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4-63190-01102-02 Rev. B
Garmin G500 Pilot’s Guide
Foreword
Sec 1
System
Sec 2
PFD
Sec 3
MFD
Sec 4
Hazard
Avoidance
Sec 5
Additional
Features
Sec 6
Annun.
& Alerts
Sec 7
Symbols
Sec 8
Glossary Appendix A
Appendix B
Index
4.8 GWX Weather Radar (Optional)
4.8.1 Garmin GWX 68 Radar Description
The Garmin GWX 68 Airborne Color Weather Radar is a four color digital
pulsed radar with 6.5 kilowatts of power. It combines excellent range and
adjustable scanning profiles with a high-definition target display. The pulse
width is four microseconds on all ranges except the 2.5 NM range. The GWX 68
uses a one microsecond pulse width at this range to reduce the smearing of
targets on the display. This allows better target definition at close range.
To focus radar scanning on specific areas, Sector Scanning offers pilot-
adjustable horizontal scan angles of 20º, 40º, 60º, or 90º. A vertical scanning
function helps to analyze storm tops, gradients, and cell buildup activity at
various altitudes.
Other features include:
•ExtendedSensitivityTimeControl(STC)logicthatautomaticallycorrelates
distance of the return echo with intensity, so cells do not suddenly appear
to get larger as they get closer.
•WATCH™ (Weather Attenuated Color Highlight) which helps identify
possible “shadowing” effects of short-range cell activity – identifying
areas where radar return signals are weakened, or attenuated, by intense
precipitation (or large areas of lesser precipitation) and may not fully reflect
the “storm behind the storm.”
•WeatherAlertthatlooksaheadforintensecellactivityinthe80-320NM
range, even if these ranges are not being monitored.
4.8.1.1 Principles of Pulsed Airborne Weather Radar
The term RADAR is an acronym for RAdio Detecting and Ranging. Pulsed
radar locates targets by transmitting a microwave pulse beam that, upon
encountering a target, is then reflected back to the radar receiver as a return
“echo.” The microwave pulses are focused and radiated by the antenna, with
the most intense energy in the center of the beam and decreasing intensity near
the edge. The same antenna is used for both transmitting and receiving. The
returned signal is then processed and displayed on the G500 MFD.
Radar detection is a two-way process that requires 12.36 micro-seconds for
the transmitted microwave pulses to travel out and back for each nautical mile