The methods of radio frequency interference (RFI) suppression presently widely used in automobiles have operating problems when employed with capacity discharge or magneto ignition systems in “off-the-road” types of equipment. Tests have shown that several new methods have been extremely effective with these two types of ignition systems and are compatible with satisfactory engine performance.
RFI has been recognized for many years as a considerable source of interference to television, aircraft navigation equipment, mobile-two-way radio installations, and the rapidly expanding use of many new electronically controlled devices requiring a radio signal to operate.
This paper describes a series of tests using several suppression devices on snowmobiles, power mowers, chainsaws, and a motorcycle. Although the varied electrical characteristics of the ignition system do not affect RFI suppression, the construction details of the engine and the geometry of the cable routing do.