Robert, You have now tracked the problem down to the radio link between the transmitter and the receiver. Thats progress. Once you have eliminated mismatched crystals and the possibility suggested above that the tx and rcv might be on differnt bands, the next thing is to find someone with a 40 MHz tx and rcv that work well and use them to isolate the fault to either your tx or rcv. Once that is done you can take the offending equipment apart and look for loose wires or send it off for repair.