Narco Avionics AT165 Users Manual

NARCO AVIONICS

AT165 TSO

Transponder

Operation Manual

03609-0621

NARCO AVIONICS INC.

270 Commerce Drive, Suite 200
Ft. Washington, PA. 19034
U.S.A.

PRINTED IN U.S.A. March, 2004

NOTICE

While every effort has been made by Narco Avionics

Inc. to ensure accuracy in the preparation of this

Operation Manual, Narco assumes no responsibility

for errors or omissions

NARCO AVIONICS CAN BE REACHED BY CALLING:

215-643-2900

FAX: [phone]

PRODUCT DESCRIPTION

The AT165 TSO is a panel-mounted transponder with additional altitude and timing functions. The AT165
consists of a receiver tuned to the frequency of a ground interrogation station (1030 MHz), logic circuitry to
check the validity of the received interrogation and encode a reply containing pertinent identification
information, and a transmitter, which sends the coded reply to the ground station. When connected to an
optional Altitude Digitizer (AR850) coded altitude information will be transmitted to the ground station.

The AT165 utilizes a single knob for error free code entry even in turbulence. Push button controls are used to
access and manipulate the added features. The front panel display has two distinct areas, one for the primary
transponder functions and the second for the altitude and timing functions.

The AT165 has been designed for 14V or 28V operation. If the AT165 is replacing an existing AT50TSO,
AT50A, AT150, or AT155 that uses an MP10 or a passive voltage converter, these do not need to be removed.

OPERATION

Function Selector

Switch

Code Selector /

Data Entry

FIGURE 1-1 AT 165 FRONT PANEL

Function Selector Switch

The function selector is a four position rotary switch. The four positions are:

OFF- Turns off all power to the transponder.
SBY- Turns the transponder power supply on. When in SBY, the transponder will not reply to any

interrogation. SBY is used at the request of the air traffic controller to selectivity clear his scope of
traffic. When in this mode SBY will be shown on the Code display window.

ON- Places the transponder in Mode A, the aircraft identification mode. In addition to the aircraft's

identification code, the transponder will also reply to altitude interrogations (Mode C) with discrete
signals that do not contain altitude information. When in this mode ON will be shown on the Code
display window.

ALT- The ALT position activates all the necessary circuitry (transponder to optional altitude digitizer and

return) to respond to ATC (Air Traffic Control) altitude interrogations and aircraft identification
interrogations with standard pressure altitude (29.92 inches Hg). The ALT position may be used in
aircraft that are not equipped with the optional altitude digitizer, however, the only response will be
discrete signals that do not contain altitude information. When in this mode ALT will be shown on the
Code display window.

Switch

March, 2004 1