On my 9Z futaba with digital servos and y harness to rudders and extentions to the elevons all servos jittered severly with antenna up and right next to the plane in my basement. Unplugging the four digital servos solved the problem. My solution was to put the reciever in the back of the plane eliminating the long runs. I have never used JR. The plane flys fine with this setup and range check is the same as all my other planes.