VHF COMMUNICATIONS
The primary voice communication system
with air traffic controllers or other aircraft
consists of two VHF radios (VHF 1 and 2). The
VHF radios provide short-range AM voice
communication in the frequency range of
118.000 to 151.975 MHz.
Each VHF radio system consists of an antenna
(Figure 16-1), a transceiver, and a control unit
(Figure 16-3). Separate antennas and dual
channels allow backup capabilities for VHF
transmission and reception. Located in the
nose compartment, the transceiver receives
signal input from the antenna and provides
voice output to the audio integrating system.
The flight crew may manually select VHF fre-
quencies with the VHF control panel or the
FMS. The flight crew may also select any of
six preset frequencies stored in the VHF con-
trol panels memory. Pressing the test button
starts a built-in-test routine.
16-4
CL 601-3A/R
FOR TRAINING PURPOSES ONLY
FlightSafety Canada
L t é e
L t d .
CL-600-2B16 PILOT TRAINING MANUAL
MEM
COM
MEM
RMT
TX
Collins
A
C
T
XFR
STO
TEST
ACT
SQ
OFF
OFF
ON
V
RMT ANNUNCIATOR
INDICATES WHEN THE VHF
COMMUNICATION SYSTEM IS REMOTELY
TUNED. NOT USED IN THIS INSTALLATION.
ACTIVE ANNUNCIATOR
FLASHES WHILE THE ACTIVE FREQUENCY
IS CHANGED. CONTINUES TO FLASH IF THE
ACTUAL FREQUENCY DIFFERS FROM THAT
SHOWN ON THE DISPLAY.
PRESET FREQUENCY DISPLAY
DISPLAYS THE PRESET (INACTIVE)
FREQUENCY, DIAGNOSTIC MESSAGES,
AND MEMORY CHANNEL FREQUENCIES.
MEM ANNUNCIATOR
INDICATES WHEN A STORED FREQUENCY
IS DISPLAYED IN THE LOWER DISPLAY.
VOLUME CONTRO
L
CONTROLS THE RECEIVER AUDIO LEVEL.
MODE SELECTOR
ON AND OFF POSITIONS SWITCH
SYSTEM POWER. SQ OFF POSITION
DISABLES THE RECEIVER SQUELCH.
AUTOMATIC DISPLAY DIMMER SENSOR
AUTOMATICALLY CONTROLS THE
DISPLAY BRIGHTNESS.
ACTIVE FREQUENCY DISPLAY
DISPLAYS THE ACTIVE FREQUENCY,
DIAGNOSTIC MESSAGES, AND MEMORY
CHANNEL NUMBERS.
TRANSFER/MEMORY RECALL SWITCH
IN THE XFR POSITION, THE DISPLAYED
PRESET FREQUENCY BECOMES THE
ACTIVE FREQUENCY AND THE
TRANSCEIVER RETUNES. IN THE MEM
POSITION, ONE OF THE SIX MEMORY
FREQUENCIES IS LOADED INTO THE
PRESET DISPLAY. SIX OPERATIONS
OF THE SWITCH CYCLE ALL MEMORY
FREQUENCIES THROUGH THE DISPLAY.
TRANSMIT ANNUNCIATOR
INDICATES THAT THE TRANSCEIVER
IS TRANSMITTING.
FREQUENCY SELECTORS
SELECTS THE ACTIVE OR PRESET
FREQUENCY. THE OUTER KNOB
CHANGES TWO DIGITS TO THE LEFT OF
THE DECIMAL POINT IN 1-MHZ STEPS.
THE INNER KNOB CHANGES THE TWO
DIGITS TO THE RIGHT OF THE DECIMAL
POINT IN 50-KHZ STEPS, OR IN 25-KHZ
STEPS AFTER THE DIRECTION OF
ROTATION IS REVERSED.
ACTIVE PUSHBUTTON
ENABLES THE FREQUENCY SELECT
CONTROLS TO DIRECTLY RETUNE THE
TRANSCEIVER ACTIVE FREQUENCY.
DELETES THE PRESET FREQUENCY
DISPLAYS WHILE DIRECT TUNING
IS IN PROGRESS.
STORE PUSHBUTTON
ALLOWS UP TO SIX PRESET
FREQUENCIES TO BE
SELECTED AND STORED IN
THE CONTROL UNIT MEMORY.
SELF-TEST PUSHBUTTON
INITIATES THE TRANSCEIVER
SELF-TEST DIAGNOSTIC
ROUTINE.
CENTER PEDESTAL
Figure 16-3. VHF Control Unit