I can't remember what ground i have to change to get rid of the hum from the motor.

You'll get the cleanest power by running both power leads and the ground lead from your CB straight to the battery. I personally didn't do it, but that's the sure-fire way to get rid of alternator noise.

Some of the new radios have a filter that takes out the noise. Check the book the CB came with.


If you have a new Uniden I know they have one(switch).


Hope this helps.

Like CStone said, wire directly to battery and good grounds will get you a long way in reducing unwanted noise. You may want to check out www.cbradioforum.com