[amsat-bb] PicSat demodulator?

Nitin Muttin 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
Nitin [VU3TYG]

      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.

-Scott,  K4KDR


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.
> Tnx,
> Ken, W7KKE
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