Receiving Analog TV from Turkmenistan Unintentionally Bouncing off a Russian Military Satellite

Over on Twitter @dereksgc has been monitoring the 'Meridian' communications satellites, which are Russian owned and used for civilian and military purposes. The satellites are simple unsecure repeaters, meaning that actually anyone with the hardware can transmit to them, and have their signal automatically rebroadcast over a wide area. This has been taken advantage of recently by anti-Russian invasion war activists who have been trolling the satellite with SSTV images of the Ukrainian flag, as well as audio.  

Apart from intentional abuse, a side effect of being an open repeater is that sometimes the satellite can pick up powerful terrestrial signals unintentionally, such as analogue broadcast TV from Turkmenistan. Over on his blog, @dereksgc has written up an excellent post documenting the background behind this finding, his entire setup involving the hardware he's using and how he's aligning with the satellite, and what software he is using to decode the TV signal. In his hardware setup he notes that he uses a HackRF, but that a RTL-SDR would suffice.

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Stopped reading after the phrase “totalitarian dictatorship”. Politics has no place in science, you know.

caesar

I live there and it is unfortunately true. I think the fact of North Korea being a dictatorship is not a politics, it is more than that.

dereklol

that is literally by definition what the country is, I pointed that out just to add to the uniqueness of the situation

Evert Guzman

If it affects the outcome then yea it does.

Peer-Axel Kroeske

So are there any conclusions about the uplink frequency? It seems unlikely that a regular UHF channel would be used for this. Rather a transmitter feed, harmonic or intermodulation of the Turkmen TV station. It reminds me of receiving Radio Maria Nicaragua constantly a few years ago presumably on a MILSAT transponder with a very distorted but strong signal somewhere around 260 MHz here in Europe, besides all the Brazilian nonstop-talk pirates and a trance music station, probably a pirate, too.