diff --git a/app/src/main/java/com/rtbishop/look4sat/presentation/passesScreen/PassesViewModel.kt b/app/src/main/java/com/rtbishop/look4sat/presentation/passesScreen/PassesViewModel.kt
index 684b32c2..ae19fe10 100644
--- a/app/src/main/java/com/rtbishop/look4sat/presentation/passesScreen/PassesViewModel.kt
+++ b/app/src/main/java/com/rtbishop/look4sat/presentation/passesScreen/PassesViewModel.kt
@@ -41,9 +41,16 @@ class PassesViewModel @Inject constructor(
 
     init {
         viewModelScope.launch {
-            predictor.passes.collect { passes ->
+            predictor.calculatedPasses.collect { passes ->
                 passesProcessing?.cancelAndJoin()
-                passesProcessing = viewModelScope.launch { tickPasses(passes) }
+                passesProcessing = viewModelScope.launch {
+                    while (isActive) {
+                        val time = System.currentTimeMillis()
+                        val newPasses = predictor.processPasses(passes, time)
+                        _passes.postValue(DataState.Success(newPasses))
+                        delay(1000)
+                    }
+                }
             }
         }
     }
@@ -70,25 +77,4 @@ class PassesViewModel @Inject constructor(
         settings.setHoursAhead(hoursAhead)
         settings.setMinElevation(minElevation)
     }
-
-    private suspend fun tickPasses(passes: List<SatPass>) = withContext(Dispatchers.Default) {
-        var currentPasses = passes
-        while (isActive) {
-            val timeNow = System.currentTimeMillis()
-            currentPasses.forEach { pass ->
-                if (!pass.isDeepSpace) {
-                    val timeStart = pass.aosTime
-                    if (timeNow > timeStart) {
-                        val deltaNow = timeNow.minus(timeStart).toFloat()
-                        val deltaTotal = pass.losTime.minus(timeStart).toFloat()
-                        pass.progress = ((deltaNow / deltaTotal) * 100).toInt()
-                    }
-                }
-            }
-            currentPasses = currentPasses.filter { it.progress < 100 }
-            val passesCopy = currentPasses.map { it.copy() }
-            _passes.postValue(DataState.Success(passesCopy))
-            delay(1000)
-        }
-    }
 }
diff --git a/app/src/main/java/com/rtbishop/look4sat/presentation/radarScreen/RadarViewModel.kt b/app/src/main/java/com/rtbishop/look4sat/presentation/radarScreen/RadarViewModel.kt
index 8c2bc8bc..558aee65 100644
--- a/app/src/main/java/com/rtbishop/look4sat/presentation/radarScreen/RadarViewModel.kt
+++ b/app/src/main/java/com/rtbishop/look4sat/presentation/radarScreen/RadarViewModel.kt
@@ -54,7 +54,7 @@ class RadarViewModel @Inject constructor(
     val orientation: LiveData<Triple<Float, Float, Float>> = _orientation
 
     fun getPass(catNum: Int, aosTime: Long) = liveData {
-        predictor.passes.collect { passes ->
+        predictor.calculatedPasses.collect { passes ->
             val pass = passes.find { it.catNum == catNum && it.aosTime == aosTime }
             pass?.let { satPass ->
                 emit(satPass)
@@ -105,21 +105,13 @@ class RadarViewModel @Inject constructor(
         }
     }
 
-    private fun processTransmitters(satPass: SatPass) {
+    private fun processTransmitters(pass: SatPass) {
         viewModelScope.launch {
-            val transmitters = dataRepository.getTransmitters(satPass.catNum)
+            val transmitters = dataRepository.getTransmitters(pass.catNum)
             while (isActive) {
-                val satPos = predictor.getSatPos(satPass.satellite, stationPos, Date().time)
-                val copiedList = transmitters.map { it.copy() }
-                copiedList.forEach { transmitter ->
-                    transmitter.downlink?.let {
-                        transmitter.downlink = satPos.getDownlinkFreq(it)
-                    }
-                    transmitter.uplink?.let {
-                        transmitter.uplink = satPos.getUplinkFreq(it)
-                    }
-                }
-                _transmitters.postValue(copiedList.map { it.copy() })
+                val time = System.currentTimeMillis()
+                val list = predictor.processRadios(pass.satellite, stationPos, transmitters, time)
+                _transmitters.postValue(list)
                 delay(1000)
             }
         }
diff --git a/core/src/main/java/com/rtbishop/look4sat/domain/predict/Predictor.kt b/core/src/main/java/com/rtbishop/look4sat/domain/predict/Predictor.kt
index 582d3a8d..5f61d544 100644
--- a/core/src/main/java/com/rtbishop/look4sat/domain/predict/Predictor.kt
+++ b/core/src/main/java/com/rtbishop/look4sat/domain/predict/Predictor.kt
@@ -17,6 +17,7 @@
  */
 package com.rtbishop.look4sat.domain.predict
 
+import com.rtbishop.look4sat.domain.model.Transmitter
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.SharedFlow
@@ -24,9 +25,8 @@ import kotlinx.coroutines.withContext
 
 class Predictor(private val predictorDispatcher: CoroutineDispatcher) {
 
-    private val _passes = MutableSharedFlow<List<SatPass>>(replay = 1)
-    private var selectedSatIds = emptyList<Int>()
-    val passes: SharedFlow<List<SatPass>> = _passes
+    private val _calculatedPasses = MutableSharedFlow<List<SatPass>>(replay = 1)
+    val calculatedPasses: SharedFlow<List<SatPass>> = _calculatedPasses
 
     suspend fun getSatPos(sat: Satellite, pos: GeoPos, time: Long): SatPos {
         return withContext(predictorDispatcher) { sat.getPosition(pos, time) }
@@ -44,40 +44,55 @@ class Predictor(private val predictorDispatcher: CoroutineDispatcher) {
         }
     }
 
-    suspend fun triggerCalculation(
-        satellites: List<Satellite>,
-        pos: GeoPos,
-        time: Long,
-        hoursAhead: Int = 8,
-        minElevation: Double = 16.0
-    ) {
-        if (satellites.isEmpty()) {
-            _passes.emit(emptyList())
-        } else {
-            val newCatNums = satellites.map { it.params.catnum }
-            if (selectedSatIds != newCatNums) {
-                forceCalculation(satellites, pos, time, hoursAhead, minElevation)
+    suspend fun processRadios(sat: Satellite, pos: GeoPos, radios: List<Transmitter>, time: Long): List<Transmitter> {
+        return withContext(predictorDispatcher) {
+            val satPos = sat.getPosition(pos, time)
+            val copiedList = radios.map { it.copy() }
+            copiedList.forEach { transmitter ->
+                transmitter.downlink?.let {
+                    transmitter.downlink = satPos.getDownlinkFreq(it)
+                }
+                transmitter.uplink?.let {
+                    transmitter.uplink = satPos.getUplinkFreq(it)
+                }
             }
+            copiedList.map { it.copy() }
+        }
+    }
+
+    suspend fun processPasses(passList: List<SatPass>, time: Long): List<SatPass> {
+        return withContext(predictorDispatcher) {
+            val copiedList = passList.map { it.copy() }
+            copiedList.forEach { pass ->
+                if (!pass.isDeepSpace) {
+                    val timeStart = pass.aosTime
+                    if (time > timeStart) {
+                        val deltaNow = time.minus(timeStart).toFloat()
+                        val deltaTotal = pass.losTime.minus(timeStart).toFloat()
+                        pass.progress = ((deltaNow / deltaTotal) * 100).toInt()
+                    }
+                }
+            }
+            copiedList.filter { it.progress < 100 }.map { it.copy() }
         }
     }
 
     suspend fun forceCalculation(
-        satellites: List<Satellite>,
+        satList: List<Satellite>,
         pos: GeoPos,
         time: Long,
         hoursAhead: Int = 8,
         minElevation: Double = 16.0
     ) {
-        if (satellites.isEmpty()) {
-            _passes.emit(emptyList())
+        if (satList.isEmpty()) {
+            _calculatedPasses.emit(emptyList())
         } else {
             withContext(predictorDispatcher) {
                 val allPasses = mutableListOf<SatPass>()
-                selectedSatIds = satellites.map { it.params.catnum }
-                satellites.forEach { satellite ->
+                satList.forEach { satellite ->
                     allPasses.addAll(satellite.getPasses(pos, time, hoursAhead))
                 }
-                _passes.emit(allPasses.filter(time, hoursAhead, minElevation))
+                _calculatedPasses.emit(allPasses.filter(time, hoursAhead, minElevation))
             }
         }
     }