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 😉)
I don’t know how easy it would be to catch, suppose that depends on the range. That being said, I would not fuck with the FCC.
It does depend on what band you transmit on. If you transmitted a two second burst, once, on 23cm, and never did it again? You’re almost certainly going to get off scot free. Try that on the HF bands, or even on 2 meters where a lot of people are listening, transmit for longer and do it regularly? We WILL find you.
Encryption does not hide the presence of a message. Transmitting with a radio is literally the act of shining a light into the sky. That light is redder than the reddest infrared so we can’t see it, but it’s light nonetheless. We transmit meaning using that light by blinking it on and off, or varying either its brightness or color in ways that mean something to each other. Encrypting just means the scheme you use to vary the brightness or color doesn’t mean anything to the general public, only the person you’re trying to talk to. Everyone else sees meaningless noise. But, they still see it.
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. It’ll literally point to the transmitter. Do this from at least two locations and you can draw a line on a map that crosses pretty close to where the signal is coming from. Hams do this for fun, it’s called fox hunting.
On a related note, numbers stations do exactly this. If you listen to the HF bands, you may hear voices reading strings of numbers or letters in some foreign language. At least one of these has been confirmed to be a one-way communication system for governments to talk to their spies in the field. The messages are encrypted with a one-time pad system which is not breakable unless you have the one-time pad, the message which might sound like “three, three, seven, three, nine. Three, three, seven, three, nine. Eight, four, six, three, two. Eight, four, six, three, two.” is meaningless to most, but it’s trivial to detect where it comes from.
Look up the account of the Yosemite Sam station, some hams started hearing the voice of Looney Tunes character Yosemite Sam saying “Varmint! I’ma gonna bloooow ya ta smithereenies!” from the cartoon Bunker Hill Bunny, followed by a digital data burst. This would happen on several frequencies at regular times. So they tracked it down, ended up at an R&D facility with a bunch of antenna masts out back and were quickly met by employees telling them to stop taking pictures.
Even if you aren’t bothering anyone, hams will foxhunt you because it’s a fun mystery to solve. If you are bothering anyone, hams will foxhunt you to turn you over to the FCCs punishment division.
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.
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.
I agree, ham radio isn’t an FCC enforcement priority.
In would say that hams do have access to this level of technology via Software Defined Radio.