I've just bought a 2000 pontoon boat with a Merc 115HP OB.<br /><br />I have a terrible alternator whine in my AM radio and on transmit of my marine radio.<br /><br />I have placed a filter in both the radios. I have tried another fixed mount radio. I have run a ground wire from both radios to the aluminum frame. None of this has made any difference in the whine.<br /><br />I am an electrical engineer and a HAM operator (KO4R) so I have I solved this problem in cars many times and can eventually solve this problem. I know that I must stop the noise at the source so I hope some of you have already done this to save me some troubleshooting time.<br /><br />Thanks in advance for any assitance.<br /><br />J.W. Roberts<br />Central Florida
