TM 11-5840-281-12-1
4-28. CIRCUIT ALINEMENT. (CONT)
PPI ORIENTATION
To orient ppi display, three targets of known range and azimuth bearings must be selected. The ppi display is oriented to
one target and its accuracy is then checked using the other two targets of known range and azimuth bearings.
WARNING
To prevent exposure to hazardous rf radiation, ensure no personnel are within an 80- foot
(24.5 m) radius of radar site before performing step 1.
NOTE
If radar set is operated with IFF equipment, ppi display is oriented when radar set IFF system
synchros are alined. Refer to TM 11-5895-468-12 for alinement of radar set IFF system
The ppi orientation procedure must be performed for both control-indicators. Unless
otherwise indicated, perform the following steps only on control-indicator on which ppi
orientation procedure is being performed.
1.
On master control-indicator, place TRANSMITTER switch to WIDE PLS position and press HV OF indicator
switch.
2.
On master pulse generator, place SCAN switch to ON position.
3.
On pulse generator, place SCAN MODE switch to SEARCH position.
4.
Perform Crt Display Adjustments (para 2-5).
NOTE
A grid line overlay, which is located over radar display, is used to center the start of ppi
display.
5.
Set RANGE MILES switch on pulse generator to a position that will result in one of three targets of known
bearing to be located as close to the edge of ppi display as possible.
6.
Unlatch five link locks and remove control-indicator rear cover.
7.
Adjust PPI ORIENT control on back of control-indicator until target (step 5) is located at proper bearing on
compass rose ring.
8.
Adjust PPI DELAY control on top deck of pulse generator so target is at proper range on crt.
9.
Check that bearings of two remaining targets on compass rose ring are within 2 degrees of their actual bearings
and at proper range.
10.
Slide pulse generator back in control-indicator and secure with two knurled front panel screws.
11.
Place TRANSMITTER switch on master control-indicator to OFF position.
12.
On pulse generator, place SCAN switch to OFF position.
PERFORMANCE TESTS
A system performance check should be performed prior to any operational activity. The performance test procedures are
the responsibility of organizational personnel. These procedures are located In section V of this chapter.
4-102
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