I recently got a Raspberry Pi 400 and I tried this https://github.com/markondej/fm_transmitter without an antenna. The range was approximately of about 5 feet, from what I could notice.

Now I've heard a lot about square wave harmonics and Raspberry Pis; without an antenna, could it be legally dangerous for me to try some things with it in my house, or is it low-power enough so that those harmonics are properly contained within a very small perimeter ? I live in Canada.



1 Answer 1


In the US, unless you modify the hardware (e.g. attach an antenna), you are covered by the Part 15 of the FCC's rules if the device you are using (the Pi) is certified. For FM, the allowed transmission radius of an unlicensed transmitter should be less than approximately 200 feet (61 meters). If your range is only a couple of meters, you don't have to worry.

Of course, you should check the actual rules that apply to you in Canada, but considering the tiny range I'd say you're safe.

For comparison, EM noise from cheap LED lightbulbs can be heard over hundreds of meters on AM / Ham radio, and it's almost impossible to make people get rid of them even if you complain to FCC.

PS. Don't consider anything you read on the Internet (including this answer) legal advice.

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