Rain Echo Attenuation Compensation Technique (Rct); Turbulence (Trb) - Honeywell SPZ-8000 Maintenance Manual

8.1 B. (3) Rain Echo Attenuation Compensation Technique (RCT)
Mode -
The rain
echo attenuation compensation technique (REACT) function permits
the radar receiver to adjust its own sensitivity automatically to
compensate for attenuation losses as the radar pulse passes through
weather targets on its way to illuminate other targets. This is
done by measuring the intensity of signals, and deducing from them
the density, and therefore, the attenuation of the target, and then
using this information to adjust the sensitivity. This is done
continuously on each radar azimuth radial. There is a maximum
value to which sensitivity may be set due to the receiver
generating
noise,
and
would fill the display with noise if it were
too high. When this maximum value is reached, a blue color is
displayed for the remainder of the displayed range.
This gives the
pilot an unmistakable warning that attenuation is hiding possible
severe weather areas that cannot be accurately detected. REACT is
always selected in TEST
mode. REACT is available in all modes
except GMAP.
(4) Turbulence (TRB) - When the turbulence submode is selected, the
radar processes return signals in order to determine if a
turbulence signature is present. Areas of potentially hazardous
turbulence are displayed as gray white. The high power of the
PRIMUS@ 870 permits detection of hazardous turbulence in areas of
otherwise weakly reflective rainfall. Any areas shown as
turbulence should be avoided. TRB may only be engaged in the WX
mode and in selected ranges of 50
NM or less.
(5) Brightness (BRT) Control - The BRT control is used to control radar
(raster) information brightness (intensity) of the navigation
display (ND).
(6)
GAIN - A single-turn rotary control which varies the RTA receiver
gain. A pull for variable gain position is provided. Selection of
RCT overrides the GAIN control setting and forces preset gain.
Rotation of knob CCW from the 12 o'clock (straiclht up) Dosition
reduces receiver gain.
Rotation CW from the 12-O'C1;
reduces STC so that receiver gain is increased until
maximum when GAIN control is at the full CW position
(7) Mode Control - The rotary MODE control is used to se"
following positions:
OFF - This position turns the weather radar system
off.
ik"position
it is at
ect one of the
functionally
STBY - Standby is useful for keeping radar in ready state while
taxiing, loading, etc.
In standby, the antenna does not
scan, the transmitter is disabled, the display memory is
erased, and the antenna is stowed in a tilt-up position.
NOTE: In dual control mode, if one controller is in STBY mode and
the other controller is in an operating mode, (WX, MAP,
etc.) the radar is not in STANDBY mode.
22-14-00
Page 198.94
Apr 15/93
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