So… I found out a way to send encrypted messages using amateur radio.

There is an app called Rattlegram that lets you convert a string of text into soundwaves that plays though your phone’s speaker. If I just use an app like Secure Space Encryptor (SSE) to encrypt a text, then copy-paste it to the Rattlegram app, then transmit that over radio, then using the same app to record the sound and reverse the process on the other end. Voila! Encrypted long(ish) range communications without a centralized server!

But I looked it up and apparantly its illegal to encrypt communications over the amateur radio bands. What are the odds of actually getting in trouble? 🤔

(To the FCC agents reading this: this is just a hypothetical, a thought experiment, I’m totally not gonna do this 😉)

  • Rivalarrival
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    2 days ago

    You can tell which direction a radio signal is coming from, using a directional antenna like a yagi, you literally sweep the antenna around and listen for where the signal is strongest.

    This is valid, but old school.

    Modern WiFi routers use a technology called MIMO. Basically, they use multiple antennas. Each one picks up the same incoming signal at a slightly different time. Once the router knows the time difference, they can listen only for signals with that specific difference. This allows them to focus on signals from thst specific directiin, and reject noise from different sources.

    The router can then turn around and send outgoing signals at slightly different timings on each antenna. This strengthens the signal in the direction of the intended receiver, but not in other directions.

    The underlying technology is certainly capable of direction finding, but it does so instantaneously, for every signal it hears.

    This technology is broadly available in consumer-grade electronics; it is certainly available to the “radio cops” of the FCC, if they choose to use it.

    • Captain Aggravated@sh.itjust.works
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      1 day ago

      Hams are much more likely to use yagi antennas and physically rotate them, it’s simpler, for one thing.

      I don’t think the FCC has many employees sitting around listening to the ham bands for violations, they rely on licensed amateurs to report issues, so at least the first folks who are gonna try to find you are going to do so with the kit they’ve got.