Advanced Marine Electrics and Electronics Troubleshooting A Manual for Boatowners and Marine Technicians

• Follow Standard E-11 to determine the
  appropriate wire size to use. Remember
  that wire size is based on the length of the
  wire run from the power source to the
  VHF radio (see the ABYC voltage drop
  table, page 43).

DSC and GMDSS

DSC is integrated into all new VHF radios and
is a part of GMDSS. The interface between the
VHF radio and GPS receiver allows position
information to be transmitted in the event of a
DSC emergency call; all you have to do is push
the emergency button now found on all new
radio sets to transmit your boat’s exact position
and time data to the U.S. Coast Guard.

Installation guidelines:

• Use an NMEA-approved cable attach-
  ment to link your VHF radio to the GPS

unit (see above illustration). (This inter-

face may be part of your boat’s network;

see Chapter 17 for more on networking.)

• Follow the manufacturer’s recommenda-
  tions for the exact terminal connections.

As the last step to a fully capable DSC

installation, the boatowner must acquire a

Maritime Mobile Service Identity (MMSI)

number. Once entered, this nine-digit number

becomes the permanent identifier for your

boat. When DSC is activated, the MMSI will

provide rescue personnel with pertinent boat

and owner information along with time and

position data.

In the United States, you can get an

MMSI from the FCC for a fee, or for free by

contacting BoatU.S. (www.boatus.com/mmsi)

or Sea Tow (www.seasmartvhf.com). In Canada,

all applications for MMSI numbers must be

DC panel

GPS receiver

DC –

DC +

VHF

coaxial cable

antenna

bus bar

in-line fuse

DC— from

electronic

equipment

bus bar

NMEA

cable

installing communicationsand position-finding systems 141

The wiring and cable connections to a VHF radio. Notice the interface with the GPS receiver via an NMEA cable link.