AM Radio Reception Noise

[lawrencedesigns]

I just put a new Sony radio in my 84 Spider. The only issue is extreme static(just in AM reception). The static follows the engine revs.
My solutions? I disconnected the windshild antenna and installed a rear post antenna. With noise filter. I also installed an aftermarket in-line power supply filter. (I question the need for these)
Also replaced the plug/coil wires with new Bosch from IAP.

Seems to have improved, but is still very loud. What have I missed? I suspect perhaps something in the charging system?

Keeth Lawrence

[lowmileage]

Is the noise filter you put in like this?
http://www.crutchfield.com/S-oMpFpz7...150&I=127ANS80

cause I know alternators can cause noise.

The Crutchfield ad also says FWIW,
"Sometimes alternator whine can be cured just by topping off the fluid in your battery or properly grounding your in-dash stereo."

[Alfacliff]

a ground for the hood and exhaust help a lot, the exhaust hangs by rubber hangers and acts like an antenna. a ground strap across the hood hinges helps keep the noise inside. alternator noise is usually a whine that gets higher pitched with engine rpm, spark plug noise is a popping that gets faster with rpm. the fuel pumps also can get noisey, thats where I would put an inline filter.
cliff