John, I had a problem with a Goldberg Sukhoi ( not a gasser) that was a pain in the ***** to figure out. After trying just about everything including a PCM reciever I finally realized that the hub on my tail wheel was metal and I had also used a metal washer for a spacer on my main gear. After replacing the tail wheel and switching to a plastic washer my problems went away. The PCM receiver helped to lessen the interference but it still happened occasionally. Don't know why some of these companys use a metal hub without some kind of non-metalic bushing.