71Detailed OperationNEXRAD IntensityColors are used to identify the different NEXRAD echo intensities (reflectivity) measured in dBZ (decibels ofZ). “Reflectivity” is the amount of transmitted power returned to the radar receiver. Reflectivity (designated bythe letter Z) covers a wide range of signals (from very weak to very strong). So, a more convenient number forcalculations and comparison, a decibel (or logarithmic) scale (dBZ), is used. The dBZ values increase as thestrength of the signal returned to the radar increases.CurrentThe Current sub-function provides an overlay of the currently selected weather information. The four pages ofmenu 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, weatherlegends, 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.NEXRADWhen enabled, NEXRAD weather information is shown. Composite data from all of the NEXRAD radar sitesin the United States is shown. This data is composed of the maximum reflectivity from the individual radarsweeps. The display of the information is color-coded to indicate the weather level severity. Information aboutwhich 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.CoverageThe Coverage menu item when selected shows the currently available NEXRAD radar coverage areas in cyanwhere information is being collected. Areas where radar capability exists, but is not active or is off-line, will notbe shown as available.GDL 69/69A FIS Radar CoverageGDL 69/69A FIS with NEXRAD Weather and LegendGDL 69/69A - FIS
