diff --git a/doc/img/APTDemod_plugin.png b/doc/img/APTDemod_plugin.png
index 24d98125b..573fb0dc7 100644
Binary files a/doc/img/APTDemod_plugin.png and b/doc/img/APTDemod_plugin.png differ
diff --git a/doc/img/APTDemod_plugin_settings.png b/doc/img/APTDemod_plugin_settings.png
index 5934b4e54..fed33a7cf 100644
Binary files a/doc/img/APTDemod_plugin_settings.png and b/doc/img/APTDemod_plugin_settings.png differ
diff --git a/doc/img/RadioClock_waveforms.png b/doc/img/RadioClock_waveforms.png
new file mode 100644
index 000000000..365890455
Binary files /dev/null and b/doc/img/RadioClock_waveforms.png differ
diff --git a/plugins/channelrx/demodapt/aptdemod.cpp b/plugins/channelrx/demodapt/aptdemod.cpp
index 11c99bb1b..4fbe8fec6 100644
--- a/plugins/channelrx/demodapt/aptdemod.cpp
+++ b/plugins/channelrx/demodapt/aptdemod.cpp
@@ -584,6 +584,7 @@ int APTDemod::webapiActionsPost(
         {
             SWGSDRangel::SWGAPTDemodActions_aos* aos = swgAPTDemodActions->getAos();
             QString *satelliteName = aos->getSatelliteName();
+            qDebug() << "APTDemod::webapiActionsPost - AOS " << *satelliteName;
             if (satelliteName != nullptr)
             {
                 if (matchSatellite(*satelliteName))
@@ -617,6 +618,7 @@ int APTDemod::webapiActionsPost(
         {
             SWGSDRangel::SWGAPTDemodActions_los* los = swgAPTDemodActions->getLos();
             QString *satelliteName = los->getSatelliteName();
+            qDebug() << "APTDemod::webapiActionsPost - LOS " << *satelliteName;
 
             if (satelliteName != nullptr)
             {
diff --git a/plugins/channelrx/demodapt/aptdemodgui.cpp b/plugins/channelrx/demodapt/aptdemodgui.cpp
index fcbc9c175..163332c61 100644
--- a/plugins/channelrx/demodapt/aptdemodgui.cpp
+++ b/plugins/channelrx/demodapt/aptdemodgui.cpp
@@ -25,9 +25,10 @@
 #include <QAction>
 #include <QRegExp>
 #include <QFileDialog>
+#include <QGraphicsScene>
+#include <QGraphicsPixmapItem>
 
 #include "aptdemodgui.h"
-#include "util/ax25.h"
 
 #include "device/deviceuiset.h"
 #include "dsp/dspengine.h"
@@ -42,6 +43,7 @@
 #include "gui/devicestreamselectiondialog.h"
 #include "dsp/dspengine.h"
 #include "gui/crightclickenabler.h"
+#include "gui/graphicsviewzoom.h"
 #include "channel/channelwebapiutils.h"
 #include "maincore.h"
 
@@ -101,7 +103,20 @@ bool APTDemodGUI::handleMessage(const Message& message)
         const APTDemod::MsgImage& imageMsg = (APTDemod::MsgImage&) message;
         m_image = imageMsg.getImage();
         m_pixmap.convertFromImage(m_image);
-        ui->image->setPixmap(m_pixmap);
+        if (m_pixmapItem != nullptr)
+        {
+            m_pixmapItem->setPixmap(m_pixmap);
+            if (ui->zoomAll->isChecked()) {
+                ui->image->fitInView(m_pixmapItem, Qt::KeepAspectRatio);
+            }
+        }
+        else
+        {
+            m_pixmapItem = m_scene->addPixmap(m_pixmap);
+            m_pixmapItem->setPos(0, 0);
+            ui->image->fitInView(m_pixmapItem, Qt::KeepAspectRatio);
+        }
+
         QStringList imageTypes = imageMsg.getImageTypes();
         if (imageTypes.size() == 0)
         {
@@ -171,7 +186,19 @@ bool APTDemodGUI::handleMessage(const Message& message)
         }
 
         m_pixmap.convertFromImage(m_image);
-        ui->image->setPixmap(m_pixmap);
+        if (m_pixmapItem != nullptr)
+        {
+            m_pixmapItem->setPixmap(m_pixmap);
+            if (ui->zoomAll->isChecked()) {
+                ui->image->fitInView(m_pixmapItem, Qt::KeepAspectRatio);
+            }
+        }
+        else
+        {
+            m_pixmapItem = m_scene->addPixmap(m_pixmap);
+            m_pixmapItem->setPos(0, 0);
+            ui->image->fitInView(m_pixmapItem, Qt::KeepAspectRatio);
+        }
 
         return true;
     }
@@ -302,7 +329,9 @@ void APTDemodGUI::on_startStop_clicked(bool checked)
 
 void APTDemodGUI::on_resetDecoder_clicked()
 {
-    ui->image->setPixmap(QPixmap());
+    if (m_pixmapItem != nullptr) {
+        m_pixmapItem->setPixmap(QPixmap());
+    }
     ui->imageContainer->setWindowTitle("Received image");
     // Send message to reset decoder
     m_aptDemod->getInputMessageQueue()->push(APTDemod::MsgResetDecoder::create());
@@ -332,6 +361,30 @@ void APTDemodGUI::on_saveImage_clicked()
     }
 }
 
+void APTDemodGUI::on_zoomIn_clicked()
+{
+    m_zoom->gentleZoom(1.25);
+    ui->zoomAll->setChecked(false);
+}
+
+void APTDemodGUI::on_zoomOut_clicked()
+{
+    m_zoom->gentleZoom(0.75);
+    ui->zoomAll->setChecked(false);
+}
+
+void APTDemodGUI::on_zoomAll_clicked(bool checked)
+{
+    if (checked && (m_pixmapItem != nullptr)) {
+        ui->image->fitInView(m_pixmapItem, Qt::KeepAspectRatio);
+    }
+}
+
+void APTDemodGUI::on_image_zoomed()
+{
+    ui->zoomAll->setChecked(false);
+}
+
 void APTDemodGUI::onWidgetRolled(QWidget* widget, bool rollDown)
 {
     (void) widget;
@@ -389,7 +442,9 @@ APTDemodGUI::APTDemodGUI(PluginAPI* pluginAPI, DeviceUISet *deviceUISet, Baseban
     m_deviceUISet(deviceUISet),
     m_channelMarker(this),
     m_doApplySettings(true),
-    m_tickCount(0)
+    m_tickCount(0),
+    m_scene(nullptr),
+    m_pixmapItem(nullptr)
 {
     ui->setupUi(this);
 
@@ -425,6 +480,13 @@ APTDemodGUI::APTDemodGUI(PluginAPI* pluginAPI, DeviceUISet *deviceUISet, Baseban
     connect(&m_channelMarker, SIGNAL(highlightedByCursor()), this, SLOT(channelMarkerHighlightedByCursor()));
     connect(getInputMessageQueue(), SIGNAL(messageEnqueued()), this, SLOT(handleInputMessages()));
 
+    m_zoom = new GraphicsViewZoom(ui->image); // Deleted automatically when view is deleted
+    connect(m_zoom, SIGNAL(zoomed()), this, SLOT(on_image_zoomed()));
+
+    m_scene = new QGraphicsScene(ui->image);
+    ui->image->setScene(m_scene);
+    ui->image->show();
+
     displaySettings();
     applySettings(true);
 }
diff --git a/plugins/channelrx/demodapt/aptdemodgui.h b/plugins/channelrx/demodapt/aptdemodgui.h
index 7c324af48..b80c35f8d 100644
--- a/plugins/channelrx/demodapt/aptdemodgui.h
+++ b/plugins/channelrx/demodapt/aptdemodgui.h
@@ -42,6 +42,9 @@ class DeviceUISet;
 class BasebandSampleSink;
 class APTDemod;
 class APTDemodGUI;
+class QGraphicsScene;
+class QGraphicsPixmapItem;
+class GraphicsViewZoom;
 
 namespace Ui {
     class APTDemodGUI;
@@ -79,6 +82,9 @@ private:
 
     QImage m_image;
     QPixmap m_pixmap;
+    QGraphicsScene* m_scene;
+    QGraphicsPixmapItem* m_pixmapItem;
+    GraphicsViewZoom* m_zoom;
 
     explicit APTDemodGUI(PluginAPI* pluginAPI, DeviceUISet *deviceUISet, BasebandSampleSink *rxChannel, QWidget* parent = 0);
     virtual ~APTDemodGUI();
@@ -107,6 +113,10 @@ private slots:
     void on_showSettings_clicked();
     void on_resetDecoder_clicked();
     void on_saveImage_clicked();
+    void on_zoomIn_clicked();
+    void on_zoomOut_clicked();
+    void on_zoomAll_clicked(bool checked=false);
+    void on_image_zoomed();
     void onWidgetRolled(QWidget* widget, bool rollDown);
     void onMenuDialogCalled(const QPoint& p);
     void handleInputMessages();
diff --git a/plugins/channelrx/demodapt/aptdemodgui.ui b/plugins/channelrx/demodapt/aptdemodgui.ui
index 2579d8c26..d7eb1f9fc 100644
--- a/plugins/channelrx/demodapt/aptdemodgui.ui
+++ b/plugins/channelrx/demodapt/aptdemodgui.ui
@@ -356,6 +356,9 @@
     </item>
     <item>
      <layout class="QHBoxLayout" name="buttonLayout">
+      <property name="spacing">
+       <number>4</number>
+      </property>
       <item>
        <widget class="ButtonSwitch" name="startStop">
         <property name="toolTip">
@@ -372,7 +375,7 @@
        </widget>
       </item>
       <item>
-       <widget class="QPushButton" name="showSettings">
+       <widget class="QToolButton" name="showSettings">
         <property name="toolTip">
          <string>Show settings dialog</string>
         </property>
@@ -386,7 +389,7 @@
        </widget>
       </item>
       <item>
-       <widget class="QPushButton" name="resetDecoder">
+       <widget class="QToolButton" name="resetDecoder">
         <property name="toolTip">
          <string>Reset decoder (clears current image)</string>
         </property>
@@ -400,7 +403,7 @@
        </widget>
       </item>
       <item>
-       <widget class="QPushButton" name="saveImage">
+       <widget class="QToolButton" name="saveImage">
         <property name="toolTip">
          <string>Save image to disk</string>
         </property>
@@ -413,6 +416,54 @@
         </property>
        </widget>
       </item>
+      <item>
+       <widget class="QToolButton" name="zoomIn">
+        <property name="toolTip">
+         <string>Zoom in to image</string>
+        </property>
+        <property name="text">
+         <string/>
+        </property>
+        <property name="icon">
+         <iconset resource="../../../sdrgui/resources/res.qrc">
+          <normaloff>:/zoomin.png</normaloff>:/zoomin.png</iconset>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <widget class="QToolButton" name="zoomOut">
+        <property name="toolTip">
+         <string>Zoom out from image</string>
+        </property>
+        <property name="text">
+         <string/>
+        </property>
+        <property name="icon">
+         <iconset resource="../../../sdrgui/resources/res.qrc">
+          <normaloff>:/zoomout.png</normaloff>:/zoomout.png</iconset>
+        </property>
+       </widget>
+      </item>
+      <item>
+       <widget class="ButtonSwitch" name="zoomAll">
+        <property name="toolTip">
+         <string>Zoom image to fit window</string>
+        </property>
+        <property name="text">
+         <string>^</string>
+        </property>
+        <property name="icon">
+         <iconset resource="../../../sdrgui/resources/res.qrc">
+          <normaloff>:/zoomall.png</normaloff>:/zoomall.png</iconset>
+        </property>
+        <property name="checkable">
+         <bool>true</bool>
+        </property>
+        <property name="checked">
+         <bool>true</bool>
+        </property>
+       </widget>
+      </item>
       <item>
        <spacer name="horizontalSpacer_3">
         <property name="orientation">
@@ -426,13 +477,6 @@
         </property>
        </spacer>
       </item>
-      <item>
-       <widget class="QLabel" name="channelsLabel">
-        <property name="text">
-         <string>Channels</string>
-        </property>
-       </widget>
-      </item>
       <item>
        <widget class="QComboBox" name="channels">
         <property name="minimumSize">
@@ -645,25 +689,13 @@
      </layout>
     </item>
     <item>
-     <widget class="ScaledImage" name="image">
-      <property name="sizePolicy">
-       <sizepolicy hsizetype="Expanding" vsizetype="Expanding">
-        <horstretch>0</horstretch>
-        <verstretch>0</verstretch>
-       </sizepolicy>
-      </property>
+     <widget class="QGraphicsView" name="image">
       <property name="minimumSize">
        <size>
         <width>300</width>
         <height>350</height>
        </size>
       </property>
-      <property name="text">
-       <string/>
-      </property>
-      <property name="alignment">
-       <set>Qt::AlignCenter</set>
-      </property>
      </widget>
     </item>
    </layout>
@@ -677,9 +709,10 @@
    <container>1</container>
   </customwidget>
   <customwidget>
-   <class>ButtonSwitch</class>
-   <extends>QToolButton</extends>
-   <header>gui/buttonswitch.h</header>
+   <class>ValueDialZ</class>
+   <extends>QWidget</extends>
+   <header>gui/valuedialz.h</header>
+   <container>1</container>
   </customwidget>
   <customwidget>
    <class>LevelMeterSignalDB</class>
@@ -688,15 +721,9 @@
    <container>1</container>
   </customwidget>
   <customwidget>
-   <class>ValueDialZ</class>
-   <extends>QWidget</extends>
-   <header>gui/valuedialz.h</header>
-   <container>1</container>
-  </customwidget>
-  <customwidget>
-   <class>ScaledImage</class>
-   <extends>QLabel</extends>
-   <header>gui/scaledimage.h</header>
+   <class>ButtonSwitch</class>
+   <extends>QToolButton</extends>
+   <header>gui/buttonswitch.h</header>
   </customwidget>
  </customwidgets>
  <tabstops>
diff --git a/plugins/channelrx/demodapt/readme.md b/plugins/channelrx/demodapt/readme.md
index a81ec7b7a..ff24edc88 100644
--- a/plugins/channelrx/demodapt/readme.md
+++ b/plugins/channelrx/demodapt/readme.md
@@ -62,7 +62,19 @@ Clears the current image and restarts the decoder. The decoder must be reset bet
 
 Saves the current image to disk. Images can be saved in PNG, JPEG, BMP, PPM, XBM or XPM formats.
 
-<h3>10: Channel selection</h3>
+<h3>10: Zoom in</h3>
+
+Zooms in to the image. You can also zoom in with the scroll wheel.
+
+<h3>11: Zoom out</h3>
+
+Zooms out from the image. You can also zoom out with the scroll wheel.
+
+<h3>12: Zoom image to fit</h3>
+
+Zooms so that the image fits in to the available space.
+
+<h3>13: Channel selection</h3>
 
 Selects whether:
 
@@ -70,29 +82,29 @@ Selects whether:
    - only channel A is displayed
    - only channel B is displayed
 
-<h3>11: Crop noise</h3>
+<h3>14: Crop noise</h3>
 
 When checked, noise is cropped from the top and bottom of the image. This is noise that is typically the result of the satellite being at a low elevation.
 
-<h3>12: Apply denoise filter</h3>
+<h3>15: Apply denoise filter</h3>
 
 When checked, a denoise filter is applied to the received image.
 
-<h3>13: Apply linear equalisation</h3>
+<h3>16: Apply linear equalisation</h3>
 
 When checked, linear equalisation is performed, which can enhance the contrast. The equalisation is performed separately on each channel.
 
-<h3>14: Apply histogram equalisation</h3>
+<h3>17: Apply histogram equalisation</h3>
 
 When checked, histogram equalisation is performed, which can enhance the contrast. The equalisation is performed separately on each channel.
 
-<h3>15: Overlay precipitation</h3>
+<h3>18: Overlay precipitation</h3>
 
 When checked, precipitation is detected from the IR channel and overlayed on both channels using a colour palette.
 
 This option will not work if linear or histogram equalisation has been applied.
 
-<h3>16: Pass direction</h3>
+<h3>19: Pass direction</h3>
 
 The pass direction check button should be set to match the direction of the satellite pass.
 i.e. select down arrow for satellite passing from the North to the South and the up arrow for the satellite passing from the South to the North.
diff --git a/sdrgui/resources/res.qrc b/sdrgui/resources/res.qrc
index c426baebb..f62409640 100644
--- a/sdrgui/resources/res.qrc
+++ b/sdrgui/resources/res.qrc
@@ -107,6 +107,7 @@
     <file>load.png</file>
     <file>keyboard.png</file>
     <file>kill.png</file>
+    <file>zoomall.png</file>
     <file>zoomin.png</file>
     <file>zoomout.png</file>
     <file>LiberationMono-Regular.ttf</file>
diff --git a/sdrgui/resources/zoomall.png b/sdrgui/resources/zoomall.png
new file mode 100644
index 000000000..574cdcdf2
Binary files /dev/null and b/sdrgui/resources/zoomall.png differ