Cessna 152 - Page 223

PILOT'S OPERATING HANDBOOK
SUPPLEMENT
CESSNA 400 TRANSPONDER
AND ALTITUDE ENCODER (BLIND)·
SUPPLEMENT
CESSNA 400 TRANSPONDER
(Type RT-459A}
AND
OPTIONAL ALTITUDE ENCODER (BLIND)
SECTION 1
GENERAL
The Cessna 400 Transponder (Type RT-459A), shown in Figure 1, is
the airborne component of an Air Traffic Control Radar Beacon System
(ATCRBS), The transponder enables the ATC ground controller to "see"
and identify the aircraft, while in flight, on the control center's radar-
scope more readily.
The Cessna 400 Transponder system consists of a panel-mounted unit
and
an externally-mounted antenna. The transponder receives interroga-
ting pulse signals on 1030 MHz and transmits pulse-train reply signals
on 1090 MHz. The transponder is capable of replying to Mode A (air-
craft identification) and also to Mode C (altitude reporting) when coupled
to an optional altitude encoder system. The transponder is capable of re-
plying on both modes of interrogation on a selective reply basis on any of
4, 096 information code selections. The optional altitude encoder system
(not part of a standard 400 Transponder system) required for Mode C
(altitude
reporting) operation, consists of a completely independent remote-
mounted digitizer that is connected to the static system and supplies en-
coded altitude information to the transponder. When the altitude encoder
system is coupled to the 400 Transponder system, altitude reporting
capabilities are available in 100-foot increments between -1000 feet and
the airplane's maxi.mum service ceiling.
All Cessna 400 Transponder operating controls are located on the
front
panel of the unit. Functions of the operating controls are described
in Figure 1.
1 July 1978
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