Gnuradio progress!

Had a lot of gnuradio success today! Still a lot of work to go, and aside from the voice demod from SO-50 I have not had a chance to try decoding any data packets from the others, and I would not expect them to decode, but we are getting closer! The amount of voice decoded from SO-50 alone is an epic win, about 9 minutes worth!

Note, on the cw birds this is going through an FM Demod process - ultimately when selecting a CW mode for a satellite in network we will want a different demod process on the client, but hearing something is promising at the least!

SO-50 (voice):
STRAND-1 (data):
CO-65 (CW):
ALSAT 1N (data):

The gnuradio script is below. This is my own amateur edit, improvements are very much welcome:

/cc @Acinonyx @pierros @surligas @fredy


Hi kb9jhu,

If you are able to extract Alsat-1N frames would you mind to send me a file with them?
I would like to do some experiments and I have a particular interest on that satellite.

Many thanks,

Are you looking for the frames or the audio to generate them?

If the latter, click on the green ID numbers here:

If they are green I have checked and verified them good. Red means I’ve verified them “empty”… Yellow is either undetermined or not triaged.

You can then download each data file (look for a button below the audio spectrum) and decode.


I am looking for the frames. I am developing a tool for processing any kind of frame.