Weather Radar System Component Location
Figure 1 (Sheet 2)

EFFECTIVITY

CONFIG 3
AF 121,122;
799 Page 3
SN 351-399
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 Sep 25/94

INDICATOR

RANGE
SWITCH

BRIGHTNESS CONTROL

AF 121,122 INDICATOR
SN 351-399
SN 351

Weather Radar System Component Location Figure 1 (Sheet 3)

SCAN HOLD SWITCH

EFFECTIVITY

 CONFIG 3
AF 121,122;
799 Page 4
SN 351-399
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Sep 25/94
SYSTEM TRANSFER
GAIN CONTROL
SYSTEM
GAIN CONTROL
SYSTEM
GAIN CONTROL
MODE SELECTOR
SWITCH

ANTENNA TILT CONTROL
ANTENNA TILT CONTROL
5 10

CONTROL PANEL 
SN 351 
 
 
SN 352-399 
AF 121,122 
Weather Radar System Component Location 
Figure 1 (Sheet 4) 

E39241
EFFECTIVITY

CONFIG 3
AF 121,122;
799 Page 5
SN 351-399
34-43-00

 Sep 25/94
 B.  The control panel provides all the weather radar controls except for the range controls and brightness (BRT) control on the indicator.
 C.  The control panel has a system transfer (SYS) toggle switch, a rotary mode selector switch, a rotary antenna TILT control, and a rotary receiver GAIN control.
 (1)  
The SYS transfer switch allows selection of system 1 or 2.

 (2)  
AF 121, 122; The rotary mode selector switch allows selection of OFF TEST, WX, TURB and MAP mode of operation.

 (3)  
SN 351; The rotary mode selector switch allows selection of TEST, WX and MAP modes of operation.

 (4)  
SN 352-399; The rotary mode selector switch allows selection of TEST, WX, TURB and MAP modes of operation.

 (5)  
The antenna TILT control provides manual control of the radar antenna elevation.

 (6)  
The GAIN control is used to adjust the gain of the receiver in the receiver 1 transmitter.

 3.  Indicator
_________
 A.  Two weather radar indicators are installed. One indicator is on the captain's auxiliary side panel P44 and the other on the first officer's auxiliary side panel P45.
 B.  The weather radar indicator is a color indicator that provides a constant, nonfading display of all detectable targets within the scan angle and range selected. The indicator can display weather, turbulence on airplanes equipped with a turbulence mode, or ground maps. The display is generated from the information contained in a 1600-bit serial word, provided by the receiver/transmitter.
 C.  SN 351; Targets are displayed in green, yellow and red according to the strength of the microwave pulses which return to the antenna. Displayed in blue are the azimuth line (0, |30, |60 degreees) and the range marks. Blue numerics are generated to show the range interval between range marks and the range selected on the indicator.
 D.  SN 352-399; Targets are displayed in green yellow, red and magenta according to the strength of the microwave pulses which return to the antenna. Displayed in blue are the azimuth lines (0, |30, |60 degrees) and the range marks. Blue numerics are generated to show the range interval between range marks and the range selected on the indicator.
 E.  The indicator contains ARINC 453 interface receivers, azimuth tracking, scan converter and sweep circuits, front panel controls, high and low voltage power supplies, a microprocessor and analog-to-digital converter.
 F.  SN 351-399; The indicator control panel consists of a rotary range switch and SCAN/HOLD switch and brightness (BRT) control.
 G.  On SN 352-399; the indicator control panel consists of a rotary range switch and brightness (BRT) control.
 4.  Receiver/Transmitter
____________________
 EFFECTIVITY
 AF 121, 122; SN 351-399  CONFIG 3  01 Page 6  Apr 25/9834-43-00
 A.  Access to an R/T is gained through the right crawlway that extends forward from the main electronics equipment center. The R/T units are installed in a dual R/T mount on the forward right equipment center rack E5. The R/T mount has quick-disconnect waveguide fittings, a waveguide switch, a cooling fan and a fan text switch.
 B.  The R/T is a completely solid state unit which transmits, receives, processes video, supplies antenna stabilization signals, and provides system timing and monitoring for the weather radar system. The R/T provides 9375 MHz pulse transmission in the X-band frequency range for detection of storm conditions at ranges of up to 320 miles and for terrain mapping. The R/T contains circuitry which automatically compensates for near and far targets and weakened radar returns due to penetration of weather storm cells. The R/T contains a microprocessor-controlled antenna stabilization servo loop, which provides antenna line-of-sight stabilization. Microprocessor-controlled system timing and monitoring of key system parameters for fault detection is also an integral part of the R/T function. See the R/T monitoring operations in the receiver/transmitter functional description discussion.
　
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