I love these little $20 short range fm transmitters. They turn an early 1990s car stereo into a speaker system for any device over Bluetooth 
Of course, artificially boosting the transmission power to do a pirate radio broadcast from your moving truck would be highly illegal. So don’t ever do it. Ever. https://image.nostr.build/4b6cb21da1da721efa9b4b375d3a4bfd9eab2603a22f32a236c4132c03856af5.jpg