(6) Observe bubble level MP548 on elevation
(4) On master Control-Indicator C-6988/TPN-18,
Antenna Drive TG-114/TPN-8.
place ANTENNA (servo) switch to L and R as required to
(7) If bubble is not in exact center of circle in
position elevation Antenna AS-1291/TPN-8 at 0 degree
bubble level MP548, loosen adjustments on bubble level.
as indicated on elevation servo protractor.
Adjust three bubble level adjustments as required to
(5) Attach sighting scope to sighting scope mount
position bubble in exact center of circle.
on elevation Antenna AS-1291/TPN-8.
(8) Tighten three bubble level adjustments.
(9) Glyptol seal three bubble level adjustments.
Elevation Antenna AS-1291/TPN-8 maybe
3-17. Radar Receiver-Transmitter RT-818/TPN-18 Dc
positioned by hand by rotating knurled end of
elevation Antenna Drive TG-114/-TPN-8 drive
Voltage Supply Adjustments
motor shaft located under cover on right side of
Refer to TM 11-5840-281-12 for Radar Receiver-
elevation Antenna Drive TG-114/TPN-8 (as
3-18. Elevation Servo and Azimuth Scan Protractor-
(6) Position elevation Antenna AS-1291/TPN-8 by
hand until sighting scope is approximately horizontal.
a. Test Equipment and Materials Required.
(7) Position sighting aid (any flat surface marked
(1) Sighting scope MP3509.
(2) Sighting aid (flat surface such as a board,
feet so that elevation mark is aligned with vertical cross-
hair in sighting scope. Manually position elevation
Antenna AS-1291/TPN-8 as in step (6) above, as
b. Equipment Conditions.
required. Hold sighting aid in this position while
(1) Radar Set AN/TPN-18 turned on and remove
performing steps (8) through (14) below.
cover from transmitter side of Receiver-Transmitter RT-
(8) Remove sighting scope from elevation
Antenna AS-1291/TPN-8 and attach to sighting scope
(2) On Radar Receiver-Transmitter RT-818/TPN-
mount beneath antenna support tube.
18 control panel, SCAN and HV switches placed to OFF.
(9) Sight through sighting scope at sighting aid.
On drive motor amplifier, place AZ DRIVE POWER
Observe alignment of vertical cross-hair to antenna
switch to OFF.
support tube mark.
(3) On master Control-Indicator C-6988/TPN-18
(10) If vertical cross-hair of sighting scope is not
aligned with antenna support tube mark, loosen screws
switch placed to SIMULT, SCAN switch OFF, and
in sighting scope mount and position sighting scope
TRANSMITTER switch OFF.
mount to align vertical cross-hair in sighting scope with
antenna support tube mark on sighting aid. Tighten
screws in sighting scope mount.
(1) On master Control-Indicator C-6988/TPN-18,
(11) Remove sighting scope from antenna support
place ANTENNA (servo) switch to R until rear inside
tube and attach to sighting scope mount on azimuth
back structure support of elevation Antenna AS-
1291/TPN-18 reflector clears tubular member of
(12) Rotate azimuth Antenna AS-1292/TPN-8 by
elevation yoke by 3/8 inch.
hand to align vertical cross-hair in sighting scope with
(2) Loosen screws in elevation antenna servo
azimuth mark on sighting aid. Tilt azimuth Antenna AS-
protractor index block and position so index is aligned
1292/TPN-8 as required by placing ANTENNA (servo)
with 15 degree mark.
switch on master Control-Indicator C-6988/TPN-18 to U
(3) Tighten screws in elevation servo protractor
or D. Maintain alignment of vertical cross-hair in sighting
index block securely.
scope with azimuth mark on sighting aid while performing
steps (13) and (14) below