Additional Test Equipment Required

TM 11-6625-667-45/NAVAlR 16-30APM123-2/TO 33A1-3-367-22

4-5. Receiver Section and Decoder Section

(7) Disconnect the MX-2144A/U from the

Adjustments

A N / A P M - 1 2 3 ( V ) l PROBE connecting. Set the

TS-779A/U RANGE switch to 10 DBM and

NOTE

again zero its meter with the ZERO control.

See para

4-8 when

using

(8) Reconnect the MX-2144A/U to the

AN/TPM-25A.

AN/APM-123(V)1 PROBE connection. Observe

The test equipment listed in the chart below is

the TS-779A/U power meter indication. It should

required for these adjustments. Additional test

j u s t barely move upscale (approximately -21

equipments required are described in a below.

dB).

Technical manual

Test equipment

11-6625-700-25

Frequency Meter AN/USM-207 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11-6625-493-15

Comparator. Frequency CM-77A/USM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11-6625-299-15

Generator, Signal AN/URM-64A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11-6625-403-14

Test Set, Radar AN/USM-98 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11-6625-200-15

Multimeter ME 26B/U . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

11-6625-1703-15

Oscilloscope AN/SM-281A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

and the normal indication columns in

a. Additional Test Equipment Required.

the chart.

(1) Modulator. A pin diode type modulator

with a minimum operating frequency range of

(3) The ME-26B/U is shown in figure 3-5;

from 1,000 to 1,100 megacycles and a power of 9

however, it is used in e below. Instructions are

d B m MD-796 is required. Pulse risetime and

provided in e below for its connections and use.

falltime must be preserved to within 25

c. Receiver Sensitivity Adjustment. A d j u s t

nanoseconds.

c o n t r o l A8R5 (fig. 3-7) completely count-

b. Test Setup.

t e r c l o c k w i s e . Then, turn the control until the

(1) Connect the equipment as shown in figure

ACCEPT indicator just lights.

3-5.

d. Decoder Adjustments. The chart below lists

(2) Adjust the equipment as specified in 9a

the decoder adjustments. The oscilloscope probe

t h r o u g h h of the chart in paragraph 3-4d. This

should be connected to the test point indicated.

establishes the test conditions for all receiver and

The Control column indicates the control to be

adjusted, and the Limits sec column indicates

decoder adjustments.

NOTE

the requirements. The decoder reply evaluator

adjustment procedure is given in e below.

Disregard the specified measurements

Test point

Limits m sec

Control

Adjustment

1.80.2

A10TP5

A10R7

Video enable delay (DSS4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A1lTP1

0.70.0

AllR6

Video pulse width (DSS1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0.05

0.60.01

A4R6

Line drive generator (ISS1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A4TP1

A11TP3

A11R30

0.350.01

Accept reject pulse width (DSS3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(4) Set the AN/UPM-98 switches to 7777.

e. Reply Evaluator Adjustment.

Note the ME-26BKJ indication.

(1) Set the ME-26B/U SELECTOR switch

at (+) and Range switch at 10V. Connect the

NOTE

common lead to test point A13TP2 (ground and

The setting of the SUB PULSE POS

the dc probe to test point A12TP2.

control is extremely critical. Vary the

(2) Set the AN/UPM-98 CODE swithes to

control very slowly in the following

7767.

steps.

(3) Adjust the ME-26B/U ZERO ADJ for a

(5) Set the AN/UPM-98 SUB PULSE

zero meter indication.

C h a n g e 5 4-5