> Please do your due diligence and check local laws before attempting anything I do in this post. Transmitting radio signals can become legally problematic very quickly, and the band I specifically transmit on here (868Mhz) is illegal in the United States without a license. I'd rather you didn't have men in suits knocking on your door on my account. You've been warned!
Let's be honest here: the FCC is gonna have to see a helluva lot of problems coming from your transmissions before they bother to send the black Suburbans filled with men in suits to knock on your door. You're going to get a series of letters that basically say "please don't do that" if anything.
An American thermostat would be using around 920MHz which is the equivalent unlicensed band in the US. Funnily enough, the author warns Americans as an example but he is running more foul of the local rules an American would be (assuming an American would use 920MHz and not 868MHz).
In the US you are allowed to tinker around there with home-built RF devices for personal use and prototyping in unlicensed bands, to some extent. Although, using an SDR for this requires a certain interpretation of the rules. In Europe it's basically not allowed, one shall only use pre-certified modules. Or only use the device you've built in an RF anechoic chamber until you've undertaken the certification process (totally impractical for a hobbyist).
Let's be honest here: the FCC is gonna have to see a helluva lot of problems coming from your transmissions before they bother to send the black Suburbans filled with men in suits to knock on your door. You're going to get a series of letters that basically say "please don't do that" if anything.