TM 11-5840-281-35/1
4-10. Testing Difference Receiver
b. Equipment Conditions.
Channel
(1) Radar Set AN/TPN-18 turned on,
aligned, and tuned.
(2) Front and rear covers removed from
a. Test Equipment Required.
Radar Receiver-Transmitter RT-818/TPN-18.
(1) Radar Test Set AN/UPM-56 (radar test
(3) Clinometer MP3502 installed on elevation
set).
Antenna AS-1291/TPN-8.
(2) Oscilloscope AN/USM-140B (oscillo-
scope).
NOTE
(3) Tee adapter UG-274/U (bnc coaxial).
(4) Clinometer MP3502 (clinometer).
(5) Test prod (1:1 voltage divider ratio).
In the test procedure column of the chart
below, the oscilloscope pulse will be seen
c. Procedure.
on the trace only when the azimuth and
elevation condition is obtained by the
proper positioning of the antennas.
Control settings
Step No. Test equipment Equipment under test
Test procedure
Performance standard
a. None.
Oscilloscope
Radar Receiver-
a. Connect oscilloscope CHAN-
1
NEL INPUT test prod (1:1
Transmitter RT-818/
POWER: ON
voltage divider ratio) to IAGC
TPN-18 control panel
CHANNEL A VERTI-
PULSE testpoint TP3602 on
CAL POSITION: Midpo-
SCAN: OFF
Intermediate Frequency Ampli-
sition
HV: OFF
fier AM-3338/TPN-8.
HORIZONTAL POSI-
MAIN POWER: ON
b. None.
b. Connect test cable between trig-
TION: Midposition
Master Pulse Generator
ger INPUT connector on oscil-
HORIZONTAL DIS-
O-1333/TPN-18
loscope and PRE TRIG test-
PLAY INTERNAL
SCAN MODE:
point TP3901 on stc unit or
SWEEP MAGNIFIER:
SEARCH then to
PRE TRIGGER testpoint
X1
NORM
TP211 on radar transmitter.
SWEEP TIME MICRO-
SCAN: OFF
Use tee adapter at TP211.
Master Control-Indicator
SECONDS/CM: 50
c. None.
c. On right side of elevation An-
C-6988/TPN-18
SWEEP TIME VER-
tenna Drive TG-114/TPN-8
NIER: CAL
FOCUS: Fully ccw
(viewed from front of Radar
TRIGGER SLOPE: As
INTENSITY: Fully ccw
Receiver-Transmitter RT-818/
required
POWER: ON
TPN-18) disconnect elevation
TRIGGER LEVEL: As
IF GAIN-AZ: Maximum
difference channel waveguide
required
cw
from right rotary coupler. In-
SWEEP MODE: PRE-
IF GAIN-EL: Maximum
stall waveguide-to-coaxial
SET
cw
adapter on right rotary coupler.
TRIGGER SOURCE:
EL TARGET:
d. None.
d. Connect calibrated rf cable
EXT AC
Maximum cw
(part of radar test set) between
Vertical presentation:
FTC: OFF
RF POWER connector on radar
CHANNEL A
STC: OFF
test set and waveguide-to-co
CHANNEL A SENSITIV-
axial adapter installed in c
ITY (VOLTS/CM): 1
above.
CHANNEL A SENSITIV-
e. Connect coaxial cable between
e. None.
ITY VERNIER: CALI-
SYNC IN connector on radar
BRATED
test set and tee adapter on
CHANNEL A AC-DC:
PRE TRIGGER testpoint
DC
TP211 on radar transmitter.
Radar test set
POWER: ON
Rf power switch:
POWER SET
Function switch: OFF
RF TUNING: Operating
4-16
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