Question: if two people are caught having SDR units that could cause the jamming, how do they know who is guilty?

Both. It's not who caused the jam. Operating these things isn't legal to begin with.

Actually, just being in possession of such a device in the US isn't legal. Whole FCC page on it with citations: https://www.fcc.gov/general/jammer-enforcement

This is probably an area where SDR's with send capability could in theory be prosecuted as a jamming device. Whether it's been interpreted that way or enforced ever is unknown to me. A purpose built device advertised as a jammer would absolutely be a problem.

Oh also, the 1934 communications act is supposed to prohibit US/state governments from using such devices as well, but they've ignored the law. Some companies in the 2000's challenged it for use in their buildings and afaik lost the cases. My experience dates from that same time range when they were sort of accepted as de jure illegal but there wasn't de facto enforcement.... also networks use more bands now so a jammer covering more frequency ranges would be needed. back then they could do 3 ranges (850mhz-ish, 1900mhz-ish, 2100mhz-ish), now there would be way more like 3.7ghz down to 600mhz. Ignoring mmwave, that's not going to be in your bathroom.

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amelius 6 hours ago | parent [-]

> Actually, just being in possession of such a device in the US isn't legal.

Wait, SDR devices are not legal in the US? That doesn't sound plausible.

My "computerized legal advisor" says:

> There’s no rule from the Federal Communications Commission (FCC) that forbids individuals or hobbyists from buying, importing, or owning SDR hardware in the United States. You can legally purchase and have them.

> Radios that transmit need FCC equipment authorization (such as certification or Supplier’s Declaration of Conformity) before they can be marketed in the U.S. if they are capable of operating in ways that could cause interference. That’s primarily a manufacturer obligation, not something that restricts private ownership.

> Owning a device is fine, but you must not transmit illegally. Sending signals on unauthorized frequencies or at unauthorized power levels can lead to fines, equipment seizure, and other penalties.

	▲	kstrauser 5 hours ago \| parent [-]
		As with so many other things, intent matters. Owning lockpicks? Fine! Owning lockpicks when you're caught burgling a house? You're extra screwed. Owning an SDR? Fine! Owning an SDR and getting caught using it to illegally disrupt communications? You're extra screwed. Yes, you can absolutely own an SDR, and transmit with it on legal frequencies. If you're busted using it to break the law, then it's strong evidence that you went out of your way to deliberately, premeditatedly break it, and that makes for a bad day.