Are you trying with a set of matched crystals - I mean the TX and RX crystals made by the same company? I have had no luck 'mixing' crystals, but have always been able to run a mixed Tx and rcvr pair in 75Mhz FM when I use a matching set of crystals.


Its 75Mhz that has the phase shift differences, thats not supposed to be an issue in 27Mhz.