Spectrum Analyzer

A radio running OpenTX 2.3.0 or higher can use an internal or external MULTI-Module as a 2.4GHz spectrum analyzer.

The spectrum analyzer will show the strength of signals in the 2.4GHz band.

2.4GHz Spectrum Analyzer

Using the Spectrum Analyzer

  1. Long-press the SYS button to access the TOOLS menu

  2. Scroll down and highlight the appropriate Spectrum option in the menu

    1. Choose Spectrum (INT) for radios with an internal MULTI-module

    2. Choose Spectrum (EXT) for radios with an external MULTI-Module

  3. Press ENT to start the Spectrum Analyzer

Spectrum Analyzer in the TOOLS Menu

Spectrum (EXT) only appears in the menu if a model which uses the external MULTI-Module is selected.

A bug in OpenTX 2.3.9 and earlier prevents the spectrum analyzer from starting when a recently-added MULTI-Module protocol (e.g. FrSkyX2) is configured in the currently-selected model.

As a workaround, select a model which uses an older protocol (e.g. DSM, FrSky, or Flysky) before starting the spectrum analyzer.

Spectrum Analyzer Display

Spectrum Analyzer Display

The display shows frequencies on the 2.4GHz spectrum, from 2400MHz to 2480MHz. The X (horizontal) axis shows the frequency in MHz and the Y (vertical) axis shows relative signal strength.

F: Frequency at the center of the plot (fixed at 2440MHz) S: Bandwidth of the plot (fixed at 80MHz) T: Position of the cursor (vertical line)

Pressing ENT and scrolling left and right allows the T value to be changed, which will move the vertical line to highlight a specific frequency.

In a future firmware release the F and S values will be adjustable, allowing the analyzer to be focused on a particular part of the spectrum.