For those of you who have installed additional sound systems in your boats and the sound you get is a hum or buzzing noise in the speakers, the fix is easy. When I installed Sirius satellite radio/weather, the unit had to be located near the helm in order to connect the input wire to the chartplotter (a very short wire by the way). Unfortunately, I had to use a different power source (on a different circuit breaker) than what was feeding power to my Sony radio/CD player down below. What this did was create a "ground loop" in the system. Noise was being created in the audio cables with the two grounding systems in play. To fix this, I bought a $16 ground loop isolator at Radio Shack and installed it on the audio cables between the Sirius unit and the radio/CD player. Obviously, it would have been ideal to connect a single circuit breaker to feed both units, but in my case running another 25 feet of power cable from the instrument panel to the helm was something I did not want to do. With the isolator, I get clear sound from all the speakers, full adjustment of volume and a system that works great. I also installed the corresponding Sony Aux player, so I can hook up my Ipod or MP3 player.
