COMMUNICATIONS, UHF COM
Description
Aircraft Operations Manual
4/6.1
O
PAGE
1
Apr 01/15
1.
GENERAL
The Bendix/King KTR 909B UHF communication
system is a two
−
way voice communication system.
It is amplitude modulated in the 225.000 to 399.975
MHz frequency range with 25 kHz frequency spac-
ing.
System utilization is through the Audio Integrating
System.
2.
MAIN COMPONENT AND SUBSYSTEMS
2.1
UHF Transceiver
The UHF transceiver is located in the Avionics
Rack.
It contains two receivers with the second receiver
fixed at the internationally recognized 243.000 MHz
emergency frequency. The transceiver allows conti-
nuos monitoring of that frequency while simulta-
neously receiving on the tuneable main receiver.
The operating frequency may be set manually or by
a preprogrammed channel.
2.2
UHF control unit
The UHF control unit is located in the center pedes-
tal in the cockpit. It provides channel, frequency and
mode selections. The transceiver power ON/OFF is
also controlled by the control unit.
2.3
Antenna
The transmitting and receiving is through a com-
bined VHF/UHF antenna mounted on the bottom of
the aircraft.
Antenna
UHF COM
Transceiver
Selected
frequency
Control
Unit
Audio Integrating System
Digital Flight Data Recorder
Cockpit Voice Recorder
Fig. 1 UHF COM
−
schematic