[amsat-bb] Unusual ISS SSTV signal

[John Brier]

Reports suggest two SSTV transmissions at same time.

https://twitter.com/bobbylittle/status/1313665745734324225?s=19

Crossband is totally diff setup in diff ISS modules.

73, John Brier KG4AKV

On Tue, Oct 6, 2020, 23:04 Greg D via AMSAT-BB <amsat-bb at amsat.org> wrote:

> That was my first thought, but I'm presuming they're running from
> separate power sources, and using separate antennas, in different
> modules of the Station.  If anything, the interference would be the
> reverse, with the SSTV desensing the x-band repeater's uplink.
>
> Also, my audio sounds rather different from Loren's, so perhaps
> different (or degrading) situations?
>
> Greg  KO6TH
>
>
> Gary wrote:
> > A local told me the ISS repeater was on the air. Is that possible in
> conjunction with the SSTV?
> >
> > 73,
> > Gary "Joe" kk0sd
> >
> > -----Original Message-----
> > From: AMSAT-BB <amsat-bb-bounces at amsat.org> On Behalf Of Greg D via
> AMSAT-BB
> > Sent: Tuesday, October 6, 2020 9:38 PM
> > To: Loren M. Lang <penguin359 at gmail.com>; AMSAT BB <amsat-bb at amsat.org>
> > Subject: Re: [amsat-bb] Unusual ISS SSTV signal
> >
> > I just heard something even weirder here during the just-completed
> 02:04z pass here in CM98.  3 images during the pass, the first two totally
> wiped out.  The third started off just fine, then the interference started
> in.
> >
> > I captured the screen and audio for the second and 3rd images here:
> >
> >
> https://www.dropbox.com/s/jzlp9jzs4k29sy1/ISS%20SSTV%20Pass3-2020-10-06_19.08.39.mp4?dl=1
> >
> > I'm no where near where Loren is, so it's unlikely to be local.  This is
> with the same equipment and setup as two passes yesterday, which were
> totally clean.  The 8pm (PDT) pass yesterday was recorded for our local
> club, and can be viewed here:
> >
> > https://www.youtube.com/watch?v=Z_SkJ8_mtA4
> >
> > Thoughts?
> >
> > Greg  KO6TH
> >
> >
> > Loren M. Lang via AMSAT-BB wrote:
> >> During one of the SSTV transmissions today, I heard an unusual signal
> >> overlaid on top of the regular SSTV signal. It started just after the
> >> original SSTV signal, and was initially quite strong, but eventually
> >> lost out to the regular SSTV signal. It sounds similar to SSTV, but
> >> not quite the same. This started at 2020-10-06 02:54:32Z. You can hear
> it here:
> >>
> >> https://www.dropbox.com/s/abcizkoly8rn1ij/funny-sstv-signal.mp3?dl=0
> >>
> >> You can see the waterfall during the initial decode here:
> >>
> >> https://www.dropbox.com/s/dxmy4rhruiit84v/funny-sstv-signal.png?dl=0
> >>
> >> It does look like a separate signal on top of the original SSTV signal
> >> and it looks more centered on 145.800 MHz than the Doppler shifted ISS
> >> transmission which makes me thing it might be terrestrial, but I have
> >> no idea where it would be coming from. It definitely looks like it was
> >> targeting 145.8 and it sounds SSTV-like. The signal poped in several
> >> more times as can be seen in this waterfall:
> >>
> >> https://www.dropbox.com/s/gwh4h4b1d8qtnbv/funny-sstv-signal2.png?dl=0
> >>
> >> Any ideas what this came from?
> >>
> >> Here's the image I received during that pass:
> >>
> >> https://www.dropbox.com/s/j11wj6yo9s2ceg9/sstv-202010060311.png?dl=0
> >>
> >> I do have the raw baseband signal if anyone's interested.
> >>
> >> -Loren
> >> K7IW
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> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
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> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
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>