Is there a portable civilian device that allows for short to medium range (10 miles or so) that would allow for 128 or 256 bit encrypted data bursts, and if so, what level certification would one need to go about for using it legally in the US? I’m imagining a data burst to convey less than 1 MB of data with an accompanying bit total that could then be “delivery confirmed” by a return message with that bit total. Bonus points if it could play nicely with a Disco32 Discus.
I know it wouldn’t fool a foxhunt, but was curious if such a thing exists and if so, what’s the entry cost in money and time?
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WiFi will need some big dish antennas and unobstructed line of sight to get that kind of range. Just be careful not to exceed the EIRP limits.
There is also 900MHz WiFi (802.11ah) for longer range, low speed use. The equipment is not very common though.
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Rattlegram or similar with something like an RT10 (license free ism band 900mhz dmr with encryption) or Moto DTR (license free frequency hopping spread spectrum, tricky AF to intercept)
I’d love to hear more about the frequency hopping thing. What devices would I need, and how difficult is it to program?
The Motorola DTR and DLR series radios are both compatible with each other. I’ve only gotten to tinker with DTR 600 and 700. They’re not hard to program, and the software is free. Each “channel” is more like a time synchronized algorithm to calculate the next frequency. Iirc they change every 0.25ms within 902-928mhz, or 2.4ghz ism (hidden with wifi and Bluetooth) on the dtr 23x0 models. There are also other fhss radios that use their own incompatible hopping order like the trisquare exrs radios.
Big note that I am a technician class with not much experience.
To get long distances, you can either rely on prolongation (you radio signal follows the curve of the earth), or line of site (your antenna can see the other antenna directly).
For propagation, HF generally gives you the best distance. You can use digital modes on the 20 meter band with a General class amateur radio license. You would need a portable transceiver and antenna likely mounted on your vehicle.
For line of sight, your antenna will need to be 20-30 feet above ground surface to see over the horizon. Hypothetically portable with a dipole on a pvc mast. You can use digital modes on the 2 meter and 70 cm bands with a Technician class license.
To send and receive data, you need to connect both radios to their own computer and agree on a language. Most commonly, you use two different frequencies to represent ones and zeroes. There are established protocols, but I think the one that would best lend itself to data bursts is proprietary D Star.
Digital isn’t something I’ve used yet, so hopefully I haven’t given any bad information.