Garmin GTN 725 Pilot's Manual page 374

12.6
Foreword
The Flight Information Services (FIS-B) function is capable of displaying text
Getting
Started
and graphic weather information with GDL 88 installations. No subscription for
Audio &
FIS-B services is required with the GDL 88.
Xpdr Ctrl
The FIS-B Function is a graphic weather display capable of displaying
Com/Nav
graphical weather information on UAT equipped installations. Graphical data is
overlaid on the map indicating the rainfall detected by ground based radar for a
FPL
specific area. Colors are used to identify the different NEXRAD echo intensities
(reflectivity) measured in dBZ (decibels of Z). "Reflectivity" (designated by the
Direct-To
letter Z) is the amount of transmitted power returned to the radar receiver.
The dBZ values increase as returned signal strength increases. Precipitation
Proc
intensity is displayed using colors corresponding to the dBZ values. Review the
Limitations section in the front of this guide for the limitations that apply to the
Charts
FIS-B data. An example of how rainfall data is color coded follows:
Wpt Info
Map
Traffic
Terrain
Weather
Nearest
Services/
Music
NOTE: METAR
Utilities
The FIS-B Function is based on a ground-to-air data link and requires that
System
the appropriate ground systems are broadcasting weather data and the aircraft is
within reception range of the Ground Broadcast Transceiver (GBT).
Messages
Symbols
Appendix
12-70
Index
FIS-B Weather
Figure 12-88 FIS-B Weather Precipitation Legend
Garmin GTN 725/750 Pilot's Guide 190-01007-03 Rev. D