Garmin GTX 330 User manual

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GARMIN International, Inc.
1200 E. 151st Street
Olathe, KS 66062 USA
190-00207-02 Revision 1
March 2002
GTXTM 330, GTXTM 330D
TRANSPONDER
INSTALLATION
MANUAL

Page A GTX 330 Installation Manual
Rev. 1 190-00207-02
© Copyright 2002
GARMIN Ltd. or its subsidiaries
All Rights Reserved
Except as expressly provided herein, no part of this manual may be reproduced, copied, transmitted,
disseminated, downloaded or stored in any storage medium, for any purpose without the express prior
written consent of GARMIN. GARMIN hereby grants permission to download a single copy of this manual
and of any revision to this manual onto a hard drive or other electronic storage medium to be viewed and to
print one copy of this manual or of any revision hereto, provided that such electronic or printed copy of this
manual or revision must contain the complete text of this copyright notice and provided further that any
unauthorized commercial distribution of this manual or any revision hereto is strictly prohibited.
Information in this document is subject to change without notice. GARMIN reserves the right to change or
improve its products and to make changes in the content without obligation to notify any person or
organization of such changes or improvements.
GARMIN International, Inc.
1200 E. 151st Street
Olathe, KS 66062 USA
Telephone: [phone]
Dealer Line: 1-800-800-1420
Web Site Address: www.garmin.com
INFORMATION SUBJECT TO EXPORT CONTROL LAWS
This document may contain information which is subject to the Export Administration Regulations (“EAR”)
issued by the United States Department of Commerce (15 CFR, Chapter VII, Subchapter C) and which may
not be exported, released, or disclosed to foreign nationals inside or outside of the United States without
first obtaining an export license. A violation of the EAR may be subject to a penalty of up to 10 years
imprisonment and a fine of up to US$1,000,000 under Section 2410 of the Export Administration Act of
1979. Include this notice with any reproduced portion of this document.
RECORD OF REVISIONS
Revision Revision
Date
Description ECO #
103/22/00 Preliminary Release -

GTX 330 Installation Manual Page i
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TABLE OF CONTENTS
To be supplied

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GTX 330 Installation Manual Page 1-1
190-00207-02 Rev. 1
1. GENERAL DESCRIPTION
1.1 INTRODUCTION
This manual describes the physical, mechanical, and electrical characteristics and the installation requirements for the
GTX 330 Mode S Transponder and GTX 330D Diversity Mode S Transponder. In this manual, the term GTX 330
applies to both transponders unless otherwise stated. Information pertaining to the maintenance, alignment, and
procurement of replacement parts is found in the GTX 330 Maintenance Manual, P/N 190-00207-05. After
installation of the GTX 330, FAA Form 337 must be completed by an appropriately certificated agency to return the
aircraft to service.
1.2 EQUIPMENT DESCRIPTION
The Garmin GTX 330 is a panel mounted Mode S Transponder with the addition of timers, altitude reporting, mode S
interrogation and reply, and multiple transmit/receive ARINC 429 and RS232 data ports. The Mode S transponder
has the capability to transmit a unique address for every aircraft.
The GTX 330 is a radio transmitter and receiver that operates on radar frequencies, receiving ground radar or TCAS
interrogations at 1030 MHz and transmitting a coded response of pulses to ground-based radar on a frequency of
1090 MHz. The GTX 330 is equipped with IDENT capability that activates the Special Position Identification (SPI)
pulse for 18 seconds.
As with other Mode A/Mode C transponders, the GTX 330 replies with any one of 4,096 codes, which differ in the
position and number of pulses transmitted. By replying to ground transmissions or TCAS interrogations, the
GTX 330 enables ATC to display aircraft identification, altitude and ground speed as well as identification numbers
on ATC radar screens or TCAS traffic indicators.
The GTX 330 is configured with all key controls. The layout of the front panel keys and displays segregates the
transponder’s primary functions from the secondary functions. The unit can be configured so the aircraft avionics
master bus can turn the unit on.
1.3 INTERFACE SUMMARY
The GTX 330 provides the following interface connections via the rear connector:
•Ten (10) encoding altimeter inputs.
•External IDENT input.
•External STBY input.
•External suppression pulse input.
•Switched power output of up to 1.5 amps (for digital altitude encoder power).
•Aircraft power input (11 to 33 volts).
•Aircraft dimming buss input voltage.
•Aircraft master switch turn-on option.

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Rev. 1 190-00207-02
•Serial altitude or GPS groundspeed input.
•Serial altitude output.
•Mode S with Extended Squitter, Comm A and Comm B protocol.
•Temperature, Altitude Hold, Density Altitude and the ability to enter flight ID or tail numbers.
•Digitally recorded voice and discrete warning annunciator activated by Altitude Hold when limits are exceeded.
•Diversity: GTX 330 is available with or without the Diversity feature.
1.4 GTX 330 TECHNICAL SPECIFICATIONS
1.4.1 GTX 330 Electrical Specifications
SPECIFICATION CHARACTERISTIC
TSO, JTSO; GTX 330 TSO-C112 CL2A4 121 010, JTSO-2C112a.
TSO, JTSO; GTX 330D TSO-C112 CL2A4 121 011, JTSO-2C112a.
TSO ENV CAT Refer to appendix A
Applicable Documents RTCA DO-160D, DO-181C
Temperature Range -45°C to +55°C (Continuous Operation)
Power Requirements 11.0 to 33.0 Vdc; Power Input: 22 Watts typical,
45 Watts Maximum
Humidity 95% @ +55°C for 16 Hours; 85% @ +38°C for 32
Hours
Altitude 55,000 Feet
Transmitter Frequency 1090 MHz
Transmitter Power 125 Watts minimum, 250 Watts nominal.
Receiver Frequency 1030 MHz
Receiver Sensitivity -74 dBm Nominal for 90% replies
Mode A Capability 4096 Identification Codes
Mode C Capability 100 Foot Increments from -1000 to 62,700 feet.
25 Foot Increments with suitable serial data link.
Mode S Capability Aircraft Identification, Altitude and Ground Speed
External Suppression Input Low ≤0.5 V; High ≥8 V

GTX 330 Installation Manual Page 1-3
190-00207-02 Rev. 1
1.4.2 Physical Characteristics of the GTX 330
SPECIFICATION CHARACTERISTIC
Bezel Height 1.65 inches (42 mm)
Bezel Width 6.25 inches (159 mm)
Rack Height (Dimple to Dimple) 1.68 inches (43 mm)
Rack Width 6.30 inches (160 mm)
Depth Behind Panel with
Connectors (measured from face
of aircraft panel to rear of
connector backshells)
11.25 inches (286 mm)
GTX 330 Unit Weight 3.4 lbs. (1.5 kg)
GTX 330 Rack Weight (Installed
with rack and connectors)
4.2 lbs. (1.9 kg)
1.4.3 GTX 330 Configurations Available
GARMIN P/N GTX 330 Description
010-00230-00 Black Front Panel
010-00230-20 Gray Front Panel
010-00230-10 Black Front Panel, Diversity
010-00230-30 Gray Front Panel, Diversity
1.4.4 Equipment Available
ITEM GARMIN P/N
Sub Assy, Connector Kit, GTX 330 011-00583-00
SMP, Install Rack, GTX 330 115-00294-00
Sub Assy, Backplate, GTX 330 011-00582-00
(For use with GTX 330)
Sub Assy, Backplate, GTX 330D 011-00582-01
(For use with GTX 330D)
GARMIN GTX 330 Antenna kit 010-10160-00

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Rev. 1 190-00207-02
1.4.5 Additional Equipment Required
•Antenna Sealant - Use antenna manufacturer’s instructions, install according to FAA AC 43.13-2A.
•Cables - The installer will supply all system cables including circuit breakers. Cable requirements and
fabrication is detailed in Section 2 of this manual.
•Hardware - #6 Flat Head Screw (6 ea.) and #6-32 Self-Locking Nut (6 ea.). Hardware required to
mount installation rack is not provided.
•Encoding Altitude Digitizer - Use encoding altimeter manufacturer’s instructions, install according to
FAA AC 43.13-2A.
1.5 INSTALLATION APPROVAL
The conditions and tests required for TSO approval of the GTX 330 Transponder and antenna are minimum
performance standards. It is the responsibility of those desiring to install this transponder and antenna either on or
within a specific type or class of aircraft to determine that the aircraft installation standards are within the TSO
standards. For GTX 330 TSO compliance, see Appendix A. For antenna TSO compliance, refer to antenna
manufacturer’s literature.
1.6 AIRCRAFT STATION LICENSING REQUIREMENTS
The Telecommunications Act of 1996, effective February 8, 1996, provides the FCC discretion to eliminate radio
station license requirements for aircraft and ships. The GTX 330 installation must comply with current transmitter
licensing requirements. To find out the specific details on whether a particular installation is exempt from licensing,
please see FCC Fact Sheet PR 5000 or contact the FCC at (800)-322-1117.
If an aircraft license is required, make application for a license on FCC form 404, Application for Aircraft Radio
Station License. The FCC also has a fax-on-demand service to provide forms by fax at (202)-418-0177.
The GTX 330 owner accepts all responsibility for obtaining the proper licensing before using the transponder.

GTX 330 Installation Manual Page 1-5
190-00207-02 Rev. 1
1.7 LIMITED WARRANTY
GARMIN warrants this product to be free from defects in materials and manufacture for one year from the date of
purchase. GARMIN will, at its sole option, repair or replace any components that fail in normal use. Such repairs or
replacement will be made at no charge to the customer for parts or labor. The customer is, however, responsible for
any transportation costs. This warranty does not cover failures due to abuse, misuse, accident or unauthorized
alteration or repairs.
THE WARRANTIES AND REMEDIES CONTAINED HEREIN ARE EXCLUSIVE AND IN LIEU OF ALL
OTHER WARRANTIES EXPRESS OR IMPLIED OR STATUTORY, INCLUDING ANY LIABILITY ARISING
UNDER ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE,
STATUTORY OR OTHERWISE. THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, WHICH MAY
VARY FROM STATE TO STATE.
IN NO EVENT SHALL GARMIN BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT OR
CONSEQUENTIAL DAMAGES, WHETHER RESULTING FROM THE USE, MISUSE, OR INABILITY TO USE
THIS PRODUCT OR FROM DEFECTS IN THE PRODUCT. SOME STATES DO NOT ALLOW THE
EXCLUSION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS MAY
NOT APPLY TO YOU.
To obtain warranty service, call the GARMIN Customer Service department (913-397-8200) for a returned
merchandise tracking number. The unit should be securely packaged with the tracking number clearly marked on the
outside of the package and sent freight prepaid and insured to a GARMIN warranty service station. A copy of the
original sales receipt is required as the proof of purchase for warranty repairs. GARMIN retains the exclusive right
to repair or replace the unit or offer a full refund of the purchase price at its sole discretion. SUCH REMEDY
SHALL BE YOUR SOLE AND EXCLUSIVE REMEDY FOR ANY BREACH OF WARRANTY.

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GTX 330 Installation Manual Page 2-1
190-00207-02 Rev. 1
2. INSTALLATION
2.1 INTRODUCTION
This section provides the necessary information for installing the GTX 330 Mode S Transponder, and where
required, optional accessories. Installation of the GTX 330 will differ according to equipment location and other
factors. Cabling will be fabricated by the installing agency to fit these various requirements. Appendix B contains
interconnect wiring diagrams, mounting dimensions, and information pertaining to installation. Each installation
shall be accomplished to meet the requirements of FAA AC 43.13-2A.
2.2 UNPACKING AND INSPECTING EQUIPMENT
Carefully unpack the equipment and make a visual inspection of the unit for evidence of damage incurred during
shipment. If the unit is damaged, notify the carrier and file a claim. To justify a claim, save the original shipping
container and all packing materials. Do not return the unit to GARMIN until the carrier has authorized the claim.
Retain the original shipping containers for storage. If the original containers are not available, a separate cardboard
container should be prepared that is large enough to accommodate sufficient packing material to prevent movement.
2.3 ANTENNA INSTALLATION
2.3.1 Location Considerations
Figure 2-1. Antenna Installation Considerations
A. The antenna (GARMIN P/N 010-10160-00) should be mounted away from major protrusions, such as
engine(s), propeller(s), and antenna masts. It should also be as far as practical from landing gear doors,
access doors, or other openings that could effect its radiation pattern.
B. The antenna should be mounted on the underside of the aircraft and in a vertical position when the
aircraft is in level flight. The diversity antenna should be mounted on the top of the aircraft.
C. Avoid mounting the antenna within three feet of the ADF sense antenna or any other communication
antenna and six feet from the DME antenna.
D. To prevent RF interference, the antenna must be physically mounted a minimum distance of three feet
from the GTX 330.

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Rev. 1 190-00207-02
NOTE
If the antenna is being installed on a composite aircraft, ground planes must sometimes be
added. Conductive wire mesh, radials, or thin aluminum sheets embedded in the composite
material provide the proper ground plane allowing the antenna pattern (gain) to be maximized
for optimum transponder performance.
2.3.2 Antenna Installation
Install the antenna according to the antenna manufacturer’s instructions and FAA AC 43.13-2A.
2.3.3 Installation Approval Considerations for Pressurized Aircraft
Antenna and cable installations on pressurized cabin aircraft require FAA approved installation design and
engineering substantiation data whenever such installations incorporate alteration (penetration) of the cabin pressure
vessel by connector holes and/or mounting arrangements.
For needed engineering support pertaining to the design and approval of such pressurized aircraft antenna
installations, it is recommended that the installer proceed according to any of the following listed alternatives:
1. Obtain approved antenna installation design data from the aircraft manufacturer.
2. Obtain an FAA approved Supplemental Type Certificate (STC) pertaining to and valid for the subject
antenna installation.
3. Contact the FAA Aircraft Certification Office in the appropriate Region and request identification of FAA
Designated Engineering Representatives (DERs) who are authorized to prepare and approve the required
antenna installation engineering data.
4. Obtain FAA Advisory Circular AC-183C and select (and contact) a DER from the roster of individuals
identified thereunder.
5. Contact an aviation industry organization such as the Aircraft Electronics Association and request their
assistance.

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190-00207-02 Rev. 1
2.3.4 Antenna Cable Installation
When routing antenna cables, observe the following precautions:
•All cable routing should be kept as short as possible and as direct as possible.
•Avoid sharp bends.
•Avoid routing cables near power sources (e.g., 400 Hz generators, trim motors, etc.) or near power for
fluorescent lighting.
•Avoid routing cable near ADF antenna cable (allow at least a 12-inch separation).
The following table lists examples of the recommended antenna cable vendors and the type of cable to be used for
specific lengths of cable. Any cable meeting specifications is acceptable for the installation. The maximum coaxial
cable attenuation at 1090 MHz must not exceed 1.5 dB.
Max. Length (feet) ECS Type MIL-C-17 Type RG Type
8.8 M17/128 RG400
10.0 3C142B
12.5 M17/112 RG304
17.0 311601 M17/127 RG393
21.0 311501
27.0 311201
41.0 310801
Supplier Information Vendor: Electronic
Cable Specialists
5300 W. Franklin Drive
Franklin, WI 53132
Tel: [phone]
414-421-5300
Fax: [phone]
MIL-C-17 types: See
current issue of
Qualified Products List
QPL-17.
RG types: See current
issue of Qualified
Products List QPL-17.

Page 2-4 GTX 330 Installation Manual
Rev. 1 190-00207-02
2.4 COOLING AIR
The GTX 330 meets all TSO requirements without forced air-cooling. (The application of forced air cooling to the
rear air nozzle of the GTX 330 provides beneficial cooling to the unit. The GTX 330 is designed to dissipate its
internal heat without the need of blowing air inside the unit.)
The GTX 330 was designed to handle a constant 450 PRF, with short periods of 1200 PRF. Rate limit is set at 1200
PRF. A typical radar site would interrogate the transponder once every 5 to 10 seconds for approximately 100 msec
at a 400 PRF rate. In very high traffic areas with multiple ground stations and TCAS traffic it is possible to have
long term PRF rates above 450 PRF. The GTX 330 measures the unit temperature and without forced air-cooling the
reply rate will be reduced to protect the transmitter from overheating.
2.5 GTX 330 INSTALLATION
NOTE
Avoid installing the unit near heat sources. If this is not possible, insure that
additional cooling is provided. Allow adequate space for installation of cables and
connectors. The installer will supply and fabricate all of the cables. All wiring must
be in accordance with FAA AC 43.13-2A.
Figure 2-2 Unit Installation Considerations
1. Assemble the connector/rack kit according to figure 4-2. Install the rack assembly according to the
dimensions given in figures 4-1 and paragraph 1.4.2 Physical Characteristics of the GTX 330. Mounting
brackets are not supplied due to the wide range of mounting configurations available. Suitable mounting
brackets may be fabricated from sheet metal or angle stock. To insure a sturdy mount, rear support for
the unit must be provided.
2. Looking at the bottom of the transponder, make sure the front lobe of the locking mechanism is in a
vertical position. This can be accomplished by using a 3/32” Allen wrench through the face plate.
3. Slide the unit into the rack until the front lobe of the unit touches the rack.
4. Turn the Allen wrench clockwise until unit is secured in the rack. Continue turning until tight. Do not
overtighten the screw.
5. To remove the unit from the rack, turn the 3/32” Allen wrench counterclockwise until it disengages from
the rack.

GTX 330 Installation Manual Page 3-1
190-00207-02 Rev. 1
3. INSTALLATION PROCEDURE
3.1 ANTENNA INSTALLATION
3.1.1 Antenna Installation
Install the antenna according to the antenna manufacturer’s instructions and FAA AC 43.13-2A.
3.1.2 Antenna Cable Connectors
The antenna cable requires a BNC connector at the antenna and a male BNC “Blindmate” connector
(P/N 330-00053-01, supplied with GTX 330 backplate assembly, 011-00582-00/01 at the transponder. Follow BNC
connector manufacturer instructions for assembly of the BNC connector.
3.2 ELECTRICAL CONNECTIONS
All electrical connections, except for the antenna, are made through a single, 62 pin D-subminiature connector.
Figure 2-1 defines the electrical characteristics of all input and output signals and identifies the cable requirements
for each signal. Required connector and associated hardware are supplied in the connector kit (P/N 011-00583-00).
See figures 4-1 and 4-2 for interconnect wiring diagrams.
CAUTION
Check wiring connections for errors before inserting the GTX 330 into the rack.
Incorrect wiring could cause internal component damage.
Pin Contact Part Numbers
62 pin connector (P3301)
Wire Gauge 22-28 AWG
GARMIN P/N 336-00021-00
Military P/N M39029/58-360
Recommended Crimp Tools
Wire Gauge 20-24 AWG
Hand Crimping
Tool
Positioner Insertion/
Extraction Tool
Military P/N M22520/2-01 M22520/2-08 M81969/1-02
Positronic 9507 9502-5 M81969/1-02
ITT Cannon 995-0001-584 995-0001-604 980-2000-426
AMP 601966-1 601966-5 91067-2
Daniels AFM8 K13-1 M24308/1-02
Astro 615717 615724 M81969/1-02
NOTES
1. Insertion/extraction tools from ITT Cannon are all plastic; others are plastic with metal tip.
2. Non-GARMIN part numbers shown are not maintained by GARMIN and consequently are subject to
change without notice.
3. All wires must be passed through the backshell before being assembled to connector.

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Rev. 1 190-00207-02
3.4 POST INSTALLATION CHECKOUT
CAUTION
Be sure to check all aircraft control movements before flight is attempted to insure
that the wiring harness does not touch any moving part.
Verify proper operation of the transponder during a flight test under VFR conditions.

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190-00207-02 Rev 1
Figure 3-1 GTX 330 OUTLINE DRAWING

GTX 330 Installation Manual Page 3-7 (Page 3-8 blank)
190-00207-02 Rev 1
Figure 3-2 GTX 330 CONNECTOR/RACK ASSEMBLY DRAWING

GTX 330 Installation Manual Page 3-9 (Page 3-10 blank)
190-00207-02 Rev 1
Figure 3-3 GTX 330 RECOMMENDED PANEL CUTOUT DIMENSIONS

GTX 330 Installation Manual Page 4-1
190-00207-02 Rev. 1
4. SYSTEM INTERCONNECTS
4.1 PIN FUNCTION LIST
4.1.1 J3301
123456789101112131415
222324252627282930313233343536
44464748495051
525354
5556
161718192021
373839404142
57
5859
6061
62
Figure 4-1. Rear Connector, J3301
Connector P3301
Pin Pin Name I/O
1 AVIONICS MASTER ON SELECT* In
2 ALTITUDE A1 In
3 ALTITUDE C2 In
4 ALTITUDE A2 In
5 ALTITUDE A4 In
6 ALTITUDE C4 In
7 ALTITUDE B1 In
8 ALTITUDE C1 In
9 ALTITUDE B2 In
10 ALTITUDE B4 In
11 ALTITUDE D4 In
12 EXTERNAL IDENT SELECT* In
13 EXTERNAL STANDBY SELECT* In
14 28 V LIGHTING BUS HI In
15 AUDIO OUT HI Out
16 AUDIO OUT LO Out
17 SQUAT SWITCH IN In
18 RESERVED --
19 ALTITUDE ALERT ANNUNCIATE* Out
20 RESERVED --
21 AIRCRAFT POWER In
22 RS 232 IN 1 In
23 RS 232 OUT 1 Out
24 RS 232 IN 2 In
25 RS 232 OUT 2 Out
26 ARINC 429 IN 3 A In
27 AIRCRAFT GROUND --
28 ARINC 429 OUT 2 B Out
29 ARINC 429 IN 3 B In
30 ARINC 429 OUT 2 A Out
31 EXTERNAL SUPPRESSION I/O I/O
32 ARINC 429 IN 1 A In
33 ARINC 429 IN 2 A In
Table 4-1. P3301 Pin Assignments