Mode 4 Receiver Sensitivity and Reply Video Adjustments Using AN/UPM-137A

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

b. Set test set controls as follows:

d. C o n n e c t t h e e q u i p m e n t a s s h o w n i n f i g u r e

(1) FUNCTION to SYSTEM.

5.1-7, except connect the RF power test set to

(2) MODE to 4.

the modulator RF OUT jack.

( 3 ) DIR. RAD to RAD.

e. A d j u s t t h e s i g n a l g e n e r a t o r f o r c w

( 4 ) ISLS to OFF.

operation at 1,090 mc and RF level of 9

c. Set

AN/UPM-137A

interrogator

signal

dbm as indicated by the RF power test set.

f. D i s c o n n e c t t h e c a b l e a t t h e m o d u l a t o r R F

simulator TRANSMITTER-XMTR FREQ

switch to XTAL.

OUT jack and connect the transponder test set

d. S e t a n d a d j u s t A N / U P M - 1 3 7 A r f s i g n a l

t o the RF OUT jack.

g e n e r a t o r controls as follows:

g. C o n t i n u a l l y p r e s s t h e t r a n s p o n d e r t e s t s e t

( 1 ) OUTPUT ATTEN 0-100 dbm to 6.

PUSH-TO-TEST switch and adjust control

AlR43 (fig. 8-43) for a just accept indication.

(2) TRANSMITTERXMTR FREQ to

XTAL.

Increase the signal generator output level 3

dbm.

(3) TRANSMITTTER-CW SOURCE to

E X T 1090 MHz.

h. S e t a n d A D J U S T t h e o s c i l l o s c o p e a s

e. Set

and

adjust

AN/UPM-137A

oscilloscope

follows:

controls as follows:

( 1 ) Sweep Display Switch: Mixed.

(1) VERTICAL-CHAN A-AC/DC to DC.

(2) MAIN and DELAYED SLOPE

Switches: .

IN/OUT to

(2) VERTICAL-CHAN A-75

i. C o n n e c t t h e o s c i l l o s c o p e C H A N N E L A t o

OUT.

t e s t points listed in the chart below. Adjust the

(3) VERTICAL-CHAN A-VOLT/DIV to 2.

control indicated until performance requirement

(4) DISPLAY-CHAN A/ALT/CHAN B to

is obtained.

ALT.

NOTE

EXT

(5) HORIZONTAL-SYNC to

In order to observe the pulse at A 2 T P 2 ,

DC.

it is necessary to continuously operate

(6) CALIBRATORS-XTAL

MARK

the PUSH-TO-TEST Switch.

( SEC) to .1 & 1.

A d j u s t the oscilloscope sweep and delay controls

(7) CALIBRATORS LEVEL to mid.

as necessary to observe signal.

position.

Test point

Pulse width

Adjust control

f. C o n n e c t e q u i p m e n t a s s h o w n i n f i g u r e 5 . 1 -

( sec)

7.1.

0.3 0.01

A1TP1

A1R8

g. A p p l y p o w e r t o e q u i p m e n t a n d p e r m i t 1 5 -

0.3 0.01

A1TP2

A1R11

minute warmup.

A1TP3

0.3 0.01

A1R14

h. A d j u s t A N / U P M - 1 3 7 A r f s i g n a l g e n e r a t o r

A1TP4

0.7 0.01

A1R17

A2TP1

OUTPUT ATTEN control 9 dbm minus

269 2

A2R2

12 0.1

A2TP2

A2R7

cable attenuation marked on cable connected to

A1TP5

150 7.5

A1R22

test set PROBE jack.

5.1-13.1 Mode 4 Receiver Sensitivity and

Example:

9 dbm minus 0.9 dbm is 8.1

Reply Video Adjustments Using

dbm.

AN/UPM-137A

i. C o n t i n u a l l y p r e s s a n d r e l e a s e t e s t s e t

PUSH TO TEST switch and adjust control

a. Set

and

adjust

AN/APM-270(V)

controls

AlR43 for just ACCEPT indication. Adjust

as follows:

AN/U PM-137A rf signal generator OUTPUT

(1) CONSECUTIVE REPLIES to 64.

A T T E N 0-100 dbm to 6 dbm.

(2) REPLY

MODULATION-SPACING

j. Connect

AN/UPM-137A

oscilloscope

PULSE 2 to 0.

VERTICAL-CHAN A-VIDEO IN jack to test

(3)

MODULATION-

set test points listed in chart below. Set test set

SPACINGPULSE 3 to 0.

PUSH TO TEST switch to LOCK and adjust

(4) SYNC GAIN to mid position.

test set control indicated until performance

( 5 ) SYNC DELAY to mid position.

r e q u i r e m e n t is obtained.

(6) REPLY MODULATION1X/2X to

1X.

5.1-21

Change 3