I admit I had that gut reaction initially as well, but it seems they’ve made some decent allowances for home-built UA to be exempted from the rules. I tried to summarize these over on the CubePilot forums; I’ll save re-typing the same information.
I do also agree that they don’t detail implementation at all. However, they do seem to have given a not unreasonable amount of paths to investigate:
Since the frequency must be accessible by most consumer electronics, that leaves WiFi, Bluetooth, or NFC, or cellular. I think we can rule out NFC for obvious reasons , and cellular since most laptops don’t have that. Personally, I’d be surprised if the solution winds up being Bluetooth… at “high” power levels, my bluetooth devices lose connection after about 50 feet, whereas WiFi can easily go a few hundred with a decent tx (all of this would be directly line-of-sight). That pretty much narrows it to 2.4GHz or 5Ghz, and again for range reasons I’d bet on 2.4. Power levels would be dictated by FCC regs; they stated they don’t make a range requirement because of implementation differences.
Everything else though… \shrug.