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29 GXM 30 XM Radio Smart Antenna Owner’s Manual
FeatureData Broadcast Frequency
NEXRAD Radar5 mins
Satellite Mosaic15 mins
Storm Cells1.25 mins
Surface Winds12 mins
Surface Pressure12 mins
Buoy Reports12 mins
City Forecast12 mins
FeatureData Broadcast Frequency
Marine Warnings20 mins
Freezing Level12 mins
APPENDIX > FEATURE BROADCAST RATES
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GXM 30 XM Radio Smart Antenna Owner’s Manual 30
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.
The range of each NEXRAD is 124 nautical miles.
There are possible abnormalities regarding displayed NEXRAD
images. Some, but not all, of those include:
• Ground clutter
• Strobes and spurious radar data
• Sun strobes, when the radar antenna points directly at
• Military aircraft deploy metallic dust (chaff) which can
cause alterations in radar scans
• Interference from buildings or mountains, which may
Certain limitations exist regarding the NEXRAD radar
displays. Some, but not all, are listed for the user’s awareness:
• NEXRAD base reﬂectivity does not provide sufﬁcient
information to determine cloud layers or precipitation
characteristics (hail vs. rain).
• 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.
APPENDIX > NEXRAD OVERVIEW
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31 GXM 30 XM Radio Smart Antenna Owner’s Manual
APPENDIX > NEXRAD OVERVIEW
Colors are used to identify the different
NEXRAD echo intensities (reﬂectivity)
measured in dBZ. (decibels of Z).
“Reﬂectivity” (designated by the letter Z) is
the amount of transmitted power returned to
the radar receiver. The dBZ values increase
as returned signal strength increases.
Precipitation intensity is displayed using
colors represented by the dBZ values listed
in the table to the right.
0.00”trace - .05”Very Light
5.00”trace - .10”Light
100” - trace.01”LightLight
15.01”.1 - .2”LightLight
20.02”.2 - .3”LightLight
25.05”.3 - .5”LightLight - Moderate
30.09”.5 - .7”Light - ModerateModerate
35.24”.7 - 1.0”ModerateHeavy
40.48”1” + or sleetHeavyHeavy
451.25”1” + or sleetHeavyHeavy
The information presented in this manual is not
meant to be comprehensive. The NOAA web
site contains complete and detailed information regarding NEXRAD weather radar operation and theory. You can visit them at www.noaa.gov.
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GXM 30 XM Radio Smart Antenna Owner’s Manual 32
The GXM 30 complies with Part 15 of the FCC interference
limits for Class B digital devices FOR HOME OR OFFICE
USE. These limits are designed to provide more reasonable
protection against harmful interference in a residential
installation, and are more stringent than “outdoor”
Operation of this device is subject to the following 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 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:
• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and the receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV
technician for help.
The GXM 30 does not contain any user-serviceable parts.
Repairs should only be made by an authorized Garmin service
center. Unauthorized repairs or modiﬁcations could result in
permanent damage to the equipment, and void your warranty
and your authority to operate this device under Part 15
APPENDIX > FCC COMPLIANCE
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33 GXM 30 XM Radio Smart Antenna Owner’s Manual
This Garmin product is warranted to be free from defects in materials
or workmanship for one year from the date of purchase. Within this
period, Garmin will at its sole option repair or replace any components
that fail in normal use. Such repairs or replacement will be made at no
charge to the customer for parts or labor, provided that the customer
shall be responsible for any transportation cost. This warranty does not
cover failures due to abuse, misuse, accident or unauthorized alteration
THE WARRANTIES AND REMEDIES CONTAINED HEREIN
ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES
EXPRESS OR IMPLIED OR STATUTORY, INCLUDING
ANY LIABILITY ARISING UNDER ANY WARRANTY OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE, STATUTORY OR OTHERWISE. THIS WARRANTY
GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY VARY
FROM STATE TO STATE. IN NO EVENT SHALL GARMIN BE LIABLE FOR ANY
INCIDENTAL, SPECIAL, INDIRECT OR CONSEQUENTIAL
DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE,
OR INABILITY TO USE THIS PRODUCT OR FROM DEFECTS IN
THE PRODUCT. Some states do not allow the exclusion of incidental
or consequential damages, so the above limitations may not apply to
Garmin retains the exclusive right to repair or replace the unit
or software or offer a full refund of the purchase price at its sole
discretion. SUCH REMEDY SHALL BE YOUR SOLE AND
EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY.
To obtain warranty service, contact your local Garmin authorized
dealer or call Garmin Product Support for shipping instructions and an
RMA tracking number. The unit should be securely packed with the
tracking number clearly written on the outside of the package. The unit
should then be sent, freight charges prepaid, to any Garmin warranty
service station. A copy of the original sales receipt is required as the
proof of purchase for warranty repairs.
APPENDIX > LIMITED WARRANTY