Hammarlund SP-600-JX-21 User guide

...---------------*---------------;;r

HANDBOOK

OPERATION INSTRUCTIONS

1.0.

31R2-4-10l-1

RADIO

MODEl

RECEIVER

SP·600·JX·21

(HAMMARLUND)

LATEST

THE

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publication. Destroy

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PUBLISHED

CHANGES HAVE

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COMPLETE

UNDER

AUTHORITYOFTHE

BEEN

PUBLICATION.

SECRETARYOFTHE

* ---31

MERGED

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CHANGED 1 AUGUST

TO

MAKE THIS

FORCE

15

DECEMBER 1955(

1956-

T.O. 31R2-4-101-1

Reproduction
licationisnot permitted
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and

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1956
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USAF·ACTIVITIES.-In
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1956

T.O. 31R2-4-101-1

Table

of

Contents

Section

I

DESCRIPTION

1-1.
1-3.
1-11.

1-26.

1-31.

1-36.

II

PREPARATION

2-1.
2-3.

2-5.

2-8.

2-12.

TABLE

OF CONTENTS

General
PurposeofEquipment
DescriptionofEquipment
Operational
Capabilities
Equipment

Theory

and

Limitations.

Required

. 4

for

Phone

or

Slow-speed

Telegraph

Reception . 6

FOR

USE
Uncrating
Inspection
ReplacementofDefective

..

Parts

..

SettingUpthe Receiver

Installation

Page

1

1

1
1

5

7

7

7
7

7

10

2-19.

III

OPERATION

3-1.

3-3.

3-22.
3-25.
3-54.
3-57.

IV

EMERGENCY

4-1.

4-3.
4-5.

Testing

General
Description

Presentations
Operating
De-energizing the

of

Controls

and

Readings .

Procedures .

Equipment

PrecautionsToBe Observed

OPERATION

General

Antenna
Emergency

System

Tube

Replacement

..

.................. 22

....

13

14
14
14

16

17

21

21

22
22

22

Revised

1

August

1956

Section

T.O. 31R2-4-101-1

Figure

ii

J- 1. Radio Receiver, Model SP-600-JX-2 J

T.O. 31R2-4-101-1

SECTION I

DESCRIPTION

1-1.

GENERAL.

1-2.

This

handbook
Radio Receiver, Mod!'.! SP-600-JX-21,
manufactured
Ine.,

New

1-3.

PURPOSE OF EQUIPMENT.

1-4.

The
station, fixed
airborne,
two-way
for

the receptionofkeyed, amplitude-modulated,
frequency-shift carrier signals.
gence may be slow-speed
(automatic)
For

Morse code
cow

and
tion, two-tone

also be used.
1-5.

To
recordable, auxiliary
receiver is to be used
slow-speed
speaker are used;
components
high-speed
lor

a tape ink recorder are required.

shift

teletype reception, use is

shift

converter
writer.
1-6.

The
phone,
denoteadot
(space),
successionofdots
developed
terval
dot
result.
to
ink
in the
the system;orit
unit
inputtoa suitable frequency-shift
with
1-7.
to
monitor.Itmay also be fedtoa transmission linetopro­vide the signal
tone
requiring
may be used
phone

may be developedinthe

of

(mark)

The

operate

recorder, a line relay,ora tone

formofa-c

associated

a teletypewriter.

The

provide

used is in

signals.

by the

York1,N.

radio receiver is designed

or

or

field applications,

operational

telegraph,

single-tone carrier signals.

render

telegraph

are usedtomonitor

telegraph

outputofthe receiver,

(mark)

the signal intelligence

in

the

each

and

signalinthe

applicable

tone
the

signal to the headset

a frequency

for

contains

HRmmarlund

Y.

mobile use.Itis

activity.

and

teletype

and

frequency-shift carrier signals may

the signal intelligence audible

components

signals, a headset

in

other

signals, a recorder

equipment

andnodoc

and

formofa-c

dot

(mark),

each dash (space), keyed-tone signals

recording

output

is usedtooperatearecorder

with

the tape

generator

at

the

remote

the

voice frequency range, each signal

bandof170 cycles,

several such tone signals, as well as

operation

adaptable

and

The

radio

The

(manual)

phone,

for

dashes. Alternately,itmay be

teletype, facsimile, ete.

operation,

are required.

the reception

modes

madeofsuitable frequency-

associated

formofdoc
output
being

output

or

for

formofdoc

equipment

provides the audible

ink

recorder,orto

keyed

endofthe line.

instructions

(figure

Manufacturing

for

enclosed-

to shipboard,

may be used

receiver provides

carrier signal intelli-

or

high-speed

use is

made

For

teletype opera-

When

of

phone

and/or

of

operation,

the signal.

for

signals

wherein,

the intervalofeach

generator.

converter

output

and/or

To

driving

with

to denote a dash

containedinthe

output

unit

For

frequency-

a teletype-

other

output

for

is suitable

such as a

The

output

driving

provide

associated

may be used

loudspeaker

The

and

the line

for

1-1)

Co.,

in

and

and/or

the

loud-

these

receive

and

than

the in-

tape

signal

keyed-

for

of

or

to

of

Paragraphs

1-8.

The

radio

receiver provides for continuously vari-

able reception

54.0 mc,
ception
me.

The
its three lower frequency bands
conversion
The

receiver signal-to-noise ratio

teristics

a

signals
of
nonselective

1-9.
oscillator used in heterodyne detection
signals to
set

1-10.
ply designed
phase a-c source
volts.

The
rately fused.
and
tained
apronofthe receiver.

1-11.

1-12.

communications type designed
a
light
top

1-13.
ception
locatedonthe
nector (8, figure
nals are located
of

1-14.
date
input
a 95-ohm transmission line.
stallations specifically designed
frequency may also be used.
the receiver
with

1-15.
provides a received signal (usually frequency-shift)
the
usually as
i-f
b-f-o circuits,
availableatthe

and

short-wave signals which are

The

and/or

The

The

power

the o/g-ampere high-voltage secondary fuse are con-

in

GENERAL.

standard

grey front-panel assemblytowhich are

cover

RECEIVER

of

the

receiver is also locatedonthe

The

a balanced

impedanceofthe

type

The

receiver i-f

output

within

and

for

within

receiver uses single heterodyne conversion

for

provide

the receiver is well suited

and

radio

provide

loudspeaker
radio

to

receiver

transformer

The

cartridge-type fuseholders located

DESCRIPTION OF EQUIPMENT.

19-inch relay rack.Itcomprises a chassis

andabottom

the

headset

re-::eiver

"ANT"

RG-22/U

"IF

partofa space-diversity receiving system.

circuitinthe

the frequency

crystal-controlled fixed-frequency re-

the frequency

its three

for

selective fading.

receiver has an

receiver has a self-contained

operate

within

front

2-1),

on

doubletorstraight-wire

OUTPUT"

output

therefore

"IF

higher

the reception

audio

signal intelligence to the head-

monitor.

from
the

voltage

power

1.6-ampere slow-blow

The

CONNECTOR

panel,

the

input

cable.

OUTPUT"

consumption

primary

radio

plate.

"PHONES"

and

all receiver connectors

rear

apron.

circuit is designedtoaccommo-

receiver is designedtomatch

Other

The

input

connector (8, figure

connector

for

frequency-shift

receiver is isolated

b-f-o injection

rangeof0.54 mc

rangeof0.75 mcto54.0

and

double

bands

and

of

inherently

internal

a 50-cps to 60-cps, single-

rangeof90to270

and

secondary are sepa-

receiver is a 20-tube radio-

for

direct

USES.

jack (20, figure

the

"ANT"

The

rear

suitable

for

the desired

antenna

connector.

Section I

1-1

to

1-15

for

heterodyne

(above

sensitivity charac-

extremely weak

for

of

a-c

(6, figure

7.4

mc).

the reception

subject

beat-frequency

keyed-carrier

power

sup-

is 130 watts.

primary

mounting

With

power

apron.

antenna.

is connected

converter

voltageisnot

on

the

mounted

the

3-1),

input

and

termi-

antenna

operating

from

fuse,

rear

and

ex-

con-

cable

The

in-

2-1)

2-2)

use,

The

the

to

to

to

in

a

at

1

Section I

Paragraphs

1-16

T.O. 31R2-4-101-1

to

1-23

1-16.

The

reveiver

figure

2-2)

are suited

transmission line.

"AUDIO

for

a 600-ohm loudspeaker

The

receiver a-c signal

OUTPUT"

terminals (8,

output

(phone,
single-tone telegraphorteletype,ortwo-tone teletype)
is available
render
tone signals intelligible, the tape
high-speed
teletype reception are associated
ment connected
line.
another

at

the

"AUDIO

high-speed telegraph

When

telegraph

a local teletypewriter is used to

and

to

the receiver by suitable transmission

OUTPUT"

and

ink

terminals.

single-tone

recorder used

or

the teletypewriter used

with

demodulator

teletypewriter remotelyorlocally connected to

To

two-

for
for

equip-

operate

the transmission line, the send teletypewriter relay is
connected to the
nals so

that
between the balanced split
of

the receiver, for which the

vides a

mid-point

simultaneous to its
1-17.

The

(2, figure

jumpered

the line

receiver

2-2)

current

tap.

other

"DIODE

and

"AUDIO

output

This

uses.

the

on

"mark"
transformer

jumpered

use

of

OUTPUT"

"AVC"

OUTPUT"

termi-

balances

windings

connection pro-

the line may be

terminals

terminals

out

(3)

are used to interconnect two receivers in a space-

diversity receiving system.
nated

"G"isgrounded

ground

between receivers.

between receivers

while

that

Thisisdonetoprovide

for

amplitude-modulated

this

arrangement,

ceived

the

on

one receiver decreases

noise

output

diversity reception

one

receiver is used.
OUTPUT"
the

"-"

terminal

provides

the

ceptionofcwtoa

the avc duetothe

of

of

terminals

connectedtothe

output.

tone

recorder, the receiver interconnections are as

for

phone,
case
"DIODE
output
with
output
each receiver.
tion
or

the audio

provide

butnoavc

when

the

doc

output

OUTPUT"

is used, the diversity

the

tape

ink

recorder, is

from

the

"AUDIO

To

provide

of

frequency-shift

output

inputtosuitable

The"AVC"

for

each receivertoa

designated

"-"

terminal desig-

is

interconnected

space-diversity reception

or

frequency-shift signal.

stronger

the

weaker signal

the

other.

To

provide

phone,

To

To

the

audio

do this,

are

opened

the

on

jumpered

other

provide

keyer

andnobfo

from

for

space-diversity re-

(generator)

are used.

the three interconnected

terminals is used.

output

one receiver

receiver, which

When

demodulator,

provided

OUTPUT"

for

the space-diversity recep-

carrier

from

each receiver may be used to

frequency-shift

signals,

terminals

the

converter

common

common

signal re-

for

from

"DIODE

or

tape

outlined

This

associated

with

i-f

of

With

and

space-

only

and

is the

the

the

(8)

output

equip-

avc

ink

a-c

a-c

ment.
1-18.

The

"AC"

power

the

rear

apronofthe
an accessory, such as an electric clockorlamp.
available
nected to a

at

power

the

receptacle

source, regardlessofthe settingsofthe

receptacle (12, figure

receiver may be used

whenever

the

2-2)

for

operating

Power

receiver is con-

receiver controls.
1-19.

RECEIVER

tivities require

properly

set
These

controls are all locatedonthe

OPERATION.

that

the receiver switches

for

the

mode

of

operation

All

front

operational
and

ac-

controls be

contemplated.

panelofthe

or

an

of

on

receiver,
control
control
3-1)
control
on
factory adjusted,
adjustment

1-20.
ational
(21, figure
(11)
the a-c sourceisconnectedtothe
applied
When
is disabled
carrier
a two-way communication activity.
in

with

the

on

the

(5,

figure

(7)

used to calibrate

the

front

(4, figure

rear

apron

and

exceptionofthe

2-2)

and

the

panel,

and

2-2),

all threeofwhich are located

of

the

receiver.

are

nottobe

the

the

tuning
"BFO

"METER

"METER

meter

IN]"

These

moved

positions. "

The

radio

activity

turned

through

3-1).

clockwise

receiver is

With

adaptabletoa two-way oper-

useofthe

the

receiver

from

"SEND/REC"

"RF

its

"OFF"

GAIN"

position,

receiver, a-c

for

either

positionofthe

the switch isinits

for

protectioninthe presenceofa

such as

that

produced

"SEND"

"SEND/REC"

position,

by local tranmission

When

its "REC" position, the receiver provides

AD]

RF"

AD]

AF"

(1,

figure

adjustment

controls are

from

their

switch

control

when

power

switch.

the

receiver

strong

local

during

the

switch is

for

instant

is

reception.

1-21.

When

s~lector

tlOn, the
variable
quency

(17).

When

s~t

to

oneofthe

vides

for
any signal
mc,

provided

into

the

selected switch position.

functions
used

to

frequency. Exact

heterodyne oscillator is

control

clockwise, provides
nier

dial
mechanism, to
ceiver

duetovibrationoraccidental

trols.

The

turn

even

1-22.

The

ure

3-1)

or

selectivity.
provides
qualityofthe
of

its

"XT

trol

(23)

is

signal, even
signal.

The
"LIMITER"
ignition
ceiver

audio

1-23.

The

3-1)

in its

"BEAT

justing

the tone

the

radio

switch ;8, figure

"TUNING"

tuning

band

of

any desired
selected by the
the

"FREQ

"XTALS"

receiver

3-1)

control

CONTROL"

"FREQ

is settothe

(15)

provides continuously

carrier

"BAND

within

CHANGE"

selector switch is

positions,

the

CONTROL"
"VFO"

receiver

fixed-frequency crystal-controlled reception

within

numbered

as

adjust

(7).

(6),

the

that

before,

the

frequency

proper

crystal socket

The

and

rangeof0.75 mcto54.0

crystal has been inserted

correspondingtothe

"BAND

the

"TUNING"

the r-f amplifier circuits to

tuning

of

the crystal-controlled first

provided

The

"TUNING

the

main

prevent

optional

LOCK"
locking means

tuning

dial

accidental

CHANGE"

the

by the "6.

(14),

when

for

(4),

and

detuning

control

the
of

shiftofthe con-

"TUNING"

when

the

receiver

provides

The

optimum

received signal.

AL"

positions, the

is used to

control

"TUNING
"SELECTIVITY"

itself remains free

LOCK"islocked.

switch (22, fig­a choiceofsix degreesofbandwidth
switch

receiver

position

chosen is

performance

When

that

for

the existing

the switch isinone

"XTALPHASING"

highly

attenuate

any

interfering

whenitis closely adjacenttothe

receiver

noise

"LIMITER/OFF"

position

and

other

provides

for

pulse-type noise

switch

effectively

from

(19)inits

output.

receiver

"CW"

OSC."

position

control

output

"MOD/CW"

renders

(10)

provides the meansofad-

within

a frequency

switch (13, figure

the

bfo

operative.

rangeof±3

posi-

the

fre-

switch

pro-

switch

operating

FREQ"

turned

the ver-

tuning

the

re-

which

con-

desired

reducing

the

re-

The

of

is

to

2

w

3.5MC

CRYSTAL

OSCILLATOR

~

l--.-I

R-F

AMPLIFIERS

l....c

r--1

"XTALS"

MIXER

A

"FREQ CONTROL"

"VFO"

~+-C;1f

O)~

'/

,,?J

r

v

MIXER

i'~s

. .

S~.

uf-o"

V'G'

GATE •

'.~...

'f-('

",

'.le,

t>-~

CRYSTAL

FILTER

~

1-

F H DETECTOR

AMPLIFIERS AVC

-----

, , • , , , SIGNAL

SIGNAL

~

L....j FREQUENCY

BEAT

OSCILLATOR

PATH

FOR

PATH

FOR

LOUDSPEAKER

1-+

AMPLlF~

POWER
SUPPLY

A-C -

SOURCE

FREQUENCIES ABOVE

FREQUENCIES BELOW

!4-

7.4MC

7.4

MC

-l

?

Co)

;:lll

-

~

.

,Ill.

I

-

o

-

•

-

CRYSTAL

CONTROLLED

OSCILLATOR

w

VARIABLE

FREQUENCY

OSCILLATOR

figure

i

-2.

Radio Receiver,

Simplified

Block Diagram

VI

(1)

n

-

o'

~

Section I

Paragraphs

1-24

to

T.O. 31R2-4-101-1

1-29

kc.

The

"BEAT
directiononscale to
ceived

cow

the

"MOD"
tionofamplitude-modulated
is to be used
nal,

the

"MOD/CW"

whether

the receiver i-f

OSc."

signal.

provide

When

control

the

may be

the 3-kc

range

"MOD/CW"

turnedineither

position, the receiver provides

signals.

for

the receptionofa frequency-shift sig-

switch

positionisdependent

When

outputorthe receiver a-f

for

switch is

for

the recep-

the

the re-

receiver

upon

output
istobe furnishedtothe associated frequency-shift con­verter

equipment.

the use

of

the
monitoring
used,

the

bfo
istoprovide
band)

reception, the

at

the receiver.

controlisset

When

bfo

purposes.

the receiver i-f

provides

When

mustbein

suppressed-carrier

bfo

For

this application, the

to a

position

output

optional

receiver

output

the receiver a-f

operation.

When

the receiver

(singleordouble

is usedtoreinsert the

"BEAT

providing

a bfo frequency

is used,

for

output

side-

carrier

OSc."

455 ke.
1-24.

The

receiver

3-1)

is adjustable to compensate
encountered in the level
maintain the receiver a-f
limits

for

the
receiver incorporates automatic volume control.
ceiver
"A
cluded

"AYC/MAN"

YC"

position, provides this action. Provisions are in-

in

the receiver
the reception
"RF

GAIN"

control

the"AYC/MAN"
1-25.

The

receiver

vides a

tuning
the"AYC/MAN"
position.
to

When

its maximum clockwise setting, the meter

"RF

"RF

GAIN"

of

slow-speed

switch.

tuning

indication

switch

the

"RF

GAIN"

of

output

control

control
for

wide

(11, figure

variations

any carrier received.

constant

setting

within

chosen, the

narrow

The

switch

for

a-v-c

(12),

operation

telegraph

when

set to the

even

during

signals.

is effective in either position

meter (1, figure

for

the desired signal,

(12)

is

set to the"AYC"

GAIN"

control

3-1)

(11)

when

is set

top

To

re-

The

pro-

scale
indication is the ratioofthe received signal level to a
signal

of

one microvolt, expressed

"METER"

switch
position, the meter
of

the receiver audio

(18)isheldinits depressed

bottom

scale indication is the ratio

outputtothe

in

db.

standard

When

reference

the

"AF"

outputofsix milliwatts, expressedindb.

1-26.

1-27.
radio
path

OPERATiONAL THEORY.

GENERAL.

An

analysisofthe

operationofthe

receiver is best evolved by considering the signal

through

the receiver r-f, i-f,

and

a-f sections,

into
which the receiver may be considered theoretically sub­divided.
is considered separately.
(figure
between the various sections

1-28.
vides selective circuitry
receiver frequency
through
housed in a rotary

one
tenna
oscillator r-f tuner.
figure

The

1-2)

R-F

SECTION.

self-contained

indicatesinblock

power

supplyofthe receiver

The

simplified block

form

of

the receiver.

The

r-f

sectionofthe receiver pro-

for

any selected signal

the relationship

rangeof0.54to54.0 me.Itdoes this

the useofsix setsofr-f

turret

frequency

bandofthe receiver

assembly. Each set is used

tuner

subassemblies

and

comprises an an-

r-f tuner, two identical interstage r-f tuners,

The

3-1)

provides

"BAND

for

CHANGE"

indenting

the rotary

diagram

within

switch

turret

and

the

for

an

(17,

as-

of

of

in

sembly so

frequency

ceiver.

the signal assures

developed in the r-f section· is

very weak signals

r-f

the signal is greatlyinexcessofthat

that

the

r-f

tuner

subassemblies

band

The

become

antenna

partofthe

and

two-stage r-f

that

the signal-plus-noise to noise

provide

useful receiver

section preselection assures

r-f

high

enoughsothat

that

the

sectionofthe re­gain

gain

provided
desired signal. Since the receiver utilizes the principles
superheterodyne reception, a signal removed

sired signal by twice the 455-kc

is

also provides
the receiver.
sired signal, is

tunedinon

an

i-f signal acceptable to the i-f section

This

image frequency, like any

greatly

the three
ceiver, the image frequency
quency
signal.
ceiver provides
these bands.

7.4
i-f signal.
first

of

455 kc

To

maintain

On

me),

the signal

On

heterodyned

would

for

double

the three lower frequency

tunedinis

the three

to a 3955-kc i-f signal, which is
heterodynedtoa 455-kc i-f signal.
"FREQ

CONTROL"
position, the receiver provides
tuning.

When

the switch isinoneofits

tions, the receiver first

attenuated. However,

higher

high

image-rejection ratios, the re-

higher

selector switch

heterodyne

intermediate

frequency

for

bandsofthe re-

an intermediate fre-

be too close

superheterodyne reception

heterodyned

frequency bands,itis

With

(8)inits

for

continuously variable

variable oscillator is
replaced by a fixed-frequency crystal-controlled hetero­dyne oscillator.
stability
frequency
tion

channel, even

without

necessitating a time-consuming search by the

superior

tuning.

Doing

this resultsinreceiver frequency

to

that

attainable

Its use pre-establishes the communica-

when

receiving conditions are poor,

operator.
1-29.

I-F

SECTION.
corporates the 455-kc i-f amplifier
all

of

the overall

developed. Also,

The

i-f sectionofthe receiver in-

wherein

gain

and

selectivityofthe receiver is

it

incorporates the single-double con­version switch, which assumes its single
version position
is

indented

three

higher

dependentonwhether

respectively

for

frequency bands.

the

oneofits three

For

signals
oneofthe three lower frequency bands, the signal has
access

to

the 455-kc i-f amplifier

gate.

For

this

condition

the switch
conversion i-f channel inoperative.
on

oneofthe three

higher
reaches the 455-kc i-f amplifier
double-conversion channel.
renders the 455-kc i-f
of

receiver selectivity

switch (22, figure

channel

of

3-1)

the receiver.

For

gate

provided

are developedinthe 455-kc i-f

At

through

renders

For

signals

frequency bands,

through

this cOJ;ldition the switch

inoperative.

by the

the

"SELECTIYITY"

input

to the 455-kc i-f
amplifier is the 455-kc i-f crystal-filter circuit incorpo­rated

in

the receiver.
the receiver to
selectivity.

The
mechanism provides
and

calibration accuracyofthe receiver so

The

useofthe crystal filter enables

attain

the

three degreesofsharp

precise antibacklash

for

completely accurate resetability

gear-train

foraparticular

provided

ratio
even

output.

The

available

any un-

from

the de-

frequency

other

unde-

for

signals

to

the desired

bands

(below

to a 455-kc

then

the receiver

"YFO"

"XT

ALS" posi-

for

variable-

practically

or

double

rotary

con-

turret

lower

tunedinon

a 455-kc i-f

the double-

tuned

the

signal

the 3955-kc i-f

The

six choices

"XTAL"

tuning

that

maximum

to

to

of

of

on

or

in

4

benefit can be derived
of

the 455-kc i-f crystal filter.

control

bfo
"IF

ated

1-30.

sectionofthe

develop
"AUDIO
control
terminals

(23)ispartofthe crystal filter.

and

associated

OUTPUT"

with

the 455-kc i-f channelofthe

A-F

SECTION

receiver incorporatesana-f amplifier to

the

a-f

GAIN"

the receiver

(8,

figure

jack (20, figure
develops all

rhe receiver.
lated to
stability.

the

The

maintain

The

"RF

from

the

sharp,

The

"BEAT

OSc."

connector (6, figure

AND

POWER

power

control

output

(16, figure

of

outputtothe

2-2)

and

thattothe

3-1).

The

self-contained

a-c

and

the

doc

supply

critical

constant

GAIN"

doc

supply

the sensitivity

control

crystal passbands

"XTALPHASING"

The

455

control

(10)

2-2)

receiver.

SUPPLY.

the receiver.

3-1)

"AUDIO

OUTPUT"

"PHONES"

power

voltages used by

voltages are regu-

and

(11)ispartofthe

power-supply bias rectifier. Its chosen setting,

junction
used, determines the

sections

1-31.

1-32.
receiver
ated.
tiontoa balanced
tem.
relative locationsofthe receiver
In
within
relative humiditiesashigh
minute
from
quency.

shielding

mum.
in
board
chassis rigidity

It

ditionitfor

1-33.
signal
tent
volt,
have tobeat
velop

quencies

would havetobe
to 600 kc, a 455-kc signal
to
microvolt
600 kc, this 455-kc i-f rejection
better. Likewise,
receiver is 'it least 50,000
bands4,5,or6,
kc

1-34.

(minimum

with

the

a-v-c system

gain

developedinthe

of

the receiver.

CAPABILITIES

GENERAL.

performance

The

antenna

The

95-ohm cable used provides flexibility astothe

AND

The

when

input

doublet

LIMITATIONS.

radio

receiver provides

properly

connector

or

single-wire

and

use,

the

receiver may

the

rangeofO°C

be

subjected to temperatures

(32°F)

as 95 percent.

warmup

0.001
The

to reduce

This

multi-receiver installations

regulations.

is adequately treated

period,

percentto0.01

the

frequency stability ranges

percent

receiver incorporates advanced design

radiation

characteristics to a mini-

enables the receiver to

and

The

receiver embodies the necessary

to

withstand

with

severe

fungicidal

tropical use.

PRESELECTION.

tunedinon

thatifthe desired signal

the

strengthofthe image frequency signal

the

The

image frequency

receiver is

strength

least 4000 microvolts

the

same receiver

the

strength

of

output.

the

image frequency

greater. Also,ifthe receiveristuned

inputtothe receiver

be

2700 microvoltstoproduce

signalat600 kc.

the

the

frequency

i-f

channelofthe receiver is operative.

-SENSITIVITY.
signal

input

For

3955-kc i-f rejection ratioofthe

for

any

bands

The

receiver

to develop its

of

the receiver,

r-f

installed

provides

for

antenna

the

antenna

to

60°C

(140°F),
Aftera15-

of

the

signal

maintain

performance

to comply

vibration

and

varnishtocon-

attenuatedtothe

were

one

(at

7.4 mc)tode-

At

other

signal fre-

the same effect as a one-

frequencies

other

ratioofthe

signal

for

frequency

which

threshold

rated

a-f

T.O. 31R2-4-101-1

-+-

3-kc

and

the

are

associ-

The

a-f

The

is used to

supply

frequency

in

con-

when

and

i-f

optimum

and

oper-

connec-

sys-

system.

at

fre-

and

with

ship-

shock.

of

any

ex-

micro-

would

signal

will

have

than

receiver is

on

the

3955-

sensitivity
output)

is

Paragraphs

two

microvolts

a

cow

signal,orbetter.

the

receiveratthreshold

This

a-f

noise

power
optimum
signal

tuned
the first electron
not

interfere

be

reduced in

the

"RF

wise

from

to

prevenr
receiver.
turning

wise.

the

Thisisdone

sectionofthe

receptionatthe

for

an

A-M

The

sensitivity is

outputisprovided

ratio

of

ten

receiver

GAIN"

its

performanceinthe

in, since

with

the

the

tube

and

reception.

presenceofa

control

maximum

clockwise position.

(11, figure

overloadingofthe

The

receiver a-f

"AUDIO

to

receiver

GAIN"

prevent
andtoprovide

desired a-f

signal,

undistorted

at

to

background

the
The

r-f

output

control

output
ceiver a-v-c system is operative
control
ceiver
age

microvolts.

put
strong
control,

acteristics

is set to its

output

ratio

remains

when

The

when

tuning

comparedtothe

and

compensates

of

the

the

maximum

constant

input

clockwise setting, the re-

withinaone-to-four

is increased

useofave precludes excessive audio

through

a carrier signal relatively

settingofthe

for

the

signal

over

longorshort

time.

1-35.

SELECTIVITY.

of

the

receiver is adjustable to

of

a signal

under
Since noise, regardlessofits
and

comprises

audio

outputofthe

selectivity

of

the

all

receiver.

"SELECTIVITY"

noise

output

of

noise,itis advantageous to restrict

ceiver

with

intelligible

quirements

For

phone

than

bandwidth

vary
reception,

reception. However, the

with

ments are 455 kc
ment

for

single-tone

operation

words

per

kc

±

two
two

doubled.

the

such as slow-speed telegraph, teletype

per

minute),

minute),

75

tones,

cps,

one

the

and

for

requirements

channels are used,

The

bandwidth

frequency stability

frequency stabilityofthe

ofacow

provide

signal, a

for

receptionofphone

The

bandwidth,

provide

varying

conditionsofpropagation.

origin,isof

frequencies,

receiver

The

depends

"BROAD"

switch (22, figure

the

"SHARP"

to

the

narrowest

the typeofsignal
the

i-f

channel

± 2500 cps.

telegraph

and

high-speed telegraph

are

455 kc

"mark"

the

of

narrow

-+-

600 cps, respectively.
and
bandwidth

requirements

the

receiver itself.

bandwidth

may be reduced to reduce noise
use

ofanarrower
higher-frequency
nal

and

may

impair

provide

for

receptionoftelegraph

bandwidth

audio

componentsinthe received sig-

the

intelligibilityofreception. To

Section I

1-30

to

and

0.75

microvolt

power

two

output

wattsorbetter.

a signal-plus-noise

one.

This

provides

presenceofa

noise caused by

antenna

r-f

tuner

receiver sensitivity may

strong

signal by

3-1)

turning

counterclock-

Thisisdone

and

i-f sectionsofthe

may be decreased by

(16)

counterclock-

overloading

level.

and

the

from2to

"AUDIO

possible

of

for

comfortable

When

"RF

fading

the

the

GAIN"

200,000

GAIN"

intervals

or

selectivity,

for

the

reception

the

pulse type

the

noise level

upon

the

in

overall

settingsofthe

3-1)

produce

settings.Inthe

the

presence

overall

possible, consistent

bandwidth

being

received.

bandpass

This

is also

reception.

455 kc

the

For

keyed c-w

(400

-1-

50 cps, 455

require­require-

words

When

another

for

"space",

requirements

also

depend

received

signal

For

and

reception

can be used.

signals,

output;

results

the

bandwidth

however,

in

loss

or

teletype signals,

of

1-35

for

of

to

for

weak

does

a-f

re-

volt-

out·

char-

of

the

more

re-

re-

(60

or

are

upon

the

To

the

the

5

Section I
Paragraphs

1-36

to

T.O. 31R2-4-101-1

1-37

full

advantage

should

be takenofthe

switch positions to reduce

LECTIVITY"

overall

switch provides a choiceofsix degrees

bandwidth.

The
widths are 0.2 kc, 0.5 kc,
crystal

1-36.

1-37.

quired
signals is subdivided
supplied
tableI.The

bandwidths

EQUIPMENT REQUIRED FOR PHONE OR
SLOW-SPEED TELEGRAPH RECEPTION.

The

tabulation

are 3.0 kc, 8.0 kc,

of

for receptionofphoneorslow-speed telegraph

into

and

covered by this publicationislisted

components

receiving system, required

in

table II.

TABLEI.EQUIPMENT SUPPLIED

Quantity

1

Radio

Receiver,

SP-600-JX-21

antenna

1

1

1

Plug,
Adapter,
Plug, i-f

angle

output

"SELECTIVITY"

interfering

noise.

The

sharp, crystal-derived band­and

1.3 kc.

the complete

two tables.

and

auxiliary

but

not

Name

The

broad, non-

and

13.0 kc.

equipment

The

equipment

equipmentofthe

supplied, are listed

Government

Designation

Model

connector

plug

connector

UG-102/U
UG-104/U
PL-259

"SE-

of

re-

in

TABLE

EQUIPMENT REQUIRED BUT

Quantity

*AR

II.

COMPONENTS

Name

Crystal, Specification

MIL-C-3098

1

1

1

AR

1

Headset

Cord, headset

Loudspeaker

Cable, lead-in

Antenna
anced

system, bal-

doublet

single wire

1

Source, a-c, single-

phase, 90 to 270V,
50to60

cps,

watts

*One

crystal

required

for

quency.

each

AND

AUXILIARY

NOT

or

130

operational

SUPPLIED

Government

Designation

CR-18/U

Navy

Type

-49507

Navy

Type

-49534
LS-3
RG-22/U

signal fre-

6

T.O. 31R2-4-101-1

Paragraphs

2-1

Section

to

II

2-9

2-1.

UNCRATING.

2-2.

Carefully remove

container, using the

a.

Remove the two steel straps

b.

Remove the cover nailedtothe case.

c.

Remove the excelsior

"the

following

from

receiver

ceIver.

d. Remove the
e.

Remove the
waterproof
and

remove the

f.

Open

taining

the receiver.

g. Remove

paper

the

the

carton

cartoned

waterproof

wrapped

waterproof

vapor-proof

around

and

remove the

receiver

paper

carton.

Un

flatten the cornersofthe

h.

and

remove the silica gel.

wood

i. Remove the
corrugated
front, one back,

interiors

and

j. Remove the receiver

convenient

k.

Put

place

all

packing

frame

comprising

one top, each accordion folded.

and

near

its final location.

materialinthe

store.

2-3.

INSPECTION.

2-4.

When
shipping
damage
front

panel controls, the
meter
that

they are firmly seated

none

are

the

rear

of

the

the

receiver has

container, carefully inspectitfor

that

may have occurredinshipment.

tuning

for

any defects. Inspect the tubestomake

broken. Inspect the fusesinthe fuseholders

apronofthe

proper

ratings

receiver to make certain
are

insertedinthe

SECTION

PREPARATION FOR

from

its

shipping

procedure:

from

the

wooden

around

tape

the

from

from

the foldsofthe

the

cartoned

cartoned

the

wrapper.

inner

bag

from

around

inner

carton,

from

the

carton,

two

side pieces,

setitoutofthe wayina

wooden

been

removed

any signs

dial windows,

in

their

sockets

fuseholders.

case.

receiver,

carton

the

open

and

case

from

Inspect

and

and

that

case.

con-

inner

sure

fuses

re-

it,

the

one

and

its

of
the
the

that

on

II

USE

To

remove

b.

screw

holding
counterclockwise,
remove

the

is removed

c.

To

remove any electron tube

or

V19, first remove
clockwise
cept
removed

2-7.
the

while

V17

and

withanappropriate

FUSES.

o/s-ampere fuse, located respectivelyinthe

fuseholder

( 1)onthe

of

the

fuseholder

grees

in

a counterclockwise direction.

pressureinthis

spring-clamped

and

the

topofthe

To

replace

Be certaintouse fuses
fied above. Use
in

damagetothe

2-8.

SETTING UP

2-9.

POWER

When

shipped, the
the receiver is connectedtooperate
117-volt, a-c source.
from

other
tap. connection.
ratIngofeachofthe

electron

the

tube
while

tube shield.

preferably

tube

V4, loosen

shield.

with

Then

turn

exerting

The

inward

tube isofthe

a suitable tube remover.

other

the

tube shield by

exerting

V19

inward

areofthe

pin

pressure.

type,

tube remover.

To

remove

(11, figure

rear

apronofthe receiver, pressinthe

while

position

to

the
fuseholder

either

fuse,

either

the

2-2)

and

the

turningitapproximately

will

release the fuse

topofthe fuseholder.

may

nowbepulled

follow

of

any

the

having

other

reverse

the

fuses may

receiver.

THE

RECEIVER.

TRANSFORMER

power

transformer

from

If

the

receiver is

than

a 117-volt source, change the

Table

III shows

primary

the

tap

terminals,

the

knurled

the

tube

shield

pressure,

pin

type

than

V4

V17

twisting

and

c~unter~

All

tubes ex-

are

preferably

1.6-ampere fuse
"LINE"

"-B"

fuseholder

45 de-

Removing

which

The

apart.

procedure.

ratings

speci­result

CONNECTIONS.

primary

tap
a 50-to60-cps,
to

be

operated

primary

a-c source

voltage

which

and
and

or

top

the

is

fuse

of

are

2-5.

REPLACEMENT OF

2-6.

ELECTRON
discovered
before
tron

operation

tubes use the

during

TUBES.Ifdefective electron tubes are
inspection, replacement

is attempted.

DEFECTIVE

following

To

replace defective elec-

procedure. (See figure

2-1.)

a.

To

remove electron tubes

hat-type tube clamp

the clamp, press

inwardonthe

must

V17

and

first be removed.

spring,
clamp off the tube. Remove the tube by
from

its

tube

ingiton

the

ad jacenttoit
spring,
the

with

clamp

is firmly seatedinplace.

socket. Replace the

topofthe

tube so

canbethreaded

pressure

providingaratchet

top-hat

that

through

PARTS.

mustbemade

V19,

the

To

remove

while

lifting

drawingitout

clamp

by seat-

the

vertical

the

holeinthe

motion

top-

the

bolt

until

TABLE

Tap

III.

POWER TRANSFORMER

TAP VOLTAGE RATINGS

No.

2

3

4

5
6
7

8

9

Voltage

105
117
130
190
210
234
260

Rating

95

7

Section II

T.O.

31R~-4·101-1

27---

26

25

24

23

------or

3

4

5

7

8

10

II

....

15

19

tube
tube
thumbscrew
spring

sockets

tube
tube

lamp

buttons

V3
V2

assembly

V5
V13

View

18

of

17

Chassis

19.

20.

21.

22.

23.

24.

25.

26.

27.

16

Electron
Electron

Electron

Electron
Electron
Electron
Electron
Electron

Electron

tube

tube
tube
tube
tube
tube
tube
tube

tube

V4

V8

V7
V6

V9

VIO
V18

V14

Vll

1.

2.

3.

4.

5.

Electron

6.

7.

"GND"

8.

"ANT"

9.

Electron

Electron
Electron
Electron
Electron

Electron

tubeV12
tube
tubeV15
tube
tube
tube

terminal

input

tube

22

V16

V17
V19
V20

connector
V1

Figure

21

2-1.

20

10.

Electron

11.

Electron

12.

Knurled

13.

Retainer

14.

Crystal

15.

Electron

16.

Electron

17.

Pilot

18.

Metal

Radio Receiver, Top

8

T.O. 31R2-4-101-1

Paragraphs

2-10

Section

to

2-11

II

identified by numerical designation

the

power

transformer

Choose the power
whose voltage

rating

(13, figure

2-2).

transformer

is closest to the available

a-c source voltage.

2-10.

When

obtained
ure
and

adding

CRYSTAL SELECTION

fixed-frequency, crystal-controlled

be utilized, the

2-1).

and

When

proper

inserted

ordering

type

into

the signal frequency

1, 2,

and3,the

455 kctothe

the signal-frequency

crystal frequency

signal frequency;

rangeof7.4 mc to 12.045 mc,

AND

CR-18/U

the crystal

a crystal, the crystal frequency

should

be specified.

can

crystal frequency can be calculated by

on

the

bottom

primary

tap

MOUNTING.

operationisto

crystal(s)'

socket(s)

must

(14, fig-

For

bands

be calculated by

for

band4,in

adding

3955

of

be

the

kc

to the signal frequency;

12.045 mc,
can be calculated by
quency

2-11.
proceed

a.
frequency-control unit,
sembly

b.

on

and

dividing

To

mount

as

follows:

Loosen the

(13)tothe

Insert

the

bands 4,5,and

adding
the sum by three.

the crystal unitsinthe

knurled

thumbscrew

and

rear.

crystals

into

numbered1through6,on

e.

Bripg

the

retainer
the springs are over
sockets,

(9, figure

crystals are

and

tighten

d.

Usingapenorpencil,

3-1)

intended.

spring

the

the

the signal frequencies

for

signal frequencies above

6, the crystal frequency

3955 kctothe signal fre-

crystal sockets,

(12)ontopofthe

push

the

retainer

the crystal sockets

the frequency-control

tops

knurled

mark

assembly

of

thumbscrew.

forward

the crystals

on

the plastic

for

spring

in

which

as-

(14),

unit.

until

the

chart

the

13

12

L

"-B"

2.

"DIODE

3."AVC"

4.

"BFO

5.

"METER

6.

"IF

OUTPUT"

II

fuse

OUTPUT"

terminals

IN}"

AD]

control

RF"

connector

10

terminals

control

13.

9

Power

8

transformer

7

~'-

7.

"METER

8.

"AUDIO

9.

Power

10. "SPARE FUSES"
1L

"LINE"

12.

"AC"

AD]
OUTPUT"

cord

fuse

power

receptacle

AF"

6

control

cover

~

e

'"

terminals

2

3

4

5

Figure

2-2.

Radio Receiver, Rear

View

9

Section

Paragraphs

II

2-12

T.O. 31R2-4-101-1

to

2-18

2-12.
2-13.

mountingina
panel is 10
tion which permits the free access

2-14.
at the
the tap which
cps
the receiver
power

2-15.

The

accommodate a balanced

installation;
specifically designed
may be used.

INSTALLATION.

MOUNTING.

1

/

2

POWER.

bottomofthe

power

source voltage;

into

plug.
ANTENNA

antenna

input

however,

The

receiver is designed

standard

inches high.

Make

most

19-inch rack.

Mount

sure

that

power

transformer

nearly agrees

The

the receiver in a posi-

of

air.

the

primary-tap

with

the 50-cpsto60-

refertoparagraph

the

power

AND

source

GROUND

using

CONNECTIONS.

circuitofthe receiver is designed

doubletorsingle-wire

other

The

for

input

suitable

the

desired

impedance

antenna

operating

of

for

rack

receiver

front

lead

is connected

2-9.

Plug

the receiver

antenna

systems

frequency

the receiver is
designed to match a 95-ohm transmission line. Con­nect the

ure
angle
plug. Figure

tion procedure.
to be used, connect the
terminal
the
"GND"
ceiver
ing

antenna

2-1)

plug

of

other

terminalofthe connector

terminal

"GND"

a suitable

to the

using type

adapter,

2-3

If

the

connector

(7).Inall installations,

terminal

bonding

illustrates the antenna-cable fabrica-

a single-wire

"ANT"

RG-22/U

and

input

connector (8, fig-

cable, a type

a type UG-102/TJ connector

antenna
plug

andaground

antenna

installation

lead-in wire to one

plug

to the receiver

bond

to the

installation

strap.

UG-104/U

lead

from

the re-

ground,

us-

to

to

is

2-16.
headset
Either

HEADSET.

into

the

"PHONES"

For

monitoring

jack (20, figure

a high-impedanceora low-impedance headset may
be used; however, the high-impedance
is recommended.

2-17.
dynamic-type,
matching
terminals (8, figure
the
move
of
minals,

LOUDSPEAKER.

loudspeaker

'transformer

insertionofd-c

the

jumper

the 600-ohm

and

connect the

When

the 600-ohm

Connectapermanent-magnet,

w~.th

across the

2-2).

For

controlorindicating

connecting the

outputatthe

"AUDIO

insertion

outputisnot

a suitable 600-ohm

"AUDIO

applications

two

circuitinits place.

a 600-ohm, 2-watt resistor across the
OUTPUT"
age

from

2-18.

RECEIVER

DIVER~ITY

a.

Receiver interconnections

tionofphone

the"AVC"
on

each receiver to a

the"AVC"

ceivers.
minals

Open

(2)

terminals to avoid

high

transient

peak voltages.

INTERCONNECTIONS

RECEPTION.

signals are

showninfigure

terminals (3, figure

common

terminals designated

the

on

jumpered

one

of

"DIODE

the receivers,

component

for

space-diversity recep-

2-2)

ground

"-"

purposes,

plug

3-1).

(8000-ohm)

type

OUTPUT"

requiring

voltages, re-

balanced sections

OUTPUT"

used, connect

"AUDIO

dam-

FOR

2-4.

Connect

designated

and

interconnec.t

on

the

"G"

two

OUTPUT"

and

connect the

a

ter-

re-

ter-

10

COUPLING

Figure

RING

2-3.

BACK SHELL

Cut end of cable even. Remove vinyl

Bare

5/8

in. of

Slide coupling
der

hole should align with

Assemble
and
solder
cessive

For

back

final

front

shells

holes.

heat.

assembly;

Fabrication

FRONT

conductors.

ringoncable.

shell

should align.

Solder

screw

of

Antenna

SHELL

Tin

conductorsasshown.

to back

shell.

conductorstocontacts.

coupling

Cable

exposed

Screw

Solder

jacket

conductors

back

shelloncable.

Solder

holes

braidtoshells

ring

on back

1-1/8

in.

in both

Do not

shell.

and

use

braid.

Sol-

front

through

ex-

T.O. 31R2-4-101-1

JUMPER REMOVED

/"

Section

II

Figure

SP-600-JX-21

SP-600-JX-21

2-4.

Receiver

DIODE/OUTP~T

-

0

DIODE OUTPUT

-

Interconnections for

+

AUDIO OUTPUT

o.------1:l

v

+

AUDIO OUTPUT

a.---------o

Phone

AVC

1-

AVC

-

Space-diversity

G

0

~

G

TO

LOUDSPEA

Receiving

KER

System

SP-600-JX-21

SP-600-JX

-21

jV

DIODE/OUT:UT

-

AUDIO OUTPUT

0

OUTPUT

DIODE

---r.

-

+

AUDIO

I

I

-l-

JUMPER REMOVED

AVe

0 0

+

-

a...-----u

Ave

0 0

-

OUTPUT

a..-----o

AA/\

600

OHMS

2WATIS

TAPE

RECORDER

G

0

G

I

I

INK

Figure

2-5.

Receiver

Interconnections

for

Space-diversity

D-C

Output

Receiving

System

11

Section

11

T.O. 31R2-4-101-1

1-

"""'"0

AVC

G

:~

I

I

I

I
I

I

SP-600-JX-21

r----------------~

DIODE OUTPUT

a---u

-

1·.

I • • I

I

I

,

+

AUDIO OUTPUT

0-

••

••••.t\I\I'v- • •••: I

600

OHMS

2

WATTS

I

I

I

r------------------------~

I

I

I

I

I

I

I

I

I

I

I

I

I
I

I

I

I

I

I

I

I

I

I

-------------

L--

______________

SP-600-JX-21

r------

I

I

I

I

I

I

I

I

I

I

I

L

r--------------~

I

I

I

I

I

I

I

I

L

_____

___

DIODE OUTPUT

0-

.."

-

~.

I •

I

I

I

+

AUDIO OUTPUT

0.------0

eo

••••

600

I

I

I

J

~

~

-0

-0

RADIO TELETYPE

TERMINAL
EQUIPMENT

"/\/\/\,,.

2

WATTS

OHMS

AVC

-

•••

•

• I

0-

G

.~

I

I

I

I

I

I

I

I

IF

OUTPUT

[~}

~

IF

OUTPUT

[~]

----

........

INDICATES CONNECTIONS
A-F

SIGNAL OUTPUT

INDICATES CONNECTIONS
I-F SIGNAL OUTPUT

INDICATES CONNECTIONS COMMON
TO

BOTH SYSTEMS

.....

•

••

••

FREQUENCY - SHIFT

CONVERTER

10·

•

FOR

FOR

Figure

"DIODE
like
speaker across the
of

the second receiver.

b.

connect the

the

12

OUTPUT"

terminalofthe second receiver. Connect the loud-

For

space-diversity receptionofcow

jumpered

2-6.

Receiver

terminals designated

"AUDIO

two

receiversasshowninfigure

"DIODE

OUTPUT"

OUTPUT"

Interconnections

terminals

signals,

terminalsofone

for Frequency-shift

"-"

to

the

(8)

inter-

2-5.

Open

of

the receivers,
minal

designated
receiver.
OUTPUT"
ment.

c.
reception
in

figure

Connect

The

interconnections required

of

2-6.

Space-diversity

and

connect the

"-"tothe like

the three interconnected

terminalstothe associated

frequency-shift carrier signals are

Interconnect

Receiving

"DIODE

the

"AVC"

System

OUTPUT"

terminalofthe second

recording

for

terminalsofthe

ter-

"DIODE

equip-

space-diversity

shown

T.O. 31R2-4-101-1

Paragraphs

2-19

Section

to

2-20

II

,--

. .

two

receivers as

the

jumpers
the receivers.
equipment
receiver
ated

to the

ifanaudio

terminal
used, connect
2-2)

of

each receiver to the associated frequency-shift
converter
plugs.

output

equipment,

For

cable,

COUPLING RING

- -

--

.,.

per

step

across the

"DIODE

Connect

"AUDIO

signal is to be

equipment,orif

the

"IF

OUTPUT"

using

.-,

figure

"a"ofthis

OUTPUT"

2-7.

paragraph.

terminals

fabrication

the frequency-shift converter

OUTPUT"

terminalsofeach

applied

to the associ-

a 45S-kc signal istobe

connector (6, figure

RG-ll/U

cable

and

PL-259

fabrication instructions applicabletothe

refer

to figure

2-7.

Keep

of

i-f

PLUG

Cut

endofcable

Bare

5/8
coupling
braid.

Screw
braid
of

For

in. of
ringoncable.

the

through

braidtoshell.

final

assembly,

of

2-19.
2-20.

the complete
receiver
ure
tion
position.

Then

possible
following
graph

SUB-ASSEMBLY

even.

Remove

center

conductor.

Tin

plug

sub-assembly

solder

holes.

Solder

center

screw

I-f

Output

TESTING.

When

3-1)

and

check the

3-25

Cable

the

installation

onbyrotating

in

a clockwise direction

set

the

"SEND/REC"

Allow

the receivertowarmupfor
operationofthe

modesofoperation

the

operating

as applicable.

vinyl

Trim

exposed

on

cable.

Use

enough

conductortocontact.

coupling

ringonplug

equipment

for

the

"RF

procedures

jacket

1-1/8

in.

braided

center

shield.

conductor

Solder

assembly

heattocreate

sub-assembly.

Slide

and

to

bond

has been installed, check

proper

operation.

GAIN"

from

switch

(21)toits "REC"

control

its

"OFF"

Turn

(11, fig-

15 minutes.

receiverinthe various

on

eachofthe

outlined

six bands,

under

the

posi-

para-

13

Section

Paragraphs

III

3-1

to

T.O. 31R2-4-101-1

3-13

SECTION

OPERATION

3-1.

GENERAL.

3-2.

For

optimum

ing

procedures
operating
of

signal to be received,
communications
The
ation

3-3.

3-4.

are all located

figure
the

3-5.

cuits by
wise
integral
its

actuation
illuminationofthe
dial

3-6.

ables the r-f section
"SEND"
mission intervals
prevent
local transmission.

"REC"

3-7.

switch
includes the desired signal frequency.
is

indicatedatthe
the
matically positioned

frequency

3-8.

the
amplifier section
frequency first heterodyne oscillator to
ception
crystal-controlled
frequency, crystal-controlled first heterodyne oscillator

is used,
only the r-f circuits

The

procedures depends primarily

receiver is adjusted

by meansofthe

DESCRIPTION OF CONTROLS.

The

contrpls used

3-1.

All

front

panel

POWER.

rotating

from

its

partofthe

(6).

Once

power

do

not

switchitoff

on.

The

current

topofthe main-dial movable

"TUNING"

"TUNING"

may cause the o/g-ampere fuse to fail.'

"SEND/REC".

position.

possible damage to the receiver

position,

"BAND

(17)isused to select the frequency

band

"TUNING".

of

the desired signal.

and

receiver performance,

must

be observed.

and

link

between

for

appropriate

in

on

the

front

referencestothe controls

designations.

A-c

power

the

"RF

"OFF"

is indicated byanaudible click

high

the

position.

"RF

GAIN"

main

tuning

CAUTION

has been

momentarily

initial filter-capacitor

The

"SEND/REC"

of

the receiver

This

position is used

in

a two-way communication system

When

normal

CHANGE".

being

control

modeofoperation,

"TUNING"

receiver

"MEGACYCLES"

to

indicate the main-tuning-dial

used.

For

variable-frequency
(15)

of

the receiver

for

acceptanceofthe desired signal.

control

The

also

upon

transmitter

its various modesofoper-

normal

panel

is applied to the receiver cir-

GAIN"

The

control

dial

applied

the switch is

operation

The

is used

In

control

drives the vernier dial

proper

complexityofthe

upon

the

operating

receiver

and

are

control

power

(4)

and

to the receiver,

and

then

switch

when

actuated to the

from

returned

"BAND

The

window

pointer

to

and

provide

the

fixed-frequency,

a separate fixed-

is used to tune

operat-

the type

qualityofthe

and

receiver.

controls.

operation

shown

conform

(11),

clock-

switch is

assembly

and

the

charging

during

the

is restored.

CHANGE"

band

selected

(2)

operation,

tune the r-f

the variable-

by the

vernier

back

(21)

trans-

strong

to its

which

(5)

is auto-

for

an

and

dis-

band

and

re-

(6),

10

to

to

III

visible
panel,
quency selected.

3-9.

when
dial
anism

vents accidental

3-10.

selector switch

and
establishes
CONTROL"

selected,
of
CONTROL"
"XT
controlled
frequency
quency
socket

selector switch
The
however, advancing the

oscillation.
erance
has adequate
crystal frequency

3-12.

when

power
from
"RF
"AVC/MAN"

3-13.

establishes the typeofgain
sections
the
is established by the
In
system

through

and

"TUNING

turnedina clockwise direction, clamps the vernier

(6),

at

(15)

remains free to turn.

vibration
trol.

"FREQ

the first heterodyne oscillator section

also,

tion, the variable-frequency first heterodyne oscillator is

the

"TUNING"

ALS" positions, a separate fixed-frequency, crystal-

of

correspondingtothe selected switch position.

3-11.

"6

to

tune the crystal selected by the

calibrationofthe

ting

to the

of

"RF

turned

the

gainofthe r-f

the

controlisturned

switch associated

the

GAIN"

"AVC/MAN".

of

"MAN"

the"AVC"

of

the

"AUDIO

the

windowatthe

the main

[he

main

the desired setting.

or

accidental

when

the

and

its frequency is determined by the

first heterodyne oscillator is selected.
of
the crystal inserted

FREQ".

"LOW"

The

0.005 percent,

GAIN".

from

receiver as describedinparagraph

control

the receiver.

position, the

control

tuning

LOCK".

tuning

detuningofthe receiver due to severe

CONTROL".
(8)

set to its various

oscillator frequency.

selector switch is set to the

selector switch is set to any

the oscillator is determined by the fre-

(8)

crystals employed have a frequency tol-

range

within

its

and

switch

positionofthe switch, a delayed a-v-c

is selected.

GAIN"

The

dial

The

shiftingofthe

establishes the

control

The

"6

precisely to the

"/::,.

control

setting

and

to

compensate

these limits.

The

"OFF"

i-f sectionsofthe receiver.

to

the

with

functionsineither positionofthe

(12).

The

control

When

gainofthe

"RF

GAIN"

control

right

sideofthe

dial

(4)

to indicate the fre-

"TUNING

(4),

and

The

"TUNING

The

"FREQ

modeofoperation

(15).

into

the

FREQ"

"FREQ

FREQ"

from

decreases the frequency

the

"RF

GAIN"

position, is usedtocontrol

"OFF"

the

control

"AVC/MAN"

usedinthe r-f

the switch is actuated to

For

(16),

LOCK"

the

tuning

"TUNING"

LOCK"

"TUNING"

CONTROL"

of

the receiver

"XT

ALS" positions,

When

"VFO"

When

numbered

control

CONTROL"

proper

control

the

"HIGH"

"f:."

FREQ"

for

deviations in

control

position, the a-c

removes

switch

r-f

and

control

any fixed setting

the receiver

front

(14),

mech-

control

pre-

con-

the

"FREQ

posi-

setting

the

"FREQ

of

its six

The

crystal

(7)

is used

frequency.

is arbitrary;

set-

control

(11),

When

power

3-5.

The

(12)

and

i-f

i-f sections

(11)

alone.

output

of

of

of

14

T.O. 31R2-4-101-1

Paragraphs

3-14

Section

to

III

3-17

is

maintained
mined
that
delay

by

the

voltageinthe

leveloftwo

connectorisrequired

3-14.

"AUDIO

(16)

is
loudspeaker
justing
ing

3-15.

(22)

the

auxiliary

"SELECTIVITY".

has six

reasonably

the

"RF

input

signal

microvoltsatthe

GAIN".

used

to

provide

receptionorto

audio

output

equipment

positions

constantata level

GAIN"

control

levelissufficienttoovercome

a-v-c system. A

for

normal

The

"AUDIO

comfortable

provide

to a level suitable

associated

The

"SELECTIVITY"

which

establish receiver
widthsof0.2 kc, 0.5 kc,or1.3 kc
8 kc,

or

13 kc

ratedinthe
three

"XT

In

the

three

shorted

is

("NON-XT

i-f sectionofthe

AL"

positionsofthe

"NON-XTAL"

out.

The

three

AL").

receiver is utilizedinthe

"SELECTIVITY"

positions,

"XT

setting,

minimum

receiver

a-v-c

antenna

operatiqn.

GAIN"

headset

the

means

with

the

receiver.

eXT

AL"),

A crystal filter

the

crystal filter

AL"

positions

2

predeter­provided

control
and/or

for

for

operat-

or

incorpo-

switch.

provide

3

the

carrier

input

ad-

switch

band-

3 kc,

4 5

narrow
channel
extreme
ceiver

3-16.

control
paragraph

LECTIVITY"
"XT
is
justedinconjunction

to

3-17.

(19)
pulse-type noise
the
ceiver is
removed
each noise pulse.
by

bandwidths

interference

interference

usefulinthe

and

are

used

where

qualityorfidelityofthe

rejectionofadjacent-

under

outputissecondarytocontinuityofservice.
"XTAL

(23)ispartofthe

AL"

encountered,

provide

"LIMITER/OFF".

is used

"LIMITER"

actuating

6

PHASING".

3-15,

positions.

and

switch

the

(22)

When

"XT

with

attenuationofthe

under

conditions

interference.

positions,

operational,

from

the

and

the

receiver

The

internal

switchtoits

7

The

crystal filter

functions

is

settoone

only

adjacent-channel

AL

PHASING"

the

"SELECTIVITY"

interfering

The

"LIMITER/OFF"

of

When

the

limiter

noise

(and

outpt·t

limiter

"OFF"

8

"XTAL

conditions

PHASING"

referredtoin

when

the

of

its

interference

control

switch

carrier.

switch

ignition

the

or

similar

switch is set

circuitinthe

desired

for

the.

audio)

interval

circuit is disabled

position.

of

re-

"SE-

three

is ad-

to

re-

is

of

23---.:--...;

22-------;

I.

Tuning

2.

Movable

3.

Fixed

4.

Main

5.

"MEGACYCLES"

o.

Vernier

7. "I'::, FREQ"

8.

"FREQ

21

meter

pointer
pointer
tuning

dial

dial

motrol

CONTROL"

window

Figure

20

selector

3-1.

19

switch

Radio

18

Receiver, Front

17

9.

Plastic

1o."BEAT

11.

"RF

12.

"AVC/MAN"

13.

"MOD/CW"

14.

"TUNING

15.

"TUNING"

16

chart

OSc."

GAIN"

Panel

•

control

switch

LOCK"

control

control

switch

Controls

and

16.

"AUDIO

17.

"BAND

18.

"METER"

19.

"LIMITER/OFF"

20.

"PHONES"

21.

"SEND/REC"

22.

"SELECTIVITY"

23.

"XTAL

Indicators

C

\..iJ

(.;<

GAIN"

CHANGE"

switch

jack

switch

PHASING"

9

10

II

control

switch

switch

switch

control

15

Section

Paragraphs

3-18.

used to

ceiver.

the

and

the
through
provide

ditionally,aseparate

III

3-18

"MOD/CW".

control

For

reception

"MOD/CW"

the

bfo

is disabled.

"CW"

position,

the

for

switch,

the

to

3-24

The

"MOD/CW"

operationofthe

of

amplitude-modulated

switch is set to its

When

plate

and

the

voltageisappliedtothe

b-f-o

operationisrestored

receptionofunmodulated

capacitor

is switched
circuit to increase the circuit time
a-v-c

operation

3-19.

"BEAT

is

used to

receiver

bfo

a variable

of

the

controlisoptional,

the

most

kc,

the

control

signals

the

of

receiver
sideband
of

frequency-shift
OSc."
and

control

"space"
equipment.
"MOD/CW"

.1-20.

"METER".
conjunction
dicationofthe
a-f

output
switchinthe
switch
GAIN"

(12)

control
indicationasread
the

input
expressed
provides a

When

nal.
"AF"

position,

cates

in

put

to a

during

OSc.".

adjust

the

within

tone

output

intelligible

is useful

any

kind, as well as

when

signals are

is

adjustedtoprovide

frequencies

The

switch

with

the

r-f

to a

connected

normal

settothe

(11)

signal

in

means

decibels.

the

"METER"

level to a

for

the

decibels the

standard

referenceofsix milliwatts.

cow

reception.

The

"BEAT

nominal

the

during

range

455-kc

of

cow

andisnormally

reception.

for

When

locating

for

suppressed-carrier, single-ordouble-

being

received.

radio

teletype signals,

for

the

bfo

is

operative

(13)isin

The

"METER"

tuning

signal

the

meter

input

load.

"RF"

position,

"AVC"

setatmaximum,

on

the

upper

signal

The

meter

accurately

switch is

lower

scaleofthe

ratio

of

the

switch

internal

bfoofthe

"MOD"

switch is

operated

signals. Ad-

into

the

constant

OSc."

and

control

frequencyofthe

± 3 kc,

reception.

thus

providing

The

set to

set exactly to 455

and

tuninginweak

carrier

For

reinsertion

the

reception

the

the

proper

associated teletype

only

when

"CW"

switch

position.

(18)isused in

(1)toobtain

to the receiver

With

the

"METER"

the"AVC/MAN"

position,

scale is

"RF"

tuninginan

the

of

one
indication

and

tuning

the

microvolt,

input

the

heldinits depressed

tuning

receiver

meter

audio

T.O. 31R2-4-101-1

(13)

is

3-22.

re-

signals,

position

to

bfo

to

a-v-c

permit

3-23.
dial
accurately set the receivertoa desired signal frequency.
The

in megacycles,
pointer

the

(3)isusedtoread

pointer
an

(10)

pointerofthe

revolutions

any

setting

provide

main

cates 87.6,

The

tionofthe

at

into

division

the

"BEAT
"mark"

quency

ble settings.

ging

the

3-24.

for

reception can be

is

the

and

an

in-

the

ually.

teriorate

station

transmitter

switched to some

meter

ratio

"RF

of

quency.

also

sig-

strength

tuning

.1-20

indi-

out-

TER"

the

readingsofthe

ing

to

PRESENTATIONS

TUNING

(4,

figure

main

tuning

PRESENTATION.

3-1)

dial

andanarbitrary

(2)

is used to read the scale

frequency

band

the

is used to

arbitrary

read

0-to-l00

main

that

have been

setting.

tuning

EXAMPLE:

dial indicates 4

the

readingtolog

precise mechanical

main

tuning

approximately

600

calibration

vernier

dial

maybeestimated

bandisdivided

Tnis

permits

of

stations.

METER

READINGS.

headsetorspeaker

determined

used

for

teletypewriter

intelligibility

In

either

of

instance,

onaparticular

should

be notified by means

so

that

other

If

accurate

or

the

receiver

meter

for

switch

(1)

may be used

the

explanationofthe

(18).]

r-f microvoltsora-f

r-f

and

meter.

With

the

provide

500

milliwatts

AND

READINGS.

The

and

the

vernier

has six

dial

frequency

outer

scale.

(6)

scales

corresponding
chosen
arbitrary

the

scale.

tuning

vernier

vernier

points. Since

vernier

The

dial
made

When

dial

and

over

and

the fixed

outer

scale.

dial

(6),

numeral

indicates

the

for

under

the

by the

vernier

fixed

pointerofthe

the

vernier

this

settingis487.6.

system divides

each

frequency

divisions,

with

one-tenth

accurately, each fre-

into

approximately

extreme

reception,

or

reception can be

when

station

the

operational

predetermined

indications

audio

accuracyinthe log-

When

the

receiverisused

the

intelligibility

aurally.

When

telegraph

recorded

determined

reception

frequency,

of

activity may be

operational

of

the

received

output

are desired,

the associated

[Refer

functionofthe

TableIVmay be used to

milliwatts

a-f scale

"AUDIO

to a 600-ohm

equivalenttothe

calibrationsofthe

GAIN"

control

matching

main

tuning

are used to

calibrated

The

movable

pointer

The

vernier

which

has

the fixed

number

of

dial

dial indi-

the

rota-

band

one-half-

divisions

on

6000 reada-

of

the

receiver

copy,

vis-

begins to de-

the

remote

fre-

carrier

the

to

paragraph

"ME-

determine

db

tun-

(16)

set

load,

to

at

fully

the

before

"AF"

turn

counterclockwise

proper

position.

Always

(16)
that
ceiver
the
pressed, slowly advance
control
this
tuning

3-21.

the

means
sectionofthe
impedance
receiver.

16

to its

precaution

meter.

"PHONES".

for

connecting

receiver.

head

The

high-impedance

the

"AUDIO

loadisconnected

actuating

the

Then,

proper

may

The

setting.

result

"PHONES"

a headset to

Either

phones

maybeplug-connected

GAIN"

and

make

control

certain

to the re­"METER"
with

the

"AUDIO

Failure

in

the

switch de-

to observe

damage

jack

the

switch to

GAIN"

to the

(20)

provides

audio

output

high-impedanceorlow-

typeisrecommended.

to the

TABLE

08

-6
0

+6
+20
+40
+60

80

-1-

+100

IV.

METER DECIBEL

R-F

Microvolts

0.5

2

10

100

1,000
10,000
100,000

CONVERSION

08

-10
0

+6
+10
+15

A-F

CHART

Milliwatts

0.6
6

24

60

190

15

milliwatts
nected
milliwatt
OUTPUT"

3-25.

3-26.
3-27.

volve a sequence

following

tions

are
each possible
stance,

its

front

formance

nounal

3-28.

3-29.

a.

Plug

are

providedtoan

to

the

"PHONES"

of

455-kc i-f

connector

OPERATING

GENERAL.
The

operating

of

its useinan

outlinedinparagraphs

mode

the

controlorswitch

panel

designation.

check chart, table V, is

receiver

operation.

RECEPTION

TONE

TELEGRAPH

PRELIMINARY

the

headset
connectaloudspeaker
terminals

b. Set

the

"REC"

(8,

figure

the

"SEND/REC"

position.

8000-ohm

jack

(20).Aminimumof0.6

outputisprovided

(6, figure

PROCEDURES.

2-2).

procedures

operations

prior

operational

:.,-28

of

receiver

operation.

referredtois identified by

(See figure

OF

A-M

PHONE

SIGNALS.

ADJUSTMENTS.

into

the

"PHONES"

across

the

2-2).

switch

T.O. 31R2-4-101-1

for

the receiver

to,

activity.

through

headset

during,

These

In

3-1.)

at

the

3~56

each in-

con-

opera-

A per-

providedtoindicate

OR

SINGLE-

jack

(20)

"AUDIO

(21,

OUTPUT"

figure

3-1)

"IF

In-

and

for

or

c.

Set

the

"VFO"

d. Set

"OFF"

e. Set

XTAL"

f. Set

the

"FREQ

position.

the

"LIMITER/OFF"

position.

the

"SELECTIVITY"

3-kc position.

the

"AVC/MAN"

Paragraphs

CONTROL"

switch

selector switch

switch

switch

(22)

(12)

Section

3-25

(19)

to its

to the

to

3-29

(8)

to

"NON-

"AVe'

III

to

the

position.

g. Set

position

"4"

h.

it

countertlockwise.

i.
from
cating
pilot
dial

the

indicated

and

"6".

Unclamp

Rotate

its

"OFF"

that

lamps

(4)

and

"XTAL

the

the

the

should

the

by

"TUNING

"RF

position.

power

light,

verniel'

PHASING"

the

diamond

LOCK"

GAIN"

A click

switch has

illuminating

dial

(6).

control

(23)

between

(14)

control

(11)

shouldbeheard,

been

actuated,

the

main

Allow

the

to

positions

by

turning

clockwise

and

tuning

receiver

the

indi-

the

to

warmupforaperiodof15 minutes.

the

j. Set

"MOD/CW"

switch

(13)

to the

"MOD"

position.

k.

Rotate

the

to

frequency

window

(5)

the

"BAND

band

includes

CHANGE"

indicatedatthe

the

desired

signal

switch

(17)

until

"MEGACYCLES"

frequency.

A-C

power

Amplifier

A-M

reception

Dial

calibration

C-W

reception

Audio

source,

circuits,

output

Test

"LINE"

"-B"

fuse

fuse

TABLE

V.

PERFORMANCE CHECK CHART

Procedure

Rotate

Advance

"RF

wise

from

"AUDIO

"RF

GAIN"

its

"OFF"

GAIN"

GAIN"

control

position.

control

controltomaxi-

mum.

Loosely

Same as

qnency
brated
antenna

per

as

couple

A-M

meter

signal

generatortoreceiver

terminals.

paragraphs

signal

or

accurately cali-

3-29

Repeatoneachofthe

A-M

reception

Tune

receiver accurately

ing

meter.

Note

main

Tune

six

tuning

indication.

Loosely

Same as

quency

signal
tenna
per

paragraphs

couple

terminals.

cow

meter

accurately

generator

signal

to

Tune

3-35

Repeatoneachofthe

A-M

reception

With

loudspeaker
"AUDIO
and
ting

OUTPUT"

"AUDIO

reduced, depress

switchto"AF"

connected

GAIN"

position.

receiver an-

six bands.

control

clock-

and

from

Ere-

receiver

and

3-30.

bands.

procedure.

using

tun-

dial

from

fre-

calibrated

receiver as

and

3-36.

procedure.

across

terminals

set-

"METER"

Normal

Pilot

lamps

light.

Noise

output

speaker.

Tone

in

output
"AVC/MAN"
"A

VC",

tuning

deflects as

Indication

should

on

be accuratetowithin

percentofsignal

Beat

note

heard

ceiver.

Pitch

"BEATOSc."

Zero

beat

obtained

OSc."

Power

lower
Meter
"AUDIO

controlisset to

output

scale

indication

GAIN"

is varied.

Indication

in

headset

of

receiver.

switch

meter

signalistuned

main

tuning

frequency.

in

output

of

note

control

when

"0".

in

db

indicated

of

tuning

varies

control

or

loud

With

set

to

pointer

in.

dial

0.25

of

re-

varies as

is varied.

"BEAT

on

meter.

as

setting

17

Section

Paragraphs

1.

Turn

III

3-30

the
clockwise setting.
move upscale
or

loudspeaker.

m.

Turn

and

the

the receiver noise

Turn

the

n.

"TUNING"

to

3-33

"RF

GAIN"

The

tuning

noise should be

"AUDIO

output

GAIN'·
to a suitable level.

control
meter

control

to

(1)

heard

control

(15)

pointer

in the headset

(16)toadjust

until

T.O. 31R2-4-101-1

its

maximum

should

the main­tuning-dial indication corresponds to the desired signal
frequency.

Note

Reduce the
slightly
put

while the

tated

"RF

GAIN"

control

(11)

to avoid excessive receiver noise out-

through

"TUNING"

positionsatwhich there are

control

(15)

setting

is ro-

no

signal transmissions.

3-30.

RECEPTION

OSCILLATOR.

preliminary adjustments

and

continueasfollows:

a.

Rotate

the
direction to tuneinthe signal.
cated by a maximum indication
The

main-tuning-dial

USING

To

tuneinan A-M signal,

VARIABLE-FREQUENCY

outlined

"TUNING"

control

of

(4)

reading

in

paragraph

(15)

Proper

the

tuning

should be

perform

in

the

tuning

meter

within

the

3-29,

proper

is indi-

(1).

0.25

percentofthe frequencyofthe desired signal.

b.

Clamp

the

"TUNING

LOCK"

(14)byturning

clockwise.

Co

Readjust

sired, to

3-31.

RECEPTION

V

ARIABLE-FREQUENCY
desired signal is weak
any kind, the
graph

paragraph
nal

reception.

sired signal by use

a.

Set the

obtain

3-29

3-30

the

"AUDIO

a suitable

OFAWEAK

and
preliminary
and

the

may

not

Under

those conditions,

of

the

"MOD/CW"

GAIN"

audio

output

control

level.

SIGNAL

OSCILLATOR.

obscured by interference

adjustments

tuning

suffice to

outlinedinpara-

procedure

provide

tuneinthe de-

following

switch

procedure:

(13)

to the

(16)

as de-

USING

When

outlined

usable sig-

"CW"

the

position.

Rotate

b.

oneofthe

"MEGACYCLES"

c.

Locate a

required

(10)

for

"BEAT

Tuneinthe signal by

d.

trol

(15)

the

"BAND

lower

frequency bands is indicatedatthe
window

strong

to

accurately set the

A-Morcow

a b-f-o frequency

OSc."

control

in

either direction

CHANGE"

(5).

signal.

"BEAT

of

455 kc, since the dial

may

not

be accurately calibrated.

turning

until

the

the

switch

(17)

This

OSc."

"TUNING"

tuning

meter

until

signal is

control

of

the

con-

(1)

indication is maximum.

Adjust

e.

beat audio

£.

Rotate
frequency
dow

includes

Turn

g.

tion

until
signal frequency;
slightly to

the

"BEAT

output

the

"BAND

band

indicatedatthe

the

the

"TUNING"

the

main

then

obtain

and

OSc."

maintain

controltoobtain

this setting.

CHANGE"

switch

"MEGACYCLES"

desired signal frequency.

controlinthe

tuning

a zero

dial

(4)

readjust the

beat

indicates the desired
'TUNING"

in

the

output

until

proper

a zero-

the

win-

direc-

control

of

the

receiver.

of

in

h.

Return

the

"MOD/CW"

position.

i.

Clamp

the

"TUNING

clockwise.

Readjust

j.

sired,

to

3-32.

RECEPTION

TROLLED

the

obtain

a suitable audio

OSCILLATOR.

"AUDIO

crystal-controlled reception

telegraph

is desired,

outlinedinparagraph

that

follows:

"FREQ

"XT

to

thatofthe crystal socket which holds the

the

proper

have been recorded

corresponding

the

"TUNING"

dial

(4)

indicates the desired

~fully

a maximum indication

it

sequence

a.

Set the

the

numbered

responds

crystal

tion
which
and

of

can be determined

should

the

b.

Turn

tuning

quency and cal

to

obtain

(1).

c.Ifdesired, clamp the

turningitclockwise.

Turn

the

d.

"D

directiontoaccurately

quency.

The

proper
which a maximum indication is
meter.

e.

Readjust

sired to

3-33.

NOISE

the

maintain

SUPPRESSION.

"AUDIO

the

possible reception
made static conditions, follow the
ments

outlinedinparagraph
cedure
applicable,

outlinedinparagraphs

and

continueasfollows:

a.

Set the

"SELECTIVITY"
position which provides the
for

the desired

b.Ifthe

of

its

control

"XTAL"

(23)

modeofoperation.

"SELECTIVITY"

positions,

for

best

signal.

Co

Set the

ITER"

pulse-type noise

d.

During

"LIMITER/OFF"

position to reduce

from

standby periodsinthe transmission,

the desired signal is off the air,

control

to

fades so

receiver signal
receiver noise
"RF

(11)

down

cut

downonthe receiver noise

e.

During

reception,

thatatintervals the signal levelislow, the

output

output,

GAIN"

control

LOCK"

GAIN"

USING

of

follow

3-29,

the

and

CONTROL"

switch to the

(14)

control

output

level.

CRYSTAL-CON-

When

fixed-frequency

phone

preliminary

continue with the step

selector switch

"MOD"

by

turning

(16)

or

single-tone

adjustments

as de-

(8)

ALS" position whose numeral cor-

frequency.

from

The

proper

the plastic

the

switch posi-

chart

(9)

on

switch positions

signal frequencies.

readjust

FREQ"

adjust

setting

proper

under

attenuation

the

control

"TUNING

control

for

GAIN"

noisy atmospheric

turn

ignition

audio

(15)

until

the main

operating

the

"TUNING"

on

the

LOCK"

(7)

in

tuning

the

control

meter

(14)

proper

the crystal oscillator fre-

this

controlisthat

obtainedonthe

control

audio

output

To

provide for the best

preliminary

3-29

and

the

3-30,

3-31,or3-32,

switch

most

switch

switch

(22)

intelligible reception

(22)

is usedinone

the

"XTAL

of

any

(19)tothe

noiseorany

tuning

(16)asde-

level.

or

man-

adjust-

tuning

to the 5witch

PHASING"

interfering

"LIM-

other

output.

fre-

by

pro-

when

turn

the

"RF

GAIN"

from

its

maximum

clockwise

setting

output.

when

the signal fluctuates

or

may be favored, relative to the

by careful

readjustment

of

the

(11).

it

to

at

as

18

T.O. 31R2-4-101-1

3-34.

RECEPTION

3-35.

PRELIMINARY
procedures
of

A-M signals, except,
switch
con trol

3-36.

outlined

(13)

to the

(10)to"0".

RECEPTION

OSCILLATOR.

"CW"

To

OF

C-W

TELEGRAPH

ADJUSTMENTS.

in

paragraph

in

step "i", set

position. Set the

USING

tune

VARIABLE-FREQUENCY

inacow

SIGNALS.

Perform

3-29

for

reception

the

"MOD/C\.V"

"BEAT

OSc."

signal, proceed as

the

follows:

a.

Rotate
directiontotuneinthe signal.
cated by a zero
indicationonthe
properly
should be accuratetowithin

the

"TUNING"

control

(15)inthe

Proper

beatinthe audio

tuning

meter

outputormaximum

(1).

When

tuned in, the main-tuning-dial

0.25

percentofthe desired

proper

tuningisindi-

the signal is
(4)

reading

signal frequency.

b.Ifdesired,

clamp

the

"TUNING

LOCK"

(14)

by

turningitclockwise.

c.

Turn

the

"BEAT

rection

to

obtain
cps. Reception may be
one direction
the

position in either direction which provides the

most

intelligible reception.

Readjust

d.
clearest signal
the

position

3-37.

RECEPTION

than

the

and

providing

VARIABLE-FREQUENCY
desired signal is weak
any kind, the
paragraph
paragraph
nal

reception.

preliminary

3-35

3-36

Under

sired signal by use

a.

Follow

through

b.

Clamp

the

"g"ofparagraph

the

OSc."

a tone

output,

better

in

the other.

"RF

GAIN"

the

"AUDIO

the desired audio

OFAWEAK

and

and

the

may

not

those conditions,

of

the

instructions

'TUNING

control

with

(10)ineither

preferably

the

control

In

any case, choose

control

GAIN"

control

around

turned

(11)

output

SIGNAL

OSCILLATOR.

When

obscured by interference

adjustments

tuning

procedure

suffice to

referred

provide

outlined

usable sig-

tuneinthe de-

following

3-31.

LOCK"

procedure:

outlined

(14)byturning

in

steps

di-

1000

for

the

(16)

level.
USING

the

to

"b"

in

of
in
in

clockwise.

c.

Turn

the

"BEAT

direction

to

obtain

1000 cps,asoutlinedinstep

d.

Readjust
clearest signal
to

the position

3-38.

RECEPTION

TROLLED

the

and
providing

OSCILLATOR.
crystal-controlled- receptionofcow
desired,
in

through

rection to

perform

paragraph

a.

Follow

"d"ofparagraph

b.

Turn

the

obtain

the

3-35,

the instructions

"BEAT

a tone

cps. Reception may be

OSc."

a tone

output,

"c"ofparagraph

"RF

GAIN"

the

"AUDIO

the desired

USING

When

preliminary

and

continue as follows:

outlined

3-32.

OSc."

control

output,

better

with

control

(10)

preferably

control

GAIN"

audio

CRYST

fixed-frequency

telegraph

adjustments

(10)ineither

preferably

the

control

(11)

control

output

AL-CON-

signals is

referred

in

steps

around

turned

in

around

3-36.

for

either

the

(16)

level.

to

"a"

di-

1000

in
one direction thaninthe other.Inany case, select the
position

which provides the

most

intelligible

reception.

c.

Readjust

the

"RF

clearest possible signal

trol

(16)toprovide

3-39.

NOISE
possible
made conditions,

referredtoin

cedure

outlinedinparagraphs

applicable,

a.

Set the

"XT

AL"

SUPPRESSION.

cow

reception

paragraph

and

continue as follows:

"SELECTIVITY"

switch

perform

position

Paragraphs

GAIN"

and

the

control

"AUDIO

the desired audio

To

provide

under

noisy atmosphericorman-

the

preliminary

3-35,

follow

3-36,

switch

which

provides

3-34

output

the

3-37,

Section

(11)

GAIN"

for

adjustments
tuning

or

(22)

11\

to

3-43

for

the

con-

level.

the best

pro-

3-38,

as

to

the

the best

reception.

b.

Turn

the

"XT

AL

PHASING"
position
fering

ITER"
pulse-type noise

signal reception
to

3-40.

to

3-41.

procedures
nals, except,

(13)

trol

3-42.

which provides best

signal.

c.

Set

the

"LIMITER/OFF"

position

d.

Readjust

provide

the desired

RECEPTION
TELETYPE

PRELIMINARY

outlinedinparagraph

in

to the

"CW"

(10)to"0".

RECEPTION

to reduce

from

the

the

"RF

GAIN"

and

the

audio

OF

SIGNALS.

step

"j",

position. Set the

USING

attenuationofany

ignition

audio

"AUDIO

output

FREQUENCY-SHIFT

ADJUSTMENTS.

set

VARIABLE-FREQUENCY

switch

output.

control

GAIN"

3-29

the

"MOD/CW"

"BEAT

control

(19)

noise

(11)

level.

(23)

to the

or

any

for

control

Perform

for

A-M

OSc."

to a

inter-

"LIM-

other

clearest

(16)

the

sig-

switch

con-

OSCILLATOR.Totuneina frequency-shift signal, pro­ceed as follows:

a.

Turn

the

"TUNING"

direction so

that

the two-tone
the receiver is slightly detuned, is
tone

output

indication

it

may be usedtotune
receiver is
quency
cent

of

If

b.

signal,oradjust

on

the

properly

indication

should

the signal frequency.

desired, clamp the

tuning

tuned, the

control

output

(15)inthe

signal,

changedtoa single.

the

control

meter

(1).

Either

foramaximum

the receiver properly.

main-tuning-dial

be accurate to

"TUNING

within

LOCK"

proper

heard

procedure

When

(4)

0.25 per-

(14)

when

the

fre-

by

turningitclockwise.

c.

Adjust
two-tone
shift. Reception may be
in

one direction

3-43.

VARIABLE-FREQUENCY
desired signal is
any

kind,
paragraph
paragraph
nal

reception.

sired signal by use

a.

Follow

through

the

"BEAT

outputat2500 cps

thaninthe

RECEPTION

weak

the

preliminary

3-41

and

the

3-42

may

not

Under

those conditions,

of

the

the instructions

"f"ofparagraph

OSc."

control

(10)toobtain

plusorminus the

better

with

the

other.

OF

WEAK

SIGNAL

OSCILLATOR.

and

obscured by interference

adjustments

tuning

procedure

sufficetoprovide

tuneinthe de-

following

procedure:

outlined

3-31.

control

When

referred

outlined

usable sig-

In steps

carrier
turned

USING

the

to

"b"

a

of
in

in

19

Section III

Paragraphs

Turn

b.

direction
sponds
carefully

two-tone
slightly

nal,

or

the

tuning

properly
receiver is
quency indication

3-44

to

3-50

the

"TUNING"

until

the

main-tuning-dial

to the frequency

readjust

output

the

signal,

"TUNING"

detuned,ischanged

adjust

the

control

meter

(1).

Either

adjust

the

properly

"TUNING"
tuned,

shouldbewithin

control

(15)inthe

(4)

of

the desired signal.

control

heard

when

to~single-tone

foramaximum

procedure

control.

the

main-tuning-dial fre-

0.25

desired signal frequency.

c.Ifdesired, clamp the

"TUNING

turningitclockwise.

d.

Adjust

two-tone

the

"BEAT

OSc."

control

outputat2500 cps plusorminus
shift. Reception may be better with the
in

one

direction

e.

Readjust

the

clearest signal

(16)toprovide

3-44.

RECEPTION
OSCILLATOR.
reception

the

preliminary

3-41,

and

a.

Follow

through

"d"ofparagraph

b.

Turn
direction to
minus

the

control

the

turnedinone

c.

Readjust

clearest signal

(16)toprovide
3-45.

NOISE
sible frequency-shift reception
or

man-made static conditions,

adjustments

tuning

or

tions

procedure

3-44,

outlined

thaninthe

the

"RF

and

the

desired audio

USING

When

of

frequency-shift signals is desired,

adjustments

other.

GAIN"

the

control

"AUDIO

output

CRYST

AL-CONTROLLED

fixed-frequency, crystal-controlled

referred

continue as follows:

the instructions

outlined

3-32.

the

"BEAT

obtain

OSc."

a two-tone

control

outputat2500 cps

carrier shift. Reception may be better with

the

"RF

the

direction

GAIN"

and

proper

the

thaninthe

control

"AUDIO

audio

output

SUPPRESSION.Toprovide the best pos-

under

noisy atmospheric

perform

referredtoin

paragraph

outlinedinparagraphs

as applicable, and

in steps

"a"

then

through

follow the instruc-

"d"

3-39.
3-46.

3-47.
sideband

done
vide a 455-kc carrier which can be
or

3-48.

XT

RECEPTION

MULTICHANNEL

AND

TELETYPE

GENERAL.

reception,

transmitter,

must

be reinsertedatthe receiver.

by useofthe

double-sideband signals

PRELIMINARY

a.

Perform

through

b.

Set

AL"

the

"d"ofparagraph

the

"SELECTIVITY"

3-kc, 8-kc,

OF

SUPPRESSED-CARRIER

PHONE,

TELEGRAPH,

SIGNALS.

To

provide

the

signal carrier, suppressedatthe

internal

for

single-

bfoofthe

addedtothe single-

prior

to detection.

ADJUSTMENTS.

procedures

outlined

3-29.

or

13-kc position,

switch

(22)toits

T.O. 31R2-4-101-1

proper

reading

corre-

Then

so

that

the receiver is

output

indication

may be used

When

percentofthe

LOCK"

(14)

(10)toobtain

the

carrier

control

turned

(11)toprovide

GAIN"

control

level.

perform

to in

paragraph

in

steps

(10)

in

either

plus

other.

(11)toprovide
GAIN"

control

level.

the

preliminary

3-41,

follow the

3-42,

3-43,

of

paragraph

or

double-

This

receivertopro-

in

steps

"NON-

depending

upon

the

sig-

on

the

by

"a"

or

the

"a"

to

the

bandwidth
templated.
ation

are usually 170 cps,

for

single-sideband
ception,
required.
intelligence

required

Channel

either

the

For

double-sideband transmissions, the signal

for

each side

for

the

modeofoperation

separations

reception;

in

and

the 3-kc position suffices

for

8-kcorthe 13-kc

bandisindependent

multichannel oper-

double-sideband re-

position

con-

may be

of

the

other.

c.

Set the

d. Perform the procedures outlined in steps Hf"

through

set

the

3-49.
OSCILLATOR.

a

perform

graph

a.

Turn
directiontoaccurately resonate
the

desired signal frequency.
control
ing

meter
reading
carrier
ceiver by listening
but

one
LECTIVITY"
tion.

Then
direction until
cuit is clearly intelligible as
signals (595 cps

or

as automatic Morse-code keyingofa

as applicable.

(22)tothe

of

paragraph

b.Ifdesired, clamp

"BEAT

"n"

"MOD/CW"

RECEPTION

the

preliminary

3-48,

and

the

OSc."

of

paragraph

USING

To

tuneina suppressed carrier signal,

switch

control

3-29,

(13)

VARIABLE-FREQUENCY

adjustments

continueasfollows:

"TUNING"

control

the

Proper

is indicated by

(1).

At

shouldbewithin

frequency.

maximum

resonance, the main-tuning-dial

0.25

percentofthe

Whenitis desired to

to

the

audio

channelofthe transmission by

switch

turn

(22)toits

the

"TUNING"

the

receiver audio

phone,

for

Then

required

"mark"

reset the

position as

and

"SELECTIVITY"

determined

3-48.

the

"TUNING

(10)to"0".

except,instep

to the

"CW"

outlined

(15)

in the

position.

in para-

proper

receiver circuits to

adjustmentofthis

deflectiononthe

suppressed

tune

the

output,

"XT
control

output

attenuate

setting

the

ALS" 1.3-kc posi-

(15)ineither

from

one

as two-tone teletype

425 cps for

"space"),

IOOO-cps

in step

LOCK"

(14)

J,

tun-

(4)

re­all

"SE-

cir-

tone,

switch

"b"

by

turningitclockwise.

c.

Readjust

provide the desired audio
3-50.

TROLLED
crystal-controlled multichannel reception

the

RECEPTION

OSCILLATOR.

"AUDIO

GAIN"

output

USING

level.

When

control

CRYST

(16)

AL-CON-

fixed-frequency

of

a single-

to

or
double-sideband suppressed-carrier signal is desired, per­form

the

preliminary

3-48,

and

continue as follows:

a. Set

the

"FREQ

the

numbered

nation

is

the crystal

quency.

from
tions

cies

tion

corresponds to the crystal

the

and

should

b.

Turn
to resonate the crystal oscillator precisely. Reso-

"XT

for

The

correct switch position may be
plastic
the

corresponding

have been recorded.

the

nance is indicated by a

ing

meter

(1).

by listening to the receiver audio

adjustments

CONTROL"

ALS" position whose

the

desired suppressed-carrier signal fre-

outlinedinparagraph

selector switch

numeral

holder

which

determined

chart

(9)

on

which the switch posi-

suppressed-carrier frequen-

"6,

FREQ"

Whenitis

control

maximum

(7)ineither

deflectiononthe tun-

desired to resonate the circuit

output,

attenuate

(8)

to

desig-

carries

direc-

all

20

Section

Paragraphs

but
LECTIVITY"
tion.
tion
as phone, as two-tone teletype signals (595 cps
"mark"
code keying
set

as determined

directiontoresonate
the suppressed-carrier single-

quency.

by maximum deflection

tain

turningitclockwise.

provide

3-51.

sible single-

ception
conditions,
lined
outlinedinparagraphs
and

XTAL"

ITER"
type noise from the audio output.

the
(16)toprovide the

3-52.

3-53.
tion

ing

"SEND/REC"

ing

receiver from the
transmission has been completed,
the

signals, unclamp the

tune

3-30
applicable.
oratlonger

III

3-51

to

3-58

one channelofthe transmission by setting

s\Yitch

Then

turn

until

the receiver audio

and

425 cps

ofaWOO-cps

the

"SELECTIVITY"

in

c.

Turn

the

"TUNING"

Proper

the

"6.

FREQ"

d.Ifdesired, clamp the

e.

Readjust the

the

proper

NOISE

in

continueasfollows:

a. Set the

b. Set the

positiontoreduce ignition noise

c.

Readjust the

dearest

PERIODIC
ADJUSTMENTS.

To

providing

operating

a.

When

transmission intervals

"REC"

b.

When

the

orinsteps

SUPPRESSION.Toprovide

or

under

perform

paragraph

"SELECTIVITY"

position which provides

"LIMITER/OFF"

signal and the

maintain the communication

for

procedures, as applicable, when required.

the operational activity is two-way, set the

switch

position to provide for
the receiver is used for receptionofA-M

receiver as outlinedinstep

Do

intervals,

(22)

to its

"XTAL"

the

"6.

FREQ"

for

"space"),oras automatic Morse-

switch to

step

"b"

the

adjustmentofthis

on

control

"AUDIO

audio

double-sideband suppressed-carrier re-

noisy atmospheric

the preliminary adjustments out-

3-48,

3-49

"RF

GAIN"

proper

AND

SPECIAL

optimum

(21)

strong

"b"

this periodicallyatIS-minute intervals,

local transmission.

"TUNING

and

depending

controlineither direc-

output

tone,asapplicable.

of

control

r-f sectionofthe receiver

the

'TUNING

output

follow the

reception, repeat the follow-

to the

to

"d"

is clearly intelligible

the

required position

paragraph

(15)inthe

or

double-sideband fre-

control

tuning

(7)assetinstep

GAIN"

or

switch

switch

"AUDIO

audio

prevent damage

meter

LOCK"

control

level.

or

man-made static

tuning

3-50,

(22)tothe

the

best reception.
(19)tothe "LIM_

and

control

of

(11)

GAIN"

output
OPERATING

linkina condi-

"SEND"

return

normal

LOCK"

"a"ofparagraph

paragraph

upon

the

1.3-kc posi-

Then

3-48.

is indicated

(1).

"b".

(14)

(16)

the

best pos-

procedure

as

applicable,

"NON-

other

to provide

level.

position dur-

When

the switch

reception.

(14),

and

3-32,

the frequency

T.O. 31R2-4-101-1

"SE_

for

re-

proper

to

Main-

by

to

pulse-

control

drift
tion, repeat the procedures

c.
signals, unclamp
retune
3-36
applicable.
oratlonger
drift
tion, repeat the procedure outlined
Also reset the
as outlined

d.
frequency-shift teletype signals, unclamp the

LOCK"
step
paragraph

15-minute intervals,
upon
the quality
in

paragraph

(10),

3-42.

e.
suppressed-carrier multichannel signals, unclamp the
"TUNING
cordance
"b"and
periodically
vals, depending
noise impairs the qualityofreception, repeat the proce­dures outlined

3-54.

3-55.
when

a.
control
position.

3-56.

3-57.

to

the
the

to

re-

as

3-58.

the

factory
tons (18, figure
to

provide accesstothe various inductance
and
as well as
ADJ
driver adjustment controls, are
and

ceiver performance

noted.

When

noted.

When

"a"ofparagraph

When

advisedtodo

Turn

capacitor trimmers. These alignment adjustments,

RF"

cannot be

When

the receiver is used for the receptionofcow

the receiverasoutlinedinstep

orinsteps

Do

When

in

the

(14)

3-32,

the frequency

of

if

necessary, as outlinedinstep

the

LOCK"

with

"c"ofparagraph

at

DE-ENERGIZING

Upon

the receiver off by

(11, figure

Deleted.

PRECAUTIONS TOBEOBSERVED.

The

receiver is precisely aligned

for

the

(5),

noise impairs the qualityofrecep-

outlinedinparagraph

the

"TUNING

"b"

and

"d"

this periodicallyat15-minute intervals,

intervals,

"BEAT

step

receiver is used

and

reception, repeat

3-39.

receiver is

step

W-minute intervals,orat

upon

in

completion

optimum

2-1)

"BFO

and

manipulated

depending

noise impairs the quality

OSC." control

"c"

of

retune the receiverinaccordance

3-42orin

as

applicable.

oratlonger

drift

noted.

Reset the

uS2d

(14)

and retune the receiverinac-

"a"ofparagraph

3-50,asapplicable.

the frequency

paragraph

so,

3-1)

IN]"

the

and

3-51.

THE

of

do

the

counterclockwisetoits

performance.

cover the chassis openings used

(4, figure

"METER

without

the meter scale calibrations.

LOCK"

"a"ofparagraph

of

paragraph

upon

the

in

paragraph

(10),ifnecessary,

paragraph

steps

Do

When

the

"BEAT

for

EQUIPMENT.

the operational activity,

following:

turning

ADJ

not

3-36.

for

the reception

"b"

this periodically

intervals,

noise impairs

procedures

OSC."

"c"ofparagraph

the

3-49

drift

the

and
The

2-2),

AF"

operating

impairing

(14)

3-32,

frequency

of

"TUNING

and

"d"

depending

outlined

control

reception

orinsteps

Do

longer

noted.

When

"RF

GAIN"

"OFF"

adjusted at

metal but-

tuning

"METER

(7)

screw-

controls

the re-

3-33.

and

recep­3-39.

with

this

inter-

cores

as

of

of
at

of

Revised

1

August

1956

21

T.O. 31 R2-4-101-1

Paragraphs

Section

4-1

to

IV

4-6

SECTION

EMERGENCY

4-1.

GENERAL.

4-2.

Inanemergency, when a defect developsinthe

receiver,
extentofthe defect
panel
receiver may

the
may remain

taining

the crystal-controlled first heterodyne oscillator
the
is being used, operation may be maintained by using the

variable-frequency first heterodyne oscillator.
circuitsofthe receiver are disabled, receptionofA-M
signals may still be possible.
the
six bandsofthe
ing
link
operative bands

the

operator

controls.Inmany instances, while a sectionofthe

be

desired mode

operational

the

communications link.Ifa defect develops

fixed-frequency crystal-controlled modeofoperation

r-f sectionofthe receiver

frequencies have been assigned,

may be maintained using a frequencyononeofthe

should

through

disabled

of

operation,

receiver.Inthis case,ifalternate

of

the

attempt

manipulationofthe

and

prevent

other

and

provide

Trouble

and

receiver.

a meansofmain-

affect only oneofthe

the

The

TABLE

to determine

reception using

receiver circuits

If

may develop

communications

operator

VI.

the

front-

when

the b-f-o

operat-

should

EMERGENCY

OPE'RATION

become
these
be resorted toinan

4-3.

4-4.

anced

In

in

in

damaged, reception may be possible using a

of
to

4-5.

4-6.

each electron tube

the
used to

electron tube used

unavailabilityofspare tubes
table VI,
to maintain continuity

TUBE

IV

thoroughly

and

other

ANTENNA

For

optimum

doubletorstraight-wire

an

emergency,

insulated wire

the

"ANT"

EMERGENCY

The

type

chassis, adjacent to each tube. Figure

rapidly

when

REPLACEMENT

familiar

alternate operational procedures may

emergency.

SYSTEM.

results, a

when

strippedatone

input

connector (8, figure

TUBE

and

within

identify

in

applicable, may be usedinan

with

his equipment, so

properly

antenna

the

antenna

end

REPLACEMENT.

reference symbol designation

the

receiver is stamped

the

location

the

of

receiver.

service.

In

and

specific tube failure,

that

designed bal-

should be used.

system has been

short

piece

for

connections

2-1).

of

on

2-1

may be

of

each specific

the

instance

emergency

of

Tube Identification

JAN

Tube Type

S726/6ALSW

6C4 V4, V8,

S749/6BA6W

/6097

Emergency

Procedure

Complement

of

Specified

Tube Type

VI4,

VIS

V20

Vl3

VI,

V2

V7, V9, YIO,

VII,

VIO,

VI2

Remove

VIS

VI4
V4

V8

Vl3

V8

and

VI3
V7

VI2

Vll

Replace

YI4

Y20
Y8orYI3

Y4orYI3

Y4orV8
Y4

VI,

or

VI,
Y9, VIO,
YU

VI,
YIO,

For

or

V20

Y2, V9,

VII,

VI2

V2, V7, AM.

or

V2, V9, I-F

Y7

Operation

Limited

Any

I-F

output

Fixed freq
reception

Any

below

7.4 me
AM.
AM

below

7.4 me
Any

above

7.4 mc

output

To

Results

EffectonLimited

Operation

Limiter
af nonoperative

No

avc

None

None

None

None

None
None

None

Noavc

and

meter

22

6BE6

VS,

V6

Y6

YS

Any

below

7.4 mc

Revised

None

1

August

1956

T.O.31R2-4-101-1

Paragraphs

Section

4-1

to

IV

4-6

EMERGENCY OPE'RATION

4-1.

GENERAL.

4-2.

In

an emergency,

receiver,

the

operator
extentofthe defect
panel controls.

In
receiver may be disabled
the

desired
may remain
taining

modeofoperation,

operational

the communications link.Ifa defect develops
the crystal-controlled first heterodyne oscillator
the

fixed-frequency crystal-controlled

is being used,

operation
variable-frequency first heterodyne oscillator.
circuits

of

the receiver are disabled, receptionofA-M
signals may still be possible.
the

r-f sectionofthe receiver

six bands
ing
link
operative bands

of

the

receiver.Inthis case,ifalternate

frequencies have been assigned,

may be

maintained

of

when

a defect developsinthe

should

through

many

attempt

to determine the

manipulationofthe front-

instances,

and

and

while

prevent

other

provide

a sectionofthe

reception

receiver circuits

a meansofmain-

modeofoperation

may be maintainedbyusing the

Trouble

and

may develop

affect

only

the

communications

using a frequencyononeofthe

the receiver.

The

TABLE

operator

VI.

If

oneofthe

EMERGENCY

SECTION

using

in

when

the

b-f-o

in

operat-

should

IV

become
these
be resorted

4-3.

4-4.
anced
In
damaged, reception may be possible
of
to the

4-5.

4-6.
each electron tube
the
used to
electron tube used
unavailabilityofspare tubes
table

to maintain continuity

TUBE

thoroughly

and

other

toinan

ANTENNA

For

optimum

familiar

alternate

emergency.

SYSTEM.

results, a

with

operational

doubletorstraight-wire

an emergency,

insulated wire

"ANT"

EMERGENCY

The

type

when

the

antenna

strippedatone

input

connector (8, figure

TUBE

and

within

REPLACEMENT.

reference symbol designation

the

chassis, adjacent to each tube.

rapidly

identify

in

the

the

location

receiver.

and

VI,

when

applicable, may be usedinan

of

service.

REPLACEMENT

properly

antenna

receiver is stamped

his equipment, so

procedures may

designed bal-

should

be used.

system has

usingashort

end

for

connections

2-1).

Figure

In

of

the

2-1

may be

each specific

instance

specific tube failure,

emergency

that

been

piece

of

on

of

Tube Identification

Complement

of

JAN

Tube Type

5726/6AL5~/6097

Tube Type

6C4 V4, V8,

5749/6BA6~

6BE6

Specified

VI4,

VI5

Emergency

Remove Replace For Limited

VI5

Procedure Results

VI4

V20

VI4
V4

V20

V8

VI3

V8

VI3

V8

and

V4orVI3

V4
V4

Vl3

VI,

V2

V7

VI,
V7, V9, VIO,
VIO,

VII,

or
VI2

V12

VI,

V9, VIO,

Vll

Vll

VI,

VIO,

V6 V6

V5,

V5

or

V20

or

VI3

or

V8

V2,

V9,

VII,

VI2

V2, V7, AM.

or

V2, V9,

V7

Operation

Any

I-F

output

Fixed

freq

reception
Any

below

7.4 mc
AM.
AM

below

7.4

me

Any

above

7.4 mc

output

I-F

Any

below

7.4 mc

To

Effect on Limited

Operation

Limiter
af

and

meter

nonoperative
Noavc
None

None

None
None

None
None

None

No

ave

None

23