Receiver Section and Decoder Section Adjustments Using AN/TPM-26A

TM 11-6625-467-45/NAVAIR 16-30APM123-2/TO 33A1-3-367-22

NOTE

If necessary, adjust control A16R6.

If necessary, adjust control A4R1 to

obtain performance standards for the

e. Transmitter Pulse Adjustments. Use the

first and last pubs. Adjust control

AN/TPM-25A and the AN/USM-281A. Make

A4R29 to obtain performance stan-

the connections shown in figure 3-24. Set and

dards for the second pulse.

adjust the controls as follows:

(1) Apply power to the equipment and permit

(7) Adjust the oscilloscope MAIN AND

it to warm up for 5 minutes.

DELAYED TIME/DIV controls to observe two

(2) Set and adjust the oscilloscope controls

groups of interrogation pulses. Measure the

as given in the chart below:

spacing between the first pulse of each group. It

should be between 4,255 and 4,545 microsecond

Control

Position

(equal to prf of 230 5, -10) pps.

HORIZONTAL MAGNIFIER

NOTE

HORIZONTAL DISPLAY

INT

If necessary, adjust control A5R31 to

MAIN VERNIER

Fully

obtain performance standards.

Clockwise

50 SEC

MAIN TIME/DIV

4-8. Receiver Section and Decoder Section

SWEEP MODE Switch

AUTO

INT AUTO/EXT/EXT 10

EXT

Adjustments Using AN/TPM-26A

- SLOPE +

a. Test Equipment. The test equipment lists

DELAYED ACS/ACF/AC/DC

in the chart below is required for these ad

MAIN EXT+10/EXT/INT/LINE

EXT

MAIN - SLOPE +

justments.

MAIN ACS/AFC/AC/DC

Test equipment

Technical manual

DISPLAY

ALT

Test Set, Radar AN/TPM-25A . . . . . . TM 11-6625-2610-1

A VOLTS/DIV

Multimeter ME 26B/U . . . . . . . . . . . . TM 11-6625-200-15

(3) Set the test set FUNCTION switch at

Oscilloscope AN/USM-281A. . . . . . . . TM 11-6625-1703-15

SYSTEM and ISLS switch at OFF.

Generator, Pulse AN/USM-15A.. . . . TM 11-6626-368-10

b. System Timing Setup. P e r f o r m t h e

(4) Set the test set to each mode in the

procedures in paragraph 3-15d step 4 a through

following chart. Use the oscilloscope to observe

d. Once set, do not change AN/UPM-15A

the spacing between the first and last pulse.

DELAY setting.

Measure spacing from leading edge to leading

c. Test Setup.

edge. Performance standards are listed with the

controls to be used if an adjustment is necessary.

(1) Perform the s y s t e m timing setup

specified in step 4 of the chart in paragraph

3-15d

Adjustment

control

Mode

Limits

(2) On the A N / T P M - 2 5 A adjust SUM

ATTEN for a reading of -9 dB less the 1090

MHz loss of cable 139526. This establishes the

test conditions for all receiver and decoder ad

justments.

NOTE

Control A5R6 should be adjusted for a

Disregard the specified measurements

symmetrical P3 pulse shape.

and the normal indication columns in

the chart.

(5) Set the test set ISLS switch to ON.

(3) The ME-26B/U is not shown in figure

Measure the spacing between the first and second

pulse. It should be 3 0.1 s.

3-22; however, it is used in f below. Instruction

are provided in f below for its connections and

NOTE

use.

If necessary adjust control A4R22 to

d. Receiver Sensitivity Adjustment. Adjust

obtain performance standards.

control A8R5 (fig. 3-7) completely coun-

(6) Measure the width of each pulse. The

terclockwise. Then, turn the control until the

width should be 0.8 0. 1 s.

4-8

Change 5