[amsat-bb] Unusual ISS SSTV signal

[Greg D]

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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