First I have a question about an FM transmitter. Do I need to use FM crystals or can I use any matching set?
Second is.
can I use any 2.4 receiver with a 2.4 transmitter. Sorry for the dumb questions but i need answers. Thanks

FM RX/TX will require FM Crystals.

2.4ghz TX's must be used with matching RX's, as the signaling is different from radio to radio.

Thanks, that's what I guessed but I wasn't sure.