you are in san jose mabee some local interferance . I fly in half moon bay when it gets windy my NEXTAR blows all over the place if the throttle is surging sounds like the radio. Do you have the antenna running through the fuse? in my NEXTAR I had to re route the antenna out the fuse to the tail to pass radio check properly it was fine after about 20 steps after that there was some glitching of the servos with the engine running. the plane has metal pushrods and seemed to cause the problem.ran it out the fuse through some tubing to the tail no more problems after that