Fix bugs in setting the Tx frequency

Uses 0x25 01 command to set the Tx frequency,
which is the correct command when in split mode.

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

@@ -204,12 +204,23 @@ class Ic705Controller(
      * always writing to the active VFO is the correct strategy.
      */
     override suspend fun setWorkingFrequency(frequencyHz: Long): Boolean = withContext(Dispatchers.IO) {
-        Log.d(tag, "setWorkingFrequency: ${frequencyHz}Hz")
+        Log.d(tag, "setWorkingFrequency (0x25/00): ${frequencyHz}Hz")
         val cmd = IcomCivProtocol.buildSetWorkingFreqCommand(frequencyHz)
         Log.d(tag, "CMD setWorkingFreq → ${IcomCivProtocol.toHex(cmd)}")
         ioMutex.withLock { sendAndWaitAck(cmd) }
     }
 
+    /**
+     * Set TX VFO frequency via CMD 0x25 sub 0x01 (unselected VFO).
+     * Used in split mode while PTT is pressed.
+     */
+    override suspend fun setTxVfoFrequency(frequencyHz: Long): Boolean = withContext(Dispatchers.IO) {
+        Log.d(tag, "setTxVfoFrequency (0x25/01): ${frequencyHz}Hz")
+        val cmd = IcomCivProtocol.buildSetUnselectedVfoFreqCommand(frequencyHz)
+        Log.d(tag, "CMD setTxVfoFreq → ${IcomCivProtocol.toHex(cmd)}")
+        ioMutex.withLock { sendAndWaitAck(cmd) }
+    }
+
     // ── Internal I/O helpers ────────────────────────────────────────────────
 
     /**

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

@@ -73,8 +73,10 @@ object IcomCivProtocol {
     const val SUB_SPLIT_ON: Byte  = 0x01
     /** Sub for CMD_TX_STATUS: query TX/RX state. */
     const val SUB_TX_STATE: Byte  = 0x00
-    /** Sub for CMD_SELECTED_VFO_FREQ: selected VFO frequency. */
+    /** Sub for CMD_SELECTED_VFO_FREQ: selected (active) VFO frequency. */
     const val SUB_SELECTED_VFO: Byte = 0x00
+    /** Sub for CMD_SELECTED_VFO_FREQ: unselected (inactive / TX in split) VFO frequency. */
+    const val SUB_UNSELECTED_VFO: Byte = 0x01
     /** Sub for CMD_MISC_SETTING: CTCSS/DTCS tone squelch. */
     const val SUB_CTCSS_SETTING: Byte = 0x42.toByte()
 
@@ -167,6 +169,16 @@ object IcomCivProtocol {
         return frame(CMD_SELECTED_VFO_FREQ, SUB_SELECTED_VFO, *encodeFrequencyBcd(frequencyHz))
     }
 
+    /**
+     * Set unselected-VFO frequency via CMD 0x25 sub 0x01.
+     * In split mode while PTT is pressed the IC-705 makes VFO-B active, so
+     * this command targets VFO-A (the RX VFO) — and vice-versa when in RX.
+     * Use this to update the TX VFO when PTT is on.
+     */
+    fun buildSetUnselectedVfoFreqCommand(frequencyHz: Long): ByteArray {
+        return frame(CMD_SELECTED_VFO_FREQ, SUB_UNSELECTED_VFO, *encodeFrequencyBcd(frequencyHz))
+    }
+
     /** Read operating frequency (CMD 0x03). */
     fun buildReadFreqCommand(): ByteArray = frame(CMD_READ_FREQ)
 

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

@@ -387,17 +387,17 @@ class RadioTrackingService(
                 when (isPtt) {
                     true -> {
                         // PTT ON → radio's active VFO is VFO-B (TX)
-                        // Update TX frequency on active VFO only
+                        // Use 0x25/01 (unselected VFO) to target VFO-B directly
                         if (txRadioFreq != null) {
-                            Log.d(tag, "Split loop TX update: ${txRadioFreq}Hz")
-                            radio.setWorkingFrequency(txRadioFreq)
+                            Log.d(tag, "Split loop TX update (0x25/01): ${txRadioFreq}Hz")
+                            radio.setTxVfoFrequency(txRadioFreq)
                         }
                     }
                     false -> {
                         // PTT OFF → radio's active VFO is VFO-A (RX)
-                        // Update RX frequency on active VFO only
+                        // Use 0x25/00 (selected/active VFO) to update RX
                         if (rxRadioFreq != null) {
-                            Log.d(tag, "Split loop RX update: ${rxRadioFreq}Hz")
+                            Log.d(tag, "Split loop RX update (0x25/00): ${rxRadioFreq}Hz")
                             radio.setWorkingFrequency(rxRadioFreq)
                         }
                     }

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

@@ -62,10 +62,16 @@ interface IRadioController {
     suspend fun setSplitMode(enabled: Boolean): Boolean = false
 
     /**
-     * Set the frequency of the currently active VFO.
-     * On radios that support it (IC-705: CMD 0x25 sub 0x00) this updates
-     * the active VFO without switching.
+     * Set the frequency of the currently active VFO (CMD 0x25 sub 0x00).
      * Default: delegates to [setFrequency].
      */
     suspend fun setWorkingFrequency(frequencyHz: Long): Boolean = setFrequency(frequencyHz)
+
+    /**
+     * Set the frequency of the inactive (TX) VFO via CMD 0x25 sub 0x01.
+     * Used in split mode when PTT is pressed: the radio has made VFO-B
+     * the active VFO, so sub 0x01 targets it directly.
+     * Default: delegates to [setWorkingFrequency].
+     */
+    suspend fun setTxVfoFrequency(frequencyHz: Long): Boolean = setWorkingFrequency(frequencyHz)
 }