Okay, I have going to the extent of what I can do with this and figured I would post it here to see what you all have to say. I have a 1993 Jeep Wrangler YJ 2.5l, I have a scanner and 80 and a 2 meter rig in it. I've had the same radio and scanner in all three vehicles I've ever owned, and never had a problem with alternator noise until now. When the vehicle is off, it's the clearest radio I've ever heard, as soon as I start the jeep I get a little bit of wine from the radio, once I start driving it's almost unbearable. I've tried everything that I can think of including talking to good friends of mine to do installs for a living. I currently have a DC filter in line in the cab, I originally had it in the engine compartment and was told that it was too close to the alternator so I moved it to the inside today, still no help. I have clean power and wired it right to the battery. I've tried everything I can think of and can't figure this one out. The other thing that I figured out is that when I have my high band portable in the vehicle receiving, I still get the same whine as I do on the mobile. Does anyone have a solution to this problem? I originally was leaning towards it being alternator wine or the electrical system, but now I believe I am getting it through the antenna. I don't know how old the alternator is, it might be the original one. I know that when the alternator generates electricity it is originally AC and it is then rectified to DC. My question is, if the rectifier is starting to go bad will it cause extreme alternator noise to be received through the antenna?
Try running your ground wire from the radios, directly to the engine block. It cured the alternator/distributor whine in my Cobra 148. And others said that they could hear a bad background noise in my transmissions as well, that is gone too.
The condenser that C5 posted, will work on the older vehicles, but although its possible, its hard to put on a newer style engine, since the distributor is made different.
'87 YJ, 4.2L built and bored, 8.5" of lift, 8.8 rear, AX15/NP 231, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...