Your radio has a crystal that sets it to a certain frequency. Look on the back of your radio, there should be a number... Something like 42 or 13. I forget the exact range but I think the numbers go from like 11 through 80, or something like that. Anyway, whatever number your radio is, when you buy a new receiver just buy the crystal that matches your radio. That way you can have multiple planes that work with your radio. You can change the crystal in a receiver to match your transmitter, but don't change the crystal in your Transmitter to match a receiver. That is a no no.