TM 11-5840-281-35/1
b. Equipment Conditions. Radar Set AN/ TPN-
(1) Oscilloscope AN/USM-140B (oscillo-
18 turned on and front and rear covers of Radar
scope).
Receiver-Transmitter RT-818/TPN-18 removed for
(2) Echo Box TS-488A/AP (echo box).
access to controls.
b. Equipment Conditions and Connections.
c. Procedure.
(1) Radar Set AN/TPN-18 turned on and
(1) On master Pulse Generator 0-1333/
front and rear covers removed from Radar Receiver-
TPN-18, place SCAN MODE switch to SIMULT, SCAN
Transmitter RT-818/TPN-18 for access to controls.
switch to ON, and TRANSMITTER switch to OFF.
(2) On radar transmitter, 1/2 POWER-
(2) Observe presentations on both Control-
NORMAL switch S202 and NORMAL-MTI switch S201
Indicators C-6988/TPN-18. Master Control-Indicator C-
placed to NORMAL.
6988/TPN-18 will have a beta- scan display and slave
(3) On master Control-Indicator C-6988/
Control-Indicator C-6988/TPN-18 will have a ppi scan
TPN-18
and
Pulse
0-1333/TPN-18
display.
TRANSMITTER switch placed through WIDE to HV ON
(3) Observe that each time an elevation
and HV ON indicator lighted, and SCAN MODE switch
sweep occurs on the beta scan display, a corresponding
placed to SEARCH.
sector of the ppi scan display is blanked.
(4) Oscilloscope and echo box connected
(4) If Radar Set AN/TPN-18 is operated
as shown in figure 331.
(Ensure that METER
with Interrogator Set AN/TPX-44, place IFF ANT SCAN
SENSITIVITY control on echo box is fully ccw minimum
CONT switch on Electrical Equipment Cabinet CY-
sensitivity)).
4922/TPX-44 to IFF.
(5) On Remote Switching Control C-6989/
TPN-18, adjust SEARCH RPM control R4059 as
NOTE
required to cause blanked sectors on ppi scan of display
to rotate slowly ccw in sequence without overlapping
Local oscillator alignment (para 3-31) must be
each other from one sweep rotation to next.
performed following each alignment of radar
(6) Time rotation of ppi scan sweep with
transmitter.
stopwatch. Rotation speed of ppi scan sweep should be
approximately 16 rpm when SEARCH RPM control
c. Procedure.
R4059 is adjusted as in step (6) above.
(1) On oscilloscope, place controls to
(7) If Radar Set AN/TPN-18 is operated
positions in (a) through (k) below.
with Interrogator Set AN/TPX-44, place IFF ANT SCAN
(a) POWER: ON.
CONT switch on Electrical Equipment Cabinet CY-
(b) SWEEP MODE: PRESET.
4922/TPX-44 to RADAR
(c) TRIGGER SOURCE: INT.
(d) HORIZONTAL DISPLAY: X1.
NOTE
(e) EXTERNAL VERNIER: CAL.
(f) SWEEP TIME MILLISECONDS/
CM: .1.
Do not replace covers on Radar Receiver-
(g) SWEEP TIME VERNIER: CAL
Transmitter RT-818/TPN-18 until alignments and
(h) Vertical Presentation: CHANNEL
adjustments are completed.
A.
(i) CHANNEL A AC-DC: AC.
3-29. Ferrite
Switch
and
Ferrite
Attenuator
(j) CHANNEL A SENSITIVITY: As
Alignment
required.
(k) CHANNEL A POLARITY: +UP.
Refer to TM 11-5840-281-12, paragraph 5-19i, for
(2) On oscilloscope, adjust TRIGGER
alignment instructions for the ferrite switch and the ferrite
SLOPE and TRIGGER LEVEL controls for stable
attenuators.
waveform on oscilloscope.
(3) On oscilloscope, adjust CHANNEL A
3-30. Radar Transmitter Alignment
VERTICAL POSITION to superimpose timebase sweep
(fig. 331)
on
graduated
horizontal
gridline
and
adjust
HORIZONTAL POSITION control to superimpose left
a. Test Equipment Required.
pretrigger on far left vertical gridline.
3-37
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