What causes interference in reception in car radios?

Asked by: Gautam Malkani

Answer

The interference in automobile radios comes from a variety of sources. The most common sources for interference are other components of your auto's electrical systems. The most likely cause of this type of interference is the cars spark plug wires which degrade over time due to engine heat or chemical decomposition from engine fluids such as oil,grease,power steering fluid, brake fluid or anti-freeze. If you are experiencing this problem it's most likely because of the need for a tune-up. Another source of interference can be the charging system of your car. The alternator which produces electricity to charge your cars battery is essentially a source of electro-magnetic energy. It works by moving a magnet through a coil of wire and produces a alternating current which must then be rectified by the use of diodes. This changes the voltage to direct current which can then be used to charge your battery. If you experience any of these problems you can visit any auto parts store or electronics store and purchase an inexpensive interference filter.
Answered by: Randall Potts, President Illuminations Lighting Design , NJ

A temporary interference on your car radio can be also caused by other, external electro-magnetic sources, like power lines, transformers, generators, other radio-communication transmitters, etc.
Answered by: Anton Skorucak, M.S. Physics, Editor, PhysLink.com