>
+    <string name="lotw_sync_incremental">增量合并</string>
+    <string name="lotw_sync_rate_hint">下载速度约每 100 条 QSO 需 8 秒（另有 5–40 秒服务器生成时间）</string>
+    <string name="lotw_sync_progress_connecting">正在连接 LoTW 服务器…</string>
+    <string name="lotw_sync_progress_downloading">正在下载报告…</string>
+    <string name="lotw_sync_progress_saving">正在处理下载的数据…</string>
+    <string name="lotw_sync_progress_count">本次同步 %1$d 条 QSO…</string>
+    <string name="lotw_sync_progress_qso">本次同步 %1$d 条 QSO，预计还需 %2$d 秒</string>
     <string name="prefs_locator_text">使用梅登黑德网格设置站点位置</string>
 
     <string name="prefs_data_title">卫星数据更新</string>

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

@@ -195,11 +195,23 @@
     <string name="prefs_lotw_callsign">LoTW callsign</string>
     <string name="prefs_lotw_password">LoTW password</string>
     <string name="prefs_lotw_hint">Fetch confirmed-QSO grids directly from ARRL LoTW for this callsign and replace the stored set (currently %1$d). The password is stored on this device only. Tapping Sync saves the credentials and fetches in one step.</string>
-    <string name="prefs_lotw_sync_duration_hint">A sync usually takes about 3–10 seconds; the first one or a busy ARRL server can take longer.</string>
     <string name="prefs_lotw_sync">Sync</string>
     <string name="prefs_lotw_syncing">Syncing…</string>
     <string name="prefs_lotw_configured">Synced from LoTW — %1$d grids total</string>
     <string name="prefs_lotw_not_configured">Not configured — pull confirmed grids directly from ARRL LoTW, no self-hosted server needed</string>
+    <string name="lotw_sync_error_not_configured">LoTW callsign/password not configured</string>
+    <string name="lotw_sync_error_credentials">LoTW sync failed — callsign or password incorrect</string>
+    <string name="lotw_sync_error_rate_limited">LoTW sync failed — rate limited by server, wait a few minutes and retry</string>
+    <string name="lotw_sync_error_timeout">LoTW sync failed — connection timed out, try another network</string>
+    <string name="lotw_sync_error_network">LoTW sync failed — network error (%1$s)</string>
+    <string name="lotw_sync_full">Full sync</string>
+    <string name="lotw_sync_incremental">Incremental merge</string>
+    <string name="lotw_sync_rate_hint">Download runs at ~8 s per 100 QSOs (plus 5–40 s server generation time)</string>
+    <string name="lotw_sync_progress_connecting">Connecting to LoTW…</string>
+    <string name="lotw_sync_progress_downloading">Downloading report…</string>
+    <string name="lotw_sync_progress_saving">Processing downloaded data…</string>
+    <string name="lotw_sync_progress_count">Syncing %1$d QSOs…</string>
+    <string name="lotw_sync_progress_qso">Syncing %1$d QSOs, ~%2$d s remaining</string>
     <string name="prefs_locator_text">Set station\'s position using locator</string>
 
     <string name="prefs_data_title">Satellite data</string>

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

@@ -226,7 +226,7 @@ class MaidenheadGridOverlay : Overlay() {
                         if (xRight < 0f || xLeft > canvas.width) continue
                         val label = cellLabel(lat, lon, zoom)
                         if (label in roamedGrids && label != ownGrid) {
-                            drawStripes(canvas, xLeft, yTop, xRight, yBottom)
+                            drawStripes(canvas, xLeft, yTop, xRight, yBottom, zoom)
                         }
                     }
                 }
@@ -246,7 +246,7 @@ class MaidenheadGridOverlay : Overlay() {
                         val xRight = xRightBase + turn * worldWidthPx.toFloat()
                         if (xRight < 0f || xLeft > canvas.width) continue
                         if (yBottom < 0f || yTop > canvas.height) continue
-                        drawStripes(canvas, xLeft, yTop, xRight, yBottom)
+                        drawStripes(canvas, xLeft, yTop, xRight, yBottom, zoom)
                     }
                 }
             }
@@ -396,17 +396,21 @@ class MaidenheadGridOverlay : Overlay() {
      * rectangle, from top-left to bottom-right. The paint is nearly opaque so
      * stripes stay blue even over a green worked fill underneath.
      */
-    private fun drawStripes(canvas: Canvas, xLeft: Float, yTop: Float, xRight: Float, yBottom: Float) {
+    private fun drawStripes(canvas: Canvas, xLeft: Float, yTop: Float, xRight: Float, yBottom: Float, zoom: Double) {
         if (xRight <= xLeft || yBottom <= yTop) return
         canvas.save()
         canvas.clipRect(xLeft, yTop, xRight, yBottom)
         val height = yBottom - yTop
+        // Geographic density is kept constant: spacing is the reference pixel
+        // spacing (STRIPE_SPACING_PX at the map's max zoom) scaled by 2^(zoom-max),
+        // so stripes shrink/grow with the map instead of staying fixed on screen.
+        val spacing = STRIPE_SPACING_PX * Math.pow(2.0, zoom - MAX_GRID_ZOOM).toFloat()
         // Start one stripe-width left of the cell so the top-left corner is
         // always covered; each stripe runs from (x, top) to (x+height, bottom).
         var x = xLeft - height
         while (x < xRight) {
             canvas.drawLine(x, yTop, x + height, yBottom, roamStripePaint)
-            x += STRIPE_SPACING_PX
+            x += spacing
         }
         canvas.restore()
     }
@@ -509,5 +513,12 @@ class MaidenheadGridOverlay : Overlay() {
         // 44f spacing (was 16f — too dense per user) with 14f-wide stripes;
         // sparse GridMaster-style zebra.
         const val STRIPE_SPACING_PX = 44f
+        /**
+         * Reference zoom for stripe spacing: the map's max zoom (MapScreen sets
+         * maxZoomLevel = 7.0). At this zoom stripes are STRIPE_SPACING_PX apart;
+         * at lower zooms spacing scales by 2^(zoom-max) so the geographic
+         * density matches the max-zoom look at every level.
+         */
+        const val MAX_GRID_ZOOM = 7.0
     }
 }

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

@@ -29,6 +29,7 @@ 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.IntrinsicSize
 import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
@@ -659,10 +660,14 @@ private fun VuccGridSelector(
         shape = RoundedCornerShape(8.dp),
         modifier = modifier
     ) {
-        Column {
+        // Width = widest child (header or list item), never the full screen:
+        // the expanded rows use fillMaxWidth, which would otherwise stretch
+        // this box to the whole map width.
+        Column(modifier = Modifier.width(IntrinsicSize.Max)) {
             Row(
                 verticalAlignment = Alignment.CenterVertically,
                 modifier = Modifier
+                    .fillMaxWidth()
                     .clickable { expanded = !expanded }
                     .padding(start = 10.dp, end = 6.dp, top = 4.dp, bottom = 4.dp)
             ) {

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

@@ -45,6 +45,7 @@ import com.rtbishop.look4sat.core.presentation.R
 import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
+import java.util.TimeZone
 import kotlin.math.roundToInt
 
 /**
@@ -58,6 +59,7 @@ fun ElevationCurveChart(
     startTime: Long,
     endTime: Long,
     maxElev: Double,
+    isUtc: Boolean = false,
     progress: Float = 0.5f,
     onProgressChange: (Float) -> Unit = {},
     modifier: Modifier = Modifier
@@ -74,7 +76,11 @@ fun ElevationCurveChart(
     val textColorArgb = textColor.toArgb()
     val onSurfaceArgb = onSurfaceColor.toArgb()
     val gridColorArgb = gridColor.toArgb()
-    val timeFormat = remember { SimpleDateFormat("HH:mm", Locale.getDefault()) }
+    val timeFormat = remember(isUtc) {
+        SimpleDateFormat("HH:mm", Locale.getDefault()).apply {
+            if (isUtc) timeZone = TimeZone.getTimeZone("UTC")
+        }
+    }
 
     Column(modifier = modifier.fillMaxWidth()) {
         Canvas(

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

@@ -29,6 +29,7 @@ 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
@@ -40,6 +41,7 @@ import androidx.compose.material3.ElevatedCard
 import androidx.compose.material3.FilterChip
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
+import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.OutlinedButton
 import androidx.compose.material3.OutlinedTextField
@@ -71,6 +73,7 @@ import com.rtbishop.look4sat.core.presentation.isVerticalLayout
 import java.text.SimpleDateFormat
 import java.util.Date
 import java.util.Locale
+import java.util.TimeZone
 
 @Composable
 fun MutualScreen(
@@ -186,7 +189,11 @@ private fun MutualContent(
     onHoursAhead: (Int) -> Unit,
     onClearError: () -> Unit
 ) {
-    val timeFormat = remember { SimpleDateFormat("MM/dd HH:mm", Locale.getDefault()) }
+    val timeFormat = remember(state.isUtc) {
+        SimpleDateFormat("MM/dd HH:mm", Locale.getDefault()).apply {
+            if (state.isUtc) timeZone = TimeZone.getTimeZone("UTC")
+        }
+    }
 
     LazyColumn(
         modifier = Modifier.fillMaxSize(),
@@ -323,6 +330,7 @@ private fun MutualContent(
                 pass = pass,
                 isExpanded = state.selectedPassIndex == index,
                 timeFormat = timeFormat,
+                isUtc = state.isUtc,
                 minElevA = state.stationAMinElev,
                 minElevB = state.stationBMinElev,
                 onClick = { onSelectPass(if (state.selectedPassIndex == index) -1 else index) },
@@ -527,6 +535,7 @@ private fun MutualPassCard(
     pass: MutualPass,
     isExpanded: Boolean,
     timeFormat: SimpleDateFormat,
+    isUtc: Boolean,
     minElevA: Double,
     minElevB: Double,
     onClick: () -> Unit,
@@ -558,39 +567,62 @@ private fun MutualPassCard(
             .clickable(onClick = onClick)
     ) {
         Column(modifier = Modifier.padding(12.dp)) {
-            Row(
-                modifier = Modifier.fillMaxWidth(),
-                horizontalArrangement = Arrangement.SpaceBetween,
-                verticalAlignment = Alignment.CenterVertically
-            ) {
-                Text(
-                    text = pass.name,
-                    style = MaterialTheme.typography.bodyLarge,
-                    fontWeight = FontWeight.Medium,
-                    color = MaterialTheme.colorScheme.primary,
-                    modifier = Modifier.weight(1f)
-                )
-                Text(
-                    text = "${timeFormat.format(Date(pass.startTime))} - ${timeFormat.format(Date(pass.endTime))}",
-                    style = MaterialTheme.typography.bodySmall,
-                    color = MaterialTheme.colorScheme.onSurfaceVariant
-                )
-            }
-            Spacer(Modifier.height(4.dp))
-            Row(
-                modifier = Modifier.fillMaxWidth(),
-                horizontalArrangement = Arrangement.SpaceBetween
-            ) {
-                Text(
-                    text = stringResource(R.string.mutual_elevation_you, pass.maxElevationA.toInt()),
-                    style = MaterialTheme.typography.bodySmall,
-                    color = MaterialTheme.colorScheme.primary
-                )
-                Text(
-                    text = stringResource(R.string.mutual_elevation_opposite, pass.maxElevationB.toInt()),
-                    style = MaterialTheme.typography.bodySmall,
-                    color = MaterialTheme.colorScheme.tertiary
-                )
+            // Header: pass info (name/time + elevations) on the left, and a
+            // larger radar shortcut on the right that spans both rows vertically.
+            // The pass info column narrows, so the "Opposite" elevation shifts
+            // left to make room for the taller button.
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Column(modifier = Modifier.weight(1f)) {
+                    Row(
+                        modifier = Modifier.fillMaxWidth(),
+                        horizontalArrangement = Arrangement.SpaceBetween,
+                        verticalAlignment = Alignment.CenterVertically
+                    ) {
+                        Text(
+                            text = pass.name,
+                            style = MaterialTheme.typography.bodyLarge,
+                            fontWeight = FontWeight.Medium,
+                            color = MaterialTheme.colorScheme.primary,
+                            maxLines = 1,
+                            overflow = TextOverflow.Ellipsis,
+                            modifier = Modifier.weight(1f)
+                        )
+                        Text(
+                            text = "${timeFormat.format(Date(pass.startTime))} - ${timeFormat.format(Date(pass.endTime))}",
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
+                        )
+                    }
+                    Spacer(Modifier.height(4.dp))
+                    Row(
+                        modifier = Modifier.fillMaxWidth(),
+                        horizontalArrangement = Arrangement.SpaceBetween
+                    ) {
+                        Text(
+                            text = stringResource(R.string.mutual_elevation_you, pass.maxElevationA.toInt()),
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.primary
+                        )
+                        Text(
+                            text = stringResource(R.string.mutual_elevation_opposite, pass.maxElevationB.toInt()),
+                            style = MaterialTheme.typography.bodySmall,
+                            color = MaterialTheme.colorScheme.tertiary
+                        )
+                    }
+                }
+                // Radar shortcut, visible even on the collapsed card: a taller
+                // button spanning both header rows. The card's own click
+                // (expand) is not triggered by the IconButton's tap.
+                IconButton(
+                    onClick = onNavigateToRadar,
+                    modifier = Modifier.size(48.dp)
+                ) {
+                    Icon(
+                        painter = painterResource(id = R.drawable.ic_radar),
+                        contentDescription = stringResource(R.string.mutual_open_radar),
+                        modifier = Modifier.size(24.dp)
+                    )
+                }
             }
 
             AnimatedVisibility(
@@ -622,6 +654,7 @@ private fun MutualPassCard(
                             startTime = visibleStart,
                             endTime = visibleEnd,
                             maxElev = adjustedMaxElev,
+                            isUtc = isUtc,
                             progress = dragProgress,
                             onProgressChange = { dragProgress = it }
                         )

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

@@ -33,6 +33,7 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -53,6 +54,7 @@ data class MutualUiState(
     val isCalculating: Boolean = false,
     val hasSearched: Boolean = false,
     val selectedPassIndex: Int = -1,
+    val isUtc: Boolean = false,
     val errorMessage: String? = null
 )
 
@@ -77,8 +79,15 @@ class MutualViewModel(
             stationALat = "%.4f".format(pos.latitude),
             stationALon = "%.4f".format(pos.longitude),
             stationAMinElev = 0.0,
-            stationBMinElev = 0.0
+            stationBMinElev = 0.0,
+            isUtc = settingsRepo.otherSettings.value.stateOfUtc
         ) }
+        // Keep the time display in sync with the UTC toggle in Settings
+        viewModelScope.launch {
+            settingsRepo.otherSettings.collectLatest { settings ->
+                _uiState.update { it.copy(isUtc = settings.stateOfUtc) }
+            }
+        }
     }
 
     fun onStationALat(value: String) {

feature/mutual/src/test/java/com/rtbishop/look4sat/feature/mutual/Fakes.kt

@@ -2,11 +2,14 @@ package com.rtbishop.look4sat.feature.mutual
 
 import com.rtbishop.look4sat.core.domain.model.DataSourcesSettings
 import com.rtbishop.look4sat.core.domain.model.DatabaseState
+import com.rtbishop.look4sat.core.domain.model.GridQso
+import com.rtbishop.look4sat.core.domain.model.LoTWSettings
 import com.rtbishop.look4sat.core.domain.model.OtherSettings
 import com.rtbishop.look4sat.core.domain.model.PassesSettings
 import com.rtbishop.look4sat.core.domain.model.RCSettings
 import com.rtbishop.look4sat.core.domain.model.RadioControlSettings
 import com.rtbishop.look4sat.core.domain.model.SatRadio
+import com.rtbishop.look4sat.core.domain.model.WavelogSettings
 import com.rtbishop.look4sat.core.domain.predict.GeoPos
 import com.rtbishop.look4sat.core.domain.predict.OrbitalObject
 import com.rtbishop.look4sat.core.domain.predict.OrbitalPass
@@ -62,7 +65,17 @@ class FakeSettingsRepo(initialPosition: GeoPos = GeoPos(23.13, 113.26)) : ISetti
         RCSettings(false, "", "", "", false, "", "", "", 0L, false, "", "", "", false, "", "")
     )
     override val otherSettings: StateFlow<OtherSettings> = MutableStateFlow(
-        OtherSettings(false, false, false, false, false, false, false, false)
+        OtherSettings(
+            stateOfAutoUpdate = false,
+            stateOfSensors = false,
+            stateOfSweep = false,
+            stateOfUtc = false,
+            stateOfLightTheme = false,
+            stateOfNightMode = false,
+            stateOfMapGrid = false,
+            shouldSeeWarning = false,
+            shouldSeeWhatsNew = false
+        )
     )
     override val dataSourcesSettings: StateFlow<DataSourcesSettings> = MutableStateFlow(
         DataSourcesSettings(satelliteUrls = emptyList(), transceiversUrls = emptyList())
@@ -70,6 +83,8 @@ class FakeSettingsRepo(initialPosition: GeoPos = GeoPos(23.13, 113.26)) : ISetti
     override val radioControlSettings: StateFlow<RadioControlSettings> = MutableStateFlow(
         RadioControlSettings(false, RadioControlSettings.MODEL_YAESU_FT817, "", "", "", "", 9600)
     )
+    override val wavelogSettings: StateFlow<WavelogSettings> = MutableStateFlow(WavelogSettings())
+    override val lotwSettings: StateFlow<LoTWSettings> = MutableStateFlow(LoTWSettings())
 
     override fun setSelectedIds(ids: List<Int>) = TODO()
     override fun setSelectedTypes(types: List<String>) = TODO()
@@ -93,4 +108,16 @@ class FakeSettingsRepo(initialPosition: GeoPos = GeoPos(23.13, 113.26)) : ISetti
     override fun setSatelliteOffset(catnum: Int, offset: String) = TODO()
     override fun getAmSatCallsign(): String = ""
     override fun setAmSatCallsign(callsign: String) = TODO()
+    override fun updateWavelogSettings(settings: WavelogSettings) = TODO()
+    override fun getWorkedGrids(): Set<String> = TODO()
+    override fun setWorkedGrids(grids: Set<String>) = TODO()
+    override fun getWorkedGridQsos(): Map<String, List<GridQso>> = TODO()
+    override fun setWorkedGridQsos(qsos: Map<String, List<GridQso>>) = TODO()
+    override fun getRoamedGrids(): Set<String> = TODO()
+    override fun setRoamedGrids(grids: Set<String>) = TODO()
+    override fun updateLoTWSettings(settings: LoTWSettings) = TODO()
+    override fun getLastLotwSyncDate(): String = ""
+    override fun setLastLotwSyncDate(date: String) = Unit
+    override fun getLastLotwSyncCallsign(): String = ""
+    override fun setLastLotwSyncCallsign(callsign: String) = Unit
 }

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

@@ -101,14 +101,17 @@ fun RadarDestination(navigateUp: () -> Unit) {
     }
     LaunchedEffect(mutualData.endTime) {
         if (mutualData.endTime <= 0L) return@LaunchedEffect
-        while (true) {
-            val remainingMs = mutualData.endTime - System.currentTimeMillis()
-            if (remainingMs <= 0L) {
-                navigateUpAndClearMutual()
-                return@LaunchedEffect
-            }
+        // Auto-return only while the mutual pass is actually in progress. An
+        // already-finished pass must NOT bounce the radar page back instantly
+        // (that made the pass-card radar shortcut look broken: tapping it while
+        // the computed pass had ended returned to Mutual immediately).
+        var remainingMs = mutualData.endTime - System.currentTimeMillis()
+        if (remainingMs <= 0L) return@LaunchedEffect
+        while (remainingMs > 0L) {
             delay(remainingMs.coerceAtMost(1000L))
+            remainingMs = mutualData.endTime - System.currentTimeMillis()
         }
+        navigateUpAndClearMutual()
     }
     // Sync actual permission state on every recomposition so it survives screen re-entry
     val hasPermission = ContextCompat.checkSelfPermission(

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

@@ -50,6 +50,7 @@ import androidx.compose.material3.Checkbox
 import androidx.compose.material3.FilterChip
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.LinearProgressIndicator
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.TextButton
 import androidx.compose.material3.OutlinedTextField
@@ -228,23 +229,27 @@ fun LoTWDialog(
     initialSettings: com.rtbishop.look4sat.core.domain.model.LoTWSettings,
     workedGridsCount: Int,
     isSyncing: Boolean,
+    syncMode: LoTWSyncMode?,
+    progress: com.rtbishop.look4sat.core.domain.repository.LoTWProgress?,
     message: String?,
     dismiss: () -> Unit,
+    /** Called on cancel/back while a sync is running: aborts the job. */
+    onCancelSync: () -> Unit,
     onSave: (com.rtbishop.look4sat.core.domain.model.LoTWSettings) -> Unit,
-    onSync: (com.rtbishop.look4sat.core.domain.model.LoTWSettings) -> Unit
+    onSyncFull: (com.rtbishop.look4sat.core.domain.model.LoTWSettings) -> Unit,
+    onSyncIncremental: (com.rtbishop.look4sat.core.domain.model.LoTWSettings) -> Unit
 ) {
     val call = rememberSaveable { mutableStateOf(initialSettings.callsign) }
     val pass = rememberSaveable { mutableStateOf(initialSettings.password) }
     SharedDialog(
         title = stringResource(R.string.prefs_lotw_title),
-        onCancel = dismiss,
-        // The confirm button IS the sync action: saving credentials and
-        // fetching confirmed grids happen in one step.
-        onAccept = {
-            onSync(com.rtbishop.look4sat.core.domain.model.LoTWSettings(call.value, pass.value))
-        },
-        acceptText = stringResource(if (isSyncing) R.string.prefs_lotw_syncing else R.string.prefs_lotw_sync),
-        acceptEnabled = !isSyncing
+        // While syncing, cancel/back aborts the download instead of merely
+        // hiding the dialog — a full sync started by mistake must be stoppable.
+        onDismissRequest = { if (isSyncing) onCancelSync() else dismiss() },
+        onCancel = { if (isSyncing) onCancelSync() else dismiss() },
+        // The two sync buttons below are the primary actions: saving
+        // credentials and fetching confirmed grids happen in one step.
+        onAccept = null
     ) {
         OutlinedTextField(
             value = call.value,
@@ -268,12 +273,50 @@ fun LoTWDialog(
             style = MaterialTheme.typography.bodySmall,
             modifier = Modifier.padding(horizontal = LocalSpacing.current.large)
         )
-        Text(
-            text = stringResource(R.string.prefs_lotw_sync_duration_hint),
-            style = MaterialTheme.typography.bodySmall,
-            color = MaterialTheme.colorScheme.onSurfaceVariant,
-            modifier = Modifier.padding(horizontal = LocalSpacing.current.large)
-        )
+        if (isSyncing) {
+            // Live progress: once the report header reveals the record count,
+            // switch to "N QSOs, ~X s remaining" with a determinate bar.
+            val progressText = when {
+                progress == null ||
+                    progress.phase == com.rtbishop.look4sat.core.domain.repository.LoTWPhase.Connecting ->
+                    stringResource(R.string.lotw_sync_progress_connecting)
+                // Download finished (or the size estimate reached its cap):
+                // parsing and saving may still run — say so instead of the bar
+                // sitting at 100% with no feedback, which reads as "stuck".
+                progress.fraction >= 1f ->
+                    stringResource(R.string.lotw_sync_progress_saving)
+                progress.qsoCount > 0 && progress.remainingSeconds > 0 ->
+                    stringResource(R.string.lotw_sync_progress_qso, progress.qsoCount, progress.remainingSeconds)
+                progress.qsoCount > 0 ->
+                    stringResource(R.string.lotw_sync_progress_count, progress.qsoCount)
+                else -> stringResource(R.string.lotw_sync_progress_downloading)
+            }
+            Text(
+                text = progressText,
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(horizontal = LocalSpacing.current.large)
+            )
+            if (progress != null && progress.expectedBytes > 0) {
+                LinearProgressIndicator(
+                    progress = { progress.fraction },
+                    modifier = Modifier.fillMaxWidth().padding(horizontal = LocalSpacing.current.large)
+                )
+            } else {
+                LinearProgressIndicator(
+                    modifier = Modifier.fillMaxWidth().padding(horizontal = LocalSpacing.current.large)
+                )
+            }
+        } else {
+            // Pre-sync estimate: rate per 100 QSOs (measured ~8 s at ARRL's
+            // ~10 KB/s stream rate), plus the fixed server-side generation time.
+            Text(
+                text = stringResource(R.string.lotw_sync_rate_hint),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(horizontal = LocalSpacing.current.large)
+            )
+        }
         if (message != null) {
             Text(
                 text = message,
@@ -282,6 +325,22 @@ fun LoTWDialog(
                 modifier = Modifier.padding(horizontal = LocalSpacing.current.large)
             )
         }
+        Row(
+            horizontalArrangement = Arrangement.SpaceBetween,
+            modifier = Modifier.fillMaxWidth().padding(horizontal = LocalSpacing.current.large)
+        ) {
+            // Full sync bottom-left, incremental merge bottom-right.
+            CardButton(
+                onClick = { onSyncFull(com.rtbishop.look4sat.core.domain.model.LoTWSettings(call.value, pass.value)) },
+                text = stringResource(R.string.lotw_sync_full),
+                isEnabled = !isSyncing
+            )
+            CardButton(
+                onClick = { onSyncIncremental(com.rtbishop.look4sat.core.domain.model.LoTWSettings(call.value, pass.value)) },
+                text = stringResource(R.string.lotw_sync_incremental),
+                isEnabled = !isSyncing
+            )
+        }
         Spacer(modifier = Modifier.height(0.dp))
     }
 }

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

@@ -204,14 +204,29 @@ private fun SettingsScreen(uiState: SettingsState, onAction: (SettingsAction) ->
         )
     }
     if (dialogs.lotw) {
+        // LoTW sync failures are typed codes from the ViewModel; render them
+        // through string resources so the dialog follows the system language.
+        val lotwErrorMessage = uiState.lotwError?.let { error ->
+            when (error) {
+                LoTWError.NotConfigured -> stringResource(R.string.lotw_sync_error_not_configured)
+                LoTWError.BadCredentials -> stringResource(R.string.lotw_sync_error_credentials)
+                LoTWError.RateLimited -> stringResource(R.string.lotw_sync_error_rate_limited)
+                LoTWError.Timeout -> stringResource(R.string.lotw_sync_error_timeout)
+                is LoTWError.Network -> stringResource(R.string.lotw_sync_error_network, error.detail)
+            }
+        }
         LoTWDialog(
             initialSettings = uiState.lotwSettings,
             workedGridsCount = uiState.workedGridsCount,
             isSyncing = uiState.lotwSyncing,
-            message = uiState.lotwMessage,
+            syncMode = uiState.lotwSyncMode,
+            progress = uiState.lotwProgress,
+            message = lotwErrorMessage,
             dismiss = { dialogs.lotw = false },
+            onCancelSync = { onAction(SettingsAction.CancelLoTWSync); dialogs.lotw = false },
             onSave = { onAction(SettingsAction.UpdateLoTW(it)) },
-            onSync = { onAction(SettingsAction.SyncLoTWGrids(it)) }
+            onSyncFull = { onAction(SettingsAction.SyncLoTWGrids(it, LoTWSyncMode.Full)) },
+            onSyncIncremental = { onAction(SettingsAction.SyncLoTWGrids(it, LoTWSyncMode.Incremental)) }
         )
     }
 
@@ -521,7 +536,7 @@ private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Uni
     ElevatedCard(
         modifier = Modifier
             .fillMaxWidth()
-            .height(312.dp)
+            .height(272.dp)
     ) {
         Column(modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp)) {
             Text(
@@ -543,9 +558,6 @@ private fun OtherCard(settings: OtherSettings, onAction: (SettingsAction) -> Uni
             SwitchRow(R.string.prefs_other_switch_night_mode, settings.stateOfNightMode) {
                 onAction(SettingsAction.ToggleNightMode(it))
             }
-            SwitchRow(R.string.prefs_other_switch_map_grid, settings.stateOfMapGrid) {
-                onAction(SettingsAction.ToggleMapGrid(it))
-            }
         }
     }
 }

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

@@ -61,10 +61,24 @@ data class SettingsState(
     val wavelogMessage: String? = null,
     val lotwSettings: com.rtbishop.look4sat.core.domain.model.LoTWSettings = com.rtbishop.look4sat.core.domain.model.LoTWSettings(),
     val lotwSyncing: Boolean = false,
-    val lotwMessage: String? = null,
+    val lotwSyncMode: LoTWSyncMode? = null,
+    val lotwProgress: com.rtbishop.look4sat.core.domain.repository.LoTWProgress? = null,
+    val lotwError: LoTWError? = null,
     val updateChecker: UpdateCheckerState = UpdateCheckerState()
 )
 
+/** What a LoTW sync button does: pull everything, or only new QSLs since the last sync. */
+enum class LoTWSyncMode { Full, Incremental }
+
+/** LoTW sync failure, kept as a translatable code until the UI renders it. */
+sealed interface LoTWError {
+    data object NotConfigured : LoTWError
+    data object BadCredentials : LoTWError
+    data object RateLimited : LoTWError
+    data object Timeout : LoTWError
+    data class Network(val detail: String) : LoTWError
+}
+
 sealed interface SettingsAction {
     // Position
     data object SetGpsPosition : SettingsAction
@@ -85,7 +99,6 @@ sealed interface SettingsAction {
     data class ToggleSensor(val value: Boolean) : SettingsAction
     data class ToggleLightTheme(val value: Boolean) : SettingsAction
     data class ToggleNightMode(val value: Boolean) : SettingsAction
-    data class ToggleMapGrid(val value: Boolean) : SettingsAction
 
     // Remote control
     data class UpdateRC(val settings: RCSettings) : SettingsAction
@@ -100,7 +113,12 @@ sealed interface SettingsAction {
 
     // LoTW confirmed grids
     data class UpdateLoTW(val settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings) : SettingsAction
-    data class SyncLoTWGrids(val settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings) : SettingsAction
+    data class SyncLoTWGrids(
+        val settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings,
+        val mode: LoTWSyncMode
+    ) : SettingsAction
+    /** Abort an in-flight LoTW sync (wrong button / changed mind). */
+    data object CancelLoTWSync : SettingsAction
 
     // Update checker
     data object CheckForUpdate : SettingsAction

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

@@ -35,6 +35,7 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
 import java.io.File
 
 class SettingsViewModel(
@@ -49,6 +50,8 @@ class SettingsViewModel(
 
     private val defaultPosSettings = PositionSettings(false, settingsRepo.stationPosition.value, 0)
     private val defaultDataSettings = DataSettings(false, 0, 0, 0L)
+    /** In-flight LoTW sync job, cancelled by CancelLoTWSync. */
+    private var lotwSyncJob: kotlinx.coroutines.Job? = null
     private val _uiState = MutableStateFlow(
         SettingsState(
             appVersionName = settingsRepo.appVersionName,
@@ -149,7 +152,6 @@ class SettingsViewModel(
             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) }
-            is SettingsAction.ToggleMapGrid -> settingsRepo.updateOtherSettings { it.copy(stateOfMapGrid = action.value) }
             // Remote control & data sources
             is SettingsAction.UpdateRC -> settingsRepo.updateRCSettings(action.settings)
             is SettingsAction.UpdateRadioControl -> settingsRepo.updateRadioControlSettings(action.settings)
@@ -159,7 +161,8 @@ class SettingsViewModel(
             is SettingsAction.SyncWorkedGrids -> syncWorkedGrids(action.settings)
             // LoTW confirmed grids
             is SettingsAction.UpdateLoTW -> settingsRepo.updateLoTWSettings(action.settings)
-            is SettingsAction.SyncLoTWGrids -> syncLoTWGrids(action.settings)
+            is SettingsAction.SyncLoTWGrids -> syncLoTWGrids(action.settings, action.mode)
+            SettingsAction.CancelLoTWSync -> cancelLoTWSync()
             // Update checker
             SettingsAction.CheckForUpdate -> checkForUpdate()
             SettingsAction.DownloadUpdate -> downloadUpdate()
@@ -192,61 +195,129 @@ class SettingsViewModel(
         }
     }
 
-    private fun syncLoTWGrids(settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings) {
+    private fun syncLoTWGrids(
+        settings: com.rtbishop.look4sat.core.domain.model.LoTWSettings,
+        mode: LoTWSyncMode
+    ) {
         if (!settings.isConfigured) {
-            _uiState.update { it.copy(lotwMessage = "LoTW callsign/password not configured") }
+            _uiState.update { it.copy(lotwError = LoTWError.NotConfigured) }
             return
         }
         // Persist the credentials first, then sync with the freshly-typed values.
         settingsRepo.updateLoTWSettings(settings)
-        _uiState.update { it.copy(lotwSyncing = true, lotwMessage = null) }
-        viewModelScope.launch {
-            when (val result = lotwRepo.fetchConfirmedGridQsos(settings.callsign, settings.password)) {
+        // Incremental only makes sense for the same callsign as the last sync;
+        // a first sync, an unknown/empty record or a callsign change must fall
+        // back to a full report so no stale grids from another account linger.
+        val callsign = settings.callsign.trim().uppercase()
+        val lastCallsign = settingsRepo.getLastLotwSyncCallsign()
+        val effectiveMode = if (mode == LoTWSyncMode.Incremental &&
+            lastCallsign.isNotBlank() && lastCallsign == callsign
+        ) LoTWSyncMode.Incremental else LoTWSyncMode.Full
+        val since = if (effectiveMode == LoTWSyncMode.Incremental) {
+            settingsRepo.getLastLotwSyncDate()
+        } else ""
+        _uiState.update {
+            it.copy(lotwSyncing = true, lotwSyncMode = effectiveMode, lotwProgress = null, lotwError = null)
+        }
+        lotwSyncJob = viewModelScope.launch {
+            val result = lotwRepo.fetchConfirmedGridQsos(callsign, settings.password, since) { progress ->
+                _uiState.update { it.copy(lotwProgress = progress) }
+            }
+            when (result) {
                 is com.rtbishop.look4sat.core.domain.repository.LoTWResult.Success -> {
-                    // Wavelog entry removed: LoTW is now the only source, so the
-                    // synced set fully replaces the stored worked grids.
-                    settingsRepo.setWorkedGrids(result.grids)
-                    settingsRepo.setWorkedGridQsos(result.qsos)
-                    settingsRepo.setRoamedGrids(result.roamedGrids)
+                    // Incremental: merge new grids/QSOs into the stored set (dedup
+                    // by call + QSO time); full: the fresh report replaces it all.
+                    val existingGrids = settingsRepo.getWorkedGrids()
+                    val existingQsos = settingsRepo.getWorkedGridQsos()
+                    val existingRoamed = settingsRepo.getRoamedGrids()
+                    val mergedGrids = if (effectiveMode == LoTWSyncMode.Incremental) {
+                        existingGrids + result.grids
+                    } else result.grids
+                    val mergedQsos = if (effectiveMode == LoTWSyncMode.Incremental) {
+                        mergeGridQsos(existingQsos, result.qsos)
+                    } else result.qsos
+                    val mergedRoamed = if (effectiveMode == LoTWSyncMode.Incremental) {
+                        existingRoamed + result.roamedGrids
+                    } else result.roamedGrids
+                    // Remember when/what we synced, so the next incremental pull
+                    // asks LoTW for only the confirmations since today.
+                    val today = java.text.SimpleDateFormat("yyyyMMdd", java.util.Locale.US)
+                        .apply { timeZone = java.util.TimeZone.getTimeZone("UTC") }
+                        .format(java.util.Date())
+                    settingsRepo.setLastLotwSyncDate(today)
+                    settingsRepo.setLastLotwSyncCallsign(callsign)
+                    // Persist on the IO dispatcher: building the per-grid QSO JSON
+                    // and writing SharedPreferences synchronously blocks the
+                    // calling thread, and for large accounts (tens of thousands
+                    // of QSOs → multi-MB JSON) that froze the main thread after
+                    // the download finished — 'bar done but app stuck'.
+                    withContext(kotlinx.coroutines.Dispatchers.IO) {
+                        settingsRepo.setWorkedGrids(mergedGrids)
+                        settingsRepo.setWorkedGridQsos(mergedQsos)
+                        settingsRepo.setRoamedGrids(mergedRoamed)
+                    }
                     _uiState.update { state ->
                         state.copy(
-                            lotwSyncing = false, workedGridsCount = result.grids.size,
-                            lotwMessage = null
+                            lotwSyncing = false, lotwSyncMode = null, lotwProgress = null,
+                            workedGridsCount = mergedGrids.size, lotwError = null
                         )
                     }
                 }
                 is com.rtbishop.look4sat.core.domain.repository.LoTWResult.BadCredentials ->
                     _uiState.update { state ->
                         state.copy(
-                            lotwSyncing = false,
-                            lotwMessage = "LoTW sync failed — callsign or password incorrect"
+                            lotwSyncing = false, lotwSyncMode = null, lotwProgress = null,
+                            lotwError = LoTWError.BadCredentials
                         )
                     }
                 is com.rtbishop.look4sat.core.domain.repository.LoTWResult.RateLimited ->
                     _uiState.update { state ->
                         state.copy(
-                            lotwSyncing = false,
-                            lotwMessage = "LoTW sync failed — rate limited by server, wait a few minutes and retry"
+                            lotwSyncing = false, lotwSyncMode = null, lotwProgress = null,
+                            lotwError = LoTWError.RateLimited
                         )
                     }
                 is com.rtbishop.look4sat.core.domain.repository.LoTWResult.Timeout ->
                     _uiState.update { state ->
                         state.copy(
-                            lotwSyncing = false,
-                            lotwMessage = "LoTW sync failed — connection timed out, try another network"
+                            lotwSyncing = false, lotwSyncMode = null, lotwProgress = null,
+                            lotwError = LoTWError.Timeout
                         )
                     }
                 is com.rtbishop.look4sat.core.domain.repository.LoTWResult.NetworkError ->
                     _uiState.update { state ->
                         state.copy(
-                            lotwSyncing = false,
-                            lotwMessage = "LoTW sync failed — network error (${result.detail})"
+                            lotwSyncing = false, lotwSyncMode = null, lotwProgress = null,
+                            lotwError = LoTWError.Network(result.detail)
                         )
                     }
             }
         }
     }
 
+    /** Abort the in-flight LoTW sync job and reset its progress state. */
+    private fun cancelLoTWSync() {
+        lotwSyncJob?.cancel()
+        lotwSyncJob = null
+        _uiState.update { it.copy(lotwSyncing = false, lotwSyncMode = null, lotwProgress = null) }
+    }
+
+    /** Merge fresh QSO detail into existing per-grid lists, dedup by call + QSO time. */
+    private fun mergeGridQsos(
+        existing: Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>>,
+        fresh: Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>>
+    ): Map<String, List<com.rtbishop.look4sat.core.domain.model.GridQso>> {
+        val merged = existing.mapValues { (_, list) -> list.toMutableList() }.toMutableMap()
+        fresh.forEach { (grid, list) ->
+            val target = merged.getOrPut(grid) { mutableListOf() }
+            val known = target.mapTo(mutableSetOf()) { it.call to it.epochMs }
+            list.forEach { qso ->
+                if (known.add(qso.call to qso.epochMs)) target.add(qso)
+            }
+        }
+        return merged
+    }
+
     // endregion
 
     // region Update checker

feature/status/src/main/java/com/rtbishop/look4sat/feature/status/SatStatusScreen.kt

@@ -58,7 +58,6 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.rtbishop.look4sat.core.domain.model.SatDay
 import com.rtbishop.look4sat.core.domain.model.SatReport
-import com.rtbishop.look4sat.core.domain.model.SatSlot
 import com.rtbishop.look4sat.core.domain.model.SatStatus
 import com.rtbishop.look4sat.core.domain.repository.IContainerProvider
 import com.rtbishop.look4sat.core.presentation.CardButton
@@ -316,7 +315,6 @@ private fun HeaderRow(statuses: List<SatStatus>) {
 /** Satellite row: name takes remaining width; day tiles are fixed-width (tablet-safe). */
 @Composable
 private fun StatusRow(status: SatStatus, onClickDay: (SatDay) -> Unit) {
-    val noReportGray = 0xFFC0C0C0L
     Row(
         modifier = Modifier.fillMaxWidth().padding(vertical = 2.dp),
         verticalAlignment = Alignment.CenterVertically
@@ -329,9 +327,8 @@ private fun StatusRow(status: SatStatus, onClickDay: (SatDay) -> Unit) {
             modifier = Modifier.weight(1f).padding(end = 4.dp)
         )
         status.days.forEach { day ->
-            val slot = day.slots.firstOrNull { it.statusColor != noReportGray } ?: day.slots.first()
             DayCell(
-                slot = slot,
+                day = day,
                 modifier = Modifier.width(TILE_WIDTH).padding(horizontal = 2.dp),
                 onClick = { onClickDay(day) }
             )
@@ -339,10 +336,17 @@ private fun StatusRow(status: SatStatus, onClickDay: (SatDay) -> Unit) {
     }
 }
 
-/** Day block: newest reported status among the day's 12 slots; gray when none. */
+/**
+ * Day block: colored by the newest reported status among the day's 12 slots
+ * (gray when none); the number is the TOTAL report count of the whole day
+ * (sum over all slots), not the count of the newest slot alone.
+ */
 @Composable
-private fun DayCell(slot: SatSlot, modifier: Modifier, onClick: () -> Unit) {
+private fun DayCell(day: SatDay, modifier: Modifier, onClick: () -> Unit) {
+    val noReportGray = 0xFFC0C0C0L
+    val slot = day.slots.firstOrNull { it.statusColor != noReportGray } ?: day.slots.first()
     val color = Color(slot.statusColor)
+    val totalCount = day.slots.sumOf { it.count }
     Box(
         modifier = modifier
             .height(28.dp)
@@ -351,8 +355,8 @@ private fun DayCell(slot: SatSlot, modifier: Modifier, onClick: () -> Unit) {
             .clickable(onClick = onClick),
         contentAlignment = Alignment.Center
     ) {
-        if (slot.count > 0) {
-            Text(text = slot.count.toString(), fontSize = 13.sp, fontWeight = FontWeight.Bold, color = Color.White)
+        if (totalCount > 0) {
+            Text(text = totalCount.toString(), fontSize = 13.sp, fontWeight = FontWeight.Bold, color = Color.White)
         }
     }
 }

gradle/libs.versions.toml

@@ -1,8 +1,8 @@
 [versions]
 #noinspection UnusedVersionCatalogEntry
-appVersionCode = "474"
+appVersionCode = "476"
 #noinspection UnusedVersionCatalogEntry
-appVersionName = "4.4.7-ba7opf.4"
+appVersionName = "4.4.7-ba7opf.6"
 #noinspection UnusedVersionCatalogEntry
 compileSdk = "37"
 #noinspection UnusedVersionCatalogEntry