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   blinry ☎️2546 (blinry@chaos.social)'s status on Monday, 11-Mar-2024 05:22:27 JST blinry ☎️2546

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   38: Catch a LoRaWAN chirp

   This was a bit like trying to catch a rare insect! 🐛

   LoRaWAN is a low-power, wide-area networking protocol, intended for "Internet of Things" applications.

   You can see transmission in the lower half of the screenshot! It has a very cute structure: You can see eight "down-chirps", followed by two "up-chirps". That's the header, followed by the payload.

   To look for the signal, I made a "baseband capture" in SDR++, and opened the recording in sonic-visualizer.

   • Embed this notice
     blinry ☎️2546 (blinry@chaos.social)'s status on Monday, 11-Mar-2024 05:22:28 JST blinry ☎️2546

     in reply to

     37: Listen to The Buzzer

     There's a mysterious Russian station broadcasting at 4625 kHz. Sometimes, it sends encrypted voice messages.

     But usually, all it does is send a honking sound every two seconds, to deter other stations from using the same frequency.

     The purpose of the station is unclear, but most theories think it's military communication.

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     blinry ☎️2546 (blinry@chaos.social)'s status on Monday, 11-Mar-2024 05:22:29 JST blinry ☎️2546

     36: Receive images from amateur radio operators

     Using a protocol called "SSTV" (slow-scan television), amateur radio operators send each other postcards! :D

     I've been browsing the usual frequencies, and tried to decode images using the software QSSTV on Linux.

     And I accidentally caught a piece of what seems to be a test image!

     Also, SSTV has the prettiest noise! :3