GMR™ 18 XHD/24 XHD/18 HD+
• 4 mm (13/32 in.) hex wrench
• 13 mm (1/2 in.) wrench and torque wrench
• Marine sealant
INSTALLATION
INSTRUCTIONS
Important Safety Information
WARNING
Failure to follow these warnings, cautions, and notices could
result in personal injury, damage to the vessel or device, or poor
product performance.
See the Important Safety and Product Information guide in the
product box for product warnings and other important
information.
The radar transmits electromagnetic energy. To avoid possible
personal injury, damage to the vessel or device, or poor product
performance, ensure that the radar is installed according to the
recommendations in these instructions and that all personnel
are clear of the path of the radar beam before transmitting.
When properly installed and operated, the use of this radar
conforms to the requirements of ANSI/IEEE C95.1-1992
Standard for Safety Levels with Respect to Human Exposure to
Radio Frequency Electromagnetic Fields.
To avoid possible personal injury, do not look directly at the
antenna at close range when the radar is transmitting. Eyes are
the most sensitive part of the body to electromagnetic energy.
When connecting the power cable, do not remove the in-line
fuse holder. To prevent the possibility of injury or product
damage caused by fire or overheating, the appropriate fuse
must be in place as indicated in the product specifications. In
addition, connecting the power cable without the appropriate
fuse in place voids the product warranty.
Mounting Considerations
To complete the installation, you need the appropriate fasteners,
tools, and mounts. These items are available at most marine
dealers.
• It is highly recommended that the device is mounted out of
range of personnel, with the horizontal beam width above
head height. To avoid exposure to harmful radio frequency
(RF) levels, the device should not be mounted closer to
people than the maximum safe distance value listed in the
product specifications.
• The device should be mounted high above the ship’s keel
line with minimal blockage between the vessel and the radar
beam. Obstructions may cause blind and shadow sectors, or
generate false echoes. The higher the installation position,
the farther the radome can detect targets.
• The device should be mounted on a flat surface or a platform
that is parallel to the vessel's water line and is sturdy enough
to support the device's weight. The weight for each model is
listed in the product specifications.
• Most radar beams spread vertically 12.5° above and 12.5°
below the radome's radiating element. On vessels with
higher bow angles at cruise speed, the installation angle can
be lowered to point the beam slightly downward to the
waterline while at rest. Use shims if necessary.
CAUTION
This device should be used only as a navigational aid. Using the
device for any purpose requiring precise measurement or
direction, distance, location, or topography may result in
personal injury or damage to the vessel.
To avoid possible personal injury, always wear safety goggles,
ear protection, and a dust mask when drilling, cutting, or
sanding.
Opening the device may result in personal injury and/or damage
to the device. This device contains no user-serviceable parts,
and should be opened only by a Garmin® authorized service
technician. Any damage resulting from opening the unit by
anyone other than a Garmin authorized service technician will
not be covered by the Garmin warranty.
NOTICE
When drilling or cutting, always check what is on the opposite
side of the surface to avoid damaging the vessel.
Software Update
You must update the Garmin chartplotter software when you
install this device. For instructions on updating the software, see
your chartplotter owner's manual at support.garmin.com.
Tools Needed
• Drill
• 9.5 mm (3/8 in.) drill bit
• 32 mm (1 1/4 in.) drill bit (optional)
• The radome has two mounting options when installed on a
standard marine mount. One mounting option is closer to the
center of the radome , and the second option is offset
towards the back to move the radar further away from the
mast.
• The device should be mounted away from heat sources such
as smoke stacks and lights.
GUID-FEFFD103-E5C5-42E2-9628-C69074C658E1 v5August 2020
• The device should be mounted at a different level than
horizontal spreaders and mast crosstrees.
• To avoid interference with a magnetic compass, the device
should not be mounted closer to a compass than the
compass-safe distance value listed in the product
specifications.
• Other electronics and cables should be mounted more than
2 m (6 ½ ft.) from the radar beam path.
• GPS antennas should be either above or below the radar
beam path.
• The device should be mounted at least 1 m (40 in.) from any
transmitting equipment.
• The device should be mounted at least 1 m (40 in.) away
from cables carrying radio signals such as VHF radios,
cables, and antennas.
For Single Side Band (SSB) radios, increase the distance to
2 m (6 ½ ft.).
Mounting the Radar
Before you mount the radar, you must review the mounting
location considerations and select a mounting location.
NOTE: The supplied M8 x 1.25 x 60 threaded rods can be used
on mounting thicknesses of 5 to 30 mm (3/16 to 1 3/16 in.)
(recommended). For surfaces over 30 mm (1 3/16 in.), use longer
threaded rods.
If you are not installing the device on a pre-drilled Garmin
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compatible radar mount, use the included mounting template
to drill four 9.5 mm (3/8 in.) mounting holes.
Connect the power cable to the power port and the
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network cable to the network port .
Press the cables into any of the guide grooves on the
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bottom of the case, and secure them using a cable holddown plate .
The cables should be bent or twisted as little as possible.
Using the arrow on the bottom as a reference, position the
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radome on the mounting surface aligned to the front of the
vessel.
NOTE: If you choose not to align the dome with the front of
the vessel, you can adjust the front-of-boat offset after the
dome is installed (Setting the Front-of-Boat Offset,
page 3).
Apply the included anti-seize compound to the threads of the
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four M8 x 1.25 x 60 threaded rods.
Insert the four threaded rods into the mounting holes on the
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bottom of the radome.
Up to 50 mm (2 in.) of the threaded rods may extend below
the radome.
Apply a bead of marine sealant on the mounting surface
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around each mounting hole.
Fasten the radome to the mounting surface using the
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threaded rods , flat washers , spring washers , and
hex nuts .
Using a torque wrench, tighten the nuts to 13.7 to 18.6 N-m
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(10 to 14 lbf-ft.).
Cable Considerations
It may be necessary to drill 32 mm (11/4) in. holes for routing the
power or network cables.
• When routing both the power and network cables through the
same hole, you must route the network cable before the
power cable.
• You must apply marine sealant to the hole after the cables
are in place to ensure a waterproof seal.
If the routing hole must be made in a visible location, decorative
cable grommets can be purchased from Garmin or a Garmin
dealer (optional).
• If needed, the grommet can be trimmed to enable you to
route both the network and the power cable through the
same hole.
• The optional grommet does NOT provide a waterproof seal.
You must apply marine sealant to the grommet after the
cables are in place to ensure a waterproof seal.
When installing the network and power cables, you should
observe these considerations.
• Cutting the Garmin Marine Network cable is not
recommended, but a field install kit can be purchased from
Garmin or a Garmin dealer if cutting the network cable is
necessary.
• To ensure safety, appropriate tie-wraps, fasteners, and
sealant should be used to secure the cable along the route
and through any bulkheads or the deck.
• Cables should not be run near moving objects and high-heat
sources or through doorways and bilges.
• To avoid interference with other equipment, network and
power cables should not be run next to or parallel to other
cables, such as radio antenna lines or power cables. If this is
not possible, the cables should be shielded with metal
conduit or a form of EMI shielding.
• The power cable should be installed as close to the battery
source as possible.
◦ If it is necessary to extend the power cable, the
appropriate gauge of wire must be used (Power Cable
Extensions, page 3).
◦ Incorrectly extended runs of cable may cause the radar to
malfunction due to insufficient power transmission.
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