I would suggest taking a close look at the wiring of the aerial/antenna. Is it really connected to anything it's supposed to be connected to, not just wadded up inside the boat somewhere? Wadding it up, or coiling it up isn't exactly the best thing you can do with it. Not knowing anything about your boat, how it's laid out, no idea how to run the aerial/antenna.
- 'Doc
As an absolute last resort you can do what the dog did, I guess. I don't mean the barking, but then, that probably couldn't hurt either.