FM radio stations are basically just two things: a transmitter to create the signal, and an antenna to broadcast it, which means that building your own pirate radio station is actually really, really easy.
Those FM transmitters you used to use to get music from your iPod on to your car stereo? Full-fledged radio transmitters, just ones with severely limited outputs to avoid violating any FCC laws. If you’re handy with a soldering iron, those simple car transmitters can actually be hacked to get a much better range by adding a bigger antenna and removing internal resistors.
Alternatively, you can get everything you need to build a decent long-range system on Amazon for a couple hundred bucks (although you’ll want to check local FCC rules for when it actually comes to broadcasting things).
But the easiest (and cheapest) option is a Raspberry Pi. The same principles apply: use the tiny computer to create and broadcast the signal, and attach an antenna to give it the broadcast range.
1. Set up your Raspberry Pi
You’ll need to get Raspbian, the Linux-based operating system for the Raspberry Pi.
2. Install the FM radio software
Alternatively, if you’d like something even simpler to use, Make Magazine’s Sam Freeman and Wynter Woods built a modified version of the PiFM code back in 2014, which you can find at the Make website. Simply flash that to a microSD card, add music, and just plug the Pi into a power source and it’ll automatically start broadcasting on your frequency of choice.
3. Choose some music
Get your tracks set and copy them over to the Raspberry Pi. If you’re using the base PiFM software, you’ll need 16-bit .wav files. Make Magazine’s code supports broader file support, though.
4. Add an antenna
Plug a strip of wire into the GPIO4 pin on your Raspberry Pi (the fourth pin down on the left side on most Pi hardware). You’ll want something at least eight inches long, although closer to 25 inches is recommended for better range. Depending on your setup and surrounding environment, the Pi can broadcast between about a foot to roughly 300 feet away.
Run the PiFM code. You’ll do that by running a command like “sudo ./pifm awesomejams.wav 100.0”, where that “100.0” is the frequency in MHz on which you’re broadcasting.
6. Tune your radio and enjoy
Get your FM radio of choice, tune to your broadcast station, and enjoy!