QTH.COM Swap Chat

hello, i recently installed a mobile and im having terrible static and engine reving coming across the radio. i would appreciate any ideas to help correct this, thanks jason

Jason:

Does your "engine revving" increase in pitch as the speed of your engine increases? If it does, you have ":alternator whine", AC current from the alternator that bypasses the your car's filtering network and gets into your radio. no vehicle and no rig is absolutely immune; I've even heard alternator whine on fire and police mobile transmissions.

SOLUTION: An alternator filter. The capacity of the filter, in amps, will depend on you car's electrical system and the current your mobile rig draws. I can't recommend a particular filter because I don't know what's available in your area.

Static is a different problem. It would help to know what band(s) you're operating on and your car and what kind of ignition system it has. Certain types of electric motors generate a lot of "hash" that can get into even VHF FM receivers by conduction; I've had that problem at home on and above 2 meters.

N9LCD

Hi
Your whinning sounds like AC ripple from the alternator.try disconnecting the output lead & firing up.If whine goes away,then install a PIE filter in line close to alternator or a Large 20-30V Cap between output & grnd.Either one will help.
As for the static problem try a couple of bonding straps between hood and body.This problem is commom in Ford products as their hood hinges are lousy conductors.
73 & GdLk
Paul