106 Boating New Zealand
BOATINGNZ.CO.NZWANT TO KNOW MORE ABOUT THESE PRODUCTS?
Call Auckland’s Navstation at 09 360 8535 or email [email protected].We chose to flush-mount the unit into the dashboard for a
neat finish – so first job was finding a suitable open area. The
GX600 is a shallow-mount model, and requires minimal space
behind the unit. But it pays to check there’s nothing in the way
behind the dash before you start cutting.
As always, measure twice and cut once. Or, measure, mark,
check, measure again, then cut. Cutting a hole in our plywood
dash was easy with a jigsaw – fibreglass or aluminium boats will
require a bit more grunt. The template supplied with the radio has
cross-marks for the corners; these are punched and drilled with a
12mm bit. After that a saw is used to cut from hole to hole.
The unit is held in position by two brackets screwed in
from the back, but it is best to loosely place the unit first and
get everything connected before fixing it firmly. Once we’d
connected the power and worked out how to feed the antenna
cable through from the roof, we attached a clip to hold the
microphone in an easily-accessible spot.As soon as you start exploring the VHF purchase process, you’ll
notice that some models come with a red button on the front, either
marked “DSC” or “Distress”. This is Digital Selective Calling, a standard
for sending pre-defined digital messages over the VHF band.
This capability allows the radio to quickly send your vessel’s
identifier and GPS co-ordinates (provided you have linked a GPS
to your VHF radio) to other similarly-equipped vessels – all with
a single button. To prevent false signals this button usually has a
safety cover over it.
Given it is a digital message, DSC has purportedly got a
greater effective range than a normal call over the VHF, plus in a
time of crisis is more likely to get your location details through
correctly. Some models allow different type of distress to be
programmed, such as “sinking” or “fire”, and other VHF radios with
DSC capability can also pick up and display or relay the signal.
The downside is that Maritime NZ currently does not
support DSC, and has no immediate plans to do so. This should
not prevent you getting a model with DSC capabilities, since
the chances are that other vessels nearby may also have a
DSC-capable radio and be able to transmit your distress signal
(including location) to the appropriate authorities.
Also, most new models now come with DSC, even the
cheaper options, so it makes sense to get one with this capability
to future-proof your investment.WHAT IS DSC?THE ANTENNA
Your VHF’s range is a direct function of the height of the
antenna above the water (see sidebar). So it should be mounted
on the highest part of the boat, either the top of the cabin or
on a radar arch if you have one. In the case of a launch a fixed
mount may be adequate, but for trailer boats an adjustable base
that allows the antenna to be folded down is the best way to
prevent damage when driving.
In our case the mooring ropes on the Tamaki River piles
meant that we sometimes want to fold the antenna down, so
we installed a folding base unit. The cabin top is virtually the
highest spot on the boat and easiest to reach, so we mounted the
base to this, using appropriate sealant on the bolt holes.
The antenna cable was fed through its own waterproof cable
gland into the ceiling void, and from inside the cabin it was fed
down to behind the dash and connected to the head unit.
Once everything was wired up and tested we then tightened
the fixing brackets to hold the unit flush against the dash area.
We have a second VHF on board, a floating handheld unit, which
serves as a backup.
A handheld unit also useful when someone goes ashore- they can use it to contact the boat when they want picking
up again. Total cost of the project (GME GX600 and Trident
Antenna and base) was $350, and installation time was under
two hours. BNZ
RIGHT
Adjusting
the locking
base....by getting your
antenna mounted as
high as you possibly
can you maximise
your range and
increase overall
capability.