My club is looking into this problem, Futaba told out club that cell phones can effect the transmition, the AMA didn't have a comment about it. The man who i fly with was flying with another man. The mans cell Phone started ringing all of a sudden both planes go to the ground and are totalled. Now we shut out cell phones off. It doesn't seem to efect if when it is not ringing. that's just our expereince.