Garmin GTX 330 Installation Manual page 17

A. The antenna(s) (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. The optional
second (diversity) antenna should be mounted vertically on top of the aircraft. Horizontal
separation must be no more than 7.6 meters (25 feet).
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.
If the antenna is being installed on a composite aircraft, ground planes must be
considered. 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.
GTX 330 Installation Manual
190-00207-02
Figure 2-1. Antenna Installation Considerations
NOTE
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Revision G