"Steve Lusardi" wrote in
:

If your boat is fiberglass or wood, make certain you have a ground
plane for the antenna. The earth connection of your transceiver needs
to connect to large matt or screen on the hull which is connected
electrically with the water. Some boat builders bond the screen into
the deck. As a check, borrow a VHF base station antenna and see if it
performs correctly. If it does, you have found your problem. Now
fixing it, is another matter. Steve



The end-fed halfwave antennas, such as the Metz Manta-6 do not require any
ground or groundplane at all. The antenna rod, itself, is a total 1/2
wavelength dipole, but fed from the bottom end. No ground is necessary.

http://www.metzcommunication.com/manta6.htm
Guaranteed for life....