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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).

Summary of Contents for Gxm 51

Page 1: ...n the USA go to www garmin com support or contact Garmin USA by phone at 913 397 8200 or 800 800 1020 See the Important Safety and Product Information guide in the product box for product warnings and...

Page 2: ...ven 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 unobstructe...

Page 3: ...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 Y...

Page 4: ...twork 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...

Page 5: ...e 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...

Page 6: ...ll 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 repr...

Page 7: ...ance 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 Su...

Page 8: ...ns 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 interf...

Page 9: ...FIC 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 4...

Page 10: ...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 Ga...

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