fix: broaden linear transponder matching and deduplicate same-range entries

- isNamedLinearTransponder: match ' Lin' prefix (AO-7 style) and
  add fallback branch (hasLinearName && hasLinearMode) for entries
  with 'Linear'/'Lin' but no 'transponder' word (AO-7, AO-73)
- add deduplicateTransponders: merge entries sharing the same
  uplink/downlink frequency range, preferring non-CW entry
  (AO-7 Mode A had separate SSB and CW entries; JO-97 had
  separate CW and SSB Transponder entries)
- apply dedup in CalculatorPage filter chain
- 6 new tests, 23 total, all passing

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

@@ -112,11 +112,30 @@ object DopplerFrequencyCalculator {
         val modes = listOfNotNull(transponder.downlinkMode, transponder.uplinkMode)
             .joinToString(separator = " ")
             .lowercase(Locale.ENGLISH)
-        val hasLinearName = info.contains("linear")
+        val hasLinearName = info.contains("linear") || info.contains(" lin") || info.startsWith("lin")
         val hasTransponderName = info.contains("transponder") || info.contains("transp") ||
                 info.contains("xponder") || info.contains("xpdr")
         val hasLinearMode = listOf("ssb", "usb", "lsb", "cw").any { modes.contains(it) }
 
-        return (hasLinearName && hasTransponderName) || (hasTransponderName && hasLinearMode)
+        return (hasLinearName && hasTransponderName) || (hasTransponderName && hasLinearMode) ||
+                (hasLinearName && hasLinearMode)
+    }
+
+    /**
+     * Removes duplicate transponder entries that describe the same physical
+     * transponder with different mode labels (e.g. SatNOGS lists AO-7's Mode A
+     * as both "Lin SSB" and "Lin CW", and JO-97's U/V transponder as both
+     * "CW Transponder" and "SSB Transponder").
+     *
+     * Entries sharing the same uplink/downlink frequency range are considered
+     * the same transponder. The non-CW entry is preferred because its invert
+     * flag is more reliable (e.g. JO-97's CW entry wrongly has invert=false).
+     */
+    fun deduplicateTransponders(radios: List<SatRadio>): List<SatRadio> {
+        return radios.groupBy { radio ->
+            listOf(radio.uplinkLow, radio.uplinkHigh, radio.downlinkLow, radio.downlinkHigh)
+        }.values.map { group ->
+            group.firstOrNull { it.downlinkMode?.equals("CW", ignoreCase = true) != true } ?: group.first()
+        }
     }
 }

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

@@ -13,6 +13,7 @@ import org.junit.Test
 class DopplerFrequencyCalculatorTest {
 
     private fun linearTransponder(
+        uuid: String = "linear",
         upLow: Long = 145_000_000L,
         upHigh: Long = 145_500_000L,
         downLow: Long = 435_000_000L,
@@ -22,7 +23,7 @@ class DopplerFrequencyCalculatorTest {
         downlinkMode: String? = "USB",
         uplinkMode: String? = "LSB"
     ) = SatRadio(
-        uuid = "linear", info = info, isAlive = true,
+        uuid = uuid, info = info, isAlive = true,
         downlinkLow = downLow, downlinkHigh = downHigh,
         downlinkMode = downlinkMode, uplinkLow = upLow, uplinkHigh = upHigh,
         uplinkMode = uplinkMode, isInverted = inverted, catnum = 12345
@@ -72,11 +73,93 @@ class DopplerFrequencyCalculatorTest {
         assertFalse(DopplerFrequencyCalculator.isNamedLinearTransponder(driftingRangeEntry))
     }
 
+    @Test
+    fun isNamedLinearTransponder_returnsTrueForAbbreviatedLinName() {
+        // AO-7 style: "Mode V/A (A) Lin SSB" — "Lin" abbreviation, no "transponder" word
+        val ao7Entry = linearTransponder(info = "Mode V/A (A) Lin SSB", downlinkMode = "USB", uplinkMode = "USB")
+        assertTrue(DopplerFrequencyCalculator.isNamedLinearTransponder(ao7Entry))
+        val ao7CwEntry = linearTransponder(info = "Mode V/A (A) Lin CW", downlinkMode = "CW", uplinkMode = "CW")
+        assertTrue(DopplerFrequencyCalculator.isNamedLinearTransponder(ao7CwEntry))
+        val ao7ModeBEntry = linearTransponder(info = "Mode U/V (B) Lin", downlinkMode = "USB", uplinkMode = "LSB")
+        assertTrue(DopplerFrequencyCalculator.isNamedLinearTransponder(ao7ModeBEntry))
+    }
+
+    @Test
+    fun isNamedLinearTransponder_returnsTrueForLinearWithoutTransponderWord() {
+        // AO-73 style: "Mode U/V Linear" — has "Linear" but no "transponder"
+        val ao73Entry = linearTransponder(info = "Mode U/V Linear", downlinkMode = "USB", uplinkMode = "LSB")
+        assertTrue(DopplerFrequencyCalculator.isNamedLinearTransponder(ao73Entry))
+    }
+
+    @Test
+    fun isNamedLinearTransponder_returnsFalseForDownlinkContainingLinInsideWord() {
+        // "Downlink" contains "lin" but is not a linear-transponder name
+        val downlinkEntry = linearTransponder(info = "Mode U Downlink", downlinkMode = "FM", uplinkMode = "FM")
+        assertFalse(DopplerFrequencyCalculator.isNamedLinearTransponder(downlinkEntry))
+    }
+
     @Test
     fun isNamedLinearTransponder_returnsFalseForFmRepeater() {
         assertFalse(DopplerFrequencyCalculator.isNamedLinearTransponder(fmTransponder()))
     }
 
+    @Test
+    fun deduplicateTransponders_mergesSameFrequencyRange() {
+        // AO-7's Mode A: same range, SSB and CW entries
+        val ssb = linearTransponder(
+            uuid = "ssb-uuid", info = "Mode V/A (A) Lin SSB",
+            downlinkMode = "USB", uplinkMode = "USB"
+        )
+        val cw = linearTransponder(
+            uuid = "cw-uuid", info = "Mode V/A (A) Lin CW",
+            downlinkMode = "CW", uplinkMode = "CW"
+        )
+        val modeB = linearTransponder(
+            uuid = "modeb-uuid", info = "Mode U/V (B) Lin",
+            upLow = 432_125_000L, upHigh = 432_175_000L,
+            downLow = 145_925_000L, downHigh = 145_975_000L,
+            downlinkMode = "USB", uplinkMode = "LSB"
+        )
+        val result = DopplerFrequencyCalculator.deduplicateTransponders(listOf(ssb, cw, modeB))
+        assertEquals(2, result.size)
+        // SSB entry should be preferred over CW (same range)
+        assertEquals("ssb-uuid", result[0].uuid)
+        assertEquals("modeb-uuid", result[1].uuid)
+    }
+
+    @Test
+    fun deduplicateTransponders_prefersNonCwEntry() {
+        // JO-97: CW entry has invert=false (wrong), SSB has invert=true (correct)
+        val cw = linearTransponder(
+            uuid = "cw-uuid", info = "U/V CW Transponder",
+            downlinkMode = "CW", uplinkMode = "CW",
+            upLow = 435_100_000L, upHigh = 435_120_000L,
+            downLow = 145_855_000L, downHigh = 145_875_000L
+        )
+        val ssb = linearTransponder(
+            uuid = "ssb-uuid", info = "U/V SSB Transponder",
+            downlinkMode = "USB", uplinkMode = "LSB",
+            upLow = 435_100_000L, upHigh = 435_120_000L,
+            downLow = 145_855_000L, downHigh = 145_875_000L,
+            inverted = true
+        )
+        val result = DopplerFrequencyCalculator.deduplicateTransponders(listOf(cw, ssb))
+        assertEquals(1, result.size)
+        assertEquals("ssb-uuid", result[0].uuid)
+        // Verify the correct invert flag is preserved
+        assertTrue(result[0].isInverted)
+    }
+
+    @Test
+    fun deduplicateTransponders_preservesUniqueEntries() {
+        val t1 = linearTransponder(uuid = "t1", upLow = 145_000_000L, upHigh = 145_500_000L,
+            downLow = 435_000_000L, downHigh = 435_500_000L)
+        val t2 = linearTransponder(uuid = "t2", upLow = 435_000_000L, upHigh = 435_500_000L,
+            downLow = 145_000_000L, downHigh = 145_500_000L)
+        val result = DopplerFrequencyCalculator.deduplicateTransponders(listOf(t1, t2))
+        assertEquals(2, result.size)
+    }
+
     @Test
     fun computeUplinkFromDownlink_linear_noDoppler() {
         val xpdr = linearTransponder()

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

@@ -122,6 +122,7 @@ fun CalculatorPage(
 ) {
     val calculatorTransceivers = remember(transceivers) {
         transceivers.filter(DopplerFrequencyCalculator::isNamedLinearTransponder)
+            .let(DopplerFrequencyCalculator::deduplicateTransponders)
     }
     val selectedTransceiver = remember(calculatorTransceivers, selectedUuid) {
         calculatorTransceivers.firstOrNull { it.uuid == selectedUuid }