Cessna TURBO CENTURION T210M 1978 Pilot Operating Handbook page 281

PILOT'S OPERATING HANDBOOK
SUPPLEMENT
SUPPLEMENT
CESSNA 400 ADF
(Type R-446A}
SECTION 1
GENERAL
CESSNA 400 ADF
(TYPE R-446A)
The Cessna 400 ADF is an automatic direction finder set which
provides continuous, visual bearing indications of the direction from
which an RF signal is being received. It can be used for plotting position,
for homing, and for aural reception of AM signals between 200 kHz and
1699 kHz. In addition, a crystal-controlled, beat frequency oscillator (BFO)
permits coded identifier of stations transmitting keyed CW signals (Morse
Code) to be heard.
The basic units of the Cessna 400 ADF are an R-446A Receiver with
dual frequency selectors, a goniometer-indicator (IN-346A), and sense and
loop antennas. The receiver and goniometer-indicator are panel-mounted
units. The sense and loop antennas are mounted on the external airplane
surfaces. Operating controls for the Cessna 400 ADF are mounted on the
receiver front panel. The goniometer-indicator presents station bearing in
degrees of azimuth. An automatic pointer-stow feature alerts the operator
to non-ADF operation by slewing the pointer to the 3:00 o'clock position
when the REC mode is selected.
The frequency range of the Cessna 400 ADF is electronically divided
into three bands: 200-399 kHz, 400-799 kHz, and 800-1699 kHz. Frequency
spacing within each band is in 1-kHz increments. The operating frequency
and band are selected by a four-section Minilever switch which displays a
digital readout of the frequency selected and supplies a binary code to
control the logic circuits within the set. A secondary (standby) operating
frequency is selected by another four-section Minilever switch. Frequency
control of the ADF is switched to the primary or the secondary operating
frequency by a toggle switch. The operating modes (ADF and REC) are
selected by individual pushbutton switches. Additional pushbutton
switches are used to select the BFO and to test signal reliability during
ADF operation. Operating controls for the Cessna 400 ADF are shown and
described in Figure
1.
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