Decoding the Delfi-n3Xt 2400 bps BPSK beacon on 145.870 MHz has proved to be very challenging but Tetsurou Satou JA0CAW in Japan has succeeded in decoding some frames.
He decoded three frames of telemetry in two passes on November 27.
In a recent update Jasper PC4JB from the Delfi-n3Xt team said:
We have noticed however that the DUDe telemetry client does not properly indicate the frequency offset and it is very difficult to get a lock on the signal.
Also our ICOM910 receivers have too limited bandwidth to receive a 2400 bit/s BPSK signal properly (although we had a few packets decoded with this, so it is just on the edge of what is possible). We now use only AR5000 in combination with an SDR to record a wide spectrum in IQ files. This way we can replay the files and retune the signal again and have been able to decode more packets than before. This morning at our second pass we were lucky to have a real time lock on the signal and retrieve many packets, so it is possible to have it right at once. But of course we would like to get the ‘luck-factor’ out of it.
A few people will look into the Costas PLL inside DUDe to see if we can improve its performance. Meanwhile, you can regard Delfi-n3Xt as a real challenging game to decode packets…
JA0CAW website in Google English http://tinyurl.com/JA0CAW
Delfi-n3Xt telemetry reception http://www.delfispace.nl/operations/delfi-n3xt-telemetry-reception
Dnepr Yasny launch https://amsat-uk.org/satellites/dnepr-november-2013/