Decode Telemetry and Packets

There are several tools available to decode telemetry and packets. SatNOGS provides some built-in demodulators for various data formats. There are also additional tools that allow you the decoding of telemetry.

Built-in demodulators

Although the SatNOGS servers support many satellites with many modes, only the following modes are supported with built-in demodulators:

• APT (Automatic Picture Transmission)
• AFSK 1k2 (Audio Frequency Shift Keying)
• CW (Continuous Wave, Morse Code)
• DUV (Data Under Voice)
• GFSK 9k6 (Gaussian Frequency Shift Keying)
• FSK 9k6 (Frequency Shift Keying)
• LRPT (Low Resolution Picture Transmission)

SoX - Sound eXchange

SoX is the Swiss Army knife of sound processing programs. SoX is cross-platform and is available for many operating systems (Windows, Linux, MacOS X, etc.).

SoX supports demodulating the following modes:

• CW (Continuous Wave, Morse Code)

References

• Chris Bagwell SoX − Sound eXchange http://sox.sourceforge.net/sox.html

Fldigi in audio playback mode

Fldigi can be used to decode a variety of data modes.

• CW (Continuous Wave, Morse Code)

FoxTelem for FOX1 series satellites

FoxTelem currently supports decoding DUV telemetry the following satellites:

• AO-85 (Fox-1A)
• AO-91 (Radfxsat / Fox1-B)
• AO-92 (Fox1-D)
• Fox-1Cliff, and
• Fox-1E.

References

• AC2CZ FoxTelem - AMSAT Ground Station Software http://www.g0kla.com/foxtelem/

multimon-ng

Multimon-ng is a general purpose decoder. It can take wav or raw files and decode a variety of modes among which: CW, AFSK, FSK...

First you have to use sox to convert ogg files from SatNOGS download to 22050Hz raw file:
sox file.ogg -r 22050 file.raw gain 6
The gain is in dB and has a considerable impact on the decoding in the special case of CW. You have to adjust gain to get proper decoding.

Then you must apply on the raw file the proper decoder:
multimon-ng -a MORSE_CW -t raw file.raw

References

• Multimon-ng - Elia Oenal https://github.com/EliasOenal/multimon-ng