Might be heat might be RF interference. Did you ever take notice if anyone was shooting or running close to you when this happens?<div> I would really try a 2.4 Gig radio set. Borrow one if you have too. For about 50.00 bucks the AeroSport 5 is a really nice radio and receiver with 5 channels and analog trims which we need. Hobby People have them and they are made by AirTronics, so you cant go wrong there. I have 2 of these radios now. I used to buy Futaba 75 and 2.4 SkySport radios but the AeroSport is much easier to add firing buttons too.  I still have to get the pics up for YHR. I havent forgotten , just busy with another project.</div>