[amsat-bb] PicSat demodulator?

Scott scott23192 at gmail.com
Wed Jan 17 18:24:48 UTC 2018


I'm finally getting around to decoding a pass from this morning & made a
screen print if the settings might benefit anyone.

Please disregard the RF frequency display; I'm replaying a recording from
another system.

http://www.qsl.net/k/k4kdr//images/2018-01-17--1455--picsat-screen.png

73!

-Scott,  K4KDR


===========================

On Wed, Jan 17, 2018 at 1:01 PM, Nitin Muttin <vu3tyg at yahoo.co.in> wrote:

> 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:
>
> http://uz7.ho.ua/modem_beta/other-versions.zip
>
> ... 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>
> wrote:
>
> > 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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