PILOT’S GUIDE Transponders

PILOT’S GUIDE

Transponders

Buyer’s Guide

B y Pau l N ovac e k COMPARISON CHART on pages 76 & 77

The venerable transponder pulses asking all aircraft to send The ACSS RCZ-852 Mode S
originally was developed a message back. This is where diversity transponder is optimized
in the 1940s for the war- the transponder earns its keep. for regional, corporate aircraft and
time need of identifying friendly helicopters.
aircraft from adversaries. Then The aircraft transponder listens
called an IFF (identify friend for these pulses on a frequency this autonomous communica-
or foe), the transponder has of 1030 MHz. The transponder tion between opposing aircraft
evolved into a vital part of our circuits determine what kind of is done over the Mode S tran-
air traffic control system. Without information the ground station sponder data link. Therefore, all
transponders, ground controllers wants, then transmits back a TCAS II aircraft must have Mode
wouldn’t know where anyone series of pulses on 1090 MHz. S transponders.
was, and the chaos soon would Those series of pulses contain
result in aluminum rain. information, and depending Mode S offers more, however.
on what type of information A substantial upgrade in technol-
Air traffic control (ATC) facili- is requested, the transponder ogy over the standard ATCRBS,
ties use both primary and sec- sends either the squawk code the Mode select beacon system
ondary radar systems. The (Mode A), the pressure altitude (Mode S) was designed to do
primary system uses the big dish (Mode C) or the coded aircraft three things: provide plane-to-
antenna seen rotating atop a identification (Mode S). plane TCAS II communication;
tower. A high frequency and very allow two-way electronic connec-
strong signal is sent into the sur- A word about Mode S capabil- tions for ATC communications;
rounding sky, only to return when ity: The collision avoidance sys- and provide traffic information
bounced off objects. Then, this tem TCAS II (ACAS II in Europe) service (TIS) from FAA ATC radar
reflected echo is analyzed so an allows nearby aircraft to commu- systems.
object’s direction and distance nicate with each other and arrive
can be displayed on a big round at a conflict resolution, taking TIS gives pilots access to
indicator screen. But this primary each out of the other’s path. The information on up to seven
radar technique has many limita- decision is made electronically nearby aircraft, including each
tions because it not only detects for one aircraft to climb while the airplane’s relative location, direc-
aircraft, it also detects trucks, other is commanded to dive. All tion of flight and relative altitude.
trees and mountains. This data-linked traffic informa-
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Step in the secondary sur- on a panel moving-map display.
veillance radar system, other-
wise known as the air traffic Avionics designed for large
control radar beacon system and air transport aircraft gener-
or ATCRBS. This system uses
a smaller directional antenna
mounted atop the big rotat-
ing dish. This secondary radar
antenna sends out a series of

ally combine the entire avionics sponder poised for future growth. Dzus-mounted unit certified for
suite into a completely inte- More than 4,000 XS-950 tran- unrestricted service to 62,700
grated system. Although the sponders have been delivered to feet. It displays the squawk code
transponder typically is a sepa- more than 100 operators world- in its left window and its operat-
rate remotely mounted unit, its wide since the product debuted ing mode or flight level altitude
integration into the entire system in 1996. in its right window. A stored VFR
prevents any meaningful price code, such as 1200, can be
comparisons. Therefore, this The XS-950 Mode S tran- recalled quickly with the VFR
Buyer’s Guide focuses on tran- sponder is easily upgradeable push button. To facilitate dual
sponders designed for retrofit for tomorrow’s technology transponder installations, provi-
or original equipment in general requirements. Major functional- sions are included for automatic
aviation, corporate aircraft and ity upgrades, such as ICAO transfer of one transponder to
helicopters. Level V data link or pending the standby mode when the
United States transponder secu- other transponder is selected
The accompanying chart offers rity modifications (also known for normal. This prevents both
a brief description and starting as the hijack mode), are easily transponders transmitting at the
price for each unit. accomplished with software-only same time.
changes. Both the RCZ-852 and
Aviation Communications XS-950 have all the required The ATC-4401 series of Mode
& Surveillance Systems functionality for ACAS II mandate A/C transponders come in four
compliance, European-enhanced flavors. The Dash-1 series is
A joint venture company of Mode S, and ADS-B. intended for mounting in stan-
L-3 Communications and Thales, dard 2¼-inch instrument holes
ACSS is located in Phoenix, Ariz. For more information, contact with either 160-watt or 250-watt
The company designs, manu- ACSS at 623-445-7070 or visit transmitters. The Dash-2 series
factures and supports a full line www.acssonboard.com. offers remote-mounted boxes
of avionics for regional airlines, used for installations when panel
business aviation, general avia- Becker Avionics depth is limited. A 2½-inch deep
tion and military customers, as CU-5401 control unit is installed
well as all aircraft operating in The German manufacturer in a 2¼-inch instrument hole. The
the former Soviet Union. Thales Becker Flugfunkwert GmbH was control unit offers a clear, high-
Avionics is the exclusive sales founded in 1956, and it brought contrast, double-line LCD display
and support agent of ACSS prod- the world’s first transistorized sin- readable under all lighting condi-
ucts to commercial air transport gle-block airborne receiver into tions, even bright sunlight. When
customers operating Airbus and the market. As technology devel- an altitude encoder is connected,
Boeing aircraft. oped, the company produced the reported altitude is displayed
a comprehensive, high-quality below the transponder code to
The ACSS RCZ-852 is a range of communications and verify correct operation of the
full-featured Mode S diversity navigation products, which are entire system.
transponder currently flying on used all over the world in military
more than 2,500 regional and and civil aircraft. To accommodate Mode S
business aircraft. Its small, light- requirements, the Becker BXP-
weight package is optimized for The Becker ATC-3401 is a
regional and corporate aircraft as complete Mode A/C transpon- Continued on following page…
well as helicopters, and is eas- der housed in a single, compact
ily compatible with all currently
available TCAS I and TCAS II Becker Avionics ATC-3401
systems. Extensive BIT (built-in Mode A/C transponder.
test) ensures approximately 90
percent of the circuitry is tested
during system operation.

Intended for the air transport
market, the bigger XS-950 also
is a full-featured Mode S tran-

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TRANSPONDER COMPARISON

MANUFACTURER MODEL DESCRIPTION PRICE

ACSS RCZ-852 Remote mount, Mode S $48,250
XS-950 Remote mount, Mode S, air transport $45,737
$4,995
ATC 3401 Dzus mount, Mode A/C, 250W, flight level display, VFR button $2,155

ATC 4401-1-175 2-inch round mount, Mode A/C, 160W, flight level display, VFR $2,370
button $2,275
$2,495
ATC 4401-1-250 2-inch round mount, Mode A/C, 250W, Flight Level display, VFR $3,595
button $4,990

ATC 4401-2-175 Remote mount, Mode A/C, 160W $2,685
$3,525
Becker ATC 4401-2-250 Remote mount, Mode A/C, 250W $2,595
$28,000
ATC 5401-1R Remote mount
$4,995
BXP 6401-1 2-inch round mount, Mode S, 250W, flight level display, VFR
button $9,995

BXP 6401-2 2-inch round mount, Mode S, 150W, flight level display, VFR $2,305
button $1,990
$2,495
BXP 6402-1R Remote mount, Mode S, 250W $4,195
$8,395
BXP 6402-2R Remote mount, Mode S, 150W

Collins TDR-94D Remote mount, Mode S, antenna diversity, corporate and air
transport

GTX-330 Panel mount, Mode S, 250W, TIS, VFR button, p-alt display, flight
timers, voice altitude alert

GTX-330D Panel mount, Mode S, antenna diversity, 250W, TIS, VFR button,
p-alt display, flight timers, voice altitude alert

Garmin GTX-327 Panel mount, Mode A/C, 200W, VFR button, p-alt display, flight
GTX-320A timers

Panel mount, Mode A/C, 200W

GTX-32 Remote mount for GNS-480, Mode A/C, 200W

GTX-33 Remote mount for GNS-480, Mode S, 250W, TIS, voice altitude
alert

GTX-33D Remote mount for GNS-480, Mode S, antenna diversity, 250W,
TIS, voice altitude alert

TRANSPONDERS boxes used for installations when Collins
panel depth is limited. A 2½-inch
Continued from page 75 deep CU-6401 control unit is For more than 70 years,
installed in a 2¼-inch instrument Rockwell Collins has been devel-
6401 and 6402 series comes in hole. oping a full line of communica-
four flavors as well. The 6401 tions and aviation electronics for
series is intended for mounting For more information, contact every facet of aviation. Its avion-
in standard 2¼-inch instrument Becker Avionics at 877-562-3253 ics are installed in the cockpits of
holes with either 150-watt or or visit www.beckerusa.com. nearly every airline and most of
250-watt transmitters. The 6402
series offers remote-mounted

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MANUFACTURER MODEL DESCRIPTION PRICE

KT-70 Panel mount, Mode S, 200W, flight level display, VFR button $5,770
Panel mount, Mode A/C, 200W, flight level display, VFR button $5,940
KT-71 Panel mount, Mode S, Data-link TIS, 200W, flight level display, $5,440
VFR button $1,800
KT-73 Panel mount, Mode A/C $2,410
Panel mount, Mode A/C, 200W, p-alt display, VFR button $21,710
Honeywell Remote mount, Mode S, non-diversity $2,300
2-inch round mount, Mode A/C, altitude alert, voltage alert AUD
KT-76A $2,100

KT-76C $1,710

MST-67A $2,036

Microair T2000SFL $1,787

Narco AT-165 Slide-in replacement for Narco AT-50/150/155, Mode A/C, 250W, $2,036
dual display, VFR button, p-alt display, altitude alert, flight timers
AT-165/VS w/alarm $1,787
AT-165/K
Slide-in replacement for Narco AT-50/150/155, Mode A/C, 250W, $2,195
AT-165/K/VS single display, VFR button
AT-165/KA $1,944
Slide-in replacement for King KT-76/78, Mode A/C, 250W, dual
AT-165/KA/VS display, VFR button, p-alt display, altitude alert, flight timers
AT-165/C w/alarm

AT-165/C/VS Slide-in replacement for King KT-76/78, Mode A/C, 250W, single
display, VFR button

Slide-in replacement for King KT-76A/78A, Mode A/C, 250W,
dual display, VFR button, p-alt display, altitude alert, flight timers
w/alarm

Slide-in replacement for King KT-76A/78A, Mode A/C, 250W,
single display, VFR button

Slide-in replacement for ARC RT-359A/459A, Mode A/C, 250W,
dual display, VFR button, p-alt display, altitude alert, flight timers
w/alarm

Slide-in replacement for ARC RT-359A/459A, Mode A/C, 250W,
single display, VFR button

All starting prices are subject to change. Please contact an authorized dealer for current pricing.

the military aircraft of the world. Collins TDR-94D Mode S
Collins offers a single, but transponder and CTL-92
control head.
fully capable, transponder for the
corporate jet and air transport
fleets. The TDR-94D Mode S
transponder is an all solid-state,
crystal-controlled receiver/trans-
mitter, operated from a variety of

Continued on following page…

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TRANSPONDERS

Continued from page 77

flight deck devices: the CTL-92

transponder control, radio tuning

unit or FMS.

The TDR-94D is designed

specifically for TCAS II-equipped Honeywell KT-73 data-link transponder with Mode S capability provides TIS from FAA ATC radar
business aircraft and regional systems.
airliners with limited space. It
is housed in a package spe- keypad and dedicated VFR but- general aviation, corporate and
cially designed for efficient heat ton. The GTX-327 also offers tim- helicopter fleets. Many of its units
transfer and resistance to high- ing functions, such as flight time have stood the test of time. As
intensity radiated fields. The and count-up/count-down timers, new communications and navi-
unit accepts either ARINC-429 as well as current pressure alti- gation equipment are replaced
or commercial standard data tude. with newer models, many of the
bus control and altitude informa- old King transponders keep their
tion to facilitate flexible system Garmin’s most capable panel- proud place at the base of the
design. The TDR-94D provides mount transponders, the GTX- radio stack.
new Mode S elementary and 330 and GTX-330D, both are
enhanced surveillance function- Mode S and TIS data-link capa- The KT-76A is a fleet standard
ality, in addition to an optional ble. Built on the same receiver in Mode A/C identification and
ADS-B capability. and transmitter technology as the was among the first transponders
GTX-327, the units’ solid-state to incorporate large scale inte-
For more information, contact design increases efficiency by grated (LSI) circuitry, reducing
Collins at 319-295-1000 or visit using less power, creating less both weight and power require-
www.collinsavionics.com. heat emissions, and eliminating ments. Its design efficiency and
warm-up time. In addition, the rugged construction continue to
Garmin GTX-330 and 330D also feature provide reliability and value.

Since purchasing the UPS-AT an altitude monitor with voice The KT-76C Mode A/C tran-
avionics products, Garmin has alerting. The GTX-330D differs sponder features a sequential
expanded its line of transpon- in that it adds antenna diversity pushbutton squawk/code entry
ders to four panel-mounted and for improved visibility to TCAS- and a programmable VFR but-
three remote-mounted models. equipped aircraft. ton. It operates with both 14- and
Its basic model, the GTX-320A, 28-volt electrical systems, and its
features a solid-state transmitter Garmin’s remote-mount tran- extensive backlighting and bright
providing 200 watts, which elimi- sponders, the GTX-32/33/33D, gas discharge display make it
nates the need for a cavity tube offer the same features as easy to read in all light levels.
that can degrade with time. It the panel-mount units but are
also fits into existing installations designed to interface directly with Identical in appearance, the
of select Narco and King tran- Garmin’s GNS-480. KT-70 is a Mode S transponder,
sponders using optional adapters while the KT-71 only replies
for simple, cost-effective upgrad- For more information, contact to Mode A/C interrogations.
ing. Garmin at 913-397-8200 or visit It matches the existing Silver
www.garmin.com. Crown line of Bendix/King panel
Adding a digital display and avionics with its distinctive red
numerous pilot-friendly features, Honeywell gas discharge displays. Both fea-
the GTX-327 features a numeric ture a programmable VFR code
Honeywell offers the Bendix/ button and flight-level altitude
King line of transponders for

readout. A handy feature enables

a landing gear switch control

over the ground/flight mode,

automatically keeping the tran-

sponder in standby mode while

Garmin GTX-330 Mode S (TIS) transponder with flight timers and voice altitude alerting. on the ground.

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The KT-73 data-link tran- The Microair T2000 SFL Mode A/C transponder revolutionary products to the
sponder is Mode S capable and with altitude and voltage alerting mounts in a general aviation scene since
provides TIS from FAA ATC 2 ¼-inch round hole. 1945. Its latest effort enables
radar systems. TIS can be dis- an aircraft owner the option of
played on the KMD 250, 550 or world, the Microair T2000 Mode upgrading an old transponder
850 multi-function displays. The A/C transponder is extremely with a digital slide-in replace-
KT-73 is fully field-upgradeable power-efficent, producing a ment.
(software only) to include air- nominal 200 watts. The TSO
to-ground automatic dependent certification of the T2000 The all-new AT-165 series
surveillance-broadcast (ADS-B) transponder has expanded has a one-touch code-entry
operation. This transponder func- Microair’s customer base into knob, one-touch 1200 VFR
tion enables aircraft to transmit the general aviation sector. button, multiple timers with
position, altitude and vector infor- alarm output, and an altitude
mation derived from the onboard The T2000 is available in two display with visual and audible
GPS system for use by ATC versions. The T2000 SFL uses altitude hold warnings. Audible
facilities. a backlit LCD display, while the alerts from the AT-165 warn the
T2000 SL uses an LED display. pilot when flying outside of the
Intended for corporate and Both fit a standard 2¼-inch desired altitude range.
regional aircraft, the remote- round instrument hole. For tight
mounted MST-67A offers all the panel applications, a compact Narco’s new Value Series
capabilities needed to operate in control head can be added to — denoted by a “VS” after the
the evolving world airspace. The the system to remotely mount model number — employs only
MST-67A features a unique flight the T2000. Both models feature a single display of mode and
ID function that converts the tran- a dual-line display with controls squawk code. The elimination
sponder’s Mode S address (for for mode, VHF hot key with of the pressure altitude display,
U.S.-registered aircraft only) into ability to input the VFR default, altitude alerter and flight timers
the tail number of the aircraft. For encoder altitude, assigned reduces the cost.
most Part 91 operators, this is altitude and input voltage. In
also the flight ID, so it’s automati- addition, the altitude display is All AT-165s use the latest
cally stored in the transponder switchable between feet, meters digital technology to provide a
register, eliminating the need to or flight level. lightweight (1.7 pounds) system
install and use an additional con- with a high-power, 250-watt
trol head or FMS. For more information, contact (nominal), 100 percent solid-
Microair Avionics at +61-7- state transmitter. They are fully
For more information, contact 41553048 or visit www.microair. compatible with modern altitude
Honeywell at 800-601-3099 or com.au. encoders and are a slide-in
visit www3.bendixking.com. replacement for all older Narco
Narco Avionics AT-50, AT-50A, AT-150 and
Microair AT-155 transponders. The “KA”
Narco Avionics was a pioneer model replaces all King KT-76A
Microair Avionics is an in the avionics world, bringing or KT-78A transponders, while
Australian company developing, the “K” model replaces
manufacturing and distribut- the KT-76 or KT-78. The “C”
ing sophisticated avionics for model replaces the Cessna
worldwide markets. Its products ARC 300 and 400 series tran-
are designed and manufactured sponders.
in Bundaberg, Queensland,
Australia. Because kit-build- For more information, contact
ers comprise a large part of Narco Avionics at 800-234-
Microair’s customers, it offers 7551 or visit www.narcoavion-
wiring harnesses to suit all ics.com. ■
designs, or will customize har-
nesses to suit requirements. The Narco AT-165 is a modern
slide-in replacement for
One of the smallest and light- older ARC, King and Narco
est (21 oz.) transponders in the transponders.

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