Nexrad Intensity; Current; Nexrad - Garmin 20 Pilot's Manual

NEXRAD Intensity

Colors are used to identify the different NEXRAD echo intensities (reflectivity) measured in dBZ (decibels of
Z). "Reflectivity" is the amount of transmitted power returned to the radar receiver. Reflectivity (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.

Current

The Current sub-function provides an overlay of the currently selected weather information. The four pages of
menu item selections allow you to modify the display of NexRad, radar coverage, METARs, lightning, thunder-
storm cell movement, cloud tops, echo tops, winds aloft, information labels, flight plan course line, weather
legends, map and navaids, and map orientation.
1. Press the FN key and then the FIS function key when displayed.
2. Press the fourth function smart key on the right to select the Current (Crnt) sub-function.
3. The Menu/Enter key brings up menu items for more detail on each sub-function.

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. Information about
which sites are operational or off-line is also available (see coverage below). The update rate is every five min-
utes. Refer to the legend for a description of the color code.
1. Press the  or  arrow keys to display the legends for the selected services.
2. Press Done to turn the Legends off.
Coverage
The Coverage menu item when selected shows the currently available NEXRAD radar coverage areas in cyan
where information is being collected. Areas where radar capability exists, but is not active or is off-line, will not
be shown as available.
Detailed Operation
GDL 69/69A - FIS
GDL 69/69A FIS with NEXRAD Weather and Legend
GDL 69/69A FIS Radar Coverage
71