Spectrum and Waterfall






The spectrum display has very powerful configuration options,

  • Scale - dBm, dBµV, S-Units.
  • Advanced smoothing algorithms to remove 'noise' and enhance signal visibility,
  • Peak signal indication, maximum display, signal history.

To change these options: Ribbon bar, View Spectrum.


The spectrum display supports a range of smoothing options to remove 'noise' and leave the signals present.

The default averaging option is Hang & Decay, smoothing Triangular.


The S-Meter (Signal Meter) shows the peak and mean (average) values before smoothing is applied (see abiove), so the values shown in the spectrum will generally be lower than the S-meter value.

In the above image the peak value (yellow dot) is -77 dBm, the mean (gradient bar) is ~-98 dBm. The mean will always be less than or equal to the peak. It can never be greater than the peak.


The peak value is the peak value detected during the previous 1,000ms.


The mean value is the mean of the values for the previous 500ms.

Signal History

The signal history can store up to 48 hours of data, the data can be exported in CSV format to third-party programs such as:

An example from Nils Schiffhauer using QtiPlot:







The waterfall is one of the most important areas of the console display. You can adjust:

  • Colour: select either a standard colour palette or a custom palette which you design yourself with the built-in colourmap editor.
  • Resolution - enhance the display by increasing the resolution, this is acheived by using FFT overlapping.
  • Speed - usually 40 lines/second is acceptable.
  • Windowing - see Wikipedia.


Additional overlays are:

  • Clock
  • Statistics
  • Frequency