Ive had many Futaba radios, but the problems like you described almost always were associated with the electronics in the airplane. I know one gent that was using JR and had a similar problem. The final problem was that the antenna was not screwed in firmly. Always something simple, but always hard to find or figure out. If you had a flying buddy with the same channel, you could have him check your plane using his radio to eliminate an airplane problem. Or since Futaba receivers are high or low, you could have a friend put in a compatible receiver crystal in your receiver and range check your plane to ensure it is not in the airplane. Remember, a good range check is done with the engine running and shut off, to make sure engine vibrations are not causing loose metal parts to chatter and generate RFI. Hope this helps. You already got some good leads from our friends above. Good luck and happy landings.