I have 3 FMA M5 receivers, and have had problems with two of them. I'm using a Hitec Eclipse 7 transmitter (without the variable frequency module). I'm not getting very good range with two of the three receivers. I've tried new crystals in the receivers and I've tried an after-market antenna on one of the receivers. Even still, I lose control completely sporadically and have crashed once due to it. Is it possible that my transmitter crystal is damaged? Am I doing something wrong? I have 3 single conversion receivers (GWS, Hitec) and have had great results with them (of course their range is lower). Any ideas? I follow all antenna and receiver placement recommendations.