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ADF Tuning and Mode Control
ADF operation is the same as COM and NAV
tuning in that depressing the line select key be-
side the ADF frequency will place the cursor
over the frequency to be changed (Figure 16-
12). Rotating the small tuning knob slowly
will advance the frequency in 0.5 kHz steps.
This change will increase to 10 kHz steps
when the large knob is used. The rate at which
the frequency changes is dependent upon and
proportional to the speed at which the knobs,
small or large are rotated.
The RMU has the capacity to store one ADF
frequency in memory. This is accomplished by
selecting the desired frequency, then de-
pressing the STO function key at the bottom
of the RMU. To retrieve this stored frequency
from memory, the frequency line select key
must be depressed for 2 to 3 seconds.
ADF modes are also controlled within the
ADF window. Repetitively depressing the line
select key adjacent to the ADF mode annun-
ciation will step through the available ADF
modes of operation. This can also be accom-
plished by placing the cursor over the mode
annunciation, and using the tuning knobs to
step up or down through the available modes.
The ADF operating modes are as follows:
•
ANT
- ADF audio signal only.
•
ADF
- ADF receives signal and calcu-
lates the relative bearing to the station.
•
BFO
- ADF adds a beat frequency oscil-
lator for reception of CW (carrier wave)
signals.
•
VOICE
- ADF opens the IF bandwidth for
better aural reception. Not used for nav-
igation.
Single ADF installations operate the same as
dual configurations except that the ADF win-
dow annunciator does not identify a side num-
ber. With a single ADF, the frequency and
mode can be selected on the main tuning page
of either RMU.
Transponder/TCAS
Transponder operation is similar to COM/NAV
operation in that depressing a line select but-
ton beside the function desired will move the
cursor to that location. Those airplanes with-
out TCAS installed will have an ATC legend
at the top of the transponder window, and
t h o s e e q u i p p e d w i t h T C A S w i l l h av e
ATC/TCAS labeled above the window.
Either transponder 1 or 2 can be selected for
use and controlled by either RMU. A number
1 or 2 will appear in front of the transponder
mode in the ATC window on both RMUs in-
dicating which transponder has been selected.
Transponder side selection is toggled by de-
pressing the 1/2 button on either RMU with the
cursor anywhere within the ATC/TCAS win-
dow, and the transponder in an operating mode
(not in standby mode).
Since only one transponder can operate at a
time, both RMUs will display the same in-
formation. Therefore, if a code or mode is
changed on one RMU, the other RMU will
echo the change. To illustrate which RMU ini-
tiated the change, the echoed change will be
displayed in yellow.
The RMU has a lockout function which pre-
vents both transponders from operating at the
same time. During normal operation, one
transponder will be in STANDBY at all times.
The transponder is switched from standby to
an operating mode by depressing the line se-
lect key adjacent to the MODE line. Once the
cursor has been selected, the mode line select
key acts as a toggle to switch the transponder
between the standby mode and the active mode.
For example, if the ALT ON mode is selected,
repeatedly depressing the mode select line
key will toggle the transponder between STBY
and the ALT ON mode.
Once the transponder is in the ALT ON mode,
the mode of operation is changed using the tun-
ing knobs (cursor must be over the operating
mode field). The active mode of operation can
then be changed by rotating the concentric
L E A R J E T 4 5
P I L O T T R A I N I N G M A N U A L
16-19
FOR TRAINING PURPOSES ONLY
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