GXM 51 Installation Instructions
Packing List, Accessories, and Tools Needed
Before installing your unit, confirm that your package includes the following items. If any parts
are missing, contact your Garmin dealer immediately.
Standard Package
GXM 51 Antenna
Surface-mount bracket
Pole-mount bracket
Under-deck mount bracket
Mounting hardware (screws and adhesive
pads)
NMEA 2000 T-connector
NMEA 2000/audio cable 19 ft., 8 in. (6 m)
Audio adapter cable 1 ft. (30.5 cm)
Installation instructions
Optional Accessories
Additional NMEA 2000 network
components
Audio adapter cable extensions
•
•
•
•
•
•
•
•
•
•
•
Tools Needed
Drill
Drill bits—
1
/
8
in. (3 mm) and
3
/
4
in.
(19 mm)
Hole saw, 1 in. (25 mm)—surface-mount
cable hole
Screwdriver—surface-mount screws
Pencil (to mark surface-mount pilot holes)
Countersink bit (when mounting on
fiberglass)
Marine sealant (for some mounting
options)
•
•
•
•
•
•
•
Step 1: Mount the GXM 51 Antenna
You can surface mount the GXM 51 antenna, attach it to a standard 1 in. OD pipe-threaded-pole
marine mount (14 threads-per-inch—not included), or even install the antenna under fiberglass.
Select a suitable location for the GXM 51
antenna on your boat. To ensure the best
reception, mount the GXM 51 antenna in a
location that has a clear, unobstructed view of
the sky in all directions.
Avoid mounting the GXM 51 antenna
where it is shaded by the superstructure of
the boat, a radome antenna, or a mast.
On a sailboat, avoid mounting the GXM 51
antenna high on the mast.
The GXM 51 antenna provides more-stable
reception when located nearer to water
level.
Mount the GXM 51 antenna at least 3.3 ft. (1 m) away from (preferably above) the
path of any radar beam or a VHF radio antenna.
Temporarily secure the antenna in the preferred mounting location and test it for correct
operation. If you experience interference with other electronics, try a different location. After
verifying correct operation, permanently mount the antenna.
•
•
•
•
SS BARNET
T
Radar
VHF Radio Antenna
3 ft.
(1 m)
Above - best
Below - OK
EMI (Electromagnetic Interference)
from engine components
Best
Better
Good
EMI
GXM 51 Placement Considerations
SS BARNET
T
Radar
VHF Radio Antenna
3 ft.
(1 m)
Above - best
Below - OK
EMI (Electromagnetic Interference)
from engine components
Best
Better
Good
EMI
GXM 51 Placement Considerations
