How do you Stop automobile AM Radio ignition interference?

Answer 1

As a minimum, the engine hood needs to be electrically bonded to the car body. This is usually done with a short length of flexible copper braid that clips to the sheet metal of the hood and the sheet metal of the car body. Additionally, the 12VDC power supply to the radio should incorporate an electrical filter to prevent electrical noise from entering the radio via its power connection. Third, the antenna cable from the radio to the antenna needs to be shielded and the shield must be in good condition, with no breaks from the radio chassis to the point where it connects to the external antenna.

Although electrical generators have been largely supplanted by alternators, old cars that still use generators need to have filter capacitors added at the generator output to trap high-frequency brush arcing noise. Also, the breaker points in old car ignition systems are frequently the source of electrical popping noises in radios, and that can be reduced with the capacitor that is normally bridged across the points. If an alternator produces a whining noise in the radio, it often indicates one or more failed rectifier diodes in the alternator. In that case the diodes should be replaced, or if the rectifier diodes are build into the alternator, the alternator should be repaired or replaced.

Better radios will incorporate additional electrical filtering and voltage regulation of their power supply internally, and will use circuit designs that minimize sensitivity to power supply noise.

Answer 2

bY PUTTING p.m on