Garmin GDL 88 Weather Radio User Manual


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5-4
GDL 88 ADS-B Transceiver Pilot’s Guide
190-01122-03 Rev. A
5.1.3 NEXRAD Intensity
ColorsareusedtoidentifythedifferentNEXRADechointensities(reectivity)
measuredindBZ(decibelsofZ).“Reectivity”istheamountoftransmittedpower
returned to the radarreceiver.Reectivity(designatedbytheletterZ)coversa
wide range of signals (from very weak to very strong). So, a more convenient
numberforcalculationsandcomparison,adecibel(orlogarithmic)scale(dBZ),
isused.ThedBZvaluesincreaseasthestrengthofthesignalreturnedtotheradar
increases.
5.1.4 NEXRAD
When enabled, NEXRAD weather information is shown. Composite data
fromalloftheNEXRADradarsitesintheUnitedStatesisshown.Thisdatais
composed of the maximum reflectivity from the individual radar sweeps. The
display of the information is color-coded to indicate the weather level severity.
FIS-B NEXRAD does notdifferentiatebetween frozenand liquid precipitation.
Refertothepreviouslyshownlegendforadescriptionofthecolorcode.
The NEXRAD option has selections of Regional, CONUS, or Combined
NEXRAD(onlyavailablewithGTNunits).CONUSNEXRADincludesacomposite
ofavailableNEXRADradarimageryacrossthe48states.RegionalNEXRADisa
compositeofavailableNEXRADradarimageryinalocalarea,showingamore
detailedimagethanCONUSNEXRAD.
Continental US NEXRAD (CONUS)
TheDisplayCONUSNEXRADselectionshowsNEXRADradarinformationfor
the entire continental United States. CONUSNEXRADdataisupdatedevery15
minutes. TheresolutionofdisplayedCONUSNEXRADdataisapproximately10
kilometers(5.4NM).Theintensitylevelreectedbythesquarewillbethehighest
level sampled within the area covered by each block.
Regional NEXRAD
TheRegionalNEXRADselectionshowsregionalNEXRADradarinformation
within 500 miles of the aircraftlocation. The resolution of displayed Regional
NEXRADdataisapproximatelytwokilometers(1.08NM).
Combined NEXRAD
RegionalNEXRADdatawithin150NMoftheaircraftlocationandCONUS
NEXRADdata everywhereelse. The two typesof NEXRAD areseparated by a
white stippled border. This boundary is updated whenever new Regional or
CONUSNEXRADdataisreceived.
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