Garmin GTX 32 User manual

190-00303-60 October, 2008 Revision F
GTX 32
Transponder
Installation Manual

Page A GTX 32 Installation Manual
Revision F 190-00303-60
© Copyright 2008
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.
Garmin International, Inc.
1200 E. 151st Street
Olathe, KS 66062 USA
Telephone: [phone]
Aviation Panel-Mount Technical Support Line (Toll Free) 1.888.606.5482
www.garmin.com
Garmin (Europe) Ltd.
Liberty House, Bulls Copse Road
Hounsdown Business Park
Southampton, SO40 9RB U.K.
+44/ (0) 870.8501241
Garmin AT, Inc.
2345 Turner Rd., SE
Salem, OR 97302 USA
Telephone: [phone]
RECORD OF REVISIONS
Revision Revision
Date
Description
A 8/10/03 Production Release
B 1/10/05 Revised to reflect software 2.08
C 1/9/06 Revised to add CG information for remote mount.
D 3/29/06 Revised to conform to standard, updated manual
E 04/04/08 Added GDL 90 interconnect info
F 10/07/08 Added caution regarding handle screw torque

GTX 32 Installation Manual Page i
190-00303-60 Revision F
This manual reflects the operation of software version 2. 10. Some differences in operation may be
observed when comparing the information in this manual to earlier or later software versions.
CURRENT REVISION DESCRIPTION
Revision Page
Number(s)
Section
Number Description of Change
1-1 1.1 Replaced G1000 with Garmin Integrated Flight Deck
1-1 1.2 Replaced G1000 with Garmin Integrated Flight Deck
2-2 2.3 Replaced G1000 with Garmin Integrated Flight Deck
3-2 3.3 Replaced G1000 with Garmin Integrated Flight Deck
(3 places)
3-4 3.6 Added Final Installation Section, including caution for
handle screw torque
3-5 3.7.1 Removed G1000 from 1st line
3-6 3.8 Replaced G1000 with Garmin Integrated Flight Deck
4-2 4.3 Replaced G1000 with Garmin Integrated Flight Deck
4-3 4.3.4 Replaced G1000 with Garmin Integrated Flight Deck
4-5 4.5 Replaced G1000 with Garmin Integrated Flight Deck
F
C-1 App C Replaced G1000 with Garmin Integrated Flight Deck
DOCUMENT PAGINATION
Section Page Range
Table of Contents i – vi
Section 1 1-1 – 1-6
Section 2 2-1 – 2-8
Section 3 3-1 – 3-6
Section 4 4-1 – 4-6
Appendix A A-1 – A-2
Appendix B B-1 – B-8
Appendix C C-1 – C-10

Page ii GTX 32 Installation Manual
Revision F 190-00303-60
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. The preceding statement is required to be included on
any and all reproductions in whole or in part of this manual.
WARNING
This product, its packaging, and its components contain chemicals known to the State
of California to cause cancer, birth defects, or reproductive harm. This Notice is being
provided in accordance with California's Proposition 65. If you have any questions or
would like additional information, please refer to our web site at
www.garmin.com/prop65.

GTX 32 Installation Manual Page iii
190-00303-60 Revision F
TABLE OF CONTENTS
PARAGRAPH PAGE
1 GENERAL DESCRIPTION..............................................................................................................1-1
1.1 Introduction........................................................................................................................................1-1
1.2 Equipment Description .....................................................................................................................1-1
1.3 Mutual Suppression Pulses................................................................................................................1-2
1.4 Identification of Installed Equipment ................................................................................................1-2
1.5 Interface Summary ............................................................................................................................1-2
1.6 Technical Specifications....................................................................................................................1-3
1.7 License Requirements........................................................................................................................1-4
1.8 Certification.......................................................................................................................................1-5
1.9 Reference Documents........................................................................................................................1-5
1.10 Limited Warranty...............................................................................................................................1-6
2 INSTALLATION OVERVIEW........................................................................................................2-1
2.1 Introduction........................................................................................................................................2-1
2.2 Installation Materials .........................................................................................................................2-1
2.3 Installation Considerations ................................................................................................................2-2
2.4 Cabling and Wiring............................................................................................................................2-4
2.5 Installation Approval Considerations for Pressurized Aircraft..........................................................2-5
2.6 Cooling Air........................................................................................................................................2-5
2.7 GTX 32 Mounting Requirements......................................................................................................2-6
3 INSTALLATION PROCEDURE......................................................................................................3-1
3.1 Unpacking Unit..................................................................................................................................3-1
3.2 Wiring Harness Installation ...............................................................................................................3-1
3.3 Backshell Assembly...........................................................................................................................3-2
3.4 Weight and Balance...........................................................................................................................3-3
3.5 Electrical Load Analysis....................................................................................................................3-4
3.6 Final Installation................................................................................................................................3-4
3.7 Post Installation Configuration and Checkout...................................................................................3-5
3.8 Continued Airworthiness...................................................................................................................3-6
4 SYSTEM INTERCONNECTS..........................................................................................................4-1
4.1 Pin Function List................................................................................................................................4-1
4.2 Power Function..................................................................................................................................4-2
4.3 Altitude Functions .............................................................................................................................4-2
4.4 Discrete Inputs/Outputs .....................................................................................................................4-4
4.5 RS-232 Input/Output, Software Update Connections........................................................................4-5

Page iv GTX 32 Installation Manual
Revision F 190-00303-60
PARAGRAPH PAGE
APPENDIX A CONSTRUCTION AND VALIDATION OF STRUCTURES
A.1 Static Test Loading ..........................................................................................................................A-1
A.2 Determining Static Load Capability .................................................................................................A-1
APPENDIX B OUTLINE AND INSTALLATION DRAWINGS
APPENDIX C INTERCONNECT DRAWINGS

GTX 32 Installation Manual Page v
190-00303-60 Revision F
LIST OF ILLUSTRATIONS
FIGURE PAGE
2-1 Antenna Installation Considerations..................................................................................................2-3
2-2 GTX 32 G1000 Unit Rack.................................................................................................................2-7
2-3 GTX 32 Remote Stand-Alone Rack ..................................................................................................2-7
2-4 GTX 32 Remote Stand-Alone Rack, Suggested Mounting Locations...............................................2-8
3-1 Backshell Connector Assembly.........................................................................................................3-3
4-1 Rear Connector, J3271.......................................................................................................................4-1
4-2 GTX 32, Software Update Connections............................................................................................4-5
A-1 Upward Static Load Test ..................................................................................................................A-2
A-2 Forward Static Load Test..................................................................................................................A-2
B-1 GTX 32 Outline Drawing, in G1000 Rack,......................................................................................B-1
B-2 GTX 32 G1000 Rack/Connector Assembly Drawing ......................................................................B-3
B-3 GTX 32 Remote Mounted Stand-Alone Rack/Connector Assembly Drawing (Sheet 1 of 2)..........B-5
B-3 GTX 32 Remote Mounted Stand-Alone Rack/Connector Assembly Drawing (Sheet 2)................. B-7
C-1 GTX 32 Typical Garmin Integrated Flight Deck System Interconnect Wiring Diagram.................C-1
C-2 GTX 32 to GNS 480 (CNX80) Interconnect Wiring Diagram ........................................................C-3
C-3 GTX 32 to GDL 90, Typical Interconnect Wiring Diagram.............................................................C-5
C-4 Dual GTX 32 Transponders, Single Altitude Encoder, Interconnect Wiring
Diagram (Sheet 1 of 2)......................................................................................................................C-7
C-4 Dual GTX 32 Transponders, Single Altitude Encoder, Interconnect Wiring
Diagram (Sheet 2).............................................................................................................................C-9
LIST OF TABLES
TABLE PAGE
3-1 Pin Contact Part Numbers..................................................................................................................3-1
3-2 Recommended Crimp Tools..............................................................................................................3-1
3-3 Unit Power Loads..............................................................................................................................3-4
4-1 P3271 Pin Assignments.....................................................................................................................4-1
4-2 Aircraft Power Pin Assignments........................................................................................................4-2
4-3 Encoded Altitude Pin Assignments ...................................................................................................4-3
4-4 Discrete Input/Output Pin Assignments.............................................................................................4-4
4-5 RS-232 Input/Output Pin Assignments..............................................................................................4-5
A-1 Static Test Load................................................................................................................................A-1

Page vi GTX 32 Installation Manual
Revision F 190-00303-60
GTX 32 HARDWARE MOD LEVEL HISTORY
The following table identifies hardware modification (Mod) Levels for the GTX 32
Transponder. Mod Levels are listed with the associated service bulletin number, service bulletin date,
and the purpose of the modification. The table is current at the time of publication of this manual (see
date on front cover) and is subject to change without notice. Authorized Garmin Sales and Service
Centers are encouraged to access the most up-to-date bulletin and advisory information on the Garmin
Dealer Resource web site at www.garmin.com using their Garmin -provided user name and password.
MOD
LEVEL
SERVICE
BULLETIN
NUMBER
SERVICE
BULLETIN
DATE
PURPOSE OF MODIFICATION

GTX 32 Installation Manual Page 1-1
190-00303-60 Revision F
1GENERAL DESCRIPTION
1.1 Introduction
This manual presents mechanical and electrical installation requirements for installing the Garmin
GTX 32 Transponder as part of a Garmin Integrated Flight Deck.
The GTX 32 can also be incorporated as a remote mounted unit in installations with other compatible
control/display units such as the Garmin GNS 480 (CNX80).
The information in this manual is STC approved. Only the equipment interfaces covered in this manual
are within the scope of the STC. Other equipment may be suitable for use with the GTX 32 but additional
FAA approval may be required. After installation of the GTX 32 in an aircraft not covered by an airframe
manufacturer’s TC, FAA Form 337 must be completed by an appropriately certificated agency to return
the aircraft to service.
1.2 Equipment Description
The Garmin GTX 32 rack-mounted transponder 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 32 is equipped with
IDENT capability that activates the Special Position Identification (SPI) pulse for 18 seconds.
The GTX 32 replies to Mode A and Mode C interrogation. Mode A replies consist of framing pulses and
any one of 4,096 codes, which differ in the position and number of pulses transmitted. Mode C replies
include framing pulses and encoded altitude.
By replying to ground transmissions or TCAS interrogations, the GTX 32 enables ATC to display aircraft
identification, altitude and groundspeed on ATC radar screens or TCAS traffic indicators.
The GTX 32 is configured to be turned on by the aircraft avionics master bus. Transponder code entry
and function control are accessed through keys on the GDU Primary Flight Displays or the GNS 480
(CNX80).
The GTX 32 features transmit/receive RS-232 data ports. The unit concentrates data from gray code,
RS-232 input data and discrete inputs to the high-speed RS-232 data ports for display on the Garmin
Integrated Flight Deck displays. The unit is designed to feed all outgoing data via RS-232 data ports that
send and receive data to/from the GIA 63 Integrated Avionics Units (IAU) or GNS 480 (CNX80) display.
The GTX 32 can also be incorporated to act as the controller for a GDL 90.
Provision is made for unit software upgrade by means of RS-232 data through rear connector pins. In
installations where the transponder interfaces with a GNS 480 (CNX80) the installation of an optional
connector is highly recommended. If the optional connector is placed in the aircraft, transponder removal
and reinstallation for software upgrade is not required. The software can be changed while the unit is still
mounted inside the aircraft.

Page 1-2 GTX 32 Installation Manual
Revision F 190-00303-60
1.3 Mutual Suppression Pulses
Other equipment on board the aircraft may transmit in the same frequency band as the transponder, such
as DME or another transponder. Mutual suppression is a synchronous pulse that is sent to the other
equipment to suppress transmission of a competing transmitter for the duration of the pulse train
transmission. The transponder transmission is suppressed by an external source and other equipment on
board is suppressed by the GTX 32 transponder. This feature is designed to limit mutual interference.
1.4 Identification of Installed Equipment
The STC for the installation of a GTX 32 system in an aircraft may contain interfaces into the aircraft’s
existing equipment. This GTX 32 installation manual identifies an installation to include:
•GTX 32 Transponder
•Transponder Antenna
•Control and Display unit
•An Altitude Encoder
The STC includes all the data needed to support the installation of the GTX 32 in all the aircraft identified
on the AML. Although the interface to other equipment is present in the manual, the STC does not
include data for the installation of the Transponder Antenna, Control/Display, or Altitude Encoder. The
installation of the GNS 480 (CNX80) or GDU Multifunction Display, or any other interfaced equipment
is assumed to be covered under the aircraft original TC, another STC, or field approval and is not
modified by or covered under the GTX 32 STC.
1.5 Interface Summary
The GTX 32 provides the following interface connections via the rear connector:
•Ten (10) encoding altimeter inputs.
•Serial altitude output.
•External IDENT input.
•External STBY input.
•External suppression pulse input and output.
•Aircraft power input (14/28 Vdc).
•Switched power output of up to 1.5 amps (for digital altitude encoder power).
•Remote power turn on.
•Serial airdata or GPS groundspeed input.
•Serial altitude input. (Reduces wire count vs. parallel wire gray code altimeter interface.)
•Software update input.
•Outputs 4096 code and current operating mode to GDL90

GTX 32 Installation Manual Page 1-3
190-00303-60 Revision F
1.6 Technical Specifications
It is the responsibility of the installing agency to obtain the latest revision of the GTX 32 Environmental
Qualification Form. This form is available directly from Garmin under the following part number:
GTX 32 Environmental Qualification Form, Garmin part number 005-00174-02
To obtain a copy of this form, see the dealer/OEM portion of the Garmin web site (www.garmin.com).
1.6.1 Physical Characteristics
Characteristic Specification
G1000 Rack Width 1.71 Inches (43 mm)
G1000 Rack Height 6.30 Inches (160 mm)
Remote Mount Stand-Alone Rack Width 1.73 Inches (44 mm)
Remote Mount Stand-Alone Rack Height 6.85 Inches (174 mm)
Depth Including Connectors (measured from
face of unit to rear of connector backshells)
8.78 Inches (223 mm)
(G1000 and Remote Mount Rack)
GTX 32 Unit Weight 2.2 lbs. (1.00 kg)
GTX 32 Weight (Installed with G1000 rack
and connectors)
2.8 lbs. (1.27 kg)
GTX 32 Weight (Installed with remote mount
stand-alone rack and connectors)
3.4 lbs. (1.54 kg)
1.6.2 Electrical Specifications
Characteristic Specification
FCC Authorization Emission Designator 11M0M1D
Unit Software RTCA DO-178B Level D
Temperature Range -20°C to +55°C (Continuous Operation)
Altitude 55,000 Feet
Transmitter Frequency 1090 MHz ±1 MHz
Transmitter Power 125 Watts minimum, 150 Watts nominal at the antenna
through 1.5 dB coax.
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 63,000 feet
External Suppression Input Low ≤0.5 V; High ≥8 V

Page 1-4 GTX 32 Installation Manual
Revision F 190-00303-60
1.6.3 Power Requirements
Characteristic Specification
Input Voltage 14/28 Vdc See the Environmental Qualification Form
for details on surge ratings and minimum/maximum
operating voltages.
Power Input 15 Watts Typical, 22 Watts Maximum
Maximum Full TSO Reply
Rate; 1200 PRF, Code 7777
0.95 A @ 27.5 Vdc, 1.85 A @ 13.75 Vdc
Maximum Quiescent 0.50 A @ 27.5 Vdc, 0.90 A @ 13.75 Vdc
1.7 License 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 32 installation must comply
with current transmitter licensing requirements. To find out the specific details on whether a particular
installation is exempt from licensing, please visit the FCC web site http://wireless.fcc.gov/aviation.
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. The GTX 32
owner accepts all responsibility for obtaining the proper licensing before using the GTX 32.
CAUTION
The UHF transmitter in this equipment is guaranteed to meet federal communications
commission acceptance over the operating temperature range. Modifications not
expressly approved by Garmin could invalidate the license and make it unlawful to
operate the equipment.

GTX 32 Installation Manual Page 1-5
190-00303-60 Revision F
1.8 Certification
The conditions and tests required for TSO approval of this article are minimum performance standards. It
is the responsibility of those installing this article either on or within a specific type or class of aircraft to
determine that the aircraft installation conditions are within the TSO standards. TSO articles must have
separate approval for installation in an aircraft. The article may be installed only if performed under
14 CFR Part 43 or the applicable airworthiness requirements.
1.8.1 TSO/ETSO Compliance
Function TSO/ETSO Category
Applicable LRU
SW Part
Numbers
Airborne ATC Transponder
Equipment
TSO-C74c
ETSO-C74c Class 1A
006-B0125-00
and later
006-B0125-()
1.8.2 TSO/ETSO Deviations
None.
1.9 Reference Documents
The following publications are sources of additional information for installing the GTX 32. Before
installing the unit, the technician should read all relevant referenced materials along with this manual.
Part Number Document
190-00303-00 G1000 System Installation Manual
190-00303-04 G1000 Line Maintenance and Configuration Manual
560-0982-01 GNS 480 (CNX80) Installation Manual
560-1049-02 GDL 90 Installation Manual

Page 1-6 GTX 32 Installation Manual
Revision F 190-00303-60
1.10 Limited Warranty
This Garmin product is warranted to be free from defects in materials or workmanship for two years from
the date of purchase. Within this period, 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, provided that the customer shall be responsible for any transportation cost. 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.
Garmin retains the exclusive right to repair or replace the unit or software 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.
To obtain warranty service, contact your local Garmin Authorized Service Center. For assistance in
locating a Service Center near you, call Garmin Customer Service at one of the numbers shown below.
Products sold through online auctions are not eligible for rebates or other special offers from Garmin.
Online auction confirmations are not accepted for warranty verification. To obtain warranty service, an
original or copy of the sales receipt from the original retailer is required. Garmin will not replace missing
components from any package purchased through an online auction.
Garmin International, Inc. Garmin (Europe) Ltd.
1200 East 151st Street Liberty House, Bulls Copse Road
Olathe, Kansas 66062, U.S.A. Hounsdown Business Park
Phone: [phone] Southampton, SO40 9RB, U.K.
FAX: [phone] Phone: [phone]
FAX: [phone]

GTX 32 Installation Manual Page 2-1
190-00303-60 Revision F
2INSTALLATION OVERVIEW
2.1 Introduction
This section provides hardware equipment information for installing the GTX 32 Transponder, related
hardware and optional accessories. Installation of the GTX 32 should follow the data detailed in this
manual. Cabling is fabricated by the installing agency to fit each particular aircraft. The guidance of
FAA advisory circulars AC 43.13-1B and AC 43.13-2A, where applicable, may be found useful for
making retro-fit installations that comply with FAA regulations.
Refer to the G1000 System Installation Manual, Garmin part number 190-00303-00 for further details on
the mechanical aspects. For installation in an aircraft using the remote mounted stand-alone rack refer to
Appendix B for rack drawings and dimensions.
2.2 Installation Materials
The GTX 32 is available as a single unit under the following part numbers:
Item Catalog Part Number
GTX 32 (011-00768-00) 010-00265-00
2.2.1 Equipment Available
Each of the following accessories is provided separately for the GTX 32 unit and is required for
installation.
Item Garmin Catalog Part Number
G1000 Install Rack, GTX 32 115-00439-00
G1000 Nutplate Kit 011-00915-01 (preferred) or
011-01148-01
Or
GTX 32 Remote Stand-Alone Install Rack
(Alternate Configuration)
115-00628-00
Connector Kit, GTX 32 011-01013-00 (SPIDER) or
011-01013-01 (Shield Block)
Backplate Assembly, GTX 32 011-00677-01
Garmin Transponder Antenna kit* 010-10160-00
*Note: A transponder antenna approved to TSO C66( ) or C74( ) that has been installed to meet
the requirements of this manual may be used with the GTX 32.

Page 2-2 GTX 32 Installation Manual
Revision F 190-00303-60
2.2.2 Additional Equipment Required
The following installation accessories are required but not provided:
•Cables – The installer will supply all system cables including circuit breakers. Cable
requirements and fabrication is detailed in Section 3 of this manual.
•Hardware – #6-32 x 100° Flathead SS Screw [(MS24693, AN507R or other approved fastener)
(4 ea.)] for horizontal mounting.
•Hardware – #8-32 x 100° Panhead Machine Screw [(MS35206, AN526 or other approved
fastener) (4 ea.).] for vertical mounting of the remote stand-alone rack
•Encoding Altitude Digitizer – For GNS 480 (CNX80) installation. Use encoding altimeter
manufacturer’s instructions. The Garmin GAE 43 (Garmin P/N 013-00066-00) can provide
altitude data in either serial or parallel gray code format.
2.3 Installation Considerations
When installed as part of a Garmin Integrated Flight Deck system, the GTX 32 interfaces with
GIA 63/GIA 63W units. Optional available discrete line interfaces are shown in Section 4.4 Discrete
Inputs/Outputs.
In other system installations, the GTX 32 can interface with equipment including altimeters and Air Data
Computer (ADC). RS-232 provides a serial communication path between interfacing equipment.
Fabrication of a wiring harness is required.
Optional available discrete line interfaces are described in Section 4.4 Discrete Inputs/Outputs, and shown
in the Interconnect Drawings provided in Appendix C.
2.3.1 Preservation of Previous Systems
It is the installer’s responsibility to preserve the essential characteristic of the aircraft being modified with
this equipment to be in accordance with the aircraft manufacturer’s original design. This includes the
preservation of multiple power buses, which reduces the probability of interrupting power to essential
instruments and avionics.

GTX 32 Installation Manual Page 2-3
190-00303-60 Revision F
2.3.2 Antenna Location Considerations
Antenna mounting should utilize the aircraft manufacturer’s Type Certificated antenna location and style
of antenna. The antenna installation should be installed in accordance with AC 43.12-2A Chapter 3.
Note that penetration of the pressure vessel on the pressurized aircraft requires additional data not
contained in this manual (see Section 2.5).
Figure 2-1. Antenna Installation Considerations
A. The antenna (Garmin P/N 010-10160-00) or equivalent 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 affect the
radiation pattern.
B. The main antenna should be mounted vertically on the bottom 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 32.
NOTE
If the antenna is being installed on a composite aircraft, sufficient ground plane
material must 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.

Page 2-4 GTX 32 Installation Manual
Revision F 190-00303-60
2.4 Cabling and Wiring
Use MIL-W-22759/16 or other approved wire, AWG #24 or larger wire for all interface connections. The
standard pin contacts supplied in the connector kit are compatible with up to AWG #22 wire. In cases
where some installations have more than one unit sharing a common circuit breaker, sizing and wire
gauge is based on aircraft circuit breaker layout, length of wiring, current draw of units, and internal unit
protection characteristics. Do not attempt to combine more than one unit on the same circuit breaker
unless it is specified on aircraft manufacturer approved drawings.
In some cases, a larger gauge wire such as AWG #18 or #16 may be needed for power connections. If
using #16 or #18 barrel contacts, ensure that no two contacts are mounted directly adjacent to each other.
This minimizes the risk of contacts touching and shorting to adjacent pins or to ground.
Ensure that routing of the wiring does not come in contact with sources of heat, RF or EMI interference.
Check that there is ample space for the cabling and mating connectors. Avoid sharp bends in cabling and
routing near aircraft control cables.
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, including connectors.
The following table is for reference only, and lists some suitable cable types, along with the maximum
length based on an assumed loss figure of 0.2 dB per connector. Any 50 Ω, double shielded coaxial cable
assembly that meets airworthiness requirements and the 1.5 dB maximum loss figure (including
connectors) may be used.
Max. Length
(feet –[m])
Insertion loss
(dB/100ft)
ECS Type MIL-C-17 Type RG Type
6' 1.3" [1.86m] 18.0 M17/128-RG400 RG-400
7' 7.3" [2.32m] 14.45 3C142B
9' 2.0" [2.79m] 12.00 M17/112-RG304 RG-304
12' 6.0" [3.81m] 8.80 311601 M17/127-RG393 RG-393
15' 5.4" [4.71m] 7.12 311501
19' 9.4" [6.03m] 5.56 311201
30' 3.6" [9.24m] 3.63 310801
Supplier
Information
Vendor: Electronic
Cable Specialists
5300 W. Franklin
Drive
Franklin, WI 53132
Tel: [phone]
414-421-5300
Fax: [phone]
www.ecsdirect.com
See current issue
of Qualified
Products List
QPL-17.
RG types are
obsolete and
are shown for
reference only;
replaced by
M17 type
numbers.

GTX 32 Installation Manual Page 2-5
190-00303-60 Revision F
2.4.1 Cable Routing Considerations
When routing cables, observe the following precautions:
•All cable routing should be kept as short and as direct as practical.
•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 antenna cables near ADF antenna cable (allow at least a 12-inch separation).
2.5 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. Use of existing bulkhead
connectors previously approved by other means is permissible without additional approval.
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 options:
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.
Antenna installation in the pressure vessel of pressurized aircraft is beyond the scope of the GTX 32 STC.
Additional manufacturer’s data may be necessary and FAA approval may be required to cover the
installation of the antenna.
2.6 Cooling Air
Refer to the G1000 System Installation manual, Garmin part number 190-00303-00, for information on
cooling requirements. For remote mounted units, forced air cooling is not required. However, the
application of forced air cooling is recommended to provide beneficial cooling if the unit is located in a
confined space or near a source of heat.
A 5/8 inch air fitting is provided on the rear of the backplate for the purpose of admitting cooling air
under such conditions. If a form of forced air cooling is installed, make certain that rainwater or
condensation cannot enter and be sprayed on the equipment.

Page 2-6 GTX 32 Installation Manual
Revision F 190-00303-60
2.7 GTX 32 Mounting Requirements
The GTX 32 mounting surface must be capable of providing structural support and electrical bond to the
aircraft to minimize radiated EMI and provide protection from High-Intensity Radiation Fields (HIRF).
The GTX 32 can be mounted using the G1000 main system rack, or may be mounted remotely if desired.
Figure 2-2 shows the GTX 32 unit rack. The unit rack is fastened to the main system rack using the
nutplate kit listed in Section 2.2. Refer to Figure B-2, GTX 32 Rack/Connector Assembly Drawing, for
nutplate placement locations. The installer must provide any additional remote mounting equipment.
2.7.1 Remote Mounted Stand-Alone Rack Considerations
Figure 2-3 and Figure B-3 Sheets 1 & 2 show the GTX 32 remote mounted stand-alone rack. The remote
rack can be installed in a variety of locations, such as the electronics bay, under a seat or on an avionics
shelf behind the rear baggage area. Refer to Figure 2-4 for suggested location. Leave sufficient clearance
between the GTX 32 and any obstruction. Install the rack in accordance with AC 43.13-2A Chapter 2
“Radio Installations.” The rack should be mounted to a surface known to have sufficient structural
integrity to withstand additional inertia forces imposed by a 3.4-pound (1.54 kg) unit. If it is necessary to
build a shelf or bracket to mount the GTX 32 stand-alone rack or it is not certain that the chosen location
is of sufficient structural integrity, refer to Appendix A for validation of rack mounting structures and
determining static load capability.
Figure B-3 Sheet 2 gives the GTX 32 stand-alone rack dimensions. The rack can be mounted vertically
using four 8-32 pan head screws (MS35206, AN526 or other approved fastener). It can also be mounted
horizontally using four 6-32 100° counter-sunk flathead screws (MS24693, AN507R or other approved
fastener). Ensure that the GTX 32 chassis has a ground path to the airframe by having at least one
mounting screw in contact with the airframe. If more water-resistance is desired, the rack should be
installed in the upright vertical orientation only, otherwise, the rack may be mounted in either vertical or
horizontal orientation.
After the cable assemblies are made and wiring installed to the rack back plate, route wiring bundle as
appropriate. Use cable ties to secure the cable assemblies and coax to provide strain relief for the cable
assemblies.