diff --git a/doc/img/MainWindow_spectrum_gui.png b/doc/img/MainWindow_spectrum_gui.png
index 682c7ec0b..22efbe6cf 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 604b476f3..7cb62743c 100644
Binary files a/doc/img/MainWindow_spectrum_gui.xcf and b/doc/img/MainWindow_spectrum_gui.xcf differ
diff --git a/doc/img/MainWindow_spectrum_gui_B.png b/doc/img/MainWindow_spectrum_gui_B.png
index 996ca59a7..c76bd3902 100644
Binary files a/doc/img/MainWindow_spectrum_gui_B.png and b/doc/img/MainWindow_spectrum_gui_B.png differ
diff --git a/doc/img/MainWindow_spectrum_gui_B.xcf b/doc/img/MainWindow_spectrum_gui_B.xcf
index b0f1e6c84..cb7e2e2c8 100644
Binary files a/doc/img/MainWindow_spectrum_gui_B.xcf and b/doc/img/MainWindow_spectrum_gui_B.xcf differ
diff --git a/sdrgui/readme.md b/sdrgui/readme.md
index 2f65aed9f..b6ae02996 100644
--- a/sdrgui/readme.md
+++ b/sdrgui/readme.md
@@ -369,7 +369,7 @@ Most devices will also present an interface to control automatic DC removal and
-These are the controls of the main spectrum display in (7). The same controls are found in the plugins that feature a spectrum display:
+These are the controls of the main spectrum display in (7). The same controls are found in the plugins that feature a spectrum display. For example:
- Channel Analyzer
- Broadcast FM demodulator
- ChirpChat (LoRa) demodulator
@@ -529,6 +529,12 @@ The server only sends data. Control including FFT details is done via the REST A
Opens the [spectrum markers dialog](spectrummarkers.md)
+3B.8. Spectrum calibration
+
+Use the toggle button to switch between relative and calibrated power readings.
+
+Right click to open the [calibration management dialog](spectrumcalibration.md)
+
3C. Spectrum display control line 3
