Automotive Manual PDF

Almost every reception problem is caused by one of two things: a bad ground on the antenna, or a bad antenna cable running from the antenna to the radio.
There are (2) parts to an antenna and you have to understand the antenna cable itself. Antenna cables are coaxial style cables. Coax cables have a thin center conductor wire at the center of the cable and an outer metal braid just under the plastic jacket of the cable. The center conductor carries the signal and the outer shield serves two purposes, it shields the inner conductor from radiated noises and acts as the negative voltage path. 99% of antenna reception problems can be traced to either one of these two parts of the antenna cable.

Bad Grounds At The Antenna
Bad grounds are synonymous with static on the AM/FM reception. Bad grounds are caused by a couple of things: the base of the antenna is loose, or there is corrosion on the antenna connector plugged into the radio. The base of the antenna is loose: most antennas a secured to the frame of the vehicle by clamping or “sandwiching” the base of the antenna to the metal frame of the vehicle. This effectively grounds the antenna to the frame of the vehicle. When the base of the antenna loosens from vibration, the ground path between the frame of the vehicle and the antenna input of the radio tends to gain electrical resistance. This added electrical resistance is carried through the metal braided shield inside the antenna cable and is picked up by the tuner inside the radio. This resistance can cause static on the AM/FM reception. Corrosion on the antenna cable connector plugged into the radio: the concept is the same, corrosion causes an increase in resistance between the metal braided shield inside the antenna cable and the ground of the antenna input of the radio. This increase in resistance caused by corrosion is also picked up by the tuner inside the radio and can cause static on the AM/ FM reception.

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