Wednesday, 15 November 2017

How to go about decoding telemetry from the FOX satellite (AO-85)


Fox Telemetry Decoder

The Fox Telemetry Decoder is being released to demodulate, store and analyze telemetry data from AMSAT’s Fox series of Cube Sats. We hope that you will also upload the telemetry you receive to the AMSAT server so that it can be used by other Amateur Scientists and our research partners, whose experiments fly with the Fox satellites.
FoxTelem is experimental. We are sure it can be improved. Please provide feedback and suggestions
Fox-1 satellites include two telemetry formats:
  • Slow Speed, also called Data Under Voice (DUV) is 200 bps FSK data sent at the same time as the transponder audio. Whenever the transmitter is on, data is being sent. This happens during beacons and during live QSOs.
  • High Speed is 9600 bps FSK sent instead of the transponder. This is used for data intensive experiments such as the Virginia Tech Camera and the University of Iowa HERCI experiment. This is only active when commanded from the ground. You can recognize High Speed because it sounds like an old school computer modem.
  • FoxTelem will receive and store both formats assuming you can feed it audio that does not have the frequencies below 200 Hz filtered.  For High Speed, the audio must also extend to include the full 9600bps bandwidth of the FM signal.  For both modes this is best achieved from a Software Defined Radio or from the 9600 bps packet port of some radios.  See the user guide for more details.
You can download the software from their website: https://www.amsat.org/foxtelem-software-for-windows-mac-linux/

I used my FunCube Pro-Plus dongle, as the software will recognise it and tune it automatically.
You can opt to feed sound using a virtual cable from another SDR or radio of choice.

here are a few screen shots of what James (M0JFP) was able to get from AO-85