Transponder Sets AN/APX-68 and AN/APX-72 Tests

TM 11-6625-667-12/NAVAlR 16-30APM-123-1/TO 33A1-3-367-1

because the test will not be valid if it is too

(8) Set the test set ISLS switch to OFF.

c. Emergency Tests (Military and Civil).

close. In addition, damage to the detector

diode in the aircraft transponder set re-

(1) Military emergency tests can be performed in

ceiver may result.

modes 1, 2, and 3A. Civil emergency tests can be

performed in mode 3/A only. Set the C-2714/APX-44

(6) Connect the test set to the aircraft transpon-

der set for nonradiation operation (direct coupling)

(control unit) function switch to EMER and use the

(para 2-7b). Press the test set PUSH TO TEST switch.

chart below to set the mode and code controls of the

If the ACCEPT indicator lights, the transponder set

test set and transponder set.

antenna system is defective. If the REJECT indi-

NOTE

cator lights, the transponder set is defective.

Emergency operation may interfere with

(7) Set the test set ISLS switch to ON. The

distress signals. Do not radiate Code 7700.

REJECT indicator should light.

Perform the tests as quickly as possible.

AN/APX-44

Test set controls

Mode

Function

Mode

Mode/code setting

Function

Mode

Code

0000

MOD or CIVIL

ALL OFF

1/00

EMERGENCY

0000

EMERGENCY

MOD or CIVIL

MODE 2 control to ON

All receiver-trans-

mitter mode 2 toggle

switches to OFF

MOD or CIVIL

EMERGENCY

3/A

0000

MODE 2 control to OFF

3/00

MODE 3 control to ON

d. Identity Test.

(2) Press the PUSH TO TEST switch. The

(1) Set the C-2714/APX-44 (control unit) I/P

ACCEPT indicator should light.

switch to I/P and use the chart below to set the

controls of the test set and transponder set for the

(3) Set the C-2714/APX-44 master control to

desired code.

NORM.

Test set controls

AN/APX-44

Code

Mode

Mode

Function

Mode/code setting

Function

0000

MOD

I/P

All controls to OFF

1/00

0000

MOD or CIVIL

MODE 2 control to ON

SYSTEM

All receiver-trans-

mitter mode 2 toggle

switches to OFF.

MODE 2 control to OFF

MODE or CIVIL

3/00

0000

3/A

MODE 3 control to ON

EMERGENCY

a. Preliminary Panel Control Settings. The trans-

(2) Press the PUSH TO TEST switch. The

ponder set receiver-transmitter coder selector

ACCEPT indicator should light for 30 seconds +20--

switches for mode 2 code are preset to a four-digit

15.

code. Set Transponder Control C-6280A(P)/APX

(3) Set the C-2714/APX-44 master control to

controls as outlined in the chart below.

OFF.

Position

Control

MASTER Switch . . . . . . . . . . . . . . . . . . . . . . . . . . STBY for 1 min-

ute then set to

2-10. Transponder Sets AN/APX-68 and AN/

NORM.

APX-72 Tests

IDENT-MIC switch . . . . . . . . . . . . . . . . . . . . . .. OUT

M-l TEST switch . . . . . . . . . . . . . . . . . . . . . . . .. OUT

The operating control positions (code, mode, etc.) of

M-2 TEST switch . . . . . . . . . . . . . . . . . . . . . . . .. OUT

the test set must agree with the operating control

M-3/A TEST switch . . . . . . . . . . . . . . . . . . . . . .. OUT

positions of the transponder set under test. Perform

M-C switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. OUT

the preliminary test setup for radiation operation

MODE 4 switch . . . . . . . . . . . . . . . . . . . . . . . . . .. OUT

(para 2-7a), starting procedure (para 2-8), and

MODE l code control . . . . . . . . . . . . . . . . . . . ...00

MODE 3/A code control . . . . . . . . . . . . . . . . . .0000

proceed as follows:

Change 3 2-10