Decode telemetry from PicSat

PicSat (was launched on the same PSLV-C40 flight from India that delivered AO-92 to orbit) has a telemetry downlink on aprox. 435.525 MHz USB +/- doppler. The format is 1k2 BPSK AX25 and can be decoded using different software.

The downlink is strong if using some kind of Yagi. I’m using 2 * 13 el Yagi with fixed RHCP polarization and have good signal during most of the pass.

I will try to give a short guide how to use the software needed for decoding. First your have to feed the audio into your computer, if using SDR sw use an audio pipe software (like VB Audio), if using external radio use your computer soundcard.

First your need to decode the 1k2 BPSK audio, this can be done with Soundmodem. Be sure to use the version that can be found in ”other-versions.zip”.

Then you need to decode the KISS data with AGWOnlineKISS from DK3WN. AGWOnlineKISS connects to Soundmodem be default:

AGWOnlineKISS creates kss (KISS) files that can be imported with DK3WN software KISSDump+:

From this software export as HEX (Write -> Complete frame). Now you have a txt-file with telemetry data as HEX values.

All DK3WN software above can be downloaded here.

Now you need to go to the PicSat webpage and create an account. Here you can manually upload one frame at a time or upload the HEX-file you created. The HEX-file will be handled by the server at 01.00 UTC. If all is OK, you can see that you have uploaded telemetry OK: