KT70 Mode S Transponder
Panel design
Components and PCB
PCB, using the opencockpits 7-segment display holders in my own PCB.
PCB with the opencockpit 7-segment display holders
Transparency sheet that will cover the 7-segment display and the leds
Components (roughly) in place
Design
PCB Design (draft)
Print of design and components
Functions of the KT 70
Real KT70
Picture of Real KT70
Restyled and equipped with enhanced backlighting and controls, the
Bendix/King Silver Crown Plus KT 70 Mode S transponder also offers Mode A and
Mode C compatibility. Identical in appearance, the Silver Crown Plus KT 71 Mode
A/C transponder is a cost-effective alternative.
Functions
IDENT BUTTON – Marked
IDT, the KT 70/71’s Ident button is pressed when ATC requests an “Ident”
or “Squawk Ident” from your aircraft.
ID CODE – The
ATCRBS Transponder Identification code (squawk code) for the aircraft is
displayed inthe Ident Window on the right side of the display. Each
of the four Transponder Code Selector Knobs selects a
separate digit of the identification code.
REPLY– The lighted
“R” reply indicator blinks when the transponder is replying to a valid
interrogation.
ALTITUDE DISPLAY–
The KT 70 and KT 71 display Flight Level Altitude, marked
by the letters “FL” and a number in hundreds of feet.
VFR – The VFR
Pushbutton recalls the preprogrammed VFR code, superseding whatever code was
previously entered.
FUNCTION SELECTOR KNOB –
The Function Selector Knob enables you to choose from among the following
operating modes:
OFF– The unit is not
receiving power.
SBY (STANDBY) – In
Standby, the KT 70 and KT 71 are energized but are inhibited from replying
to any interrogation.
TST (TEST) – Replies
are disabled in test mode, and the unit illuminates all segments of the display
for at least four seconds. A series of internal tests is
performed to check the KT 70/71’s integrity, verifying all EEPROM data and
making hardware and squitter checks.
GND (GROUND) – In the
KT 71, all interrogations are inhibited. In the KT 70, Mode A & C
interrogations are inhibited, but the KT 70 will reply to
all valid Mode S interrogations. An optional remote
“air/ground” switch may be installed on the aircraft’s
landing gear strut to keep the KT 70 and KT 71 in the GND
mode until the airplane is airborne.
ON– The KT 70 is able
to reply to all valid Mode A, C and S interrogations (Mode A and C on the KT
71); however, altitude information is suppressed.
ALT – In the “ALTITUDE”
mode, the KT 70 replies to all valid Mode A, C and S interrogations (Mode
A and C on the KT 71).
