Okay, basically what I'd like to be able to do is have some sort of "universal" RF (FM) audio circuit. Actually, two: One for transmitting, and a separate one for receiving. (I'd prefer to keep it simple, and therefore not a transceiver circuit. This is for one-way communication.) My ideal setup would be like the diagram below; I don't know if I'm using the proper terms for the different parts, of if this particular type of circuit is even physically possible. The red line separates the transmitter diagram from the receiver diagram - rather than draw two completely separate ones, I just put them both there, and the red line is like the "transmitting distance" that the signal goes (not drawn to scale). The Arduino microcontroller sends a "frequency selection pulse" to the RF circuit (sort of doing what an oscillator would, was my thinking). Audio is the analog waveform - I think I can figure out amplification for the audio by myself, but this RF circuit thing has gotten me stuck. Arrows indicate direction of data flow.