I have one I made in two different planes. One I have flown about 1 1/2 gallons of gas through with a PCM receiver and the other just 4 tanks with a PPM receiver. The devices work very well and I don't think there are any interferences but I go out of my way to make sure the wires are away from the radio equipment which are also kept away from any metal pushrods or such.

Materials: I went to Sams Club and bought the rechargeable NiCad pack with 8 batteries and a charger for $20 (AA size) a battery holder and switch from Radio Shack and an old micro servo.

Setup: On the first plane I hooked it up to an external kill switch for safety (not needed unless you forget to turn it off) and on both planes the servo is slaved to the throttle to activate at 1/4 throttle and an auxiliary switch on the radio to turn it off.

Operation: After turning the electronics on I go to full throttle and trottle trim, prime, come back down on throttle till I hear the servo arm move on the switch (the cheap micros are noisy--that's a good thing) and when I flip the switch on the radio I can hear the switch engage. I start as normal and leave it on for about 45 seconds to warm up the engine then I flip the switch on the radio to turn it off and tune the engine.

I've used both the metal glow clip and the rubber one (newest) and I haven't had any problems but the rubber one is still new.

Good luck