I worked for the General Motors Proving Grounds back in the early 1970s when GM tried out windshield antennas in various cars and trucks. It was not very successful.
As an electronic tech for GM at that time, we did extensive testing of various radio antenna systems. All the discussions about AM radio reception that I have seen do not mention one particular item: If you want good static-free reception on AM, the antenna must be well grounded at the antenna! Grounding of an FM radio antenna is not critical, but AM radio is.
I suspect that a lot of RV antennas are not mounted to the metal structure of the coach. If this is the case, you should run a heavy braided strap from the base of the antenna to a very good ground. The shorter this cable is the better. Also, on motorhomes, if you properly ground the antenna, you will not need a lot of the filters, etc., that are made for reducing interference.
— L.D., Tyler, Minnesota
Thanks for the tips, Larry. As a licensed Ham radio enthusiast and hobbyist, I’ve noticed some of these factors too, and I’m happy to pass them along.
Ken Freund’s more than three decades of auto-repair experience and 20-plus years of RVing helped him author numerous books and articles on vehicle repair. In addition to RV Clinic and Performance, he writes the Powertrain column in MotorHome magazine. Ken has been a California Automotive VO-Tech and Smog-Test Program Instructor and an ASE-certified Master Automobile Technician.