PSAT2 has plenty of power all the time to support the PSK31 and SSTV HF/UHF transponder because it lost its VHF xcvr. So this mode will be around a long time with plenty of power. Same goes for PSAT since most of the time its VHF xponder is off.
And I looked up the PSAT PSK31 telemetry is at 312 Hz and the PSAT2 telemetry is a 374 Hz, so any pilot tone between about 400 and 800 Hz should be fine and not interfere with the SSTV.
On Sat, May 16, 2020 at 12:13 PM Robert Bruninga [email protected] wrote:
I dont think a baseband 31.25 Hz tone will work. There has to be a tone, say 400 Hz that is then AM modulated at 31.25 Hz. The 500 Hz or so lets it get through your transmitter audio circuits, and then the 31.25 Hz AM modulation of that tone is what looks like PSK31 carrier.
Both PSAT and PSAT2 both have an audio PSK31 telemetry down around 300 Hz (I need to look them up) so we need to avoid those areas so as not to interfere with telemetry. And not go above say 800 to avoid being in the area where the SSTV tones are.
Bob WB4APR
On Fri, May 15, 2020 at 4:27 PM Pedro Converso [email protected] wrote:
Nice Idea, worth to be tried, as alternative:
Use online generator setted to 31.25 Hz that can be adjusting volume using:
http://onlinetonegenerator.com/
73, lu7abf, Pedro
On 5/15/20, Robert Bruninga via AMSAT-BB [email protected] wrote:
As soon as we see a report that 2-way SSTV through PSAT2 actually works, then we can solicit the popular SSTV Authors to add the 31.25 Hz
optional
modulation that will automatically bring up the SSTV (PSK31 actually) transponder.
Will this be the first practical SSTV transponder? I know SSTV 2-way
has
been done before, but with the Very low Doppler shift on the 10m uplink and the no-tone Doppler on the FM downlink, this should be pretty
straight
forward... And it does not compete with the high demand that prohibits SSTV via other popular satellites.
Who will be first? (I updated these comments on the http://aprs.org/psat2.html page).
And remember, you can do this on the identical HF/UHF PSK31 transponder
on
PSAT too. That's two satellites supporting this mode.
And if still people don't use PSAT and PSAT2, for PSK31 or SSTV, then I guess we could even open up the 10m uplink on PSAT2 to voice contacts! (Cannot do this on PSAT since its uplink (28.120) is not in a voice segment.
Bob, WB4APR
-----Original Message----- From: Brian Wilkins KO4AQF via AMSAT-BB Subject: Re: [amsat-bb] Two way SSTV exchanges using PSAT2
Concur, I use CQ SSTV on iPhone. Works great! I have also used MMSTV on Windows laptop. Worst case, record it, clean up audio in Audacity and
play
it back with one of those apps listening.
On Fri, Andrew Glasbrenner via AMSAT-wrote:
Until I figured out a problem I was having, I used SSTV by Black Cat Systems on my Iphone in the shack. I just put the phone in a headphone cup on the desk and away we went.
73, Drew KO4MA
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