effectiveness. Not correcting for your boat’s
WIRED FOR SUCCESS
running angle can leave a large area around
your boat uncovered, the cone of silence. At
the same time, the narrow angle of the beam
means mounting your radome way up the
mast of a sailboat can have a similar effect,
putting targets close to the boat “under” the
radar and rendering them “invisible.”
Sailboaters have another issue to address,
as their boats tend to heel for long periods
of time. When a sailboat’s heeling, the lee-
ward side sees a reduction in range and on
the windward side, close-in targets may be
missed in some of the unit’s sweeps. The
best solution is putting the antenna on a
gimballed mount, which stays level as the
boat heels. The downside to this solution
is expense – a good gimballed mount can
cost as much as some
inexpensive radar units.
Another option is to
mount the dome in
such a way that it can
be adjusted for heel on
the fly. Some mounts
have a manual clamp,
but these don’t do you
any good if your anten-
na is mounted out of reach. If it’s too high
up on the mast for manual adjustment, you
can also mount an electric-leveling device
(essentially a trim tab) athwartship under the
radar antenna and use it to level out the heel
When post-mounting, if possible mount
the radome on the boat’s starboard side.
Masts, rigging, and gear are bound to cause
some shadowing (blockage of the radar’s
signals). Boats to starboard are most often
the stand-on vessel; therefore maximizing the
radar’s view in this direction makes sense.
Let’s say you’ve decided on the best mounting option for you and your boat. The next
question is, who will mount that antenna?
This is a fairly easy project that most competent DIY mariners can handle. But a few cautions are in order because the most common
radar installation problem is cable failure.
And often, that failure results from the installation job.
Don’t try to cut the plug end off a radar
antenna cable and think you’ll be able to
splice it back together properly, and don’t
stress a wire while pulling it through pipe
work or a chase. If the shielding of a radar
antenna cable takes even minor damage, saltwater may intrude and eat the cable from the
inside out. In fact, protecting the radar antenna’s cable should be considered a top priority.
Treat it gently during installation, and make
sure it’s supported with cushioned clamps.
If you have any doubts about your ability to install the antenna and cable, don’t
attempt it. You can always go to an NMEA-certified electronics installer and have confidence that the job will be done right.
Remember, that radar is an important tool in
your arsenal of safety gear, and you need its
eyes and ears to be as sharp as possible.
Our BoatU.S. Magazine electronics editor, Lenny
Rudow, is also senior editor for Boats.com.
HIGHER IS NOT ALWAYS BETTER
On a sailboat, the greater range of a radar mounted on the mast
must be weighed against these advantages of mounting it lower:
■ The scanner is less vulnerable to damage from an errant halyard or sail.
■ The “cone of silence” is reduced so that targets close to the
boat can still be “seen” by the radar.
■ The motion in a seaway is reduced, enhancing radar accuracy.
■ The radar is easier to service.