diff --git a/sdrbase/dsp/dspdevicesinkengine.cpp b/sdrbase/dsp/dspdevicesinkengine.cpp
index 31662fbc8..53d39895b 100644
--- a/sdrbase/dsp/dspdevicesinkengine.cpp
+++ b/sdrbase/dsp/dspdevicesinkengine.cpp
@@ -481,7 +481,10 @@ void DSPDeviceSinkEngine::handleSynchronousMessages()
 		m_basebandSampleSources.push_back(source);
 		checkNumberOfBasebandSources();
 
-        if (m_state == StRunning) {
+        if (m_state == StRunning)
+        {
+            DSPSignalNotification notif(m_sampleRate, m_centerFrequency);
+            source->handleMessage(notif);
             source->start();
         }
 	}
@@ -502,7 +505,10 @@ void DSPDeviceSinkEngine::handleSynchronousMessages()
 		m_threadedBasebandSampleSources.push_back(threadedSource);
 		checkNumberOfBasebandSources();
 
-        if (m_state == StRunning) {
+        if (m_state == StRunning)
+        {
+            DSPSignalNotification notif(m_sampleRate, m_centerFrequency);
+            threadedSource->handleSourceMessage(notif);
             threadedSource->start();
         }
 	}
diff --git a/sdrbase/dsp/upchannelizer.cpp b/sdrbase/dsp/upchannelizer.cpp
index 1f978c222..d171c3d65 100644
--- a/sdrbase/dsp/upchannelizer.cpp
+++ b/sdrbase/dsp/upchannelizer.cpp
@@ -174,7 +174,11 @@ void UpChannelizer::applyConfiguration()
 {
     if (m_outputSampleRate == 0)
     {
-        qDebug() << "UpChannelizer::applyConfiguration: m_outputSampleRate=0 aborting";
+        qDebug() << "UpChannelizer::applyConfiguration: aborting (out=0):"
+                << " out =" << m_outputSampleRate
+                << ", req =" << m_requestedInputSampleRate
+                << ", in =" << m_currentInputSampleRate
+                << ", fc =" << m_currentCenterFrequency;
         return;
     }