alternator whine

I'm getting some serious feedback through my radio, and it just started happening about 5 minutes ago. The Jeep calls for a 120amp alternator, which was optional standard is a 90 amp. The 120 amp got sand in it and quit working, so i used the extra alternator I had laying around from my previous cherokee to replace it. Everything seemed fine, until I installed the CB, i got a ton of feeback and a whining noise that changed pitched with the RPMs of the engine. I did some snooping and found it's called alternator whine. Now I'm getting the exact same issue with my stereo, is it a bad alternator or a bad ground somewhere else on the jeep.

I would check or make your grounds better.

Auto parts stores make noise suppression devices just for this reason. I don't know why your old one was fine and the new one isn't, but it's under 10 bucks for the part if you don't find a solution.