after i tried the QFM "controller joystick" mod and the "car antenna upgrade", i noticed a increased interference. no matter where i drive it when i gets even a few inches from the controller it studders. i put the motor tab forward, i tryed different areas to make sure it was caused by a another source, i even replaced the mod antenna with another one to make sure it wasn't the problem. are the joysticks causing problems or is it the antenna? or is it something else? thanks