5B8 
34-41-0 Page 10  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Feb 20/85 

T54020
563  Radar System Functional Block Diagram 
May 15/80  Figure 3 (Sheet 4)  34-41-0 
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BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details. 

Weather Radar System Schematic 5D8 34-41-0 Figure 3 (Sheet 1) Jun 20/84 Page 12/(11 Blank) BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

5D8 Weather Radar System SchematicMay 01/01 Figure 3 (Sheet 2) 34-41-0 Page 13/14 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.

(d)  The indicator control panel contains pushbutton mode selector switches, rotary TILT, GAIN, and INT control knobs, rotary RANGE and STAB selector knobs, and pushbutton AZIM, SEC SCAN, FRZ, and TGT ALRT switches/indicators.
(e) The radar operating modes selectable on the radar indicator in the control cabin are as follows: 1) OFF - Shuts down all operation of the weather radar system and removes operating power from weather radar components. If all mode select switches are out of their detent position, PUSH will be displayed in the mode field (Fig. 4). 2) STBY - Is selected from a cold start. The radar begins a 70-second warmup period, and STBY will be displayed in the mode field. After the warmup period, the radar is ready to operate in any mode. If the WX, CYC or MAP Mode are selected directly from a cold start, the system will still go through the 70-second warmup period before it will operate and WAIT (Fig. 4) will be displayed in the mode field. 3) WX (weather) - Places radar system in the normal weather detection mode of operation. The indicator shows areas of significant rainfall as colored areas on the display (Fig. 4). Areas of heaviest rainfall will appear in red, the next level of rainfall in yellow, and the least rainfall in green. A color-bar legend, in the upper right corner of the display, defines the colors. WX will be displayed in the mode field. Either the variable gain or the PRESET operation of the GAIN control may be selected in this mode. 4) CYC (cyclic) - Normal weather detection is made and displayed in the same manner as the WX mode except video from strong target echoes is displayed as flashing red instead of being illuminated steadily (Fig. 4). In CYC mode, variable gain setting of the GAIN control is overridden and a gain valve same as PRESET is substituted automatically.
5)  MAP - Depending on the setting of the TILT control, a terrain mapping effect is displayed for identifying terrain features (Fig. 4). The colors cyan (blue), yellow, and magenta represent increasing levels of return for the radar in the MAP mode; the color bar legend, defines these colors. The sensitivity timing control (STC) function in the R/T unit is not operative, allowing better resolution of geographical features. PRESET and variable gain of the GAIN control are both selectable.
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Feb 20/85  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-41-0 Page 15 

6)  RANGE selector switch - Selects one of six operating ranges (in nautical miles) for display on the indicator. The TEST position results in a test pattern display (Fig. 5). The test pattern provides video color circuit checks, R/T receiver and STC checks (by use of a noise band), video/contour circuit checks, and the target alert circuits checks. When TEST is selected, manual operation of the GAIN control is disabled and a fixed-gain condition (the same as the PRESET value) is substituted. The antenna scans in this mode and the waveguide switch rotates to direct radar RF pulses into the dummy load.
7)  TILT control knob - Tilts the antenna radiator up or down a maximum of 15 degrees from the zero reference position. When the STAB switch is set to off, the TILT control setting is referenced from airplane structure boresight zero. When the STAB switch is set to ON, the TILT control setting is referenced from earth horizontally sensed by the attitude reference system.
8)  SEC SCAN (sector scan) switch/indicator - Allows antenna to scan at 80 degrees, 40 degrees left and right from dead ahead (Fig. 4) or 160 degrees, 80 degrees left and right from dead ahead. In the 80-degree mode (pushbutton in), the antenna scanning rate is 28 scans per minute. In the 160-degree mode (pushbutton out), the scanning rate is 14 scans per minute.
9)  FRZ (freeze) switch/indicator - When FRZ is selected, display is not updated with incoming target return data. To alert the operator, FRZ is displayed in the lower left corner directly above the mode field, and flashes on and off once each second. FRZ is automatically deactivated with the selection of a different control setting.
10)  STAB (stabilization) switch - Allows selection of antenna stabilization from the attitude reference system. When the STAB switch is off, the antenna sweep is centered on the zero boresight of the airplane. When the STAB switch is on, the weather radar system uses pitch and roll signals from the attitude reference system to stabilize the antenna sweep to earth horizontal.
　
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