Starting Procedure

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

hand corner to unlock it from the vertical detent lock-

NOTE

ing pin. Lift the antenna up until a horizontal detent

The antenna test hood is used only for

locking pin locks the antenna. Direct the arrow on the

AT-884/APX-44 type antennas.

antenna toward the aircraft transponder set antenna.

(1) Release the test set cover latches and remove

(5) To position the antenna for vertical polariza-

the cover.

tion, grasp the antenna handle (fig. 2-3) and gently

( 2 ) Remove the CG-409H/U RF cable,

pull up the antenna to disengage it from a snap latch.

CN-1088A/U attenuator, and antenna test hood from

Direct the arrow on the antenna toward the aircraft

the cover and connect the equipment as illustrated in

transponder set antenna. Adjust the vertical angle of

figure 2-4.

the antenna until it is directed at the aircraft antenna.

(3) Snap the test hood in position over the

AT-884/APX-44 antenna so that the arrow on the bot-

b. Nonradiation Operation (Direct Coupling). The

test set is connected through Fixed Attenuator

tom of the test hood points toward the forward end of

CN-1088A/U directly or indirectly, to the equipment

the aircraft. Use the antenna flanges mounted on the

aircraft (fig. 2-4).

under test. Proceed as follows:

(4) Disconnect the cable from the PROBE connec-

WARNING

tor and connect the free end of the CG-409H/U RF ca-

When a 115-volt ac 400 Hertz power source is

ble to the PROBE connector.

to be used and the transponder to be tested is

2-8. Starting Procedure

installed in an aircraft, connect test set to

transponder before connecting test set power

Set up the equipment as instructed in paragraph 2-7

cable.

and proceed as follows to start the equipment:

a. Set the test set controls as follows:

(1) Place the test set near the transponder set an-

tenna input connector.

Position

Control

OFF.

28 VDC-115VAC-ON-OFF power switch

(2) Release the test set cover latches and remove

Any mode, except mode

MODE switch . . . . . . . . . . . . . . . . . . . . . . . .

the cover, Remove the CG-409H/U RF cable and at-

tenuator (fig. l-l) from the cover.

ISLS switch . . . . . . . . . . . . . . . . . . . . . . . . . .

OFF.

SELF TEST.

FUNCTION switch . . . . . . . . . . . . . . . . . . .

(3) Disconnect the antenna RF cable from the

AB-CD CODE controls . . . . . . . . . . . . . . . .

0000.

PROBE jack (fig. 2-2) and connect the RF cable,

VER BIT 1 . . . . . . . . . . . . . . . . . . . . . . . . . .

OFF.

removed from the cover, to the PROBE jack. Connect

VER BIT 2 . . . . . . . . . . . . . . . . . . . . . . . . . .

OFF.

one end of the CN-1088A/U attenuator to the RF cable

b. Remove the power cable from the cover.

and the other end of the attenuator to the selected

c. Connect the power cable between the power source

transponder set antenna test input.

and test set POWER connector (para 2-4).

NOTE

CAUTION

When testing the AN/APX-72, connect the

When connecting dc power cables supplied

UG-564/U connector adapter between the

with battery clips to a dc power source, be

AN/APX-72 antenna input and the attenua-

sure the battery clip with a red insulator is

tor.

connected to the positive (+) battery ter-

c. Nonradiation Operation (Antenna Test Hood

minal. Improper connection will damage the

equipment.

Coupling).

2-6