Ah got it. I went back and read your 'hacking sstv' web page. One answer is to just write a program that tunes your SDR to the band where the SSTV images are being transmitted, capture the transmission and decode them and then post them to the Fediverse. That all works fine on a headless RasPi with an SDR dongle and an internet connection.
It's interesting that few do it this way.
May 18, 2026, 8:53 PM@ChuckMcManis Yes, that is one way… my question was whether someone had written such a program, because the idea that I'm the first person in the world to want to do this seemed odd. Why re-invent the wheel?
Turns out, `rtl_fm` exists (as per @ai6yr 's post elsewhere in this thread). Not a 100% solution, but 90% of the way there.
May 18, 2026, 9:00 PM@ChuckMcManis @ai6yr Yes, and a tool named "rtl_*fm*" also sounds like it's for receiving Frequency Modulation signals, not Single Side-Band.
So it's a poorly named tool. I'd have called it `rtl_rx` or `rtl_demod`.
@stuartl @ai6yr
LOL. Yeah, but I would bet you a donut that in the initial commit of the code all it did was demodulate WBFM and then someone said, "Well it could also do ..." and that got added on. You could hack it to also demodulate SSTV and add a switch to tell it to produce .png files or something and the cycle would continue. 😆