TM 11-5840-281-12-1
4-27. PRELIMINARY SERVICING AND ADJUSTMENT. (CONT)
AZIMUTH TILT BLANKING ALINEMENT
A 3-degree section of range marks on the elevation display is blanked to represent tilt position of azimuth antenna during
the precision mode of operation. This blanked section must be properly oriented on elevation display in order for azimuth
antenna tilt information to be accurate. Azimuth tilt blanking alinement requires two personnel: one at radar site and one
at control-indicator site. Perform azimuth tilt blanking alinement as follows.
NOTE
Azimuth tilt blanking alinement procedure must be performed for each control- Indicator.
Unless otherwise indicated, perform the following steps only on control- Indicator on which
azimuth tilt blanking alinement is being performed.
1.
Ensure all controls and switches are in positions indicated in Preliminary Operating Procedure (para 2-5).
2.
On pulse generator, place RANGE MILES switch to position 40.
3.
At radar site, adjust clinometer to indicate + 3 degrees and tilt azimuth antenna using ANTENNA switch until
clinometer bubble indicates level.
4.
Remove clinometer from azimuth antenna clinometer mount and install on elevation antenna clinometer mount.
See Clinometer Installation (para 4-21).
5.
Adjust clinometer to indicate + 3 degrees, then manually rotate elevation antenna until clinometer bubble
indicates level.
6.
On pulse generator, alternately place ANGLE VOLTS switch to EL and OPERATE positions. Adjust ART ANGLE
V control so artificial sweep trace coincides with operate sweep trace on elevation display. Record ART ANGLE
V control dial indication.
WARNING
To prevent being hit by scanning antennas, ensure antenna scan area is clear of personnel
before performing step 7.
7.
On master pulse generator, place SCAN switch to ON position.
8.
On pulse generator, set ART ANGLE V control dial to indicate 30 divisions more than indication recorded In step
6.
NOTE
ART ANGLE V control is now set to produce a 4.5-degree artificial sweep trace.
9.
Alternately place ANGLE VOLTS switch in edge EL and OPERATE positions. Adjust R31 AZ TILT POS control
so top of blanked range mark section coincides with 4.5-degree artificial sweep
10.
On pulse generator, set ART ANGLE V control dial to indicate 30 divisions less than indication recorded in step
6.
NOTE
ART ANGLE V control is now set to produce a 1.5-degree artificial sweep trace.
4-83
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