RE: Electrifly reciever problems.
In the Great Planes Electrifly receivers, you must use the Great Planes Short Rx crystal:
GPML20** FM SHORT RX CRYSTAL $9.99
Your transmitter would use its regular transmitter crystal. Transmitters are not "dual coversion" or any kind of conversion. Only receivers. The Great Planes Electrifly 4-channel receiver is a SINGLE conversion receiver.