Thread: radio static
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Old 09-23-2005, 05:32 PM
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shorod shorod is offline
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Re: radio static

I'll have to check my wife's car, but it used to be there was a cheese-grater like piece of metal that, when the hood was closed, would allow a clean ground to the hood. The large grounded metal hood would act as a Faraday cage and reduce the amount of engine RF noise that would be picked up by the AM radio. As the ground rusted, or the metal piece was bent out of the way, people would get static like you mention on the AM stations.

I would have to guess that you have a bad (loose/dirty) ground somewhere. Since AM is amplitude modulated (by definition) and the frequency band is in the lower kHz range where the engine can produce noise, the AM stations are much more prone to engine/alternator RF noise than FM.

-Rod
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