[amsat-bb] PSAT2 PSK31 Uplink CORRECTION!

Robert Bruninga bruninga at usna.edu
Wed Jun 26 16:06:56 UTC 2019

Argh!  The Team at Brno University that built the PSK31 transponder CORRECTS
The uplink is 29.4815 MHz.


-----Original Message-----
From: Robert Bruninga <bruninga at usna.edu>
Sent: Wednesday, June 26, 2019 11:23 AM
To: 'amsat bb' <amsat-bb at amsat.org>
Cc: 'Scott' <scott23192 at gmail.com>
Subject: RE: [amsat-bb] PSAT2 PSK31 Operations Enabled

PSAT2 Ten meter PSK31 uplink and UHF FM 435.350 downlink is ON.
Who will be the first to nail down the ten-meter PSK31 center uplink
It should be around 29.40X.

The Total Doppler shift during a pass should be about 1 KHz.
What 29.40X TX uplink gives 1.5 KHz in the UHF passband at the center of the

Thanks, Ill correct  links below. (PSAT has uplink on 28.120.  But PSAT2 is
on 29.40X) Bob

-----Original Message-----
From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Scott via AMSAT-BB
Subject: Re: [amsat-bb] PSAT2 Future Operations

Regarding the PSK31 uplink, please advise the correct RF frequency.

At http://aprs.org/PSAT2/USER-Operations-Manual.doc, the uplink frequency is
listed as 29.401 MHz.

At https://github.com/alpov/PSAT-2/blob/master/README.md, the uplink
frequency is listed as 29.48 MHz.

At http://aprs.org/psat2.html, the uplink frequency is listed as 28.120 MHz
(in text, w/ a graphic indicating "29.XX?").


-Scott,  K4KDR


On Wed, Jun 26, 2019 at 10:20 AM Tomáš Urbanec via AMSAT-BB <
amsat-bb at amsat.org> wrote:

> Hi Paul,
> Thanks for the interest in the PSK31 transponder, as Bob already
> pointed up, the downlink audio spectrum is shared, so at 280Hz and
> 374Hz are
> PSK31 beacon tlm streams from camera board and transponder board
> respectively. Then every 4 minutes the SSTV signal is present so if
> you plan experiments in PSK transponder, try to stay between the
> beacons and SSTV. Description of modes you can find at
> https://github.com/alpov/PSAT-2/blob/master/README.md
> We would be glad to answer any questions about this experiments.
> We are still awaiting for any positive confirmation of downlink signal
> at 435.350MHz as for us it is still below horizon. Any audio
> recordings, IQ data or at least pictures of reception would be welcomed.
>             73! Tomas OK2PNQ and Ales OK2ALP
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