Section 923
GARMIN GTX 328 Transponder
Page Date: 5. December 2008
923 - 3
Pilot´s Operating Handbook
EXTRA 300L
923.1
GENERAL
The Garmin GTX 328 panel mounted Mode S VFR Transponder is a radio transmitter and receiver
that fulfills the role of the airborne beacon equipment according to the requirements of the Air Traffic
Radar Beacon System (ATCRBS). Its functionality includes replying to ATCRBS Mode A and C
and Mode S interrogations. The Mode S function will allow the ground station to individually select
the aircraft by its Aircraft Address assigned to the aircraft by the aviation agency.
It operates on radar frequencies, receiving ground radar interrogations at 1030 MHz and transmitting
a coded response of pulses to ground-based radar on a frequency of 1090 MHz. The GTX 328 is
equipped with IDENT capability that activates the Special Position Identification (SPI) pulse for 18
seconds. Mode S transmit/receive capability also requires 1090 MHz transmitting and1030 MHz
receiving for Mode S functions.
In addition to displaying the code, reply symbol and mode of operation, the GTX 328 screen will
display pressure altitude and timer functions. The displayed pressure altitude may not agree with
the aircraft’s baro-corrected altitude under non standard conditions. The unit also features flight
timers.
The Traffic Information Service (TIS) is not available in this installation.
N O T E
The GTX 328 owner accepts all responsibility for obtaining the proper license before
using the transponder.
The coverage you can expect from the GTX 328 is limited to „line of sight“. Low altitude or aircraft
antenna shielding by the aircraft itself may result in reduced range. Range can be improved by
climbing to a higher altitude. It may be possible to minimize antenna shielding by locating the
antenna where dead spots are only noticed during abnormal flight attitudes.
N O T I C E
Damage possible due to current peaks.
The GTX 328 should be turned off before starting or shutting down aircraft engine.
The GTX 328 Transponder is automatically powered on by the respective
AVIONIC MASTER
switch
or when previously manually powered off while
AVIONIC MASTER
switch is on by pressing the
STBY
,
ALT
or
ON
keys. After power on, a start-up page will be displayed while the unit performs
a self test.
This supplement is written for software version 5.00 or later, and is not suitable for earlier software
versions. Some differences in operation may be observed when comparing the information in this
supplement to later software versions.
Verify the information herein with the GTX 328 pilot's guide (PN 190-00420-03 applicable revision)
you received with your transponder. There you find also further information.
Page Date: 5. December 2008
Page Date: 20. January 2016
Summary of Contents for 300L
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