[amsat-bb] PicSat demodulator?
vu3tyg at yahoo.co.in
Wed Jan 17 18:01:35 UTC 2018
I have used the the software modem under G3RUH-BPSK folder. The audio is fed from an Icom 821H using a Signalink USB + doppler correction, tried in both FM and USB mode but no decode. Will try the signal centered on the 2000 Hz mark as suggested. 73
From: Scott <scott23192 at gmail.com>
To: Ken Swaggart <k.swaggart at charter.net>
Cc: AMSAT BB <amsat-bb at amsat.org>
Sent: Wednesday, 17 January 2018 10:28 PM
Subject: Re: [amsat-bb] PicSat demodulator?
Despite the documentation, PicSat beacons so far have been 1k2 BPSK.
There is a 1k2 BPSK software modem in:
... and the demod on that would be USB. Of course the bandwidth &
centering of the audio output is critical for this scheme; what works well
for me is to output the audio (I use HDSDR into VB Audio virtual cable) at
4 KHz with the signal centered on the 2000 Hz mark. If you match that 2000
Hz center on the 1k2 BPSK software modem screen, it decodes very nicely.
On Wed, Jan 17, 2018 at 11:19 AM, Ken Swaggart <k.swaggart at charter.net>
> Have been trying to decode the 435.525 MHz beacons from PicSat without
> success. The modulation is described as "GMSK modulation with G3RUH
> scrambling". I'm assuming the baud rate is 9600. Normally I use UZ7HO's
> High-Speed SoundModem for telemetry reception.
> Ken, W7KKE
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