mined by your locale. Scan through the
weather channels in your area and note
which are available. Remember that if your
locale changes, the available weather channels
may also change.
Offshore Communications
Several other communication systems are
used when cruising offshore.
HF SSB (High Frequency
Single Sideband)
High frequency single sideband (a type of
shortwave radio) is essential when traveling
in waters greater than 25 miles from shore
(Figure 12-9). These distances are at the
edge of or beyond the range of VHF radio,
depending upon how far you are from the
receiver. Mariners traveling on the high
seas use SSB to communicate with other
ships at sea as well as land bases.
Specific channels/frequencies are
allocated to marine use, and these are
restricted from normal amateur or “ham”
radio use. Using a SSB radio employs the
same protocols as VHF radio with respect
to emergency and routine calls.
• You must have a ship’s station license in
order to operate a SSB radio. Contact the
FCC to find out how to obtain one.
Section 12: Communications Afloat 145
Satellite
A variety of services, such as INMARSAT,
are available that use orbiting satellites for
communication. The services include telephone
(Figure 12-10), internet, weather
information, video, and email. Telephone
service is similar to using a cell phone. Satellite
communication services are becoming
the preferred method of communication
for vessels on the high seas. A license may be
required to operate these devices.
Global Maritime Distress &
Safety System for Recreational
Boaters (GMDSS)
GMDSS is an international system for
advancing communications technology,
initiated by the International Maritime
Organization (IMO) and is designed to
enhance ship-shore communications.
Rescue 21 is a significant part of the
system using VHF radios coupled to GPS
units, providing automated distress alerting
and positional information if available
in area sea area A-1 (coast to 21 miles
off shore). Another very useful piece of
GMDSS equipment, particularly for boats
operating beyond 20 miles off shore, is the
406 MHz Emergency Position Indicating
Radio Beacon, or EPIRB. The EPIRB is
designed to operate with satellites in the
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Figure 12-10. Satellite phone
Figure 12-9. HF SSB radio