CHAPTER
14
bus barInstalling Communications
and Position-Finding
Systems and Radar
P
roper installation of communications equipment, position-finding GPS-based sys-
tems, and radar is serious business. Boatowners rely on this gear to ensure their
safety and, if necessary, call for help, perhaps in a life-threatening situation. Such
equipment is vital to the safe operation of a boat, in contrast to, for example, installing a
CD player. Yes, a CD player is a piece of electronic equipment, but if the boatowner can’t
hear the latest Alan Jackson CD while underway, it’s not a crisis. So, please, as you read
through the material that follows, approach your work as though you might be helping to
save someone’s life. Don’t cut corners.Communications Systems
Communications systems on boats used to entail perhaps just a VHF radio. But nowa-
days most boaters consider SSBs, cell phones, satellite TV and/or Internet access basic
requirements. And of course, all this additional equipment means more work for marine
technicians!
VHF Radio
VHF radio is the most common of all marine electronic equipment used for boat-to-boat
and boat-to-land communication. It operates in the frequency range of 156 MHz to
174 MHz. In recent years, features such as digital selective calling (DSC), global posi-
tioning system (GPS), and the Global Maritime Distress and Safety System (GMDSS)
have expanded the use and functionality of VHF radios by incorporating the ability to
transmit time, position, and ownership information in the event of an emergency. While
improving safety at sea, these features have altered the VHF’s traditional installation pro-
cedure, so we’ll review the installation process.Range
In the United States, the transmitting power for marine VHF is limited by the FCC to a
maximum of 25 watts. Canadian regulations mirror the U.S. regulations in this area.
(Land-based units can have much higher power under the regulations.) I have found thatCopyright © 2007 by Edwin R. Sherman. Click here for terms of use.