GXM™ 51 Installation Instructions
The Garmin GXM 51 XM® antenna provides XM WX Satellite Weather® information and XM
Satellite Radio® for your existing NMEA 2000® network. If you do not have an existing NMEA
2000 network on your boat, you will need to install one. For more information about NMEA
2000, visit www.garmin.com.
The GXM 51 antenna must be properly installed according to the following instructions.
You need the appropriate fasteners, tools, and mounts listed in each section. These items
are available at most marine dealers. Always wear safety goggles, ear protection, and a dust
mask when drilling, cutting, or sanding. When drilling or cutting, always check what is on the
opposite side of the surface.
Contact Garmin Product Support if you have any questions while installing or using your
GXM 51. In the USA, go to www.garmin.com/support, or contact Garmin USA by phone at
(913) 397-8200 or (800) 800-1020.
S ee the Important Safety and Product Information guide in the product box for product warnings and other
important information.
Product Registration
Help us better support you by completing our online registration at www.garmin.com
/registration/.
For future reference, write the serial number assigned to your GXM 51 in the space provided. It
is located on a sticker on the back of the device.
Serial number
In addition to the device serial number, unique ID numbers are associated with your GXM 51.
XM Satellite Radio uses these ID numbers to activate and deactivate your XM weather and
XM audio. To locate the ID numbers on a Garmin NMEA 2000-compliant chartplotter, select
Configure > System > System Information.
For future reference, write the XM WX Weather ID and XM Radio ID assigned to your
GXM 51 in the spaces provided.
XM WX Weather ID
XM Radio ID
November 2009
190-01030-02 Rev. D
Printed in Taiwan
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
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)
• Additional NMEA 2000 network
components
• Audio adapter cable extensions
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.
Better
Best
Good
SS BARNETT
EMI
EMI (Electromagnetic Interference)
from engine components
• Avoid mounting the GXM 51 antenna
where it is shaded by the superstructure of
Above - best
the boat, a radome antenna, or a mast.
• On a sailboat, avoid mounting the GXM 51
3 ft.
Below - OK
antenna high on the mast.
(1 m)
• The GXM 51 antenna provides more-stable
Radar
VHF Radio Antenna
reception when located nearer to water
GXM 51 Placement Considerations
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.
GXM 51 Installation Instructions
Surface-mounting the GXM 51 Antenna
1. Use the surface-mount bracket as your mounting template.
• Use a pencil to mark the three screw locations on the surface and to trace the cable hole
in the center of the bracket.
• Set the surface-mount bracket aside. Do not drill through the surface-mount bracket.
2. Drill three 1/8 in. (3 mm) pilot holes.
Note: If you are mounting the GXM 51 on fiberglass, it is recommended to use a countersink
bit to drill a clearance counterbore through the top gelcoat layer (but no deeper). This will help to
avoid cracking in the gelcoat layer when the screws are tightened.
3. Use a 1 in. (25 mm) hole saw to cut the cable hole in the center.
4. Use the included M4 screws to attach
the surface-mount bracket to the
mounting surface.
GXM 51
5. Route the NMEA 2000/audio cable
antenna
through the 1 in. (25 mm) cable hole
and connect it to the GXM 51.
6. Make sure the large gasket is in
place on the bottom of the GXM 51
Rubber
Surface-mount
antenna, place the antenna on the
gasket
bracket
surface-mount bracket ➊, and twist it
clockwise to lock it in place ➋.
7. Secure the antenna to the mounting
bracket with the included M3 set
Mounting
screw ➌.
surface
8. Route the NMEA 2000/audio cable
away from sources of electronic interference, and connect it to your NMEA 2000 network
and to the audio input of your stereo receiver (see page 5).
➋
➊
➌
Pole Mounting the GXM 51 Antenna
With the pole-mount adapter attached to the GXM 51, you can install the GXM 51 on a
standard 1 in. OD pipe-threaded-pole marine mount (14 threads per inch—not included). You
can route the NMEA 2000/audio cable either through the pole or outside the pole.
To mount the GXM 51 with the cable routed outside the pole:
1. Route the NMEA 2000/audio cable through the pole-mount adapter, and place the cable in
the vertical slot along the base of the pole-mount adapter.
2. Thread the pole-mount adapter onto a standard 1 in. OD pipe-threaded-pole marine mount
(14 threads per inch—not included). Do not overtighten the adapter.
3. Connect the NMEA 2000/audio cable to the
GXM 51 antenna.
4. Place the GXM 51 antenna on the pole-mount
adapter ➊ and twist it clockwise to lock it in
GXM 51
place ➋.
antenna
5. Secure the antenna to the adapter with the
included M3 set screw ➌.
6. (Optional) With the GXM 51 installed on the
pole mount, fill the remaining gap in the vertical
cable slot with a marine sealant (not included).
7. Attach the marine mount to the boat if it is not
Pole-mount
already attached.
adapter
8. Route the NMEA 2000/audio cable away from
sources of electronic interference, and connect
Vertical cable
it to your NMEA 2000 network and to the audio
slot
input of your stereo receiver (see page 5).
➌
➋
➊
GXM 51 Installation Instructions
To mount the GXM 51 with the cable routed through the pole:
1. Position a standard 1 in. OD pipe-threaded-pole marine mount (14 threads per inch—not
included) in the preferred location, and mark the approximate center of the pole.
2. Drill a hole using a 3/4 in. (19 mm) drill bit for the cable to pass through.
3. Fasten the pipe-threaded pole marine mount to the boat.
4. Thread the pole-mount adapter onto the pole. Do not overtighten the adapter.
5. Route the NMEA 2000/audio cable through the pole and connect it to the GXM 51 antenna.
6. Place the GXM 51 antenna on the pole-mount adapter ➊ and twist it clockwise to lock it in
place ➋.
7. Secure the antenna to the adapter with the included M3 set screw ➌.
8. (Optional) With the GXM 51 installed on the pole mount, fill the vertical cable slot with a
marine sealant (not included).
9. Route the NMEA 2000/audio cable away from sources of electronic interference, and
connect it to your NMEA 2000 network and to the audio input of your stereo receiver
(see page 5).
Under-deck-mounting the GXM 51 Antenna
The GXM 51 can be mounted under a fiberglass surface with the adhesive pads attached to the
under-deck mounting bracket. The GXM 51 will not acquire satellite signals through metal—
you can only use the under-deck mount under a fiberglass surface.
1. Determine the location on the
fiberglass surface where you
Adhesive
pads
want to mount the GXM 51.
2. Place the adhesive pads on
the under-deck mounting
Mounting
bracket.
surface
3. Place the GXM 51 in the
under-deck mounting bracket.
4. Adhere the under-deck
GXM 51
mounting bracket to the
antenna
mounting surface.
Under-deck
5. Secure the under-deck mount
mounting bracket
to the mounting surface with
screws. Use extreme care to ensure that the screws do not penetrate the upper surface of
the deck.
6. Connect the NMEA 2000/audio cable to the GXM 51.
7. Route the NMEA 2000/audio cable away from sources of electronic interference, and
connect it to your NMEA 2000 network and to the audio input of your stereo receiver (see
step 3 below).
GXM 51 Installation Instructions
Step 2: Connect the GXM 51 Antenna to Your NMEA 2000
Network
The GXM 51 is packaged with a NMEA 2000 T-connector and a NMEA 2000/audio cable. You
will use these two components to connect the GXM 51 to your existing NMEA 2000 network.
If you do not have an existing NMEA 2000 network, you will need to install a NMEA 2000
network on your boat. For more information on NMEA 2000, visit www.garmin.com.
To connect the GXM 51 to your existing NMEA 2000 network:
1. Determine an appropriate
location to connect the
GXM 51
GXM 51 to your existing
antenna
NMEA 2000 backbone.
2. Disconnect one side of a
NMEA 2000 T-connector from
the backbone nearest to the
NMEA 2000
location where you want to
device
connect the GXM 51 antenna.
NMEA 2000
(not included)
NMEA 2000/
device
If you need to extend the
audio cable
(not included)
NMEA 2000 backbone,
(included)
connect an appropriate
T-connector
NMEA 2000 backbone
(included)
extension cable (not included)
To boat
to the side of the T-connector
audio
you disconnected.
3. Connect the included
T-connector in the NMEA
2000 backbone.
4. Route the NMEA 2000 portion
of the NMEA 2000/audio cable
from the GXM 51 antenna to
Existing NMEA 2000 network
(not included)
the top of the T-connector you
added to your NMEA 2000
network.
The 19 ft., 6 in. (6 m) NMEA 2000 portion of the NMEA 2000/audio cable is the maximum
length for a drop cable as defined by the NMEA 2000 standards. If more cable is needed,
add an extension to your NMEA 2000 backbone, based on the NMEA 2000 guidelines.
Step 3: Connect the GXM 51 Audio Cable
To hear XM Radio through the stereo on your boat, connect the audio adapter cable to the audio
portion of the NMEA 2000/audio cable and to an audio input on the stereo. Refer to the manual
provided with your stereo for audio input installation and operation.
Step 4: Update Your Chartplotter
To ensure compatibility with the GXM 51, upgrade your Garmin chartplotter with the latest
software. A GPSMAP 4/5000 series chartplotter must be at software v5.0 or later to use the
GXM 51. For more information, visit http://www8.garmin.com/support/download.jsp.
GXM 51 Installation Instructions
Step 5: Activate Your XM Subscription
1. Ensure that your XM Weather ID and your XM Radio ID are readily available. Write them on
the front page of these instructions for convenience. Contact XM Satellite Radio by phone
at (800) 985-9200. After receiving the required information from you, the XM representative
activates the account and sends out an XM signal to activate the GXM 51.
To answer other XM questions, call the above number or visit www.xmwxweather.com.
2. Confirm all components of your service package:
• XM WX Weather: Ensure that the chartplotter and the NMEA 2000 network are powered
on so that you receive the XM signal. When the components of the selected service
package appear in the Weather Products list, the XM signal is working correctly. To see
the Weather Products list, from the Home screen, select Configure > System > System
Information > Weather Subscription.
• XM Radio: From the home screen, select Configure > XM Audio, and verify that
channels 7, 9, 47, and 122 appear. This indicates that all channels on the XM basic radio
service are working correctly.
If the XM WX Weather and the XM Radio service have not activated within an hour, call XM
customer care at (800) 985-9200 and ask an XM representative to refresh the signal.
Using the GXM 51
Instructions for using the XM WX Weather and the XM Radio service on your chartplotter
are contained in the Owner’s Manual provided with your Garmin NMEA 2000-compatible
chartplotter.
Specifications
Physical
Dimensions:
3 19/32 in. (91.6 mm) Diameter × 1 15/16 in.
(49.5 mm) High
Weight:
7.1 oz. (201 g)
NMEA 2000/audio cable: 19 ft., 8 in. (6 m)
Temperature range: From -22°F (-30°C) to
176°F (80°C)
Case Material: Fully gasketed, highimpact plastic alloy, waterproof to IEC
529 IPX7 standards
Power
Power input source:
9–16 Vdc unregulated
Input current:
137 mA at
12 Vdc
NMEA 2000 Load Equivalency
Number (LEN):
5 (250 mA)
The GXM 51 is NMEA 2000
certified
NMEA 2000 PGN Information
Transmit
Receive
059392
ISO Acknowledgment
059392
ISO Acknowledgment
060928
ISO Address Claim
059904
ISO Request
126208
NMEA - Command/Request/
Acknowledge Group Function
060928
ISO Address Claim
126464
Transmit/Receive PGN List Group
Function
126208
NMEA - Command/Request/
Acknowledge Group Function
126996
Product Information
GXM 51 Installation Instructions
Weather and Sea Surface Information
The GXM 51 receives XM Weather Radio data and shows it on your chartplotter. The weather data for each feature
comes from reputable weather data centers such as the National Weather Service and the Hydrometerological
Prediction Center. (See the XM WX Satellite Weather Web site at http://weather.xmradio.com/weather for more
information.) Any weather feature can change in appearance or interpretation if the source that provides the
information changes. XM Weather Radio data is broadcast at set rates. For example, NEXRAD Radar data is
broadcast at five minute intervals. When the marine network is turned on or when a new feature is selected, the
GXM 51 has to receive new data before it can be displayed. For this reason you may experience a delay before
weather data or a new feature appears on the map.
WARNING: The XM Weather Radio data is merely supplemental and advisory in nature and is not intended to be
relied up on as safety-critical information. You should always exercise caution and common sense when confronted
with severe weather conditions.
WARNING: XM WX Weather should not be used for hazardous weather penetration. Weather information is
approved only for weather avoidance, not penetration.
Weather-Related Broadcast Rates
Feature
Broadcast Rate
(minutes)
NEXRAD
5
Cloud Tops
15
Storm Cells
1.25
Lightning
5
Wind
12
Pressure
12
Hurricanes
12
Visibility
12
Fronts
12
Sea-Surface Temperature
12
Wave Height
12
Wave Period
12
Wave Direction
12
Current Conditions
12
Forecasts
12
Sea-Surface Conditions
12
NEXRAD Overview
NEXRAD Description
NEXRAD Radar is a Doppler radar system that has greatly improved the detection of meteorological events such
as thunderstorms, tornadoes, and hurricanes. An extensive network of NEXRAD stations provides almost complete
radar coverage of the continental United States, Alaska, and Hawaii, and the majority of Canada. The range of each
NEXRAD is 124 nautical miles.
NEXRAD Abnormalities
There are possible abnormalities regarding displayed NEXRAD images. Some, but not all, of those include the
following circumstances:
Ground clutter
Strobes and spurious radar data
Sun strobes, when the radar antenna points directly at the sun
Military aircraft deployment of metallic dust (chaff), which can cause alterations in radar scans
Interference from buildings or mountains, which may cause shadows
NEXRAD Limitations
Certain limitations exist regarding the NEXRAD radar displays. Some, but not all, are listed here for your awareness:
NEXRAD base reflectivity does not provide sufficient information to determine cloud layers or precipitation
characteristics (for example, determining between hail and rain).
GXM 51 Installation Instructions
NEXRAD base reflectivity is sampled at the minimum antenna elevation angle. An individual NEXRAD site cannot
depict high altitude storms at close ranges, and has no information about storms directly over the site.
Software License Agreement
BY USING THE GXM 51, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS OF THE
FOLLOWING SOFTWARE LICENSE AGREEMENT. PLEASE READ THIS AGREEMENT CAREFULLY.
Garmin grants you a limited license to use the software embedded in this device (the “Software”) in binary
executable form in the normal operation of the product. Title, ownership rights, and intellectual property rights in and
to the Software remain in Garmin.
You acknowledge that the Software is the property of Garmin and is protected under the United States of America
copyright laws and international copyright treaties. You further acknowledge that the structure, organization, and
code of the Software are valuable trade secrets of Garmin and that the Software in source code form remains
a valuable trade secret of Garmin. You agree not to decompile, disassemble, modify, reverse assemble, reverse
engineer, or reduce to human readable form the Software or any part thereof or create any derivative works based on
the Software. You agree not to export or re-export the Software to any country in violation of the export control laws
of the United States of America.
Declaration of Conformity (DoC)
Hereby, Garmin, declares that this GXM 51 is in compliance with the essential requirements and other relevant
provisions of Directive 1999/5/EC.
To view the full Declaration of Conformity, see the Garmin Web site for your Garmin product:
www.garmin.com/products/gxm51/. Click Manuals, and then select the Declaration of
Conformity link.
FCC Compliance
This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this
device may not cause harmful interference, and (2) this device must accept any interference received, including
interference that may cause undesired operation.
This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part
15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interference in
a residential installation. This equipment generates, uses, and can radiate radio frequency energy and may cause
harmful interference to radio communications if not installed and used in accordance with the instructions. However,
there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one of the following measures:
XM Satellite Radio Service Agreement
XM Satellite Radio Inc.
Hardware and required monthly subscription sold separately. Subscription fee is consumer only. Other fees and taxes,
including a one-time activation fee may apply. All programming fees and weather data subject to change. XM WX
weather data displays and individual product availability vary by hardware equipment. Reception of the XM signal
may vary depending on location. Subscriptions subject to Customer Agreement included with the XM Welcome
Kit and available at www.xmradio.com. Available only in the 48 contiguous United States. XM WX is a registered
trademark of XM Satellite Radio Inc.
Weather Data Warranty
THE SOFTWARE PRODUCT IS PROVIDED “AS IS.” ALL OTHER WARRANTIES, EXPRESSED OR
IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE OR OF NON-INFRINGEMENT ARE HEREBY EXCLUDED.
User Safety
If you use XM Services it is your responsibility to exercise prudent discretion and observe all safety measures
required by law and your own common sense. You assume the entire risk related to your use of the Services. XM
and Garmin assume no responsibility for accidents resulting from or associated with use of the Services. Your Radio
Service includes traffic and weather information, and you acknowledge that such information is not for “safety for
life”, but is merely supplemental and advisory in nature, and therefore cannot be relied upon as safety-critical in
connection with any aircraft, sea craft or automobile usage. This information is provided “as is” and XM and Garmin
disclaim any and all warranties, express and implied, with respect thereto or the transmission or reception thereof.
XM and Garmin further do not warrant the accuracy, reliability, completeness or timeliness of the traffic and weather
information disclosed on the Radio Service. In no event will XM and Garmin, their data suppliers, service providers,
marketing/distribution, software or Internet partners or hardware manufacturers be liable to you or to any third party
for any direct, indirect, incidental, consequential, special, exemplary or punitive damages or lost profits resulting
from use of or interruptions in the transmission or reception of the Services.
GXM 51 Installation Instructions
Limits On Our Responsibility
a) DISCLAIMERS.
EXCEPT AS EXPRESSLY PROVIDED HEREIN, WE MAKE NO WARRANTY OR REPRESENTATION,
EITHER EXPRESS OR IMPLIED, REGARDING THE RADIO SERVICE. YOUR USE OF THE SERVICE IS
AT YOUR SOLE RISK. THE CONTENT AND FUNCTIONALITY OF THE SERVICE IS PROVIDED “AS
IS” WITHOUT ANY WARRANTY OF ANY KIND, EXPRESS OR IMPLIED. ALL SUCH WARRANTIES
OR REPRESENTATIONS (INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT) ARE
HEREBY DISCLAIMED.
b) LIMITATIONS OF LIABILITY.
WE ARE NOT RESPONSIBLE FOR ANY SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR
LOSSES RELATING TO THE USE OF THE RADIO SERVICE, WHETHER BASED ON NEGLIGENCE OR
OTHERWISE. OUR TOTAL LIABILITY TO YOU AND ANY OTHER PERSONS RECEIVING OUR SERVICES,
REGARDLESS OF THE CAUSE, WILL IN NO EVENT EXCEED THE AMOUNTS THAT YOU HAVE PAID
TO US FOR THE SERVICE THAT YOU RECEIVED DURING THE SIX (6) MONTH PERIOD IMMEDIATELY
PRIOR TO THE SPECIFIC EVENT THAT GAVE RISE TO THE APPLICABLE DAMAGE OR LOSS. THIS
ALLOCATION OF RISK IS REFLECTED IN OUR PRICES. YOU MAY HAVE GREATER RIGHTS THAN
DESCRIBED ABOVE UNDER YOUR STATE’S LAWS.
a. Under 10 U.S.C. 456, no civil action may be brought against the United States on the basis of the content of a
navigational aid prepared or disseminated by either the former Defense Mapping Agency (DMA), National Imagery
and Mapping Agency (NIMA), or the National Geospatial-Intelligence Agency (NGA).
b. The DAFIF™ product is provided “as is,” and no warranty, express or implied, including, but not limited to the
implied warranties of merchantability and fitness for particular purpose or arising by statute or otherwise in law or
from a course of dealing or usage in trade, is made by NGA as to the accuracy and functioning of the product.
c. Neither NGA nor its personnel will be liable for any claims, losses, or damages arising from or connected with the
use of this product. The user agrees to hold harmless the United States National Geospatial-Intelligence Agency. The
user’s sole and exclusive remedy is to stop using the DAFIF product. This product was developed using DAFIF, a
product of the National Geospatial-Intelligence Agency.
GXM 51 Installation Instructions
For the latest free software updates (excluding map data) throughout the life of your
Garmin products, visit the Garmin Web site at www.garmin.com.
© 2009 Garmin Ltd. or its subsidiaries
Garmin International, Inc.
1200 East 151st Street, Olathe, Kansas 66062, USA
Garmin (Europe) Ltd.
Liberty House, Hounsdown Business Park, Southampton, Hampshire, SO40 9LR UK
Garmin Corporation
No. 68, Jangshu 2nd Road, Shijr, Taipei County, Taiwan
www.garmin.com
November 2009
Part Number 190-01030-02 Rev. D
Printed in Taiwan