(2)
The elevation axis is normally driven by the pitch stabilizing synchro signals from the INS, keeping the antenna level during normal flight regimes. The tilt signal control located on the control panel, allows the elevation to be increased or decreased from level. The azimuth axis position is resolved and added to the elevation motor drive to keep the antenna stabilized throughout its travel.
EFFECTIVITY
AF 101-120, 123-156, 158,
159, 172-182, 185-199; SN 301-350; IB 405; GN ALL; CONFIG MD ALL; VM ALL 01 Page 10
Sep 25/94
34-43-00
(3)
The azimuth control motor drive sweeps the antenna through a 180-degree arc at a rate of fifteen sweeps per minute. The azimuth axis position is coupled to the indicator sweep resolver, which accepts the indicator unresolved sweep and provides resolved X and Y sweep to the indicator circuits.
(4)
The roll axis is driven in response to the INS roll synchro data, to keep the antenna perpendicular to the ground.
(5)
The control panel system transfer switch determines which R/T will supply the stabilization controls, 26-volt ac synchro excitation, and motor and clutch controls. The nondriving system (R/T) components follow the driving components to assure smooth R/T transfer.
(6)
When the MAP mode is selected at the control panel, the antenna feed rotator rotates the antenna feed 90 degrees. Also, a horizontally-polarized spoiler is brought into action, and a cosecant-squared antenna pattern results. This facilitates ground mapping. Selecting the NORM (normal) mode reverts the antenna to the pencil-beam configuration.
C. Functional Description, Self-Test and Fault Monitoring
(1)
A self-test feature allows a rapid test of R/T and indicator operation. To accomplish the self-test, the TEST mode is selected with the range set at the maximum range indicated on the test pattern display (facimile). (Refer to operational test; Weather Radar System Adjustment/Test, 34-43-00.) The indicator displays then may be compared to the normal test display. During the test mode, the ANT and R/T FAULT lamps in the control panel light giving a test of the light bulb.
(2)
Each R/T unit has lamps, annunciators, and test switches. The lamps indicate an R/T or ANT failure. A maintenance annunciator is included for the R/T or ANT failure. The modulator may be turned off for maintenance by the MOD ON and OFF pushbuttons. A stabilization test is included; these push-to-test lights, if remaining on 3 seconds after a test initiated on the R/T unit indicates a faulty elevation, azimuth, or roll stabilization loop.
D. Control
EFFECTIVITY
AF 101-120, 123-156, 158,
159, 172-182, 185-199; SN 301-350; IB 405; GN ALL; CONFIG MD ALL; VM ALL 01 Page 11
Sep 25/94
34-43-00
INS 1 PITCH STAB ROLL STAB
TILT CONTROL
R/T CONTROL TO ANTENNA MAPPING MAP SPOILER AND FEED ROTATOR
R/T 1
TILT CONTROL
PITCH STABILIZATION
UNRESOLVED SWEEP
IND 1 RESOLVED SWEEP RESOLVED SWEEP UNRESOLVED SWEEP
IND 2
AZIMUTH CONTROL
26V AC EXCITATION
MOTOR AND CLUTCH CONTROLS
ROLL STABILIZATION 26V AC EXCITATION
1
R
INDICATOR SWEEP RESOLVER
Weather Radar Antenna Stabilization - Block Diagram
Figure 4 (Sheet 1)
EFFECTIVITYPPPP AF 101-120,123-156,158,159,
CONFIG 2 172-182,185-199; SN 301-350;799 Page 12 IB 405; GN ALL; MD ALL; VM ALL Sep 25/94
34-43-00
EL RESOLVER FROM WAVEGUIDE SWITCHSYSTEM 1 AND ONE FOR DRIVE SYSTEM 2
Weather Radar Antenna Stabilization - Block Diagram
Figure 4 (Sheet 2)
EFFECTIVITY AF 101-120,123-156,158,159,
CONFIG 2 172-182,185-199; SN 301-350;799 Page 13IB 405; GN ALL; MD ALL; VM ALL Sep 25/94
34-43-00
(1) The weather radar system requires 115 volts ac, 400 Hz from the essential radio bus and number 2 radio bus. The system is placed in operation by selecting the STBY mode to allow filament warmup. If any other mode is selected, the filament warmup period will take place prior to assuming the selected mode.
WARNING: DO NOT OPERATE WEATHER RADAR WHILE THE AIRPLANE IS BEING
_______ REFUELED OR DEFUELED AND DO NOT OPERATE IN ANY RADIATING MODE WHILE A FUELING OPERATION IS BEING CONDUCTED WITHIN 200 FEET OF THE ANTENNA OR AN EXPLOSION MAY OCCUR.
PERSONNEL MUST NOT ENTER AN AREA CLOSER THAN 10 FEET IN FRONT OF A SCANNING RADIATING ANTENNA AND 80 FEET IN FRONT OF A STATIONARY RADIATING ANTENNA OR INJURY TO PERSONNEL MAY OCCUR.
CAUTION: WHEN THE WEATHER RADAR IS OPERATED IN ANY MODE OTHER THAN
_______ STANDBY OR TEST, DIRECT THE NOSE OF THE AIRPLANE SO THE FORWARD 180-DEGREE SECTOR IS FREE OF LARGE METALLIC OBJECTS (HANGARS, TRUCKS, OTHER AIRPLANES, ETC.) FOR A DISTANCE OF 300 FEET AND TILT THE ANTENNA UPWARD 14 DEGREES OR DAMAGE TO RECEIVER MAY OCCUR.
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