GTX 327 Installation Manual
Page 2-3
190-00187-02
Revision K
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 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 327.
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.
2.4.2 Antenna Installation
Install the antenna according to the antenna manufacturer’s instructions and FAA AC 43.13-1B and
AC 43.13-2A.
2.5
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
, double shielded coaxial cable
assembly that meets airworthiness requirements and the 1.5 dB maximum loss figure (including
connectors) may be used.
