Alternator Noise Filter
 

Hi, anybody have any feed back or experience with adding alternator noise filter/s to there boat? My ship to shore radio transmits and receives perfectly and very clear when the engines are not running.But when the engines are running their is alot of interference when I receive someone trying to talk to me and they have a hard time receiving me.I also had this problem on another boat but never pursued fixing it. I am hoping alternator noise filters installed would cure the problem,Any thoughts or feedback would be appreciated.

All noise filters are a capacitor and an inductor. Any one from a car stereo shop will do the same thing.

Most likely your problem stems from having daisy chain grounds- more than one ground path back to your source negative. If you isolate the radio from other grounds (like a possible chassis ground) and run a dedicated ground wire back to your boat's common neutral point (where the boat's electrical system ties into the battery) you'll probably lose the noise.

Is it a higher frequency "whine" or a mid-frequency snapping-like buzz?

I had the same problem with my stereo.

I ran the power wire directly to the battery through a relay hooked to the dash switch, rather than through the dash switch. I ran the ground directly to the battery. All my amps are run to a distribution block hooked directly to the battery (with a fuse of course). Turn on wired to the same power source but with a relay kicked on by the radio. All interference is gone. Extra benefit, everything's on one battery so if I run my stereo too long I can still start on the other battery.

The solution for your ship to shore would be a little different because you want to draw off either or both batteries in an emergency, but the basics are the same. Make sure you have a good ground path, and that you're getting power directly from the battery selector switch, with a fuse, and properly sized wire.

Thanks for all the response's should be an easy enough fix.