Ignition interference (unwanted radio frequency energy from an ignition system) can get into a radio system through 2 paths. First, and I might call this the front door, it can affect the system through the antenna port. This would be true RF interference. Second, it can come in the back door or through the power and / or servo leads. All 72 MHz. systems (or 36 Mhz, 42 MHz. etc depending on where you are in the world) are prone to interference through the antenna port. The antenna simply picks up radiated RF energy that is being leaked from the ignition system. This received ignition signal plays heck with the receiver decoder and the receiver passes a corrupted signal onto the servos as glitches. 2.4 GHz. systems are relatively immune to interference from this source. This is a frequency thing, not a radio brand thing so all systems are relatively the same here. For 72 MHz. systems, PPM will show ignition interference readily where PCM will tend to tolerate the interference until the interference reaches a level where the receiver can no longer mask it. This will happen most often when received signals from the transmitter are weakest ... such as when the plane is far away or during a range test.

2.4 GHz. systems can be interfered with when ignition noice is at a high level. The interference from the ignition system is radiated and the various battery and servo leads act as antennas and conduct the signal back to the receiver through their respective ports. This energy can affect the receiver decoder and cause servo glitching. This is a different sort of interference than when it comes in the antenna port. If you see this sort of interference, the amount of interference will be fairly constant regardless of whether the received signal from the transmitter is strong or weak. So if you solve this "back door" interference on the ground, you don't have to worry about it coming back in the air when the plane is at a distance from the transmitter. Some brands of receivers have more RF filtering on the power and servo leads than others

The time honored methods of keeping ignition parts as far away from radio components is the easiest method to prevent both kinds of interference. Eliminate wiring rats nests in the plane. Bundle servo leads as much as possible ..... leads running every which way are just small antennas looking to pick up interference. Yes ... neatness counts! Many other preventative measures have already been mentioned in this threads ....no need to repeat them here.

With quality ignitions such as RCexl, the CH variant or the original metal box CH when used with metal cap plug connectors, I (knock on wood) have never had a problem with interference ... and I'm still flying 72 MHz. equip. for the most part. I have two planes where the ignition box is mounted inside the fuselage fairly close to receiver components and there is no trace of interference.