Is it legal to spoof radar, clear the DFS channels of other users, and then use those channels for your own devices? I could see that being useful in dense 5GHz environments, so long as you don’t mind being a selfish bastard/bitch.
> Is it legal to spoof radar, clear the DFS channels of other users, and then use those channels for your own devices?
Not in the US. While incidental interference with unlicensed use of spectrum is legal in the US, intentionally blocking, jamming, or interfering with authorized (including unlicensed) radio communication is prohibited.
Regulations really depend on jurisdiction. For the case of WiFi (unlicensed users) in the US you see “(1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation.". So what is harmful interference? Poorly defined, but from what I can tell, it means “Unlicensed users may not cause harmful interference to primary or secondary users”. So, interfering with other unlicensed users seems okay, so long as you never interfere with licensed users e.g. weather radar.
However, there are other laws related to jamming (wilful or malicious interference) that seem likely to cover the situation. https://www.fcc.gov/general/jammer-enforcement Perhaps you get away if caught if you could show you didn’t have criminal intent?
An especially important example might be if you caused someone’s VoIP phone to not work, since that is related to “safety”.
Because you only need a short signal, it would be very hard to detect, unlike noisy full-time jammers.
One place to check on the legalities would be conference centres that have WiFi systems that interfere with guest hotspots - I seem to remember that Cisco||Meraki had that functionality? Presumably the manufacturers would have thoroughly vetted the legalities - especially since selling jamming devices has heavy penalties.
