Operating Instructions
Becker Avionics
Safety-Conscious Utilization
14
VHF Transceiver 0638.420-071 Issue 06 02/2021
•
Excessive pulses on the DC bus of the aircraft can cause
damage on electrical circuits of any installed instrument.
•
Do not turn on the device during engine start or shutdown.
First make a voice communication test before starting any
operation.
•
Please notice that, if the communication test is done close to a
ground station, the results may be positive even if the antenna
cable is broken or short-circuited.
Caution!
Then a communication could be not possible at a
distance of 5...10 km and above.
•
Speak always loud, clear and not too fast for optimal voice
communication.
•
Keep the microphone always close to the lips otherwise a
special suppressing circuit in the VHF COM will not be capable
to suppress normal noise.
•
Use only microphones or headsets which are suitable for
specific installations.
o
In aircraft made of wood, synthetic materials or in gliders
or helicopters, incoming radiation can affect the
integrated amplifier of the microphone (feedback), then
the ground station receives a whistling and/or heavy
distortion.
•
If the power supply voltage is less than the adjusted threshold,
the display shows the message "LOW BATT".
•
If the power supply voltage is < 10.25 V, the device continues
operation with decreased performance.
o
The speaker output of the transceiver is automatically
turned "OFF"
o
The speaker symbol is no longer shown.
o
The user must use headphones to continue listening.
•
If power supply voltage is < 9.0 Volt, the device turns off
automatically.
