Tear off this section along this line and fold in center for use as convenient Pilot's Operating Cuide.
Operating your KMA 20
Audio Control System
Microphone Selector Switch
AUTO Switch
Receiver Selector Switches
Marker Beacon Sensitivity
| and Lamp Test Switch
/ SPEAKER ~ MKR
AUTO COMI COM? NAVI NAV? ADF DME MER) WI
Marker Beacon Lights
MICROPHONE
TRANSMISSION CONTROL
Rotary switch at left end of
faceplate connects microphone to
either COMM 1 or COMM 2 VHF
transmitter, the external ramp hailer,
or cabin address system. When you
press the mike button, the output of
all aircraft receivers is electronically
muted so there is no cockpit
feedback in your transmission.
EXT position of switch allows
microphone use in cabin address
system, ramp hailer or pilot-copilot
intercom. Any one of these systems
can be accommodated by the KMA
20. If you are listening to an incom-
ing signal while the microphone
selector switch is tumed to EXT, the
signal will also be carried to the EXT
speaker. However, as soon as you
lL]: TEST
KMA 20 TSO
Ambient Light Sensor
press the mike button to transmit,
the received signal is muted and
undesirable feedback is eliminated.
AUDIO RECEPTION CONTROL
You can pre-tune seven aircraft
receivers and listen to any of them at
will. Simply flip the appropriate
toggle switch— COMM 1, COMM 2,
NAV 1, NAV 2, ADF, DME or
Marker Beacon (MKR).
Middle switch position is OFF,
upper position is SPEAKER and
lower position is PHONES. The pilot
can be listening to one radio on the
speaker while copilot listens to
another on the headphones, without
confusion.
The Isolation/Speaker
Amplifier automatically raises signal
strength to the level necessary to
drive the speaker. During
headphone reception the amplifier is
bypassed, and the headphones are
connected directly to the selected
receiver.
AUTO SWITCH
Using this switch automatically
matches the appropriate COMM
receiver to the transmitter selected.
Put both COMM receiver
toggle switches on OFF. Set AUTO
to either SPEAKER or PHONE,
whichever you want to listen to.
Now you will automatically hear the
receiver of the COMM transmitter
selected as you change the rotary
COMM 1/COMM 2 transmitter
selector switch back and forth. No
need to manipulate the COMM
receiver toggle switches during
these changes.
MARKER BEACON RECEIVER
A complete Marker Beacon
superheterodyne Receiver is built
into the KMA 20. This radio is
crystal-controlled at 75 MHz for
stability and selectivity.
When you pass over an airway
marker or runway threshold, the
lefthand or white lamp on the
faceplate (or remote-mounted KA
40 Adapter) will illuminate. This
lamp is further identified by “A”
(Airway) engraved on the lens. A
light sensor automatically regulates
intensity of the light to conform to
the ambient cockpit lighting
conditions. (Brighter during the day;
dimmer at night.)
A 3,000 Hz tone from an
Airway Marker is also received on
the Marker Beacon audio, and can
be routed to speaker or phones by
the MKR toggle switch.
“Outer” markers are identified
by flashes on the center or blue
lamp (lettered 0"), on and off at
the rate of two cycles per second.
The audio signal is a series of 400
Hz dashes, also at a rate of two per
second. Outer markers are normally
positioned on the front localizer
course near the point where the
glideslope approach path intersects
the minimum inbound altitude,
at a distance of 4 to 7 miles from
the runway.
“Middle” markers are normally
located on the front localizer course
about 3,200 feet from the approach
end of the ILS runway. This marker
is identified by alternating dots and
dashes in a 1,300 Hz tone, and
flashes from the righthand amber
“MT (Middle) lamp.
The HI-LO/TEST toggle switch
is the Marker Beacon Sensitivity and
lamp test switch. HI sensitivity
greatly enlarges the area in which
the marker signal can be received.
With the sensitivity control on
HI, the aural tone will begin about
one mile from the outer marker. At
this point the pilot may switch to LO
sensitivity which permits more
precise detection of the center of the
marker. Descent on the glideslope
normally begins when the lamp
indicates actual passage over the
outer marker and the glideslope
is intersected.
Audio control is a basic cockpit
management tool
Incoming signals from COMM 1,
COMM 2 NAV 1, NAV 2. ADF, DME
or Marker Beacon Receiver are routed
to either speaker or headphones by
simple, three-position toggle switches.
The pilot can listen to one radio on the
speaker while the copilot listens to
another on the headphones.
A selector switch connects the
microphone to either COMM 1 or
COMM 2 transmitter. Or a ramp
hailer, cabin address system or
pilot-copilot intercom may be
selected. (The International models of
the KMA 20 uses the third COMM
selector position to provide for HF
transceiver operation.)
A separate “AUTO” switch is
provided to automatically match
the incoming signal from COMM 1
or COMM 2 receiver with the
transmitter selected.
The Isolation Amplifier
Input power levels of all radio
receivers selected are amplified to the
level necessary to drive a 4 ohm ora 9
ohm speaker, with 40 db of isolation
between each receiver channel,
eliminating cross-talk. An electronic
muting circuit automatically mutes
output of all receivers when the
microphone button is pressed, so
there is no cockpit feedback in
the transmission.
Marker Beacon is built in
A crystal-controlled
superheterodyne Marker Beacon
Receiver is incorporated in the unit. Its
excellent selectivity provides freedom
from interference by FM or TV
stations. A 3-light presentation with
colored lenses is built into the
faceplate. Dimming circuitry for the
marker lamps automatically adjusts
lamp brilliance to the cockpit ambient
light level. A HI-LO sensitivity and
lamp test switch is located at the
extreme right end of the KMA 20
faceplate.
If the KMA 20 location is not
convenient for viewing the Marker
Beacon lights, these lights can be
remote-mounted, either horizontally
or vertically, by using a King KA 40
Remote Light Adapter, which is wired
to use the Marker Beacon Receiver in
the KMA 20.
The KR 21 self-contained
Marker Beacon Receiver
If a separate TSO'd 3-light marker
receiver is desired, the King KR 21
provides all marker beacon functions
of the KMA 20. An audio amplifier
provides an audio output for headset
operation. The KR 21 can be
mounted either vertically or
horizontally.
Both KMA 20 and KR 21 are
designed to operate on either 13.75v
or 27.5v current.
Performance Specifications
Design: Self-contained, panel-mounted. All solid-state.
No moving parts. TSO'd.
Power Requirements: Idle, 300 ma @ 13.75V: 150 ma
(a 27.5V. Operating, 1.1 AMP
either voltage.
W (15.88 cm) x 1.6'H (4.06 cm) x 6.29''D
8 cm)
31
Size:
3
6.25’
(15.
ht:
Weight
.
bs. (1.04 kg).
MARKER BEACON RECEIVER
(internal or separate KR 21)
Selectivity: 6 db at + 10 kHz.
60 db at 575 kHz.
Sensitivity: Low: 2.000 uv for lamp threshold.
High: 500 uv for lamp threshold.
це.
Frequency: 75 MHz crystal-con
AGC Characteristics: [ ess
9
2
output level when th le
varied from lamp threshold to
2,000 uv.
Duty Cycle: Continuous.
Input Impedance: Designed to match 50 ohm antenna
(KA 23).
Output: Capable of 10 milliwatts into Isolation Amplifier
input of 500 n. Factory adjusted to 1.0 VRMS at
Isolation Amplifier input.
AUDIO ISOLATION AMPLIFIER
INDUTS: 2 transceivers, 4 external receivers (International
Model. 3 transceivers, 4 ext. receivers).
input impedance: 500 ohms.
input isolation: 40 db between input cha
Input Muting: 40 db or better when a transmitter is
О keyed.
speaker Output: 6.25 watts at either 4 ohms or 8 ohms
speaker output. 13.75V. 8 watts capa-
bility (2 27.5V.
Distortion: Less than 10% at rated output.
Frequency Response: Within 6 db from 350 Hz to
3,000 Hz.
TSO Compliance: TSO C50b Env. Cat
NINAS Le \’.
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Prema
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111015.
utput
KA 40 REMOTE LIGHT ADAPTER
Size: 3.2''W (8.13 cm) x1.05"H (2.66 cm) x 2.56"'D (6.5
cm), including rear connector.
Weight: 0.25 Ib. (.113 kg).
Power Requirements: Derives power from KMA 20,
125 ma for each lamp.
TSO Compliance: TSO C35c, Env. Cat. DACAAAX.
KR 21 MARKER BEACON RECEIVER
Design: Panel-mounted, 3-light, TSO'd Marker Beacon
radio receiver. All solid-state. No moving parts.
High/Low sensitivity and lamp test switch.
Lights automatically adjust to cockpit light levels.
Input impedance: Designed to match 50 ohm antenna.
Output: Capable of 10 milliwatts into Isolation Amplifier
at 5000. Factory adjusted to 1.0 VRMS output.
Frequency: 75 MHz Crystal-controlled.
Selectivity: 6 db at + 10 kHz. 60 db BW 575 kHz.
Sensitivity: Low: 2.000 uv for lamp threshold. High:
500 uv for lamp threshold.
AGC Characteristics: Less than 6 db variation in audio
output level when the rf level is
varied from lamp threshold to
- 200,000 uv.
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Size: 32'W 18.13 cm) x 105"H (2.66 ст} х 7.13"D
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n keeping with King Radio Corporation's policy of continual
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product improvement, design, prices and specifications de-
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scribed herein may be altered without notice
1 i 1 R A Math М GANAT
King Radio Corporation, 400 North Rogers Road. Olathe, Kansas 66061
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* (913) 782-0400 « TELEX WUD (0) 4-2299 + CABLE: KINGRAD
King Radio S.A.. 15 Ch. F. Lehmann, Р.О. Вох 2610, 1
Switzerland « Tel. Geneva 98 58 80 - TELEX 289445 KING
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