Observation 5166885: CAS-4B (42759) - Why isn't the CW beacon decoded correctly?

Regarding Observation 5166885

This looks like a very good recording of CAS-4B’s CW beacon signal. There is only a little bit of noise.

Each CW frame in the recording starts with “BJ1SL” and ends with “CAMSAT CAMSAT”. There are multiple frames in the recording. The CW tone is about 980 Hertz.

The CW beacon sounds okay when you listen to the recording, but on the data page it shows mostly “E” instead of the expected demodulated CW telemetry. For example, “ESHE EE EEE EEE EEE EEE EEE EEE EE EIE EE EII EEE EEE EEE”. The closest match for end-of-frame marker “CAMSAT CAMSAT” seems to be “CEASAE CAAIEE”.

Why isn’t the CAS-4B CW beacon signal being correctly demodulated? Is 980 Hertz too far off from the expected audio frequency? Is there too much noise for the CW decoder?

Douglas

Douglas,

happy holidays. Have a look at this thread. CW decoder in gr-satnogs 1.3.0

Not sure where the CW decoder stands now, but it does not work by default as you have observed.

73
Chris
G0KLA / AC2CZ