Fixed-Mount VHF Radios
Arguably one of the most cost-effective safety items you can have on any boat, a fixed-mount VHF allows you to communicate with a wide range of people and organizations: the U.S. Coast Guard, commercial ships, the Rescue 21 network, bridge tenders, TowBoatUS, race committees, and countless others stations. And its full potential is realized when units with Digital Selective Calling, or DSC, are connected to an operational GPS receiver (or have one internally). While all radios sold in the U.S. over the last decade are equipped with DSC, many operators (the U.S. Coast Guard says about 85 percent) either have not connected their radios to their GPS, nor registered for an MMSI (Marine Mobile Service Identity) number. This is vital for the full functionality of the Rescue 21 system.
Fixed-mount VHF radios are only as good as their antenna systems (a combination of the antenna, coaxial cable, and connections). Antennas should be mounted as high as possible: on the masthead of a sailboat or on the flybridge of a powerboat. Because VHF signals travel more or less in a straight line, a higher antenna will allow a VHF signal to reach more distant stations due to the Earth's curvature.