PRIMUSr 1000 Integrated Avionics System
A28--1146--112--00
PRIMUS
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II Radio System
C--26
Annunciation Mode
BFO
ADF adds a beat frequency oscillator for
detection of cw signals.
VOICE
Maximum audio clarity and fidelity. No bearing
determination.
ADF Modes
Table C--6
Part of a dual bandwidth design, the VOICE mode transmits high
quality audio in the pilot headsets or cabin speakers. The high
quality audio comes from the wider bandwidth that is activated by
selecting VOICE. Direction finding requires narrow band reception
for bearing resolution.
NOTE: Because the VOICE mode has a wider audio bandwidth,
it is possible to have some beat frequency interference
when listening to an ADF station within 3 kHz of another
ADF station. This interference can be eliminated by
selecting the ANT mode.
D Frequency/Mode Select (TUNE) Knobs -- The TUNE knobs are
usedtoselecttheADFoperatingfrequency(whenthe yellow cursor
surrounds ADF frequency line) and can also be used to select the
ADF operating mode (when the yellow cursor is surrounding the
ADF mode line.)
Turning the knob clockwise raises the frequency, and
counterclockwise decreases the frequency. The large outer knob
functionsin10kHzincrements;thesmallinnerknobin.5kHzsteps.
Slow knob movement produces slow frequency change. Rapid
turning, causes a several step jump, proportional to twistingspeed.
Large frequency changes can be tuned quickly using a quick
twisting motion.
D ADF Frequency STO Button -- The RMU can store an ADF
frequency. This is done by selectingthe desiredfrequency andthen
pushing the STO button on the RMU while the cursor is still on the
ADFfrequency.Toretrievethestoredfrequencyfrommemory,push
and hold the frequency select key for three seconds.
ADF OPERATION WITH HF TRANSMITTERS
When an HF COM is keyed, the ADF receiverfreezestheADFbearing
needles.AftertheHFtransmitscontinuouslyfor5seconds,thereceiver
”parks” the ADF bearing needles of electromechanical indicators at a
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