1
Route the power cable from the device to the power source.
2
Connect the red wire to the positive (+) battery terminal, and connect the
black wire to the negative (-) battery terminal.
3
If you have not already done so, connect the power cable to the device by
turning the locking ring clockwise.
Power Cable Extensions
Connecting the power cable directly to the battery is recommended. If it is
necessary to extend the cable, the appropriate gauge of wire must be used for
the length of the extension.
Distance
Wire Gauge
2 m (6.5 ft.)
16 AWG (1.31 mm²)
4 m (13 ft.)
14 AWG (2.08 mm²)
6 m (19 ft.)
12 AWG (3.31 mm²)
Connecting to a Device or to the Marine Network
You can connect the radar either directly to a radar-compatible Garmin device
or to a Garmin Marine Network to share radar information with all connected
devices.
NOTE: Not all Garmin devices are compatible with the Garmin Marine
Network. See the installation instructions or owner's manual provided with your
device for more information.
1
Route the network cable to your compatible Garmin device.
2
If you have not already done so, install the locking rings and o-rings on the
end of the network cable.
3
Select an option:
• If the Garmin device is not compatible with the Garmin Marine Network,
connect the network cable to the port labeled RADAR.
• If the device is compatible with the Garmin Marine Network, connect
the network cable to the port labeled NETWORK.
Radar Operation
All functions of this radar are controlled with your Garmin chartplotter. See the
Radar section of your chartplotter's owner's manual for operating instructions.
To download the latest manual, go to support.garmin.com.
If you have more than one radar on your boat, you must be viewing the radar
screen for the radar you want to configure.
Measuring the Potential Front-of-Boat Offset
The front-of-boat offset compensates for the physical location of the radar
scanner on a boat, if the radar scanner does not align with the bow-stern axis.
1
Using a magnetic compass, take an optical bearing of a stationary target
located within viewable range.
2
Measure the target bearing on the radar.
3
If the bearing deviation is more than +/- 1°, set the front-of-boat offset.
Setting the Front-of-Boat Offset
Before you can set the front-of-boat offset, you must measure the potential
front-of-boat offset.
The front-of-boat offset setting configured for use in one radar mode is applied
to every other radar mode and to the Radar overlay.
1
From a Radar screen or the Radar overlay, select Menu > Radar Setup >
Installation > Front of Boat.
2
Select Up or Down to adjust the offset.
Specifications
GMR 18 xHD/18 HD+ weight
7.7 kg (16.95 lb.)
GMR 24 xHD weight
9.5 kg (20.9 lb.)
Temperature range
From -15 to 70°C (from 5 to 158°F)
Case material
Thermoplastic resin
Maximum antenna rotation speed
GMR 18/24 xHD
48 RPM
Maximum antenna rotation speed GMR 18 HD+
24 RPM
Power input source
From 11 to 35 Vdc, 3.5 A
Fuse
7.5 A
Power output
4 kW peak
RF transmit frequency
9410 MHz nominal
GMR 18 HD+ and 18 xHD beam width
5.2 degrees
GMR 24 xHD beam width
3.7 degrees
Maximum range GMR 18/24 xHD
48 nm
Maximum range GMR 18 HD+
36 nm
Minimum range
20 m (66 ft.)
Range discrimination
16 m (52.5 ft.)
Compass-safe distance
1 m (3.28 ft.)
Minimum Safe Operating Distance
When it is transmitting, the radar should be located in a position on the vessel
that is at least this far from people. IEC 60936-1, clause 3-27.1, specifies the
maximum distances from the antenna at which radio frequency (RF) levels can
be expected.
These minimum safe distances apply for a transmitting radar with a rotating
antenna, and are much larger when the antenna is not rotating. If rotation of
the antenna is obstructed for any reason, the transmitter will automatically turn
off.
Model
100 W/m²
50 W/m²
10 W/m²
GMR 18 xHD/18 HD
+
0.08 m (3.15 in.)
0.11 m (4.33 in.)
0.25 m (9.84 in.)
GMR 24 xHD
0.08 m (3.15 in.)
0.11 m (4.33 in.)
0.24 m (9.45 in.)
Detailed Dimensions
Item
GMR 18 xHD/18 HD+
GMR 24 xHD
Length
508.2 mm (20 in.)
645.4 mm (25
7
/
16
in.)
(width)
504.7 mm (19
7
/
8
in.)
642.5 mm (25
5
/
16
in.)
(height)
248.3 mm (9 ¾ in.)
250.3 mm (9
7
/
8
in.)
3
