Embraer EMB145, Operation Manual

Page: 2355 / 2662

AIRPLANE
OPERATIONS
MANUAL
NAVIGATION AND
COMMUNICATION
JUNE 29, 2001
2-18-21
Page
3
Code
02
HF NORMAL OPERATION
There are two types of operation:
- Discrete frequency tuning.
- Programmable channel.
DISCRETE FREQUENCY TUNING OPERATION
In the discrete frequency mode of operation, the user may directly tune
any one of 280,000 frequencies over the range of 2.0 to 29.9999 MHz.
1 - Access discrete frequency operation.
Apply power to the system by rotating the volume (V) knob
clockwise from the OFF position. Wait for about two minutes, until
the system has warmed up. Until then, no frequency is displayed.
Make sure that the FREQ/CHAN button is depressed, in the FREQ
position. Confirm this by seeing that no channel number is
annunciated in the frequency display. If the button is pressed, a
momentary press unlatches it and engages FREQ (direct tune)
operation.
2 - Select the transmission mode.
Press the mode button to select the transmission mode (USB, LSB
or AM).
3 - Enter the frequency.
Each digit in a frequency is selected individually. The large
concentric knob on the lower right of the control unit may be rotated
in either direction and causes one of the displayed frequency digits
to flash. This flashing “cursor” indicates which frequency digit will be
changed by rotating the smaller concentric knob. Rotate the larger
knob until the digit you wish to change flashes, and then select the
desired number into view by rotating the smaller knob.
4 - Tune the antenna.
Momentarily key the PTT to initiate the antenna coupler tuning
cycle. During the tuning process the TX annunciator will flash and
the frequency numbers will blank. When the TX stops flashing and
the frequency reappears , the antenna tuning cycle is complete and
you are ready to transmit on the selected frequency.