ATR833S / P/N 833S-(Cxxx)-(Cxxx)
Operation and Installation
43
Document-Nr.: 01.142.010.71e / Revision:1.03
4.7.3.3 Connector EXT-NF for Monaural Audio Input
This connector is used for the input of monaural audio signals. It can be
used e.g. for acoustic traffic warnings, for radio navigation receiver’s
acoustic identifiers, or for input of music into the headsets.
The priority of radio reception in relation to this input can be configured
as described in section 3.5.
4.8 Antenna
4.8.1 Antenna Selection
A VHF-COM-Antenna with an impedance of 50 Ohm is required.
Choose an antenna type approved for the aircraft and the mounting
location.
The antenna should be located far away from ELT-antennas and
other VHF antennas.
Specified features depend on proper installation of the antenna.
4.8.2 Installation Recommendation
Take note of the antenna manufacturer’s instructions.
The metallic contact between the aircraft surface and antenna-GND
must be very good. On non-metallic airplanes a metal foil (min. 80 cm
x 80 cm) shall be used as electrical counterweight on the inside of the
fuselage.
To avoid a mutual interference of the radios, the antenna isolation
between a voice transmission and a navigation antenna as well as
between double COM antennas should be as large as possible. A
distance of 2 meters usually is sufficient.
Assemble the antenna in a vertical position on or under the fuselage
that it is as far distant as possible from all protruding parts (propeller,
chassis, vertical stabilizer)
For glider installation the internal antenna installed by the
manufacturer should be used.
The SWR shall not exceed 3:1.
