Com Antenna Location - Garmin GTN 725 Installation Manual
Hide thumbs
Also See for GTN 725:
- Pilot's manual (554 pages) ,
- Cockpit reference manual (112 pages) ,
- Reference manual (110 pages)
Table of Contents
Advertisement
2.4.2
COM Antenna Location
The GTN COM antenna should be well removed from all projections, engines and propellers. The ground
plane surface directly below the antenna should be a flat plane over as large an area as possible (18"
square, minimum). The antenna should be mounted a minimum of six feet from any DME or other COM
antennas, four feet from any ADF sense antennas, and two feet from the GTN and its GPS antenna. The
COM antenna should also be mounted as far apart as practical from the ELT antenna. Some ELTs have
exhibited re-radiation problems generating harmonics that may interfere with GPS signals. This can
happen when the COM (GTN or any other COM) is transmitting on certain frequencies such as 121.15 or
121.175 MHz, which may cause the ELT output circuit to oscillate from the signal coming in on the ELT
antenna coax.
If simultaneous use of two COM transceivers is desired (split-COM or simul-comm), use of the TX
interlock function is mandatory. In addition, the COM antennas should be spaced for maximum isolation.
A configuration of one topside antenna and one bottom side antenna is recommended.
Page 2-8
GTN 725/750 TSO Installation Manual
Rev. A
190-01007-02
Advertisement
Table of Contents
