receiver. The procedure for entering the MMSI
is radio specific—it is imperative you have the
owner’s manual for your radio in hand.Location, Location, Location
As mentioned in the ergonomics discussion in
Chapter 13, the mounting location for the
radio is a concern, not only from the point of
view of ergonomics, but also regarding EMI.
A VHF has two built-in magnets, one for the
cabinet speaker and one for the microphone.
If the radio and compass are too close
together, stray magnetism from the VHF will
interfere with the boat’s steering compass. The
NMEA recommends that the radio and its
microphone should be no closer than 3 feet
from the compass or any onboard antenna.
Note: Always check for compass deviation
when installing electronic equipment of any
type near a magnetic steering compass, regard-
less of whether the equipment has built-in
magnets or not. Look for compass needle
movement as you place or activate electronic
equipment nearby, and modify your place-
ment as needed.Single-Sideband Radio
Single-sideband (SSB) radio is the long-range
counterpart to VHF radio. Where marine
VHF is limited to line-of-sight communica-
tions and a maximum of about 25 miles, SSB
radio has the potential to transmit and receive
over hundreds or even thousands of miles. An
SSB radio bounces radio signals off the lower
layers of the earth’s atmosphere, which in turn
reflect the signals back to earth. (You can
think of SSB transmissions as giant triangles
spanning many miles.)Voltage and Current Requirements
An SSB’s appetite for amps covers a fairly
broad spectrum, ranging from about 2 to
3 amps in Standby/Receive mode to about142 marine electronics installation and troubleshooting
DEVIATION THE HARD WAYA few years ago, I learned my lesson about electronics-
induced compass deviation the hard way——almost literally.
My 25-foot walkaround has a very compact helm station,
and all the electronic equipment——GPS chartplotter,
fishfinder, water temperature gauge, and VHF radio——was
tightly clustered at the helm. In the center of the cluster, and
no more than 12 to 18 inches from any of them, was the
magnetic steering compass.
When my VHF radio failed, I bought a new unit, complete
with all the bells and whistles, and mounted it in the same loca-
tion as the original unit. I tested it and it worked fine. Several
weeks later, I was fishing on Narragansett Bay when a thick
fog rolled in. I decided to head for home, and checked the
chartplotter for the magnetic heading I would need to get to
the breakwater at the entrance to my home port.
Off I went, paying more attention to the compass than
the chartplotter and following the predetermined heading
using the steering compass. About the time I thought I
should see the breakwater, it suddenly appeared about
100 feet dead ahead—not the openingin the breakwater,
where my heading should have positioned me, but the
wall itself. Fortunately I was cruising slowly at 5 knots, and
was able to avoid disaster. But what had happened?
After replotting everything, I realized that I had a
12-degree deviation in my compass. The cause was sim-
ple to figure out. I’d never had a lick of deviation in that
trusty Ritchie compass until I installed the new VHF. The
speaker magnets in the new radio were much more pow-
erful than those in the old unit, and they had caused this
new deviation.
I removed the radio and reinstalled it in a new loca-
tion, away from my compass but still ergonomically placed
for ease of use. Another lesson learned, and almost the
hard way——breakwater hard!submitted to the Canadian government directly
via Industry Canada. To learn more about their
process, go to http://strategis. ic.gc.ca/epic/
internet/insmt-gst.nsf/en/ sf01032e.html.
Once you acquire an MMSI number, be
careful to enter it correctly into the radio