diff --git a/app/main.cpp b/app/main.cpp
index d88bf36ce..a8b3ba9e2 100644
--- a/app/main.cpp
+++ b/app/main.cpp
@@ -35,7 +35,7 @@ static int runQtApplication(int argc, char* argv[], qtwebapp::LoggerWithFile *lo
 */
 	QCoreApplication::setOrganizationName("f4exb");
 	QCoreApplication::setApplicationName("SDRangel");
-	QCoreApplication::setApplicationVersion("4.0.2");
+	QCoreApplication::setApplicationVersion("4.0.3");
 
 #if 1
 	qApp->setStyle(QStyleFactory::create("fusion"));
diff --git a/appbench/main.cpp b/appbench/main.cpp
index 8224f2dcb..04e011e60 100644
--- a/appbench/main.cpp
+++ b/appbench/main.cpp
@@ -57,7 +57,7 @@ static int runQtApplication(int argc, char* argv[], qtwebapp::LoggerWithFile *lo
 
     QCoreApplication::setOrganizationName("f4exb");
     QCoreApplication::setApplicationName("SDRangelBench");
-    QCoreApplication::setApplicationVersion("4.0.2");
+    QCoreApplication::setApplicationVersion("4.0.3");
 
     int catchSignals[] = {SIGQUIT, SIGINT, SIGTERM, SIGHUP};
     std::vector<int> vsig(catchSignals, catchSignals + sizeof(catchSignals) / sizeof(int));
diff --git a/appsrv/main.cpp b/appsrv/main.cpp
index 360568442..1f9080571 100644
--- a/appsrv/main.cpp
+++ b/appsrv/main.cpp
@@ -56,7 +56,7 @@ static int runQtApplication(int argc, char* argv[], qtwebapp::LoggerWithFile *lo
 
     QCoreApplication::setOrganizationName("f4exb");
     QCoreApplication::setApplicationName("SDRangelSrv");
-    QCoreApplication::setApplicationVersion("4.0.2");
+    QCoreApplication::setApplicationVersion("4.0.3");
 
     int catchSignals[] = {SIGQUIT, SIGINT, SIGTERM, SIGHUP};
     std::vector<int> vsig(catchSignals, catchSignals + sizeof(catchSignals) / sizeof(int));
diff --git a/debian/changelog b/debian/changelog
index d36d04fb2..6e814b12f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+sdrangel (4.0.3-1) unstable; urgency=medium
+
+  * Spectrum: linear mode for spectrum
+
+ -- Edouard Griffiths, F4EXB <f4exb06@gmail.com>  Sat, 07 Jul 2018 15:14:18 +0200
+  
 sdrangel (4.0.2-1) unstable; urgency=medium
 
   * Spectrum: added averaging
diff --git a/doc/img/MainWindow_spectrum_gui.png b/doc/img/MainWindow_spectrum_gui.png
index 59d6e8209..ec92eaf15 100644
Binary files a/doc/img/MainWindow_spectrum_gui.png and b/doc/img/MainWindow_spectrum_gui.png differ
diff --git a/doc/img/MainWindow_spectrum_gui.xcf b/doc/img/MainWindow_spectrum_gui.xcf
index 30bff4c32..0745ac0c2 100644
Binary files a/doc/img/MainWindow_spectrum_gui.xcf and b/doc/img/MainWindow_spectrum_gui.xcf differ
diff --git a/sdrgui/readme.md b/sdrgui/readme.md
index b4013862f..6ef34bfe7 100644
--- a/sdrgui/readme.md
+++ b/sdrgui/readme.md
@@ -323,6 +323,12 @@ Toggles the grid display
 
 Controls the intensity of the grid display
 
+<h4>4.J. Logarithmic/linear scale</h4>
+
+Use this toggle button to switch between spectrum logarithmic and linear scale display. The face of the button will change to represent either a logaritmic or linear curve.
+
+When in linear mode the range control (4.4) has no effect because the actual range is between 0 and the reference level. The reference level in dB (4.3) still applies but is translated to a linear value e.g -40 dB is 1e-4. In linear mode the scale numbers are formatted using scientific notation so that they always occupy the same space.
+
 <h3>5. Presets and commands</h3>
 
 The presets and commands tree view are by default stacked in tabs. The following sections describe the presets section 5A) and commands (section 5B) views successively