diff --git a/plugins/samplesink/testsink/testsinkgui.cpp b/plugins/samplesink/testsink/testsinkgui.cpp
index de0da1327..9fc1e58e2 100644
--- a/plugins/samplesink/testsink/testsinkgui.cpp
+++ b/plugins/samplesink/testsink/testsinkgui.cpp
@@ -25,6 +25,7 @@
 #include "plugin/pluginapi.h"
 #include "gui/colormapper.h"
 #include "gui/glspectrum.h"
+#include "dsp/spectrumvis.h"
 #include "dsp/dspengine.h"
 #include "dsp/dspcommands.h"
 
@@ -41,7 +42,6 @@ TestSinkGui::TestSinkGui(DeviceUISet *deviceUISet, QWidget* parent) :
 	m_doApplySettings(true),
 	m_forceSettings(true),
 	m_settings(),
-    m_deviceSampleSink(0),
     m_sampleRate(0),
     m_generation(false),
 	m_samplesCount(0),
@@ -49,6 +49,7 @@ TestSinkGui::TestSinkGui(DeviceUISet *deviceUISet, QWidget* parent) :
 	m_lastEngineState(DeviceAPI::StNotStarted)
 {
 	ui->setupUi(this);
+    m_sampleSink = (TestSinkOutput*) m_deviceUISet->m_deviceAPI->getSampleSink();
 
 	ui->centerFrequency->setColorMapper(ColorMapper(ColorMapper::GrayGold));
 	ui->centerFrequency->setValueRange(7, 0, pow(10,7));
@@ -56,6 +57,13 @@ TestSinkGui::TestSinkGui(DeviceUISet *deviceUISet, QWidget* parent) :
     ui->sampleRate->setColorMapper(ColorMapper(ColorMapper::GrayGreenYellow));
     ui->sampleRate->setValueRange(7, 32000U, 9000000U);
 
+    m_spectrumVis = new SpectrumVis(SDR_TX_SCALEF, ui->glSpectrum);
+    m_sampleSink->setSpectrumSink(m_spectrumVis);
+    ui->glSpectrum->setCenterFrequency(m_settings.m_centerFrequency);
+    ui->glSpectrum->setSampleRate(m_settings.m_sampleRate*(1<<m_settings.m_log2Interp));
+    ui->glSpectrum->connectTimer(MainWindow::getInstance()->getMasterTimer());
+    ui->spectrumGUI->setBuddies(m_spectrumVis->getInputMessageQueue(), m_spectrumVis, ui->glSpectrum);
+
 	connect(&(m_deviceUISet->m_deviceAPI->getMasterTimer()), SIGNAL(timeout()), this, SLOT(tick()));
 	connect(&m_updateTimer, SIGNAL(timeout()), this, SLOT(updateHardware()));
 	connect(&m_statusTimer, SIGNAL(timeout()), this, SLOT(updateStatus()));
@@ -63,12 +71,12 @@ TestSinkGui::TestSinkGui(DeviceUISet *deviceUISet, QWidget* parent) :
 
 	displaySettings();
 
-    m_deviceSampleSink = (TestSinkOutput*) m_deviceUISet->m_deviceAPI->getSampleSink();
     connect(&m_inputMessageQueue, SIGNAL(messageEnqueued()), this, SLOT(handleInputMessages()), Qt::QueuedConnection);
 }
 
 TestSinkGui::~TestSinkGui()
 {
+    delete m_spectrumVis;
 	delete ui;
 }
 
@@ -202,7 +210,7 @@ void TestSinkGui::updateHardware()
 {
     qDebug() << "TestSinkGui::updateHardware";
     TestSinkOutput::MsgConfigureTestSink* message = TestSinkOutput::MsgConfigureTestSink::create(m_settings, m_forceSettings);
-    m_deviceSampleSink->getInputMessageQueue()->push(message);
+    m_sampleSink->getInputMessageQueue()->push(message);
     m_forceSettings = false;
     m_updateTimer.stop();
 }
@@ -239,12 +247,14 @@ void TestSinkGui::updateStatus()
 void TestSinkGui::on_centerFrequency_changed(quint64 value)
 {
     m_settings.m_centerFrequency = value * 1000;
+    ui->glSpectrum->setCenterFrequency(m_settings.m_centerFrequency);
     sendSettings();
 }
 
 void TestSinkGui::on_sampleRate_changed(quint64 value)
 {
     m_settings.m_sampleRate = value;
+    ui->glSpectrum->setSampleRate(m_settings.m_sampleRate*(1<<m_settings.m_log2Interp));
     sendSettings();
 }
 
@@ -255,6 +265,7 @@ void TestSinkGui::on_interp_currentIndexChanged(int index)
     }
 
     m_settings.m_log2Interp = index;
+    ui->glSpectrum->setSampleRate(m_settings.m_sampleRate*(1<<m_settings.m_log2Interp));
     updateSampleRateAndFrequency();
     sendSettings();
 }
@@ -264,7 +275,7 @@ void TestSinkGui::on_startStop_toggled(bool checked)
     if (m_doApplySettings)
     {
         TestSinkOutput::MsgStartStop *message = TestSinkOutput::MsgStartStop::create(checked);
-        m_deviceSampleSink->getInputMessageQueue()->push(message);
+        m_sampleSink->getInputMessageQueue()->push(message);
     }
 }
 
diff --git a/plugins/samplesink/testsink/testsinkgui.h b/plugins/samplesink/testsink/testsinkgui.h
index 8a9ad0bc7..4d0ca5aaf 100644
--- a/plugins/samplesink/testsink/testsinkgui.h
+++ b/plugins/samplesink/testsink/testsinkgui.h
@@ -28,8 +28,9 @@
 #include "testsinksettings.h"
 
 
-class DeviceSampleSink;
+class TestSinkOutput;
 class DeviceUISet;
+class SpectrumVis;
 
 namespace Ui {
 	class TestSinkGui;
@@ -63,7 +64,7 @@ private:
 	TestSinkSettings m_settings;
 	QTimer m_updateTimer;
     QTimer m_statusTimer;
-	DeviceSampleSink* m_deviceSampleSink;
+	TestSinkOutput* m_sampleSink;
     int m_sampleRate;
     quint64 m_deviceCenterFrequency; //!< Center frequency in device
     bool m_generation;
@@ -71,6 +72,7 @@ private:
 	std::size_t m_tickCount;
 	int m_lastEngineState;
 	MessageQueue m_inputMessageQueue;
+    SpectrumVis* m_spectrumVis;
 
 	void blockApplySettings(bool block) { m_doApplySettings = !block; }
 	void displaySettings();
diff --git a/plugins/samplesink/testsink/testsinkgui.ui b/plugins/samplesink/testsink/testsinkgui.ui
index db86a4268..49ef375eb 100644
--- a/plugins/samplesink/testsink/testsinkgui.ui
+++ b/plugins/samplesink/testsink/testsinkgui.ui
@@ -7,7 +7,7 @@
     <x>0</x>
     <y>0</y>
     <width>350</width>
-    <height>190</height>
+    <height>400</height>
    </rect>
   </property>
   <property name="sizePolicy">
@@ -19,7 +19,7 @@
   <property name="minimumSize">
    <size>
     <width>350</width>
-    <height>190</height>
+    <height>400</height>
    </size>
   </property>
   <property name="font">
@@ -292,6 +292,35 @@
      </item>
     </layout>
    </item>
+   <item>
+    <layout class="QVBoxLayout" name="spectrumLayout">
+     <property name="topMargin">
+      <number>6</number>
+     </property>
+     <property name="bottomMargin">
+      <number>6</number>
+     </property>
+     <item>
+      <widget class="GLSpectrum" name="glSpectrum" native="true">
+       <property name="minimumSize">
+        <size>
+         <width>200</width>
+         <height>200</height>
+        </size>
+       </property>
+       <property name="font">
+        <font>
+         <family>Liberation Mono</family>
+         <pointsize>8</pointsize>
+        </font>
+       </property>
+      </widget>
+     </item>
+     <item>
+      <widget class="GLSpectrumGUI" name="spectrumGUI" native="true"/>
+     </item>
+    </layout>
+   </item>
    <item>
     <layout class="QHBoxLayout" name="padLayout">
      <item>
@@ -323,6 +352,18 @@
    <extends>QToolButton</extends>
    <header>gui/buttonswitch.h</header>
   </customwidget>
+  <customwidget>
+   <class>GLSpectrum</class>
+   <extends>QWidget</extends>
+   <header>gui/glspectrum.h</header>
+   <container>1</container>
+  </customwidget>
+  <customwidget>
+   <class>GLSpectrumGUI</class>
+   <extends>QWidget</extends>
+   <header>gui/glspectrumgui.h</header>
+   <container>1</container>
+  </customwidget>
  </customwidgets>
  <resources>
   <include location="../../../sdrgui/resources/res.qrc"/>
diff --git a/plugins/samplesink/testsink/testsinkoutput.cpp b/plugins/samplesink/testsink/testsinkoutput.cpp
index 54642525d..91be4117f 100644
--- a/plugins/samplesink/testsink/testsinkoutput.cpp
+++ b/plugins/samplesink/testsink/testsinkoutput.cpp
@@ -25,6 +25,7 @@
 #include "util/simpleserializer.h"
 #include "dsp/dspcommands.h"
 #include "dsp/dspengine.h"
+#include "dsp/basebandsamplesink.h"
 
 #include "device/deviceapi.h"
 
@@ -39,7 +40,8 @@ TestSinkOutput::TestSinkOutput(DeviceAPI *deviceAPI) :
 	m_settings(),
 	m_testSinkThread(nullptr),
 	m_deviceDescription("TestSink"),
-	m_masterTimer(deviceAPI->getMasterTimer())
+	m_masterTimer(deviceAPI->getMasterTimer()),
+    m_spectrumSink(nullptr)
 {
     m_deviceAPI->setNbSinkStreams(1);
 }
@@ -65,6 +67,7 @@ bool TestSinkOutput::start()
 	qDebug() << "TestSinkOutput::start";
 
 	m_testSinkThread = new TestSinkThread(&m_sampleSourceFifo);
+    m_testSinkThread->setSpectrumSink(m_spectrumSink);
 	m_testSinkThread->setSamplerate(m_settings.m_sampleRate);
 	m_testSinkThread->setLog2Interpolation(m_settings.m_log2Interp);
 	m_testSinkThread->connectTimer(m_masterTimer);
diff --git a/plugins/samplesink/testsink/testsinkoutput.h b/plugins/samplesink/testsink/testsinkoutput.h
index 06f855b3f..76e48b0fe 100644
--- a/plugins/samplesink/testsink/testsinkoutput.h
+++ b/plugins/samplesink/testsink/testsinkoutput.h
@@ -29,6 +29,7 @@
 
 class TestSinkThread;
 class DeviceAPI;
+class BasebandSampleSink;
 
 class TestSinkOutput : public DeviceSampleSink {
 public:
@@ -103,6 +104,8 @@ public:
             SWGSDRangel::SWGDeviceState& response,
             QString& errorMessage);
 
+    void setSpectrumSink(BasebandSampleSink* spectrumSink) { m_spectrumSink = spectrumSink; }
+
 private:
     DeviceAPI *m_deviceAPI;
 	QMutex m_mutex;
@@ -111,6 +114,7 @@ private:
 	TestSinkThread* m_testSinkThread;
 	QString m_deviceDescription;
 	const QTimer& m_masterTimer;
+    BasebandSampleSink* m_spectrumSink;
 
 	void applySettings(const TestSinkSettings& settings, bool force = false);
 };
diff --git a/plugins/samplesink/testsink/testsinksettings.cpp b/plugins/samplesink/testsink/testsinksettings.cpp
index a73ffff14..89ad8b87c 100644
--- a/plugins/samplesink/testsink/testsinksettings.cpp
+++ b/plugins/samplesink/testsink/testsinksettings.cpp
@@ -16,6 +16,7 @@
 ///////////////////////////////////////////////////////////////////////////////////
 
 #include "util/simpleserializer.h"
+#include "settings/serializable.h"
 #include "testsinksettings.h"
 
 TestSinkSettings::TestSinkSettings()
@@ -28,14 +29,20 @@ void TestSinkSettings::resetToDefaults()
     m_centerFrequency = 435000*1000;
     m_sampleRate = 48000;
     m_log2Interp = 0;
+    m_spectrumGUI = nullptr;
 }
 
 QByteArray TestSinkSettings::serialize() const
 {
     SimpleSerializer s(1);
 
-    s.writeU64(1, m_sampleRate);
-    s.writeU32(2, m_log2Interp);
+    s.writeU64(1, m_centerFrequency);
+    s.writeU64(2, m_sampleRate);
+    s.writeU32(3, m_log2Interp);
+
+    if (m_spectrumGUI) {
+        s.writeBlob(4, m_spectrumGUI->serialize());
+    }
 
     return s.final();
 }
@@ -52,8 +59,18 @@ bool TestSinkSettings::deserialize(const QByteArray& data)
 
     if (d.getVersion() == 1)
     {
-        d.readU64(1, &m_sampleRate, 48000);
-        d.readU32(2, &m_log2Interp, 0);
+        QByteArray bytetmp;
+
+        d.readU64(1, &m_sampleRate, 435000*1000);
+        d.readU64(2, &m_sampleRate, 48000);
+        d.readU32(3, &m_log2Interp, 0);
+
+        if (m_spectrumGUI)
+        {
+            d.readBlob(4, &bytetmp);
+            m_spectrumGUI->deserialize(bytetmp);
+        }
+
         return true;
     }
     else
diff --git a/plugins/samplesink/testsink/testsinksettings.h b/plugins/samplesink/testsink/testsinksettings.h
index 42fb1a327..355537569 100644
--- a/plugins/samplesink/testsink/testsinksettings.h
+++ b/plugins/samplesink/testsink/testsinksettings.h
@@ -20,15 +20,19 @@
 
 #include <QByteArray>
 
+class Serializable;
+
 struct TestSinkSettings {
     quint64 m_centerFrequency;
     quint64 m_sampleRate;
     quint32 m_log2Interp;
+    Serializable *m_spectrumGUI;
 
     TestSinkSettings();
     void resetToDefaults();
     QByteArray serialize() const;
     bool deserialize(const QByteArray& data);
+    void setSpectrumGUI(Serializable *spectrumGUI) { m_spectrumGUI = spectrumGUI; }
 };
 
 #endif /* PLUGINS_SAMPLESINK_TESTSINK_TESTSINKSETTINGS_H_ */
diff --git a/plugins/samplesink/testsink/testsinkthread.cpp b/plugins/samplesink/testsink/testsinkthread.cpp
index 50c0bab58..086ae06af 100644
--- a/plugins/samplesink/testsink/testsinkthread.cpp
+++ b/plugins/samplesink/testsink/testsinkthread.cpp
@@ -22,6 +22,7 @@
 #include <QDebug>
 
 #include "dsp/samplesourcefifo.h"
+#include "dsp/basebandsamplesink.h"
 #include "testsinkthread.h"
 
 TestSinkThread::TestSinkThread(SampleSourceFifo* sampleFifo, QObject* parent) :
@@ -177,6 +178,7 @@ void TestSinkThread::tick()
         if (m_log2Interpolation == 0)
         {
             m_interpolators.interpolate1(&beginRead, m_buf, 2*chunkSize);
+            feedSpectrum(m_buf, 2*chunkSize);
             //m_ofstream->write(reinterpret_cast<char*>(&(*beginRead)), m_samplesChunkSize*sizeof(Sample));
         }
         else
@@ -206,7 +208,29 @@ void TestSinkThread::tick()
                 break;
             }
 
+            feedSpectrum(m_buf, 2*chunkSize*(1<<m_log2Interpolation));
             //m_ofstream->write(reinterpret_cast<char*>(m_buf), m_samplesChunkSize*(1<<m_log2Interpolation)*2*sizeof(int16_t));
         }
 	}
 }
+
+void TestSinkThread::feedSpectrum(int16_t *buf, unsigned int bufSize)
+{
+    if (!m_spectrumSink) {
+        return;
+    }
+
+    m_samplesVector.allocate(bufSize/2);
+    Sample16 *s16Buf = (Sample16*) buf;
+
+    std::transform(
+        s16Buf,
+        s16Buf + (bufSize/2),
+        m_samplesVector.m_vector.begin(),
+        [](Sample16 s) -> Sample {
+            return Sample{s.m_real, s.m_imag};
+        }
+    );
+
+    m_spectrumSink->feed(m_samplesVector.m_vector.begin(), m_samplesVector.m_vector.begin() + (bufSize/2), false);
+}
\ No newline at end of file
diff --git a/plugins/samplesink/testsink/testsinkthread.h b/plugins/samplesink/testsink/testsinkthread.h
index 7179943b0..bfb4467c3 100644
--- a/plugins/samplesink/testsink/testsinkthread.h
+++ b/plugins/samplesink/testsink/testsinkthread.h
@@ -30,10 +30,12 @@
 
 #include "dsp/inthalfbandfilter.h"
 #include "dsp/interpolators.h"
+#include "util/incrementalvector.h"
 
 #define TESTSINK_THROTTLE_MS 50
 
 class SampleSourceFifo;
+class BasebandSampleSink;
 
 class TestSinkThread : public QThread {
 	Q_OBJECT
@@ -50,10 +52,18 @@ public:
 	bool isRunning() const { return m_running; }
     std::size_t getSamplesCount() const { return m_samplesCount; }
     void setSamplesCount(int samplesCount) { m_samplesCount = samplesCount; }
+    void setSpectrumSink(BasebandSampleSink *spectrumSink) { m_spectrumSink = spectrumSink; }
 
 	void connectTimer(const QTimer& timer);
 
 private:
+#pragma pack(push, 1)
+    struct Sample16
+    {
+        int16_t m_real;
+        int16_t m_imag;
+    };
+#pragma pack(pop)
 	QMutex m_startWaitMutex;
 	QWaitCondition m_startWaiter;
 	volatile bool m_running;
@@ -72,8 +82,11 @@ private:
 
     Interpolators<qint16, SDR_TX_SAMP_SZ, 16> m_interpolators;
     int16_t *m_buf;
+    BasebandSampleSink* m_spectrumSink;
+    IncrementalVector<Sample> m_samplesVector;
 
 	void run();
+    void feedSpectrum(int16_t *buf, unsigned int bufSize);
 
 private slots:
 	void tick();