TM 11-5840-208-30-1
2-8.
AZIMUTH COLLIMATION AND ORIENTATION
a. Azimuth Collimation Check. The purpose of this check is to determine the angular separation between the
optical axis and the center of scan. This check is performed as follows:
(1)
Determine the field correction in the following manner:
(a) Turn the transmitter on and allow the set to operate at least 30 minutes.
(b) Tune the echo box for maximum deflection of the meter.
(c) Read the transmitter frequency from the dial above the echo box tuning knob.
(d) Apply this frequency to the chart on the inside of the echo box cover (page 91), interpolating if
necessary. The figure obtained is called the field correction.
(2)
Select any target which can be positively identified both on the B-scope and through the orienting
telescope. This target can be improvised, if necessary, and should be at least 500 meters from the
radar.
(3)
Move the radar in azimuth and elevation until the target is centered in the orienting telescope.
Note. The use of the AZIMUTH switch on the control-power supply to move the
antenna small amounts may cause excessive wear on the azimuth brake. Use the
handwheel on the frame of the radar for these small movements, or move the antenna
by hand.
(4)
Place the RANGE SELECTOR switch in the 3750 M position, and set the EXPANDED SWEEP DELAY
switch so that the target is displayed on the B-scope.
(5)
Set the DETENT switch in the AZIMUTH ORIENT position, and place both the A AZIMUTH and the
LOWER BEAM AZIMUTH controls in detent.
(6)
The azimuth strobe should be off the center of the echo by the amount of the field correction; the strobe
should be to the left if the correction is negative or to the right if the correction is positive. To verify the
distance between the strobe and the center of the echo, note the azimuth reading; then place the
DETENT switch in the OFF position, use the LOWER BEAM AZIMUTH control to move the azimuth
strobe over the center of the echo, and reread the azimuth counter. The difference between
Page 16
Previous Page
