Cabling And Wiring - Garmin GTX 33 Installation Manual

2.4 Cabling and Wiring

Refer to the interconnect examples in Appendix D for wire gauge guidance.
For special installations that require the use of #18 or #20 AWG wire for power connections, the provided
connector kit supplies extended barrel contacts for AWG #18 wire. Special thin-wall heat shrink tubing is
also provided to insulate the extended barrels inside the backshell. If using #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 and 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 GTX 33 and GTX 33D back-plate assemblies utilize BNC-type (bayonet connection) coaxial
connectors. The GTX 33H and GTX 33DH back-plate assemblies utilize TNC-type (threaded connection)
coaxial connectors.
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. In the
diversity installation the cable loss characteristics must be the same within ±0.1 dB (cables within 4 inches
of the same length will have less than 0.1 dB difference in their loss characteristics).
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 Insertion loss
(feet - [m])
6' 1.3" [1.86m]
7' 7.3" [2.32m]
9' 2.0" [2.79m]
12' 6.0" [3.81m]
15' 5.4" [4.71m]
19' 9.4" [6.03m]
30' 3.6" [9.24m]
Supplier
Information
190-00906-00
Rev. F
Table 2-3. GTX 33 Cabling and Wiring
Carlisle IT Type
(dB/100ft)
18.0
14.45
12.00
8.80
7.12
5.56
3.63
Vendor: Carlisle
Interconnect
Technologies
100 Tensolite Drive
St. Augustine, FL
32092
Tel: 800-458-9960
904-829-5600
Fax: 904-829-3447
www.carlisleit.com
MIL-C-17 Type
M17/128-RG400
3C142B
M17/112-RG304
311601 M17/127-RG393
311501
311201
310801
See current issue
Qualified
Products List
QPL-17
RG Type
RG-400
RG-304
RG-393
RG types are
obsolete and
of are shown for
reference only;
replaced by
M17 type
numbers.
GTX 33 Installation Manual
Page 2-5