Garmin gtn 625 Manual

A SERVICE OF

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11-10

Garmin GTN 625/635/650 Pilot’s Guide

190-01004-03 Rev. B

Foreword

Getting

Started

Xpdr Ctrl

Com/Nav

FPL

Direct-To

Proc

Wpt Info

Map

Trafﬁc

Terrain

Weather

Nearest

Music

Utilities

System

Messages

Symbols

Appendix

Index

11.1.5.2 NEXRAD Limitations

NEXRAD radar images may have certain limitations:

•NEXRAD base reectivity does not provide sufﬁcient information to

determine cloud layers or precipitation characteristics. For example, it is

not possible to distinguish between wet snow, wet hail, and rain.

•NEXRADbasereectivityissampledattheminimumantennaelevation

angle. An individual NEXRAD site cannot depict high altitude storms at

close ranges. It has no information about storms directly over the site.

•Each square block on the display represents an area of four square

kilometers (2.15 NM). The intensity level reﬂected by each square

represents the highest level of NEXRAD data sampled within the area.

Block Area Is 4 km

2

(2.15 NM

2

)

Block Area Is 4 km

2

(2.15 NM

2

)

Figure 11-9 NEXRAD Data Blocks

The following may cause abnormalities in displayed NEXRAD radar images:

•Groundclutter

•Strobesandspuriousradardata

•Sunstrobes(whentheradarantennapointsdirectlyatthesun)

•Interferencefrombuildingsormountains,whichmaycauseshadows

•Metallicdustfrommilitaryaircraft,whichcancausealterationsinradar

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