PRIMUSr 880 Digital Weather Radar System
VARIABLE GAIN CONTROL
The PRIMUSâ 880 Digital Weather Radar variable gain control is a single turn rotary control and a push/pull switch that is used to control the radar’s receiver gain. With the switch pushed in, the system is in the preset, calibrated gain mode. In calibrated gain, the rotary control does nothing.
When the GAIN switch is pulled out, the system enters the variable gain mode. Variable gain is useful for additional weather analysis. In the WX mode, variable gain can increase receiver sensitivity over the calibrated level to show very weak targets or it can be reduced below the calibrated level to eliminate weak returns.
WARNING
LOW VARIABLE GAIN SETTINGS CAN ELIMINATE HAZARDOUS TARGETS.
RAIN ECHO ATTENUATION COMPENSATION TECHNIQUE (REACT)
Honeywell’s REACT feature has three separate, but related functions.
DAttenuation Compensation - As the radar energy travels through rainfall, the raindrops reflect a portion of the energy back toward the airplane. This results in less energy being available to detect raindrops at greater ranges. This process continues throughout the depth of the storm, resulting in a phenomenon known as attenuation. The amount of attenuation increases with an increase in rainfall rate and with an increase in the range traveled through the rainfall (i.e., heavy rain over a large area results in high levels of attenuation, while light rain over a small area results in low levels of attenuation).
Storms with high rainfall rates can totally attenuate the radar energy making it impossible to see a second cell hidden behind the first cell. In some cases, attenuation can be so extreme that the total depth of a single cell cannot be shown.
Without some form of compensation, attenuation causes a single cell to appear to weaken as the depth of the cell increases.
A28- 1146- 102- 00 | Radar Facts |
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