National NCX-5 User manual

37

WASHINGTON

STREET •

MELROSE,

MASSACHUSETTS

NCX-5

TRANSCEIVER

-

You

now

own a product

oldest

and

most communications superb

communications

Our

experience

highly

skilled

test

for

more

than relatively their workmanship purchased

We ment of manufacturers As a result, quality.

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Your series complex may or

For equipment all the

The cuum defective ment found examination, unit authorized to the one to

original

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National

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National

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highly

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Radio

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guarantee

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Radio

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manufacturers

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.

INDEX

Page SECTION 1 GENERAL SECTION

2 INSTALLATION

2.1 Power Supplies

2.2

Mobile

2.3

Microphone

2.4

Mobile

2.5 Auxiliary

SECTION 3 OPERATION.

3.1

Tuning

3.2

Detailed

SECTION 4 THEORY

4.1

4.2

4.3

4.4

4.5

4.6

SECTION

5 ALIGNMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.1

5.2

5.3

5.4

5.5

5.6

5. 7 Receiver Bandpass

5.8

5.9

5.10

5.11

5.12

5.

13

5.14 Neutralizing

5.15

5.16

5.1 7 Local Oscillator Crystal

5.18 Parasitic

5.19

5.20

5.21

5.22 Switching

5.23 Transceive

5.24 Anti-

5.25

OF

General The

Transmitter

The

Receiver

The

VOX

The

Function

Relay

Equipment Initial IF

Alignment Balanced Carrier Transmitter

VFO

Frequency

VFO

Linearit

VFO

Sideband Temperature Transmit Final

Amplifier Preliminary Adjustment

Final

Amplifier Final

Amplifier

Carrier

Transmit-Receive LSB-USB

VOX

VFO

Jack

DESCRIPTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

......................

Mounting

Connections

Speaker

Procedures

Use

Relay

...

. .

Inst

Control

..............

of

the

OPERATION

Circuits

Switches

Functions

Required

Control

Oscillator

Suppression, and ALC

Settings

Procedure

Modulator

Bandpass

Alignment

y Adjustment

Switching

Compensating Adjustment

Mixer

Check

and

Capacitor

Preliminar

Tuning

Switching Check

Tests

Vernier Check

allation

Terminals

Individual

......

Adjustment

Setting

Tuning

Driver

Checks

Adjustment

Sideband

Checks

Frequency

Adjustment

Alignment

y Adjustment

......................

...

........

Controls

....

.....

...........

(10

(80-15

Suppression,

Check

....

....................

. ...

Meter

)

Meter

)

Modulation,

.

.........

........

.....

3

5

11

SECTION 6 PARTS

LIST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

SECTION 7 VOLTAGE

AND

RESISTANCE

1

MEASUREMENTS

.....................

26

SECTION

1

GENERAL

The

NCX-5 transceiver for amateur stallations, as well as for portable cation. AM and features with separate receiver-transmitter combinations.

bands,

The operation high

frequency stability, together

in

is

a five

the

80, 40, 20, 15,

intended

NCX-5

all

provides choice

with unusually

three

modes normally available only

band

high-performance

and

for use in fixed

and

mobile appli-

of

SSB,

accurate

dial calibration

with

10 home

CW,

operating

DESCRIPTION

band

meter

in-

or

pression checks

the microphone critical by this system. circuit

to reduce

ALC (automatic

NCX-5.

in

splatter.

QRM

or

to make

with

the

calibrated S-meter.

le\·el control)

Effecti\·e talk power

gain

and

speech loudness

The

10 db. range

the

NCX-5

prevents "flat

accurate

is

incorporated

is

increased

are

made

of

topping"

SSB sup-

in

and

non-

the

ALC

and

NATIONAL

A

a 6

to

60 db. shape factor

of

2.8

Kc

@ 6 db. provides sideband suppression

receiver selectivity previously cial communications

DIGITAL

play provides easy

The

SOLID

warm-up

initial VFO's. crystal controlled high frequency oscillators, results a remarkably stable double conversion receiver transmitter combination.

NCX-5 frequency range frequency.

of The

The

stability

A

TRANSCEIVE allows

from

of

-+-

5

SIDEBAND

a switch; (USB-LSB)

operator

may

8-pole crystal lattice filter

of

1.7:1

and a bandwidth

found

only in

equipment.

READOUT

adjustment

STATE

drift

independent

that

of

Kc

from

SELECTION

instantly select the opposite side-

from a counter

and

resettability.

VFO

eliminates

so characteristic

of

this

VFO,

VERNIER

adjustment

the

·transmitter

the

displayed

without

is

possible

retuning

control

of

together

of

section

(transmitter

commer-

type dis-

the

tube

the

receiver

at

the

with

drastic

type

with

in

over

flick

VFO.

and

in

and

the

An

ALC

INPUT NCX-5 amplifier for control voltage from

performed from

or

operation

switching

a AM,"

tion.

a

nects to the VX-501 optional

)

VX-501, when used pletely frequencies, as well as transceive control the the transmit, receive

for use

Choice

SSB.

BREAK-1:\f

at

Two

product

and

A

VFO

independent

VX-50 1 or VX-501

with

the

NCL-2000.

of

VOX-PTT-MANUAL

the

GRID

accomplishes

the

tap

detectors are

detector for SSB,

an

excellent diode

INPUT

the

provides for crystal control

or

JACK

the

NCL-2000 2

of

the

front

panel

BLOCK

automatic

of

a key.

incorporated

JACK

with

the

control

NCX-5.

transceive frequencie;;.

Besides its \

is

NCX-5

when

KEYING

CW,

or

detector

on

the

VFO

NCX-5,

of

transmit

provided

operating

transmit-receive

in "exalted

for

rear

on

Kw

linear

by

the

ALC

operation

for

the

NCX-5:

carrier

AM

opera-

apron

console.

pro\·ides com-

and

receive

by

either

·Fo

function,

oi

!he

:\CX-5

the

is

AM

CW

conThe

2

SECTION 2

INSTALLATION

2.1

POWER

The

the

matching

NCX

-D 12 volt D.C. recommend use signed for "stiff" voltage regulation

NCX-A

ginning with

with

the with serial numbers beginning with 44, 49, 57, 63, 69, or

72

must be modified before use with the

transceiver.

connecting a the

two

the

NCX-A

revised s

2.2 MOBILE MOUNTING:

equipment with operation, this bracket should automobile dashboard with screws. located as ing transceiver directly mit from the considerable quency stability

portant cabinet and may be removed from

2.3

with a three circuit jack providing a

main

put

phone

recommended for mobile op

nected

microphone is equipped with a push-to-talk button,

the

upply

A

mounting

For

bracket. A

rapid

to

firmly tightened.

MICROPHONE CONNECTI

'rhe

shank

of

a high-impedance ceramic (a

to

push-

SUPPLIES:

NCX-5

330

mount.

that

microphone

crystal microphone

to-ta

transceiver

NCX-A

of

the

NCX-5

power supplies 73

or

transceiver.

This

modification

660

ohm

power suppl

is shown on Figure #

the

maximum

far

apart

pair

installation

vibrat

of

all mounting screws used

the

chassis

of

the

ring

lk

button

115/230 volt A.C.

power

the

National Power Supplies de-

because

and

higher

are

10

watt

10

watt

resistors R-5

y.

A partial schematic

bracket is supplied as s

NCX-5

two#

stability, these screws should be

as possible

of large threaded knobs hold

to

the

bracket. These knobs per-

or

removal

Mobile operation usually results in

ion

and

shock.

the

NCX-5

and

panel

In

mobile use,

the

bottom

input

of

three circuit plug.

of

the

three circuit

should be

may

be used with

supplies.

of

their

superior filtering.

with

serial numbers be-

designed for operation

NCX-A

power supplies

or

We

strongly

extremely

eith

NCX-5

may

be easily

resistor in parallel with

1.

transceiver.

be

mounted

10, # 12,

in

the mobile

of

For

transceiver,

assembly be

of

the

ONS:

the

NCX-5

or

may

be used,

eration)

so

made

and

R-6

of

tandard

For

mobile

under

or

1/4

mount-

the

transceiver

maximum

it

is

to

hold

in

place

the

rubber

NCX-5

is

equipped

ground

The

dynamic micro-

should

wired

audio

but

jack

on

is

be

.

If

that

er

the

by

in

the

x 20

the

fre-

im-

the

feet

.

the

out-

not

con-

the

tip

of

the

microphone plug is connected grounded button is connected

microphone plug will result volts the

equipped with a grounding contact so ulation phone plug is removed. illustrated in figure No.

a good quality, wide-range microphone, since all neces-

sary restriction the the operation may inside microphone cartridge terminals

released.

2.4

for use most convenient automobile broadcast radio. brought rear the the either

2.5

current to NCL-2000 amplifier.

ceive, closed

shank

is pressed.

Accidental interchange

to

the

microphone.

'rhe

microphone

of

NCX

-5 crys

microphone should be modifie d

be done by bending

the

MOBILE SPEAKER INSTALLATION:

When

with

out

of

the

speaker

dash

to

the

AUXILIARY

A

pair

capacity is provided

allow control of accessory

of

the

plug

when

The

microphone push-

to

the

-40

volt bias.

- CAUTI

microphone cartridge, which

the

transceiver is possible when

of

audio

tal

lattice filter.

without depressing

microphone

the

NCX-5

the

NCX-D

to

use

of

the

12

NCX-5

through a DPDT

allow choice

NCX-5

of

during

(pins 5

or

RELAY

SPST

relay terminals

transmit.

ON-

of

the

in

application of

input

jack

of

Microp

1.

bandwidth

so

is installed

the

'rerminals

hone connections

We

recommend the use

is accomplished

The

the

PTT

one

of

the

that

it

does

when

in

supply,

the

terminal Jones plug

and

of

standar

CONTROL TERMINALS:

at

it

speaker

Two

7)

and

switch

speaker operation

d broadcast radio.

rated

the

rear

equipment

are

shorting contacts

the

wmng

the

P'I'T

to

an

will usually be

of

leads should be

mounted

open

to

the

push-to~talk

to-ta

lk

button

on

the

-40

may

damage

NCX-5

that

no

mod-

the

micro-

are

circuit

permit

not the

of

VOX

button.

connected

at

This

short button

automobile

the

regular

at

under

3 amperes

the

NCX-5

such

as

during

the

with

the

re-

is

of

in of

is

to

3

INSTALLATION

FIGURE

=

1

REVIS1 NCX-5

.

3

0 N

TRANSCE IV

. .

5 4

.

7

FOR

USE

ER

WITH

I POWER SWITCH

~

POWER SWITCH

~:.60YYOLOLTT

4 5

6 COUUON GROUND

7

~

BIASo6UA

HEATER

SPEAKER

+280YOLT0200UA +700YOLTo300UA

GROUN~

5

A

II

I

...l.

6 5

I

I I

3 2

I

POWER

CONNE

MICROPHONE CONNECT.ONS

7

4

CTIONS

4

3.1 TUNING

3.1.1

PRELIMINARY

PROCEDURES:

ADJUSTMENT

SECTION

3

OPERATION

2.

VOX GAIN inside top cover should be set fully ccw, and

o'clock.

GAIN,

CARRIER

VOX

DELAY, and

BALANCE

MIC

at

12

-CAUTION-

BEFORE

THE

NCX-5 TRANSCEIVER,

PRELIMINARY MADE: A SUITABLE ANTENNA LOAD SISTIVE CONNECTED NALS, A BE TO

MICROPHONE NECTED JACKS. REMAIN THESE

PRESENTING

CONNECTED

THE

THE CONNECTIONS

1.

Set front panel controls as follows: MIC

TRANSCEIVE

RF AUDIO

BAND and

PA

VOX-PTT MOX-OFF SIDEBAND switch on desired sideband

ATTEMPTING

CONNECTIONS

40

LOAD IMPEDANCE

TO

THE

PROPER

NCX-5

TO

IN

GAIN fully ccw (counterclockwise)

tion (pushed in)

GAIN

and

frequency

TUNE,

TUNE

(usually LSB on the 80 bands, and USB bands).

POWER

FROM

OR

THE

FUNCTION

THE

fully cw (clockwise)

GAIN

MAIN

fully ccw

switch in either position

THE

TRANSCEIVER

KEY

APPROPRIATE

OFF

VERNIER

at

9 o'clock

TUNING

PA

LOAD

switch:

on

TO

THE

TO

60

ANTENNA

CABLE

POWER

SHOULD

SWITCH

POSITION

ARE

BEING

, and

OFF

20,

15,

OPERATE

FOLLOWING

SHOULD

OR

DUMMY

OHMS

SHOULD

, AND A

BE

SHOULD

in

OFF

to desired band

EXCITER

and

BE

RE-

BE

TERMI-

SUPPLY

CON-

INP

UT

WHILE

MADE.

posi-

40 meter

10

meter

3. BIAS adjust on rear panel should be set 12

o'clock.

3.1.2

RECEIVER

1.

Turn SSB. NCX-5 transmit-receive relay should close with in a receive condition on the selected band and

frequency.

2.

Adjust PA for maximum S-meter reading noi

se. approximate transmit tuning since these controls are common for both transmitter rece1ver.

3.

Adjust ing level.

3.1.3

TRANSMITTER

DO

NOT

DURES

IN

OVERHEATING OUT-OF-RESONANCE EXPERIENCE ACCOMPLISHED

SECONDS.

MORE

ORDER

1.

Turn adjust

meter reading.

2.

Adjust PA ing (dip ) indicating proper tuning

Pi network. Slowly rotate the PA LOAD control cw TUNE

TUNE-UP

FUNCTION

After several seconds warm-up,

an

audible click.

TUNE

This adjustment automatically sets

AUDIO

GAIN for comfortable listen-

TUNE-UP

-CAUTION

PROLONG

THAN

TO

IS GAINED,

FUNCTION

EXCITER

and

control until meter reads 300 MA.

30 SECONDS

PREVENT

OF

COMPONENTS

IN A MATTER

TUNE

dip

(SSB)

switch from

The

NCX-5

and

EXCITER

or

(SSB)

-

TUNE-UP

UNNECESSARY

CONDIT

TUNE

for minimum meter read-

meter reading with P.A.

IONS.

TUNE-UP

switch to

for maximum

OFF

the

is

now

TUNE

background

up

and

PROCE-

AT A TIME

DURING

AFTER

MAY BE

OF

A FEW

TUNE

of

and

the

at

to

5

3:

Return the tion, BALANCE control inside the top cover for minimum meter reading.

NOTE:

THE OPERATION, CONTROL THE THE

POSITION. CONTROL UNTIL

50 AND 60 MA.

dition

3.1.4

MOX

1.

The both

the

control.

3.

1.5

VOX

1.

Place

position.

2.

Place front panel

3.

Turn

the front panel)

(inside the top cover) completely ccw.

4. Rotate the top cover) until the relay just trips reliably while speaking into VOX the desired time after speaking. These justments interact may be necessary to repeat all adjustments once

and practical, GAIN close-talking from tripping

FUNCTION

MOX-OFF

and

carefully rotate the

IF

THIS

IS

NCX-5 HAS BEEN PLACED

SHOULD

NCX-5

MOX-OFF

Return

(MOX

OPERATION

NCX-5 transceiver will now operate in

the

MOX-OFF

OPERATION

the

receiver

DELAY until

or

Mobile

IS

THE SHOULD

THE

METER

the

switch

transmit

MOX-OFF

AUDIO

VOX

twice

to

VOX

but

should be adjusted for maximum

to

the

switch

THE

FIRST

THE

REAR

IN

TRANSMIT

SWITCH

REAR

NCX-5

OFF).

and

switch for transmit-receive

VOX-PTT

and

VOX

GAIN

the VOX

to

a small degree,

optimize results.

operation

VOX

prevent car

relay.

to

SSB.

Push

to

the

MOX

TIME

PANEL BIAS

BE

ADJUSTED.

IN

THE

PANEL BIAS

BE

ADJUSTED

READS

to

receive modes using

switch

GAIN

microphone. Adjust

BETWEEN

the

receive con-

in

switch

control (on

DELAY control

control (inside the

relay holds

is

GAIN

and

posi-

CARRIER

THAT

WITH

MOX

the

OFF

to

VOX.

in

and

quite easy

and

MIC

wind noises

IN

for

ad-

it

3.1

.7

1.

2.

3.

4.

5.

3.1.8

1.

2.

3.

4.

5. Advance

6.

by control from the external push-to-talk switch. connected adjusted for fast or slow return to receive

when the push-to-talk button

CW

It up

sired

Insert key plug in rear panel jack.

Turn

adjust transmitter as for SSB operation. Turn

key, trol (inside 300 rna.

The

and When the ator stops sending,

cally switch to receive.

DELAY control (inside the

operator may set

to

AM

It up to

Either

should be selected.

Turn adjust transmitter as for SSB operation.

Turn

MOX-OFF

CARRIER

150 rna.

on voice peaks. The

tion, in use.

The

VOX

in

OPERATION

is

assumed

for

SSB

operation

to

operate CW.

FUNCTION

and

adjust

NCX-5

is

ready for full break-in operation.

the

key

VOX

relay will hold

his liking.

OPERATION

is

asumed

for SSB operation

operate AM.

MOX,

FUNCTION

MIC

NCX-5

and

the

DELAY control remains

the

PTT

mode

and

is

that

the NCX-5 has been set

and

that

it

switch

CARRIER

top

cover) until meter reads

is

now tuned for

is

depressed

and

the

that

the

VOX,

switch

BALANCE until meter reads

is

to

GAIN

until meter just flickers

now adjusted for

AM

detector is automatically

to

CW, depress

BALANCE con-

CW

to

start sending,

in

until

then will automati-

By

adjusting the

top

"hold-in" relay time

NCX-5 has been set

and

that

or

PTT

to

MOX,

may be

released.

is

now de-

TUNE

operation

the

oper-

VOX

cover),

it

is

desired

operation

TUNE,

AM, press

and

adjust

AM

opera-

and

the

and

3.1.6

PTT

OPERATION

1.

Place

the

MOX-OFF

position.

2.

Place

the

VOX-PTT

3. Connect a suitable push-to-talk switch as shown erate in both

in

figure No.

the

switch in the

switch

1.

The

transmit

to

PTT.

NCX-5 will op-

and

receive modes

OFF

3.2

DETAILED

USE

OF

THE

INDIVIDUAL

CONTROLS:

The

operating instructions in Section

manual enable rapid setup of

AM,

or

CW

transmission. Careful study of

following paragraphs will help you get

performance from your NCX-5 transceiver.

the

NCX-5 for SSB,

6

3.1

of this

the

best

3.2.1

MAIN DIGITAL

TUNING

DIAL

CONTROL

READOUT

AND

NCX-6

T

R.

A N

The

NCX-5 transceiver incorporates a digital-

to

type direct frequency readout adjustment divisions.

to 1 Kc

The

VFO

without interpolation between

is accurate to 1 Kc, read by adding the frequency the counter dial on

the

BANDswitch. With

Me

14.0

illustration above

in

were

the

frequency would be 3.5

To

provide even greater resettability, the NCX-5

to

position,

3.5

Me

the frequency

the

frequency as shown

is

14.321 Me. position, for example, the above

Me

plus

readout incorporates a fourth window, as shown

above, calibrated in ten one-hundred-cycle divisions.

The

illustration above actually indicates

plus 200 cycles (321.2

Kc)

should be added to the

BANDswitch frequency.

3.2.2

DIAL

The frequency, such as a tional plug-in marker

SET

dial

of

the

NCX-5

100

may

Kc

XCU-27 calibrator, by tuning

frequency in the receiver out the main tuning knob of the NCX-5 the knob until the dial reading corresponds to the known marker frequency.

3.2.3

THE

FUNCTION

SWITCH

Note the various interlocking features FUNCTION the

FUNCTION

operation may

3.2.9). the SSB

left plugged closing if the

·FUNCTION

AM

position.

switch.

The

rear

or

AM

into

of

the key will

In

the

SSB

switch, either

be

used (see paragraphs 3.2.8

p~nel

key_

j~ck

positions, thus allowing a key to be

the NCX-5

not

at

trip

switch is

the SSB position,

allow frequency

and

it

in

kilocycles shown

in

megacycles shown

BANDswitch

If

the

321

Kc,

be adjusted

in

the

in

the

BANDswitch

or

3.821 Me.

that

321

Kc

to

exact

marker from the op-

to

the

and

then

by pulling

and

turning

of

the

or

AM

positions of

VOX,

MOX,

or

PTT

and

is

disconnected

all times. Accidental the

unit

to transmit

in

either

the

SSB

the

product de-

on

in

or

tector IS m use, detector

is

and

in

the

AM

position, the diode

selected. Bias is applied

oscillator during AM receiving periods, thus silencing the beat frequency oscillator

If

the front panel

CW

position,

the

rear panel key jack is connected for

of

the

receiver.

FUNCTION

switch is

automatic break-in operation. At the same time, the

of

plate

prevent accidental modulation signal by a microphone connected During in effect audio speaker result

CW

TION grounded, placing the NCX-5 At the 7360 balanced modulator balancing the tube drive

is

portant placed connected to of a CW interference. limited

3.2.4.

the microphone preamplifier

of

the transmitted

to

CW

operation, the

either the

on

VOX

the operation

"beep" which may be

at

the

beginning of each keying cycle

of

the extremely fast attack time

or

of

VOX-PT!

PTT

positions without any

the

transceiver. heard

from the loud-

circuit which eliminates "clipping"

Finally,

TUNE

position

of

in

the

switch, the keying circuit is internally

in

transmit condition.

the

same time, one

to

the final amplifier for tune-up.

to

note

in

the

TUNE

the

note will occur

Tune-up

to

as short a time as possible.

THE

PA

of

the deflection electrodes

tube

is

and

providing more

that

if the

FUNCTION

position,

and

NCX-5, full power transmission

and

can

cause unwanted

procedure should therefore be

TUNE

AND PA

LOAD

CONTROLS

Adjustment

controls

is FUNCTION The

EXCITER

meter indication.

of

the

PA

interdependent.

switch

is

TUNE

The

placed

control

P A

!UNE

For

TUNE

and

normal tune-up, the

in

the

TUNE

is

set for maximum

control for minimum indication, indicating resonance Pi network. tenna,

to

wise there will be some interaction with control, TUNE

· LOAD ing will increase.

input

For

the

PA

LOAD

a normal 40

control should

to

60

increase the meter reading.

and

it

will be necessary to slightly adjust PA

for minimum meter indication.

control

is

advanced, the minimum meter read-

Proper loading for 200 watts peak

occurs

at

300 rna (marked

in

ohm

be

As

the

red scale). This loading current should not be exceeded, since the

input

power

Pi network design is such

from a 700 volt supply will not result

that

additional power output. Above 300 rna the efficiency

of

the NCX-5 final amplifier will

no

further

depends

Proper

on

output

will be obtained.

ope~ation

of

any linear final amplifier

proper idling current adjustment

be

sufficient drive for adequate peak plate current during

an

off-resonance condition.

bias setting

of

the NCX-5 final amplifier is discussed

The

adjustment

to

the carrier

in

the

is

grounded

the NCX-5.

switch

of

can

The

slight

is

the

the break-in

the

first dot.

the

FUNC-

be

of

grounded, un-

than

normal

It

is im-

switch

an

antenna

PA

LOAD

position.

is

then set

of

the

resistive an-

rotated clock-

this is done,

PA

TUNE

As

the

PA

on

the meter

additional

in

impaired,

and

of

and

on

the

to

is is

7

in

paragraph

made

for

it

should be possible off-resonance piate current the

PA

TUNE of minimum current. supplied and

the justed, this off-resonance rna.

If

3.1.3. Assuming this setting has been

an

idling

current

to

control is

to

the plate circuit of the final amplifier,

EXCITER

this current

cannot

between

50

and

obtain a momentary maximum

in

·excess

of

350

rotated

If

700 volts

TUNE

control

current

away from

is

being properly

is

proper

should exceed 350

be achieved,

rna

the

60

when point

ly

cause

rna,

ad-

should be found. Typical causes may include any of

the following: improper Bias setting, improper EXCITER

voltage to

tions, low driver B or driver tube, stages resulting

As

to

the culty The

NCX-A

the

to The

NCX-D

the

to

volt

input

or

the

power supply

conditions,

350 rna will probably occur. operation the PA

loading conditions. control be advanced resonant

current, which is noted by momentarily

PA

TUNE

In

the

40 used with of impedance should, present a

This

nals.

ne~works

the length of

TUNE

the

adjustment, low plate supply

final amplifier under full load condi-

+, defective final amplifier tubes

or

improper alignment

in

low driving signal.

mentioned above, low plate supply voltage

final amplifier will frequently result

in

obtaining a suitable off-resonance current.

power supply is

rated

final amplifier with a 115 volt A.C. input.

power supply is

plate circuit

to

the power supply.

of

rated

the

final amplifier with a 14.0

If

mobile battery supply voltage

output

an

off-resonance

wil

be

plate

reduced.

This

of

the

NCX-5 transceiver, provided

LOAD

dip

control is

exceeds

In

so

not

no

event should

that

85%

of

adjusted for excessive

the

the off-resonant plate

control.

many to

and,

instances

60

ohm

the

NCX-5. Antennas presenting this type

proper

can

be done through the use

in

the

an

antenna

range

of

the

if

at

all possible, be adjusted to

load

at

the

NCX-5

many instances, by simply tailoring antenna

transmission line

of

the

exciter

in

to deliver 700 volts

the A.C. line voltage

is

low, the

Under

current

will

plate

of

not

impair

the

current

less

LOAD

at

detuning

load

that

is outside

Pi network will be

antenna

of

matching

to

term-

modify.

diffi-

these

than

the

that

the

its terminal impedance.

. Generally speaking, if the NCX-5 exhibits a

plate

PA

current in

LOAD

resonant

with

the

clockwise position, the below 40 ohms. dip is still less

trol rotated

load impedance modify NCX-5

the

to directions. of four

mica BANDswitch switch

and

If,

than

to

its full clockwise position,

is

Pi network

take care of some misloading

With

the

capacitors will be seen just below the

and

chassis. These capacitors, C-37 (3.5

the

dip

in excess

control rotated

antenna

on

the

other

300 rna

with

above 60 ohms.

output

PA

housing. removed, a group

to

its full counter-

load impedance hand,

the

PA

It

capacitors

connected between

of

300 rna

the

resonant

LOAD

the

con-

antenna

is possible to

of

the

in

these

the

BAND-

Me),

C-38 (7 are, respectively, 1000, 470, 220, appear control as shown be altered to extend the

Me),

C-39 (14

in parallel

on

load impedance

Me),

and

C-182 (21

and

220 pF.

with

the front

the

schematic

the

range

is

too low, the capacitance should

panel diagram

of

the Pi network.

be increased. A good quality silver mica capacitor may be used for this purpose. as large a case size

on

It

is

advisable

these capacitors as

obtained.

There between the control. ceding tuning a point where this control will

entire

to

use external matching techniques.

that

capacitive component nals. P A

TUNE

entire amateur band. Again

alter matching network culties. the NCX-5 is properly matched severe distortion matched

3.2.5

switch trode

is of course some interaction of

PA

If

load

paragraph

of

the

amateur

LOAD

matching

PA

band.

control

is

attempted,

TUNE

In

this event,

and

as described in

it

is possible

control will

no

longer cover

it

It

the

antenna

In

this event, there may be also a shift

the

antenna

SSB operation should

line will introduce

to

the

control so

that

impedance by means

or

correction

NCX-5

it

will

it

not

will

of

be

not

the

and

can

result with

SSB transmitter

CARRIER

During

of

the

in

the

TUNE

the 7360 balanced

BALANCE

tune-up

or

receiver.

CONTROL

(with

the

position) , one deflection elec-

modulator

the

will

is also possible

an

antenna

be

attempted

loaded because

any

creating complete carrier unbalance. Having accomplished proper transmitter tune-up,

to

use the

set

up

AM,

transmit condition

or

MIC

that

so RIER

CARRIER

the

NCX-5

or

CW

For

SSB operation, the

transceiver for operation

operation.

either

the

MOX-OFF

GAIN

control should be no audio modulation will occur. BALANCE control

minimum meter indication. be between

properly adjusted. control

is

for all subsequent cation

50

is

properly set,

of

CARRIER

and

60 rna

When

SSB operation. A more precise indi-

BALANCE control setting may

be obtained either by using

the

to

antenna a separate receiver. tuning

tenna

of

line should

as indicated

For

CARRIER

line

or

With

the transceiver circuits, voltage

not

on

the

oscilloscope.

AM

operation,

BALANCE control

NCX-5

by

the

switch.

In

is

This

if

the

CARRIER

it

may be left

an

oscilloscope connected

by listening

proper carrier balance

exceed 0.5 volts peak-to-peak

it

is

nec~3sary

it

is placed

push-to-talk

either

in

full ccw position

then

meter

reading should

the

BIAS control

in

to

either

Me)

They

PA

LOAD

and

may

to

can

tuning

PA

TUNE

the

pre-

that

be

shifted to

be

necessary

inductive

termiof

tune

over

necessary

of

an

external

antenna

diffi-

.unle~

improperly

FUNCTION

is

grounded,

is necessary

to

properly on

SSB,

in

button

event,

The

CAR-

adjusted for

BALANCE

this position

the

carrier

on

the

to

adjust

cw

or

If

use

be

the

or

the the

to

a

the

is

on

and

an-

the

ccw

8

from

the

balance final amplifier approximately thus assuring operation

dissipation rating.

Finally, for

just

the

CARRIER ccw from its zero setting until a meter indication 300 rna is obtained. amplifier of conditions forms approximate a is

full

for

the

to

the

assuring conservative operation

of

input

remaining time.

final amplifier

point

until

the

meter indicates a

current

100 watts

200 watts during key down transmit

CW

for

of

150 rna. input

of

the

CW

operation,

BALANCE control either

This

assures

operation. Normal keying wave

50%

about ~ of

Thus

is

still approximately 100 watts,

This

corresponds to

to

the

final amplifier,

tubes within their plate

it

is

necessary

an

input

to

duty cycle;

the

of

that

time

and

no power

time-averaged

the

final amplifier.

to

cw

the

final

is, there

input

ad-

or of

VOX

circuit. However,

no

effect

have any position. on

both be adjusted end

of

the

3.2.9

THE

The operation) position places the mode, regardless of switch useful for not equipped with a OFF or switch.

or

switch is

PTT

on

·

The

PTT

and

to

the

transmission.

MOX-OFF

the

FUNCTION

manual

returned

operation

the

this operation

VOX

DELAY

CW

break-in operation

operator's liking for delay

SWITCH

switch

the

position

operation when the microphone

PTT

switch.

to

may

be selected by

VOX

GAIN

and

may

control is effective

in

the

MOX

NCX-5

switch.

the

of

When

OFF

in

the

This

position,

the

control will

· be left in

and

should

at

the

(manual

the

transmit

VOX-PTT

position is

the

MOX-

VOX

VOX-PTT

is

CALIBRATOR

3.2.6 When

the

accessory

plugged into

Kc

crystal markers are available for precise calibration

of

the

of

a pull-push switch on

The

dial may

in

paragraph

3.2.7 Proper S-meter adjustment

tained by disconnecting

is

set for SSB reception.

clockwise (maximum gain),

(in front right corner

meter indicates between

3.2.8

The mode, depending a push-to-talk button microphone jack connections

1.

No.

Assuming operator will find DELAY free from interaction. available in the NCX-5 permits full anti-vox insertion at

all times.

ment

is required.

fully ccw,

until

the with normal speech level. Mobile operation requires close talk

road, wind, accidentally control

It

break-in operation are obtained through use of the

the

NCX-5.

S-METER

VOX-PTT

ADJUSTMENTS

is

should be further noted

The

then

3.2.2.

VOX-PTT

that

control settings

As

a result,

VOX

microphone just trips

to

the

and

trip

the

then

adjusted for

CONTROLS

XCU-27

octal socket

calibrator

the

be

set by following

ADJUSTMENT

the

With

of

chassis)

0

and 1 "S"

SWITCH

switch

on

preference

on

VOX

that

the

of

the

The

no

With

the

GAIN

microphone, since motor

control

noises will otherwise

VOX

circuit.

100

on

the

is

activated by means

AUDIO

of

antenna

the

S-meter adjustment

AND

may

and

the

microphone. Proper

are

illustrated

operation is selected,

VOX

NCX-5 are remarkably

extreme

anti-vox control adjust-

VOX

is

the

desired release time. that

Kc

calibrator

rear

apron, 100

GAIN

the

while the

RF

is

rotated

units.

VOX

be set

GAIN

VOX

DELAY advanced slowly

NCX-5

the

The

PTT

control.

instructions

NCX-5

GAIN

until the

C.IRCUIT

to

availability

in

and

sensitivity

control

to

transmit

high level of

tend

VOX

DELAY

and

is

ob-

fully

either

of

figure

the

VOX

to

CW

3.2.10

± 5

transmit frequency

pulling crease frequency

times-only

TRANSCEIVE CEIVE

useful operation. sired

pushed NCX-5 VERNIER quency enough proper out

TRANSCEIVE clear channel. NCX-5 receiver by pushing

be

to two adjacent

TRANSCEIVE

thereby instantly place

frequency.

3.2.11

tuning

the erly set for carrier balance,

should

100 microphone. so and

to 50 rna idling meter

TRANSCEIVE

The

TRANSCEIVE

Kc

separation

the

control

or

decrease receiver frequency.

of

the

the receiver frequency

VERNIER.

VERNIER

in

AM

or

It

allows

AM

or

CW

OFF

, thus placing

on

frequency.

can

be

to

part

of

the filter passband for best copy with-

"walking" of

To

escape

made

to QSY.

MIC

After

of

CARRIER

be

and

125 rna average on speech content from

developed has a rapidly varying energy content

the

meter will rapidly fluctuate between

reading. Actual peak

the

QRM

VERNIER

Once

is

the

control

VERNIER

GAIN

the

NCX-5

the

final amplifier

BALANCE control has been prop-

advanced until

The

current

VERNIER

of

the

receive frequency from the

of

the

NCX-5.

out

and

rotating

NCX-5 remains unchanged

will be

CW

QSO's, as well as

the

operator

station with

the

Then

pulled

allow

placed back

The

QSO's

single sideband audio information

ON

tuning

transmit signal.

during a

can

a clear channel is found,

IN,

casual listener

by merely

control

the

NCX-5

CONTROL

has been set

the

and

the

current

CONTROL

control allows

It

is

actuated by

the

knob to in-

The

transmit

is

affected by

The

NCX-5

found

and

to be extremely

to

the

VERNIER

transmit section

the

to

offset receiver fre-

of

the

QSO

be used to find a

on

frequency simply

arrangements may

receiver

and

exciter stages

MIC

meter

100 to 125 rna average

is about 300 rna.

TRANS-

in

SSB net

tune

to

TRANSCEIVE

station

on

SSB,

may

also listen

turning

on

and

on

up

by proper

GAIN reads between

at

all

the

de-

control

of

the

to

the

off

and

either

and

control

the

40

9

This

fluctuation will be affected by the nature

speech content

and

the individual voice. Generally speaking, the indication will be higher for long out

vowel sounds

Inclusion NCX-5 has diminished phone gain control. A provided because and

large variation in

phones

of

the same type.

is rotated from the full ccw position,

than

it

of

an

effective ALC circuit

the

MIC

of

the wide variety

output

is for crisp consonant sounds.

importance

GAIN

of

control has been

of

levels even

As

the

MIC

GAIN

the

of

the

drawn

in

the

the micro-

microphones

of

micro-

control

current on

voice peaks will increase to approximately 125 rna.

As

MIC

GAIN change will control should be set slightly above average current reaches the meter. Should this point,

and

level,

For

AM

is further increased, little additional

be

noted on

the

meter.

The

the

125

rna level

the

control be advanced well above

the

ALC

can

no longer handle the drive

severe distortion may

operation with

be

generated.

the

CARRIER

MIC

GAIN

point where

on

the

BALANCE control set as described in paragraphs 3.1.8 and

3.2.5, there will

150 rna.

If

the during speech, AM modulation will occur.

When

MIC

the

be

a steady meter reading

GAIN

MIC

control

of

GAIN

is

the final amplifier

control setting

of

advanced

reaches a point where the meter just indicates a

slight flicker

Operation with the

of

speech peaks, modulation

MIC

GAIN

control above this

is

100%.

point should be avoided, since excessive drive will cause clipping

in

will result of

the

passband

3.2.12

If

segments other

500

priate

unwanted spurious transmission outside

of

THE

'TEN-

it

is

desired to operate

than

Kc

segment

concentric with the

the

for

the

segment from 28.5

NCX-5.

If

one

the modulation envelope,

the

NCX

-5.

METER

SEGMENT on

one

of

28.5-29.0, selection is

made

by the 1 0-meter switch

PA

of

TUNE

the

control.

to

29.0

is

other segments

and

this

SWITCH

the

10-meter

of

the appro-

The

crystal

supplied with

of

the

band

of

is desired, the appropriate crystal must be plugged in. Sockets are

in

the front right-hand corner

corresponding frequencies

Me

segment-crystal frequency 24.5

segment-crystal frequency 25.5 Me

segment-crystal frequency is 26 Me. These frequencies are also shown ''Theory are available from

near

the

existing crystal

and

on

the frequency

of

Operation." Ten-meter segment crystals

the

Service Department

on

of

the NCX-5.

crystals

Me;

Me; and

the

sub-chassis

are:

28.0-28.5

29.0-29.5

29.5-30.0

chart

The

Me

under

of

the.

National Radio Company.

,

DRIV

I

~-

1

...1

KEY

MIC

1liil._

@------~-

MICROPHONE

PRE-AMPL

ER

2ND

MIXER

I

_

~SPEECH

~AMPL

1ST

MIXER

I

L - - -

BLOCK

BUFFER VFO

------

- -

---,

DIAGRAM

FIGURE

I

•

I

1

1sr

1F

2

LEGEND

·

= RECEIVE PATH

----

PRODUCT

DETECTOR

S·

METER

AMPL

--

:==

TRANSMIT CONTROL PATH TRANSMIT

RECEIVE PATH

PATH

AND

10

SECTION

4

THEORY

4.1

GENERAL:

The

NCX-5 transceiver, designed to cover

80

through 10 meter double conversion superheterodyne receiver sideband transmitter, crystal lattice filter. driver tuning ·circuits RF

circuits for VFO

are circuits while low level amplifier in The

use results in lective receiver SSB transmitter.

The by reference to frequency

the

common to

the

of

common filter

an

extremely sensitive

and

operation

the

chart,

figure

amateur

both

The

final Pi network, mixer

of

the

receiver.

the

receiver first

the

transmitter-exciter function.

and

in

a high quality, low distortion

of

the

block diagram, figure 2,

3.

bands, combines a

employing a common

transmitter also serve as

The

carrier oscillator

receiver

NCX-5

and

lF

stage is used as a

RF

input

and

image-free, se-

is

best understood

OF

the

and

single

and

transmitter

components

and

the

OPERATION

The

crystal lattice filter

and

coupled directly

first

IF

stage.

The

to

the

grid

of

The

VFO oscillator All biasing resistors

chosen for low noise Power for

a zener diode regu lator fed from volt bus. from minute period, including variations of external supply voltage capacitor

1

Kc Output the

12BE6 (V3) first transmit mixer.

and

the

The

result

"turn

on"

and

amb

is

completely linear with

at

any point within

from

the

2N2188 (Q2)

to

single-tuned plate circuit

the

12BE6 (V3) first transmit mixer.

uses a 2N706 (

a 2N2188

and

VFO

circuits

is a VFO

of

less

ient temperature.

VFO

and

is

resistance terminated

the

grid

of

the 12BA6 {V15)

is

coupled

Q1)

NPN

transistor

(Q2)

PNP

transistor buffer.

tank

circuit capacitors are

temperature characteristics.

is

double-regulated by

the

regulated + 150

circuit with a total

than

100 cycles

the

500

is taken from

fed

to

the

oscillator grid

in

The

main tuning

an

accuracy

Kc

tuning range.

the

collector of

any ·ten-

drift

of

the

4.2

THE TRANSMITTER:

The

transmit signal

on

the

cated

at

the phone dynamic push-to-talk microphone circuit. connected directly of a 6GH8

The

fier. gain control speech amplifier. amplifier of

the

A 12AU7 oscillators. its triode section,

plished by applying a negative bias

be

turned common resistive plate load of

the network containing potentiometer is connected to of

the

balance for maximum

anced primary winding secondary which serves as eight-pole crystal lattice filter.

block diagram

mike

jack

input

circuit

or

crystal microphones

(V8A)

signal is

to

one triode section

is

coupled

7360 (V10) balanced modulator.

(V7)

Each

crystal

off.

The

7360 balanced

7360.

In

addition, a

path

of

the NCX-5 is indi-

by

a dashed line starting

and

carrier

is

designed for high-impedance

to

the

tube

then

The

to

one

tube

and

sideband switching

carrier signal appears across a

modulator

the

carrier

oscillator.

and The

grid

of

the

which operates as a preampli-

fed through

of

plate circuit

of

the

deflection electrodes

is

used for

is

permanently connected

and

carrier balancing control

the

deflection electrodes

trimmer

suppression.

is

coupled to a single-ended

the

input

The

micro-

provides for a microphone is

pentode section

the

microphone

the

12AT7 (V6A)

of

this speech

the

two carrier

to

is

accom-

to

the

section to

is

fed

to

the

grid

tube V-10. A D.C.

provides phase

The

bal-

source for

an

The

output

is

always in through a bandpass double-tuned circuit of

the

pentode section

transmit mixer.

used as a crystal oscillator which feeds

transmit mixer

The

plate circuit

is single-tuned

driver.

feeds

plate circuits

band amateur exciter troL such be assuring linear operation

the level necessary

and

on

plates high-efficiency proper match a 40 80, 40, 20, 15, Pi network is designed for continuous operation

The

the

grid of the final amplifier.

switched for the 80, 40, 20, 15,

bands.

tuning

The

gains

that

obtained

The

final amplifier employs a

V2)

the

rear

of

the

inductance,

from

the

first transmit mixer (V3)

the

3.5

to

4.0

Me

band.

This

signal is fed

to

the

of

the

6KE8

The

triode section

and

the

first receive mixer.

of

the second transmit mixer

and

feeds the grid

single-tuned plate circuit

of

the

transmit mixer

The

tuning

can

be accomplished with only

of

the transmit mixer

a driving signal in excess

at

the grid

for

tubes operating in parallel. A bias control

apro

n sets proper idling current.

6GJ5 final amplifier are coupled

Pi network.

tuning

to

60

ohm

and

10

gang

of

the

of

the

proper drive.

The

and

resistive load over

meter

(V4B) second

of

the

6KE8

both

the

second

of

the

6GK6

of

The

and

is

tracked so

and

of

100 volts

final amplifier, thus

exciter

amateur

to

pair

of

band

switch selects

load capacitance to

(V5)

the

driver

coils

in

driver

10 meter

one

driver

well above

6GJ5

the

entire

bands.

grid

the are

that

con-

are

can

(V1

The

to

The

is

a

at

11

a power level capacitor coupled from amplifier grid circuit coils (driver plate coils) provides neutralization. ized, maximum occur

at

on

the

meter

An cuit is included. driven driving signal positive with respect and a negative voltage change resulting audio signal coupled will provide a negative to plifier. IF

at

. from

fying diodes,

discharge through the reverse biased diodes, resulting

in prevents cross connection

cuits

circuit will provide automatic level control for input signal variations setting

In ing background noises

without overdrive

mitter.

on

grid

the grid

When

amplifier

the

final amplifier. Charging takes place rapidly

the

a fast

at

of

addition, sudden changes

of

200 watts input. A small adjustable

the

plate of

to

the

partially by-passed

When

the final amplifier is properly neutral-

output

the

point

.

effective ALC (automatic level control) cir-

If

voice peaks, the grids will actually see a

current

to

a voltage-doubling rectifier.

return

overdrive occurs, the gain

is

reduced, resulting

low-impedance bias source through

but

attack-slow

the

common

of

the

MIC

on

a matched

of

plate

current

the

final amplifier grids

will result.

on

of

the

the negative ALC voltage cannot

IF

more

GAIN

and

This

on

the

bias circuit

D.C

output

12BA6 (V15) first

release action. A gating diode

of

the ALC

grid return point.

than

10 db.,

control quite noncritica

in

are

all instantly controlled

distortion

the

6GJ5 final

return

of

antenna

dip

as indicated

are

to

the

cathodes,

current will cause

the

bias circuit.

is

capacitively

This

which is coupled

of

in

less driving signal

the

and

AGC

The

and

makes the

voice level

of

the

or

NCX-5

the

final

will

over-

The

rectifier

IF

am-

the

first

recti-

cir-

ALC

disturb-

trans-

through separate voltage dividers. tector employs one triode of with the signal from one

the grid. A controlled 12AU7 (V7) carrier oscillator cathode audio signal is obtained across a resistive load plate circuit. tector is connected.

The

audio gain control,

maining triode section

functioning as a grid-leak biased, first audio ampli-

fier.

The

6AQ5 (V19) audio

stage feeds the secondary. phone jack.

jack

feed permits use

phones.

A secondary feed is of

cuit doubling source When cannot a long release time, thus giving

fective, fast-attack, slow-release action.

fed

l.

to

(V6B ) S-meter amplifier. AGC is connected

grid returns

through control.

BFO

signal

of

the

product

For

AM

output

the

AGC rectifier.

pro

the signal disappears,

discharge

the

the gating diode to

from

and

plate circuit

output

This

output

The

low-impedance

of

last

IF

amplifier

vides a

grid

of

rapid

through

of

the remaining

the

RF

the

IF

is

coupled from the crystal

detector,

operation, a separate

the

detectors is coupled

then

of

the 12AX7 (V18)

is

coupled to

stage.

transformer having a 3.2

signal·

either high-

obta

The

charge

the diodes, which provides

stage, second

The

12AX7 tube (V18A)

voltage divider fed to

and

to

the

grid

the

The

is

also available

nature

or

ined from and

is fed

low-impedance driving

of

the

negative AGC bus

the

AGC

half

the

first

product de-

to

the

resulting

in

the

diode de-

to

the

of

the

re-

tube

grid

of

the

audio

output

ohm

at

the

of

the phone

low-impedance

the

plate cir-

to

a voltage-

AGC bus.

a very ef-

The

AGC

is

of

the 12A

IF

stage,

IF

T7

to

the

and

stage for

4.3 THE

The solid lines cuits high-impedance point is capacitively coupled to RF

amplifier. transmit driver the

input second selectivity The

output

to

the

(V13).

(V4A) crystal oscillator. coupled to receive mixer.

grid

of receive mixer is connected directly across the secondary

of

serves as

The transmitter, couples to single-tuned

MC.

6.02

RECEIVER:

receiver circuits

in

the

block diagram.

are

common to the transmitter

The

and

output

RF

amplifier.

and

common receiver-transmitter tuning.

from the second

signal grid

The

oscillator grid is fed from

the

signal grid

VFO

this mixer.

the balanced modulator transformer which

the

input

output

of

IF

amplifier operating

The

detectors

are

indicated by

The

of

the

transmitter Pi network

the

grid of a 6BZ6

tuned

circuits

plate

of

circuits

They

of

the

first receive mixer 12BE6

The

of

signal

is

The

plate

coil to

the

crystal lattice filter, as

the

and

at

the transmit mixer are

of

the

provide for receiver

RF

amplifier

plate

the

12BE6

coupled

circuit

crystal lattice filter .

input

of

at

AGC circuits

the

double

receiver

RF

the

12BA&

of

to

of

approximately

RF

circuits.

plate

is

coupled

the

this mixer

(Vl4)

second

the ·oscillator

the· second

a three stage

are

cir-

The

(Vll) of

the

(V12)

RF

6KE8

in

the

fed

4.4

THE

VOX

Before considering the switching operations, we

must first discuss

The

signal which trips

transmit is derived from two sources.

is

the

VOX

signal which is picked phone preamplifier two stage amplifier consisting

(12AU7).

of

the

VOX

to

make a negative voltage, the

making a positive voltage.

is

are applied in series tube.

VOX derived from the

larger from loudspeaker information.

is amplified through velop enough negative voltage tube into transmit position.

The

other

audio

output

signal.

Both signals are rectified,

The

circuit constants in

detectors

than

Additional information entering

to

let

are

the

voltage generated

the

CIRCUITS:

the

VOX

circuits.

the

relay from receive

The

up

after

and

separately amplified

of

V9A signal is derived from the plate tube

and

is

called the

the

VOX

ANTI-VOX

The

two D.C. voltages

to

the

grid

of

the

relay control

the

VOX

and

arranged

ANTI-VOX

the

relay fall off

VOX

so

that

the

detector

in

the

amplifier

at the grid

and

place the circuit

D.C. voltage

VOX

microphone

and

of

to

first source

the micro-

in

and

V9B

ANTI-

signal so as

signal

ANTI-

is

always

channel

will de-

the relay

a

12

The

VOX

and

ANTI-VOX stants are so arranged relay tube grid negative in a very short time. end

of transmision, discharge backwards through charge time which eral seconds.

position

4.5

The

of

the

TION

4.5.1

is

controlled by R7,

can

be set from a fraction of a second

This

and

will be discussed

THE

FUNCTION

following paragraphs describe

various switching circuits with

switch

in

FUNCTION

that

the

relay control signal

circuit

SWITCHES:

all possible positions.

SWITCH

detector time con-

the

circuits will drive

the

diodes.

the

DELAY

is

also used in

later

·.

OFF

the

operation

the

The

At

cannot

control

to

the

FUNC-

the the

dis-

sev-

CW

first transmit mixer. V3 ( 12BE6) will now duction of screen voltage. A voltage divider connected from this screen to negative signal which and

the

MOX

The

keying tube. out,

and

The mit mixer screen and

audio

On tive bias reappears

the relay control pulls in,

and

The

relay tube will be biased off,

the

set

negative signal developed

output

release of

and

receiving conditions

The

screen of this ·miXer tube

draw

current, causing a re-

the

-80

bias line will develop a

is

tied through

switch

to

the keying

PTT

diode feeds

is

in transmitting position.

is

also fed to

amplifier for quiet switching.

the

push-to-talk button,

on

the

transmit tubes.

tube

returns

the

and

the

grid of

the

at

the

product detector

to

normal,

are

restored.

VOX-PTT

PTT

diode.

the

relay

relay falls

first trans-

the

nega-

The

grid of

the

relay

In

this position rupts the primary power, either directly in case of the

NCX-A

in

the

of all

4.5.2

In

The

VOX

the

microphone amplifier cuitry. dental keying.

Now

possible:

4.5.2.1

VOX

OFF

switch VOX Voice information from the microphone will override the

ANTI-

relay.

other from various transmitting tubes ceiving tubes switch over.

the preset

placing the set

4.5.2.2 VOX-PTT

on

OFF

is

now shorted

is

connected across push-to-talk contact grounded, which removes transmitting tubes.

power supply

NCX-D

other

switches becomes irrelevant.

FUNCTION

this

position

-PTT

The

key jack is disconnected to prevent acci-

three

VOX

switch

in

and

MOX

VOX,

The

relay will transfer

transmitting tubes. Negative bias

and

At

DELAY,

PUSH-TO-TALK

position.

to

the

FUNCTION

or

through a remote relay

12

volt D.C. supply.

SWITCH

the

following circuits

switch,

different types of operation are

OPERATION

in

VOX

OFF

position.

switches

as described before, tripping the

the

first

the

end

the

in

receiving condition.

switch on

The

output

ground,

the

transmit bias line.

is

pushed,

The

bias

SSB

the

product detector,

are

connected

position

In

this combination

ground

B+

audio

of

transmission

relay will pull

OPERATION

PTT,

of

and

the

disabling bias from

is

also removed from

switch inter·

The

position

are

set

into

the

and

the

keying diode.

to

the

final

is

removed

and

applied to re-

amplifier for quiet

and

in

MOX-OFF

the

VOX

amplifier

push-to-talk contact

When

bias line ( 135) is

up: and

cir-

MOX-

the

and

after

again,

switch

the

4.5.2.3

the transmitter bias line ( 135) Switching occurs as with tion. Returning the transmitter off dition.

4.5.3

transfers the put to ditions

erate

( 4.5.2).

4.5.4

disconnect of information from coming through, connect of detector, mitter

transmitter bias line ( 135) transmitter tubes operation. As described above

PUSH-TO-TALK divider of the relay tube through the keying diode. will fall out, placing

position. grid-block method, since control tube will hold

predetermined time. Effective break-in keying therefore realized.

MOX

With

FUNCTION

The

of

the

carrier oscillator in use during receiving con-

to

VOX,

in

FUNCTION

In

this position

the

microphone preamplifier

the

audio

bias line.

When

OPERATION

the

MOX

AM

position of

input

AM

detector. Also, disabling bias is applied

silence

PTT,

the

same

the

VOX-PTT

amplifier

and

connect the

the

first transmit mixer will now actuate

From

here

the

and

of

the

MOX

manner

key

and

The

switch in

MOX

put

SWITCH

the

BFO

operation functions now op-

SWITCH

the

to

is

depressed

the first transmit mixer into

(paragrap

the

NCX-5 into

on

in,

the

VOX-PTT

the

MOX

is

grounded directly.

PUSH-TO-TALK

switch to

the

audio

signal.

as described

FUNCTION

switch, ground

the

output

KEY

is

grounded, placing

under

h 4.5.2.2), the screen

further

the

DELAY

transmit relay

OFF

set

into

IN

AM

FUNCTION

amplifier to

IN

CW

to

prevent any speech·

of

jack

to

the

first time, the

SSB operation,

the

keying

circuits are dis-

receive con-

POSITION

switch will

the

transmitting

on

position,

will

the

under

the

product

the

The

is

done by

the

in

opera-

switch

input

trans-

for a

turn

out-

SSB

plate

the

relay

is

13

abled so The

that

MOX

the

microphone

can

be left

switch, however, will still

in

actuate

transmitter.

4.5.5

FUNCTION

SWITCH

IN

'rUNE

POSITION

In

this position ground mitter Operation" the a strong signal PTT, and fluence

4.6

the

transmitter bias line, placing

into

operation, as described

(paragraph

balanced modulator deflection plates, providing

through

key circuits

on

the

tuning

RELAY FUNCTION

In

the

foregoing discussion,

relay switching was double-throw relay of

the

6GH8 relay

in

a transmit

The

cond

first set

+ 220 volts between transmit

the

4.5.2.2)

the

are

procedure.

S:

not

is

actuated

tube

V8B.

ition when

of

contacts, 5, 6,

FUNCTION

under

and

system.

disabled

'rhe

the

and

exact

described.

by the

The

NCX-5

the

relay

and

receiving functions.

switch will

the

"SSB-

ground

MOX,

have

The

plate

is

de-energized.

7, transfers

its jack.

trans-

PTT

one

VOX, no

nature

six-pole

current

is

placed

the

of

in-

of

Contacts 8, 9,

varactor

diode by a bias depending the

TRANSCEIVE

ceiving periods

mitting

periods.

Contacts

and

are

brought

for operation

Contac relay receiver

ts 14, 15,

arm,

contact 15, grounds t

at

contact 14

and

10 transfer

in

the

VFO.

This

on

the

setting

VERNIER

and

by a fixed bias

11

and

12 are closed

out

on

the

rear

of

the

NCL-2000 linear amplifier.

and

16 operate as follows:

to

prevent excessive

apron

he

build-up during transmit periods pro

mpt

recovery

tact

15 grounds

contact 16,

Contac

tacts:

the

tact

17

to

transmit periods; contact 19, ceiving periods, for operation

Contacts

either

for receive

tubes

into

of

the

during

receiving periods.

ts 17, 18,

receiver

screens

and

of

the

19 also

when

arm, contact 18 connects

read

the

final cathode

grounded

is

connected

of

the

external VX-501 console.

20, 21,

or

transmit,

and

22

to

gro

plac

the

operation as desired.

the

bias

varactor

control

and

is

switching

during

of

the

AGC

line

and

to

req

uire

final amplifier

are

grounding con-

the

meter

current

during

accessory socket

und

the

ing

the

appropriate

on

the

actuated

of

re-

trans-

transmit

NCX-5

The

of

the

AGC

assure a

d.

Con-

at

con-

during

re-

bias line

Final

Output Transmit Second Receiver Receiver

Crystal Osc.

First

First Receive

Carrier

Second Receive

Mixer

Receiver

Transmit

Mixer

VFO

Driver

Transmit

RF

Mixer

Output

Osc.

Output

IF

Mixer

Amplifier

Input

3.5-4

None

3.5-4

USB

LSB

USB

LSB 6.02 6.0236

9.5236

10.0236

9.52 10.0236

10.02 9.5236

6.0236 6.02

7-7.5

11

4--3.5

10.02

9.52

14-14.5

18 25 24.5

4--3.5

10.02

9.52

10.0236 10.0236

9.5236 9.5236

6.02 6.02

6.0236 6.0236

21-21.5 28-28.5 28.5-29

4--3.5

10.02

9.52

29-29.5

25

3.5-4

9.5236

10.0236 10.0236 10.0236 10.0236

9.52 9.52 9.52 9.52

10.02

6.0236 6.0236 6.0236

6.02 6.02 6.02 6.02

3.5-4

9.5236 9.5236 9.5236

10.02 10.02 10.02

25.5 26

3.5-4

29.5-30

3.

5-4

6.0236

FREQUENCY

FIGURE 3

14

CHART

SECTION 5

NCX-5 TEST AND ALIGNMENT

NOTE:

TEST SHOULD PETENT,

5.1 EQUIPMENT REQUIRED:

1.

AND

ALIGNMENT

ONLY

BE

QUALIFIED

PERFORMED

PERSONNEL.

OF

Signal generator providing

following frequencies: 6.0218

THE

BY

output

Me,

4 Me, 7 Me, 7.3 Me, 14.0 Me, 14.4 Me, 21.0

Me, 21.5 Me, 28.0 Me, 28.5 Me, 29 Me, 29.5 Me.

2.

Vacuum

3.

Standard

4.

Sweep generator capable of sweeping proximately

tube voltmeter

output

meter.

60 cycles

per

(VTVM).

second over a fre-

quency range from approximately 3

Me.

5. High-frequency oscilloscope covering the range from sensitivity of 50 mv

and

a low capacity

type 545 with type L preamplifier

DC

to 30

Me

with a

per

centimeter

input

probe (Tektronix

maximum

or

lent).

6. External receiver capable of receiving Me.

7.

50

ohm

dummy meter covering to

30 Me. (A high frequency vacuum tube

voltmeter with a

be substituted for the calibrated

load with calibrated

the

frequency

range

100 volt full scale range

output

meter.)

8.

Power supply capable volts

at

300 rna,

- 80 volts

9.

1000 cycle

at

6 rna.

audio

of

supplying + 700

+280

volts

at

generator with

200 rna

an

level of 10 mv.

10.

High

quality microphone equipped

push-to-talk button.

11.

Transmitting

key.

12. Suitable alignment tools for adjustment of coils

and

capacitors.

13.

XCU-27

crystal calibrator.

NCX-5

COM-

at

the

3.5 Me,

at

ap-

to

4.5

better

equiva-

at

9.

72

output

from 3.5

may

power

and

output

with

5.2

INITIAL CONTROL SETTINGS:

FRONT

RF

and

AF

GAIN ...

FUNCTION

PA

TUNE

PA

LOAD

Switch

..........

and

EXCITER

BANDSWITCH ...............

TRANSCEIVE SIDEBAND

10-METER MOX-OFF VOX-PTT

VERNIER

Switch

Switch .............

Switch . . .

BIAS

INSIDE TOP

MIC

GAIN .....

CARRIER VOX VOX

BALANCE

GAIN ..............

DELAY .................

..............

PANEL

...........

..........

.

.........

............

........

...

.......

REAR

PANEL

.........

. .

TUNE

.....

..

...

COVER

.

...

.

Full cw OFF

.

Full cw

Full ccw

.

3.5

.

OFF

.

USB

.

28.5

.

OFF

.

PTT

Mid-range

Full ccw

.

Full cw

.

Full ccw

.

Full ccw

.

Me

or

ccw

Power Connections:

Connect

put

turned

6GJ5

sockets should be removed .

5.3

IF ALIGNMENT

Turn seconds NCX-5

Connect

leads.

This

audio

output

signal generator

grid

(Pin 7) of the 12BE6 (V-14) second receive

mixer.

Me. A 1 slugs of

(T-4,

T-5,

the

balanced modulator transformer

mum

output,

receiving channel.

the

power supply

off.

The

heater

PROCEDURE:

the

FUNCTION

the

relay should close, indicating

is

in a receive condition.

the

audio

with

the 700 volt out-

wire connecting the two

switch to SSE.

output

meter

to the speaker

may be conveniently done by plugging

meter into

through

Set the signal generator for

to

2Kc

beat note should be

the

first, second,

and

T-6

the

phone

jack. Connect

a 1000

pF

capacitor

output

heard

and

third

IF

),

as well as the bottom slug of

(T-1)

being careful to avoid overload of the

The

signal generator

output

In

a few

that

the

to the

at

6.0218

. Align

the

transformers

for maxi-

should

be reduced throughout this alignment procedure so

that

an

output

of

100

mw

is

never exceeded.

15

5.4

BALANCED

MODULATOR

ADJUSTMENT:

5.7·

RECEIVER

BANDPASS

TUNING:

Connect

grid

(Pin

Place

the

relay in

the high-frequency oscilloscope

1) of

the

first

IF

MOX-OFF

the

NCX-5

switch in

should open, placing a transmit condition. Adjust of

the

balanced modulator transformer maximum CARRIER tion of

the

control

this point, responding

may

on· the

control. to

be

adjusted

indication

on

the

BALANCE control for

scope.

This

should occur

Return

full cw

the

carrier oscilloscope trimmer ( C-6) cor-

to

the

upper to

the

or

ccw.

If

sideband crystal

insure

is functioning.

5.5

CARRIER

With adjustment, Me

crystal

peak as indicated on

Set

the corresponding level is

0.2 volts peak-to-peak as indicated

OSCILLATOR

connections set as for balanced

adjust

until

SIDEBAND

(C-6) corresponding

the signal level

the

oscilloscope.

switch

to

the

6.020

oscilloscope.

Return

move

switch

5.6

the

SIDEBAND

the

oscilloscope connection.

to

OFF.

TRANSMITTER

BANDPASS

amplifier 12BA6

the

MOX

top

position.

and

scope. Carefully

minimum

near CARRIER there

is

no

indication

at

that

the

carrier oscilla

SETTING:

to

is

0.2 volts peak-to-

to

LSB. Adjust (C-5)

Me

crystal until

switch

to

USB

Return

TUNING:

to

the

(V-15).

The

the

unit

in

bottom

(T-1)

slug

for

adjust

indica-

mid-range

BALANCE

at

6.0234

Me

tor

modulator the

6.0234

the

signal

on

the

and

re-

MOX-OFF

Connect

the

sweep generator

to

(Pin 7) of the first receive mixer 12BE6

nect

the

oscilloscope second receive mixer 12BE6 and

bottom slugs of

for

maximu

similar

Disconnect

to

that

m display

the

to

the

receiver bandpass coil

amplitude

obtained for

oscilloscope

signal grid

(V

-14) .

and

the

transmit bandpass coil.

and

sweep generator con-

nections.

5.8

VFO

FREQUENCY

Connect

the

signal grid (

12BE6 (

mer

(C-16)

mer

(C-18)

frequency

zero beat. the

main

the

high frequency signal generator

V-13).

Preset

and

the

to

mid-range. Set

to

4 Me. Adjust the

Set

the

generator

tun

ing dial should be obtained dial.

If

this

beat

note occurs

Me,

the

VFO

trimmer reduce Me

on

the

capacity.

the

dial, increase the signal generator Reset

the

VFO

coil slug for zero

serve

the

location

the

signal ge should be repea the

4.0

Me beat

of

nerator

ted

note occur within 500 cycles

ALIGNMENT:

7) of the first transmit mixer the

sideband switching trim-

temperature compensating trim-

the

VFO

input

to

3.5

toward

in

the

If

the

and

3.5 Me. A

regi

on

of 3.5

at

a dial setting above 3.5

(C-1

7")

sliould be

beat

note occurs below 3.5

the

trimmer

main

capacity.

tuning

beat

the

beat

note

near

set

to

3.5 Me.

until

the 3.5

Me

dial markings.

the

signal

grid

(V

-13) .

Con-

(Pin

7) of

the

Ad

just

the

top

(T-3)

proper response

to

signal generator

coil (L-27) for

Me

and

tune

beat

note

Me

on

the

turned

to

Return

dial

to

4 Me.

and

again ob-

3.5

Me

with

This

procedure

beat

note

and

of

the

Connect

(Pin 7) of

nect

the

and

the mixer. CARRIER

minimum dications. transmit bandpass coil amplitude outputs of frequencies.

the

sweep

generator

the

first transmit

oscilloscope

cable feeding

Press

the

MOX-OFF

to

the

mixer

grid

BALANCE control may be adjusted for carrier Adjust

to

the

avoid

top

unwanted and

(T-2

and

proper response.

the

signal generator

When

properly aligned,

display should be as indicated.

3.5Mc

MARKER-

3

TO

6db

FROM

PEAK

Return

nect oscilloscope

MOX-OFF

and

sweep generator leads.

switch

to

12BE6

junction

of

the

switch

bottom slugs

) for

maximum

The

may

to

the

signal grid

(V

-3) .

of

C-134, R-76,

second transmit

to

MOX.

oscilloscope in-

of

display

3.5

and

4.0

be used as

the

OFF

marker

oscilloscope

4.0Mc

-MARKER

3

TO

FROM PEAK

and

discon-

Con-

The

the

Me

6db

5.9

VFO

LINEARITY

A special linearity adju segmented plates rear

section justmen will

t of

be

necessary

Insert brator and obtain

socket.

set for 100

a zero

and

a stator) is incorporated

of

the

NCX-5

the

VFO

frequency

to

set

the

crystal calibrator

With

the

Kc

markers,

beat

at

the have previously been set. be adjusted these points zero of

the both) bent

as required indicated frequency one

or stator. high, It

is

important

on a gradual

point should correction plate. segments will lie

to

3.9, 3.8, 3.7, beat

should occur within

exact dial frequency.

of

the segmented adjusting plates should be

to

achieve

is

too low

both

of

the

plates should be moved toward

If

the indicated dial reading

the

plate should be moved away from the stator.

that

this linearity correction be

basis.

The

not

be

made

When

in

a smooth curve.

ADJUSTMENT:

stment (consisting

VFO

capacitor. After

at

4.0

VFO

linearity.

into

the

crystal calibrator

it

should be possible

3.5

and

4.0

Me

The

main

tuning

and

3.6

Me.

If

necessary, one

proper

calibration.

at

the

at

zero

entire correction

with

a single segment

properly aligned,

of

in

and

3.5

Me,

crystal cali-

turned

points which

should now

At

each

+500

cycles

If

beat

point,

beat

made

at

any one

of

the

corrector

two

the

ad-

it

on

to

of

(or

the

is too

the

16

5.10

tate the sideband selector switch to LSB. quency obtained should still set sideband selector switch there should be no change small interaction of this adjustment with alignment.

if any

VFO

SIDEBAND SWITCHING

ADJUSTMENT:

Set

the

main

tuning

the

sideband trimmer (C-16) for zero beat.

The

VFO

error

is introduced.

to

zero beat

be

zero beat.

is

rotated

alignment should be readjusted

of

frequency.

from LSB

at

3.8 The

If

it

to

There

the

Me,

is

As

USB,

VFO

ro-

fre-

not,

the

is

5.11 TEMPERATURE COMPENSATING

ADJUSTMENT:

During be checked. pensating capacitor should greater dial reading

ture

(C-18) should be toward a higher dial reading indicates insufficient compensation greater capacity. Adjustment trimmer will change realignment

ing procedures:

Me

dial setting. Adjust

required

(C-17) to cedure is carefully followed, not

be been made, the dial calibration should be checked the alignment

peated leads from the NCX-5.

5.12

Connect junction final amplifier. the

FUNCTION again placed in a transmit condition. dial

to the

just driver coil (L-5) slugs for oscilloscope.

peak-to-peak

exceed

Set CITER cedure mixer coil ( L-9) An

output

be

indicated

alignment

If

drift

or

less compensation.

on

80

compensation

and

of

the

and

immediately adjust the

return

seriously affected.

of

if

necessary. Disconnect the signal generator

TRANSMIT MIXER AND DRIVER ALIGNMENT:

the

of

C-46, R-42,

Set the BAND switch

drop

out,

3 .

.750

Me

80

meter

When

output

130 volts.

the

BAND switch

TUNE

at

7.300

of

more

on

of

the

NCX-5, its

is excessive,

meters indicates excessive tempera-

and

turned

the

trimmer

the

VFO

can

Set

the

NCX-5

the

NCX-5

the preceding sections should be re-

high-frequency oscilloscope

switch

indicating

and

the

mixer coil ( L-1

the slugs

voltage

control

the oscilloscope.

to

Me

while adjusting the

and

the

than

the

be adjusted

Drift

the

compensating trimmer

to

reduce capacity. A drift

should be

of

VFO

frequency. Complete

be

avoided by

to

compensating

to zero beat.

the

dial calibration should

If

a

major

and

the grids

to

TUNE.

that

Set

EXCITER

0)

maximum

are

properly adjusted, the

on

the oscilloscope should

to

7.0

6. Repeat

40

meter

130 volts peak-to-peak must

VFO

temperature com-

to

towards a lower

the compensating

zero

beat

trimmer

VFO

If

correction has

of

to

3.5

The

relay should

the

unit

the

main

control

and

the

indication

Me

and

the

above pro-

driver coil ( L-4) .

should

provide

turned

the

follow-

at

the 3.8

trimmer

this pro-

to

the 6GJ5

Me

has

been

tuning

to

5. Ad-

80

meter

on

the

EX-

40

meter

for

as

and

the

and

the

At

this point a ripple will

scope pattern. Adjust

minimize this ripple. there will be some interaction with 40

meter

mixer coil (L-9) which must

for maximum amplitude. Repeat these adjustments

until minimum ripple

obtained simultaneously.

a

trap

may

be checked by removing the

the

in crystal amplitude such

the slug should be withdrawn from above alignment procedure repeated

trap

CITER dure coil ( L-8)

CITER

dure coil (L-7)

CITER cedure mixer coil (L-6)

5.13

any alignment

this time to check the final amplifier for proper opera-

tion

it driver plate coils These quence: sockets. Place

position

warm-up

high-frequency oscillator circuit. When the

is

removed, there should

of

the

drop,

the

harmonic

frequency.

Set

the BAND switch to 14.0

TUNE

at

14.250

Me

and

the

Set the BAND switch to

TUNE

at

21.250

Set the BAND switch to 28.5

at

FINAL AMPLIFIER PRELIMINARY

ADJUSTMENT

The

at

the

is

necessary

checks should

Me

and

the

TUNE

28.750

NCX-5 construction does

of

high

and

to

Connect the heater wire between the 6GJ5

the

and

allow approximately 30 seconds for

of

the

final amplifier tubes.

the

After

and

oscilloscope display.

control

control to

make a slight final adjustment

to

while adjusting

20 meter driver coil ( L-3) .

to

while adjusting

15

meter

Me

while adjusting

and

the

(10

the final amplifier.

low ends

and

on

be

FUNCTION

appear

harmonic

this adjustment is made,

maximum amplitude

The

setting

trap

has been mistune4

3.

Repeat

7.

Repeat

driver coil

7.

Repeat

10 meter driver coil

METER):

of

the neutralizing capacitor.

made in

trap

the

of

be

a large

the

Me

the

21.0

Me

the

Me

not

It

all bands.

the

switch in

on

20 meter mixer

15 meter mixer

the

-CAUTION-

UP

UNTIL

NO

POWER

FIER.

ALL ERATING ARE

LOW AGES AND TERED FROM MAY DANGEROUS TEST TEST. NO CONNECTED DENTALLY

IN

HERE

BE

EQUIPMENT

IT

PIECE

THIS

TIME,

APPLIED

CIRCUITS

AND

WHICH

LEVEL

POWER

DAY-TO-DAY

ON,

ENCOUNTERED

TO

IS

ESSENTIAL

OF

INTENTIONALLY

TO

WHICH

CIRCUITS

NORMALLY

VOLTAGES

PERSONNEL

AND

TEST

THE

NCX-5.

THERE

THE

FINAL

HAVE

EQUIPMENT

BEEN

USING

RECEIVER

AND

WHICH

AND

THE

UNIT

TO

BE

SURE

IT

IS

on

the oscillo-

(L-29)

tuning

be

the harmonic

11

If

and

(L-2).

and

the

is necessary

CURRENTS

of

the

readjusted

are

Me

crystal

drop

in

the

there is

and

coil

and

the

the proper

the

EX-

above proce-

the

EX-

above proce-

the

EX-

above pro-

10 meter

(L-1).

provide for

In

addition,

on

the

following se-

the

OW

HAS

BEEN

AMPLI-

BEEN

OP-

TESTED

VOLT-

ENCOUN-

WORK.

ARE

TO

THE

UNDER

THAT

BE

MIS-

OR

ACCI-

FURTHER

to

no

at

17

IMPORTANT TIONED WHICH DANGEROUS IMPORT

ANT PLACED DITION DAMAGE NCX-5. TESTS

IN A NUMBER 'rHE

ERATED

INDICATIONS

TEST

IS PERIOD IS

NOT

TUNED SECONDS, UNIT

BE DITION. MANENT FINAL NENTS

AMPLIFIER

IN

Disconnect all test equipment from Attach put

the

meter D.C. voltmeter, set amplifier for maximum negative voltage. BAND switch still on the 28.5 tuning dial switch TUNE

to

for maximum meter reading

tion S-meter

THAT

AGAINST

MAY

RESULT VOLTAGES. THAT

INTO

A .TRANSM

WITHOUT

MAY

RAPIDLY

TRANSMITTER

AT

FULL

POWER

ARE

NO'r

OF

COMPLETED

15

SECONDS,

UP

IT

IS

IMPORTANT

RETURNED

OTHERWISE,

DAMAGE

THE

FINAL

50

ohm

dumm

to

the

NCX-5

the

to

28.75 Me. Now

TUNE

and

cathode

PERSONNEL

CARELESS

IN

CONTACT

IT

THE

NCX-5

BE

HANDLING

IS

FURTHER

NOT

ITTING

PROPER

OBTAINED,

OF

TUNING, RESULT THE

FOLLOWING

WILL

OUTPUT.

OR

TO

BE IF

IF

WITHIN

OR

IF

THE

WITHIN A PERIOD

THAT

'rO A RECEIVING

SERIOUS

CAN

TUBES

OUTPU'r

BE

AND

DONE

AND

CIRCUIT.

TO

COMPO-

the

y load with calibrated out-

antenna

bias

at

terminals.

the

grid

of

the

With

Me

band, set

tum

the

rapidly peak the

on

current

meter. Adjust the

the

FUNCTION

EXCITER

the combina-

CAU-

WITH

BE

CON-

SINCE

THE

OP-

MIS-

THE

A UNIT OF

15

THE

CON-

PER-

THE

NCX-5.

With

a

final

the

main

10 meter driver plate coil (L-1) for maximum meter reading while slowly rocking control.

This

will correct for

the

EXCITER

the

presence

TUNE

of

the oscilloscope probe in the previous setting. Now rotate the

PA

TUNE

curs

in

the

Note output watts

meter.

at control is adjusted so 300 rna. current dip, in

a clockwise direction.

advanced,

TUNE

PA process until sponds

5.14

to

NEUTRALIZING

With position, rotate of

the

resonant point

meter.

It exceed 350 rna. current, current It

dip

should exceed 100 watts. Carefully

control

and

observe whether a

plate current reading.

the

power This

output

power

reporded by

output

all frequencies providing

that

the

final amplifier draws

With

the PA

the

it

will be necessary

control

the

PA

TUNE

LOAD

control set for a plate

control is slowly rotated

As

the

PA

to

stay

in

the

minimum reading

300 rna on the meter.

CAPACITOR:

the

FUNCTION

the

is necessary

Having

retune

at

300 rna

the

P A

and

that

PA

and

switch in

TUNE

control observe the plate current the

off resonance

noted

the

TUNE

observe the power output.

dip

the

power

should exceed 100

the

PA

LOAD

slightly

control

retune

dip. Continue this

in

the

dip

corre-

the

TUNE

to

either side

current

off resonance plate

control

to

rotate

the plate

the

oc-

i~

the

P A

TUNE whether the power setting should fall put from the dip, izing capacitor. and and curs is achieved, maximum power minimum switch

5.15

tuning switch TUNE

meter

reading while slowly rocking control. oscilloscope probe PA pears

clockwise direction

control minimum meter reading in 300 rna. and

switch

proper driver coil for maximum

while rocking the

control

of

actually rises as the

error

observing

at

the plate

to

FINAL

ADJUSTMENT .

Set the BAND switch

dial

to

either

side

of

the

dip

and

the n

to

either side

it

output

eutra

will

'rhis

rises

or

falls.

lizing capacitor,

of

the dip.

tuning

control

be

necessary

can

to

be quickly done

With

the

power

If

the

power

is

tuned away

adjust the neutral-

on

basis by rotating the neutralizing capacitor

whether

current

plate current.

maximum power

dip. As

proper

output

Return

neutralization will occur

the

FUNCTION

output

CW.

AMPLIFIER PRELIMINARY

to

TUNE

(80-15

21.250 Me. and

rapidly peak

METERS):

to

21

Tum

Me

and

the

FUNCTION

the

EXCITER

for maximum meter reading. Adjust the 15

driver plate coil (L-2) for maximum

the

EXCITER

This

will correct for

in

previous tests. Now rotate

TUNE

control

in

the reading. Advance

and

to

stay

in

dip. Continue this process until

The

proper Repeat

power

neutralization should

this procedure

output

and tuning settings, in

EXCITER

observe whether a

slightly

the

presence

the

PA

LOAD

retune

the

dip

corresponds

PA

should exceed 100 watts

be

observed.

at

the following BAND

each

case adjusting

meter

TUNE

indication

control.

observe

a proper

output

a trial

the

meter

TUNE

of

dip

TUNE

MAIN

BANDSWITCH

14

Me

7

Me Me

3.5

5.16

FINAL

The

proper crystal should be inserted into the

TUNING

14.250

AMPLIFIER TUNING

7.250

3.750

DIAL Me Me

Me

DRIVER

L-3 L-4 L-5

CHECKS:

COIL

NCX-5 high frequency oscillator for operation

BAND switch settings

these crystals

are

checks in these BAND switch settings

Set the BAND switch

tuning

switch

dial

to

TUNE

28.250 Me.

maximum meter reading. Rotate

and

trol

observe

whether a dip

Advance the PA

tion

and

retune

the

output

until

to

300 rna

should exceed

should

circuit

the

minimum reading in

on

the

100 watts

be

observed.

of

28, 29,

not

available, final amplifier

to

28.0 Me. Set the

Tum

and

peak the

EXCITER

the

appears

LOAD

the

in

control in a clockwise direc-

PA

TUNE

the

dip. Continue this procedure

control to maintain

the

meter. Power

and

output

proper

and

29.5 Me.

cannot

the

FUNC'riON

TUNE

PA

TUNE

in

the reading.

dip

corresponds

at

this setting

neutralization

tuning

be made.

main

out-

oc-

at

main

the the

ap-

in

a

the

to

the

at

If

for

con-

18

Repeat tuning necessary, mixer adjusted to providi operation

BANDS

5.17

Set the BAND switch to 7.0 Me. crystal calibrator signal.

Two

crystal trimmer (C-9)

both beat notes

Repeat

set

the

Repeat this procedure set the

The

by this procedure according

BAND-

SWITCH

28.0

5.18

Press the CARRIER Tune

this check with BAND switch

capacitor set for

and

maintain

ng

sufficient drive

is

achieved.

WITCH

29

Me

29.5

Me

21.0

Me

21.0

Me

14.0

Me

14.0

Me

the

following frequencies.

driver coils may be slightly re-

proper tracking across

and

MAIN

7.0Mc

3.5Mc

LOCAL ADJUSTMENT:

OSCILLATOR CRYSTAL

proper

TUNING

29.25

29.75

21.00

21.50

14.00

14.50

and

final amplifier

Me Me Me Me Me Me

7.00

Me

7.30

Me

3.50

Me

4.00Mc

Turn

ON.

Tune

to

any crystal calibrator

The

dial should read

beat

notes may be noted. Adjust

and

to

zero.

this procedure

18

Me

crystal trimmer (C-10).

25

Me

crystal

trimmer

an

exact 100

Kc

the

the main tuning dial

on

the 14.0

on

the 21.0

Me

band

( C-11) .

accessory crystal trimmers may also be set

to

the

following

10METER

SEGMENT

SWITCH

Me Me Me

PARASITIC CHECK:

28.0

Me

29.0Mc

29.5

Me

MOX-OFF

CRYSTAL CRYSTAL

FRE-

TRIM-

QUENCY

24.5

Me

25.5

Me

26

Me

switch

to

MOX.

BALANCE control for minimum current.

PA

TUNE,

PA

LOAD,

and

EXCITER

the

DIAL

point.

11

chart:

MER

C-14

C-13

C-12

Adjust

main

If

band

the

Me

to

set

and

con-

trols through their ranges. Look for unwanted spu-

on

the

meter.

There

rious peaks

peat

this test

5.19

on

all bands.

CARRIER SUPPRESSION, SIDEBAND

SUPPRESSION, MODULATION, ALC

CHECKS:

Connect the audio generator

and

jack Rotate

supply

the

10

mv

FUNCTION

of

should be none. Re-

to

audio signal

switch

to

the SSB setting.

AND

the microphone

to

the

NCX-5.

Connect the high-frequency oscilloscope to the antenna

line which is connected Rotate full ccw.

the

CARRIER

Tune

the

BALANCE control full cw

final amplifier for maximum out-

to

the

dummy

load.

or

put

at

300 rna sections. A level well in excess of peak should be noted rotate

the mid-point. meter

reading should fall. Set

ANCE

control for minimum indication

oscilloscope which should correspond indication 60

rna

on oscilloscope should thus insuring carrier suppression better

If

necessary, carefully adjust

plate trimmer (C-7) for

rocking the

minimum until the required

Now clockwise direction. A signal should again the

oscilloscope. until the cathode at

the

scope should be 120-180 volts.

at

this point should

It

is

necessary to note the level form to total wave form level. exceed

that

1/50

the

unwanted sideband suppression with a 1000

cycle tone is

input

as described

in

100 volts peak-to-

on

the

oscilloscope. Now slowly

CARRIER

The

oscilloscope level should fall

on

the

meter.

CARRIER

BALANCE control towards

the

CARRIER

meter. Adjust the BIAS control for

The

level remaining

not

exceed 0.5 volt peak-to-peak,

the

balanced modulator

minimum

indication while

BALANCE control through

0.5 volt level is obtained.

rotate

the

MIC

The

MIC

current

GAIN

meter

control slowly in a

should be advanced

reads 250 rna.

The

appear

of

the total wave form. This indicates

in

excess of 34 db.-

as

indicated in figure 6A.

of

ripple

The

ripple should

the limit of this

the

on

to

minimum

on

than

50 db.

appear

Output

wave form

on

the wave

the

BAL-

the

on

not

measuring technique .

It

is

important

carrier balance

in

the

previous measurement.

ANCE

control is rotated slightly,

to

note the difference between

and

unwanted sideband suppression

If

the

CARRIER

the

wave form of

BAL-

figure 6A will be altered to the wave form of figure

If

6B.

make CARRIER justed of

meter just reaches 300 rna

this wave form is present while attempting the

sideband suppression measurement, BALANCE control should be slightly ad-

to

compensate

and

return

the

picture

figure 6A.

Now

further

advance

the

as

MIC

set by

GAIN

our tune-up procedure. Note the oscilloscope level. advance or wave form will begin

the

CARRIER

BALANCE control either cw

ccw from the balance setting.

to

develop large cusps

As

this occurs, the

and

the

to

that

until

the

peaks

to

which will tend to exceed the noted oscilloscope level. Slowly reduce the

MIC

GAIN

to

keep

the

peaks

at the predetermined level by carefully adjusting both the

MIC

GAIN

and

the

CARRIER

It

trol.

should be possible lustrated in figure 6C. of

this figure be

at

exactly the balanced carrier This

is

equivalent

to indicating distortion performance form which and

should have a sine wave envelope.

should be

of

ing

indicated

of

the

is

observed should have a clean

no

flattening

the

cusps. Typical incorrect wave forms

in

figure 6D

to

It

is

important

the

at

300 rna

a two-tone test

in

the transmitter channel

modulating circuits.

of

the

·&

6E.

BALANCE con-

obtain a picture as il-

that

the

peaks

level determined with

of

cathode current.

and

is

useful

in

and

The

wave

sharp

cusp

There

peaks

and

no

broaden-

are

19

Advance the

·

and

readjust the sharp cusps. driven

scope wave form should remain as shown Check R-35, volts junction point should be checks the action

plying oscilloscope display amplitude should decrease, indicating external control.

VOX-PTT

assume though operation do this, return the the carrier with the Now remove the audio generator from the microphone jack Press the push-to-talk button the microphone. control until the amplitude used for the previous two-tone ty test. with the speech content. average wa

5.20

3.700 Me.

function. press the

MIC rotate the

rna is indicated the oscilloscope. Press Tune lightly noted. Press the

and

the ALC

and

C-48.

at this point. Check the ALC voltage

of

The

rear

-10

Press the

If

all

of

that

it

is

of

At

this point, the meter will

around

ve form should appear as illustrated

TRANSMIT-RECEIVE FREQUENCY CHECK:

Set the BAND switch to 3.5

Tune

Return

MOX-OFF

GAIN

CARRIER

an

accessory receiver to 9.

to

the NCX-5

MIC

GAIN

CARRIER

The

final amplifier should now be over-

ALC

voltage should result.

output

D-8, D-9,

ALC

to

-15

MOX-OFF

switch to

the

the transmitter is working properly,' al-

of some value to check

the transmitter

and

replace

the

125

control to the full ccw position. Now

on

at

There

should be approximately

and

1/2

of

the internal ALC circuit.

jack may now be checked by

volts

at

PTT.

tests are

MIC

CARRIER

it

Slowly advance the

peaks

of

rna

the final amplifier using the

FUNCTION

switch to

BALANCE con trol until 300

the meter

the

VFO

MOX-OFF

control

BALANCE control for

the junction

C-50.

the previous reading. This

the

ALC

switch

met

satisfactorily, we

on

the microphone.

GAIN

The

of

to

BALANCE control.

with the test microphone.

and

the resulting signal reach

be

meter should generally

current

and

MOX-OFF switch O

. A beat note should

switch to MOX.

to

maximum

The

oscillo-

in

figure 6C.

of

D-9, R-34,

at

The

voltage

input

to

OFF

zero

speak normally into

fluctuating rapidly

and

Me

and

switch

MOX. Return

output

72

Me

at

jack.

and

set

the

dynamic

and

balance

MIC

GAIN

the

output

in

figure 6F.

the dial to

the

TUNE

to

SSB

appears

and

couple

The

pe

The

-5 the

this

ap-

the

can

To

and

the

on

FF.

of

be

beat note indicated by not

change more

switch

5.21 LSB-USB SWITCHING CHECK:

with the

5.22

connected to a dummy load with the

Balance the carrier.

now check the entire switching lowing

OFF

.

Proper sideband switching

D.C. voltmeter according to the

SWITCHING

The

transmitter portion of the NCX-5 is presently

NCX-5

1.

2. Press the MOX-

3.

4. While speaking into the micro

5.

to resonance for maximum power

manner:

Place

the

PTT-VOX

and

MOX-OFF

to-talk button

A standard single sideband appear to-talk button. to

speak into the microphone. SSB should result.

OFF

Place the position. While speaking slowly advance the the speaking to receive.

the control full ccw, stop speaking, NCX-5 should go back to receive mately 1

Tum

into the microphone. switch to NCX-5

second. sideband signal should be observed

on

receive.

and

relay trips the

NCX

/

the

accessory receiv

than

50 cycles. Press the

may

be easily checked

TESTS:

an

oscilloscope.

With

these conditions established,

se

quence

FUNCTION

switch

and

the oscilloscope. Release the push-

The NCX-

OFF swit

Return

the NCX-5 should revert to receive.

VOX-PTT

and

the

-5 to transmit, adjust

10

of

a second.

DEL

AY con

tr

ansmit; stop speaking should In

return

each case, a standard single-

switch in SSB

in

the

OFF.

Press the push-

speak into the microphone.

output

5 sho

ch to

the

MOX-OFF

switch in the

into

the microphone,

VOX

GAIN

unit

into transmit. Stop

transceiver should

ph

tro

l full cw

The

NCX-5 should

to receive

er

should

MOX-OFF

chart

below.

Tune

output

in

the fol-

PTT

position,

should

uld

revert

MOX

output

switch

VOX

control until

return

one to cause

the

DELAY

and

in

approxi-

and

speak

and

in

on

.

and

the

one

the

TEST

*SHOULD

Test Point Location:

POINT

BAND

1 2 3

BE

-40

WITH

1.

}7, Pin 3 (Calibrator Socket)

3.5 + 150

-80 0*

AM

7.0

14.0

-35 -35 0*

-80

RECEIVE

LSB

21.0

-35

0*

-80

CONDITION

2.

Jun

ction

28.0 +150

-80

of

20

0*

ONLY

R-65

and C-153

3.5

7.0

-35

+ 150

0*

- 80

-80

0*

3. Junction of R-61

USB

14.0 +150

- 80 0*

21.0 28.0

-80 0*

and

-35 0*

-80

C-64

+ 150

oscilloscope while speaking into the micro-

phone.

6.

Set

the

FUNCTION

peat

the

above tests for

MOX

operation.

7.

While speaking into

CARRIER

the balance point of

carrier into the sideband signal

switch

to

AM

PTT,

the

microphone, adjust

BALANCE control from the

and

observe the introduction

oscilloscope.

Place the

8. position. Advance the full

the microphone

result

9.

Set the

the

FUNCTION

cw

(maximum sensitivity) . Speaking into

in

transmit-receive switching.

VOX-PTT

PTT

button.

switch

VOX

GAIN

this . condition should

switch to

The

PTT

NCX-5 should

switch into transmit.

10. Press

11.

the

MOX-OFF

NCX-5 should switch

the

MOX-OFF

switch

to

transmit.

to

OFF.

to

Insert a key into the key jack. A key should place the condition. should revert

Upon

to

to one second, depending

the

VOX

DELAY

NCX-5 into a transmit

release

receive in 1

of

the key,

on

/10

the setting

control.

and

VOX,

on

in

the

control

and press

MOX.

Return

tap

the

of

a second

of

re-

and

the

CW

not

The

the

unit

of

5.23

receiver to 9.72

VFO. than Press the

TRANSCEIVE VERNIER:

Set the NCX-5 to 3. 700 Me.

Me

and

lightly couple to the NCX-5

Observe

+ 5

that

the beat note may be varied more

Kc

with the

MOX-OFF

TRANSCEIVE

switch to

Tune

MOX.

the accessory

VERNIER.

Observe

the beat note cannot be varied with the CEIVE beat note previously switch mid-range. OFF

Return

VERNIER

OFF

and

Turn

and

observe

the

NCX-5 to receive.

and

that

heard

the

TRANSCEIVE

the

TRANSC

that

the beat note does

it

corresponds to the

with the

VERNIER

EIVE

Disconnect all test equipment.

-CAUTION-

IN

THE

FOLLOWING THERE OUTPUT. TRANSMIT OUS

OUTPUT OF CONNECTED NALS. THIS

IS

NO

LOAD

IF

THE

UNDER

DAMAGE

CAN

STAGE.

TESTS, A SIGNAL

TO

SERIOUS

SIGNAL

GENERATOR

ACCIDENTALLY

UNIT

THIS

BE

ALSO

THE

DAMAGE

PLACED

SERIES

ON

THE

TRANSMITTER

SHOULD

CONDITION,

DONE

TO

DURING

GENERATOR

ANTENNA

CAN

IF

INTO

OF

THE

THIS

BE

THE

TRANSMIT.

that

TRANS-

MOX-OFF

VERNIER

not

change.

TESTS,

GO

INTO SERI-

FINAL

SERIES

WILL

BE

TERMI-

DONE

UNIT

TO

IS

at

12.

Hold

the key closed, speak into

phone

and

advance the There on

13.

Set the transmitting key for a long series

should be no evidence

the oscilloscope.

dots. Adjust

th~

CARRIER

trol for transmitter

power.

on

Observe the series

the high-frequency oscilloscope. A proper

MIC

BALANCE con-

output

of

GAIN

just below full

keying pulse should appear as

6H

and

6I

Figure

indicate improper keying

sequences.

14.

Set the serve the oscilloscope. Adjust the ANCE in

15.

Speak into the microphone MIC evidence of modulation

16.

Return

FUNCTION

that

control.

the

output

GAIN

the

full power

There

signal.

control.

FUNCTION

switch to

output

CARRIER

should be no change

and

There

on

the oscilloscope.

switch

the

micro-

control.

of

modulation

of

keying pulses

in

figure 6G.

TUNE.

is

attained

Ob-

on

BAL-

advance the

should be no

to

SSB.

5.24

terminals through a suitable dummy load the 50

for

tuning dial

ANTI-VOX CHECK:

Connect the signal generator to the

ohm

input impedance. Set the signal generator

4.0

Me,

the BAND switch to 3.5 Me,

to

4.0

Me

until a beat note is obtained

and

antenna

to

match

the

main

at a frequency of approximately 1000 cycles. Connect the power nals by use

output of

meter

to

the audio

the phone jack. Set the

output

AUDIO

termi-

GAIN

control for approximately ~ watt. Measure the D.C.

voltage

A voltage dicated

5.25

The

VFO the be signal. Remove the external signal resistor.

at

the junction of D3, R103, R107,

of

more

than + 10

at

this test point.

VFO

JACK:

Connect 100 ohms from the

volts should be in-

VFO

jack

beat note should disappear, indicating

is

not

functioning. Feed

VFO

jack between 9.52

possible

to

retune the beat note with the external

an

external signal

and

10.02 Me.

and

The

original beat note should reappear.

the

and

to

ground.

that

It

should

100

C157.

the

into

ohm

21

TOP

VIEW

FIGURE 4

R4

RB

S7

S3A

BOTTOM

FIGURE 5

VIEW

22

C

(CORRECT)

A

NCX-5

0

(CLIPPED)

WAVE

FIGURE

IPPLE

FORMS

6

E (POOR CUSPS)

F

G

I

H

23

SECTION

6

SOCKETS

Jl

J2,J3

J4

]5 ]6

]7

]8 ]9

Antenna Ext. MIC

Key

Phones Octal

Jones Male

Jones Female Relay Terminal Strip Relay Socket Navar 9 Pin 7 Pin Transistor X tal Panel Lamp, Counter Panel

POTENTIOMETERS

Rl R2 R3 R4,R8

R5 R6

R7 R9

R38

R39

R52,

R109

R108,

R114 RllO Rlll R113

C5,C6,

C17,

C18 C7 C8,C9,

ClO,

Cll,

C12,

C13,

C14

BIAS B50541-1 S-METER MIC RF

VOX TRANSCEIVE

VOX CARRIER

1.5 K 2o/o

3.2 ohm 10

2.2 470 ohm Film

33.0 K Film 470 K Film

Ceramicon 5 -

Mica, Balance Mica Assembly

AND

JACKS

VFO

In, Ext. ALC

Lamp

AND

GAIN

GAIN-

- CAL

and

AUDIO

SWITCH

GAIN

VERNIER

SWITCH

DELAY B50541-4

BALANCE B50541-1

In

CONTROLS

GAIN

RESISTORS

Y2

W

3%

2W

WW

.0 K Film

K Film

TRIMMERS

25

NPO

PARTS

A51479 A51084 A50793-2 A50793-1 A50793-3 B27674-1 A50791 A50828 A51563 A50954 A50802 B27668-1 B27669-3 A50981 A50799

A51607

B50829-2

B50541-3 B50541-9 B51550

B50541-2 B50986-2

20BF-

RS

152G

B517436-

10

A51559-3 A51559-2

A51559-1 A51559-4 A51559-5

B19783-2

A50137 B50993-6

LIST

C15 C16

Cl

C2

C3 C4 C20 C34

C35

C36, C41, C47 C70

C165 C166

C181

T1

T2,

T3

T4, T5,

T6

T7

Ll

L2

L3

L4

L5

L6

L7

L8 L9

and

L29 LlO Lll L12 L13, L16,

L17,

Ll9,

L20,

L21,

L23

L14

L15

L18

TRIMMERS

Air, Neutralization B50364

Ceramicon

1.5

(Cont)

- 7

NPO

CAPACITORS

Gang:

Gang: Gang: PA Gang: PA

Electrolytic Ceramic 82

Ceramic

C40

Ceramic Ceramic Ceramic 5pF

Ceramic 1 0

Ceramic

VFO-

Tuning

spec. rating

cial

(Main)

EXCITER

TUNE LOAD

pF

51

pF

75

pF

spec. rating A50849-3

500

pF

spec. rating A50849-5

N220

pF

N7 50

47

pF

N750

120

pF

TUNE

5%

5o/o

OTC

NPO

Spe-

TRANSFORMERS

Balanced Modulator Bandpass

IF Audio

COILS

10

15

20 40 :Meter DriYer 80

10 Meter Mixer

15

20 Meter Mixer 40 Meter Mixer

80 Meter Mix Final Choke, Special Choke,

p. a. Choke R154 Choke, Final Grid 100 Choke

3.5

6.02 Me B50766

AND

Meter DriYer

Meter Dri\·er

Meter Driver

Meter Mixer

Tank

220

[-lh

10

[-lh

to 4.0

CHOKES

er

Output

Me

B19783-5

C51507

C50790-2 C50789-2 C50788 C19458-6

A50849-4

A50849-2

CC

050 K

CC

100 K

CC

470 K

A50113-2

B50764 B51513

B19435-3

B51517 B51515 B50759 B507 B50755 B51516 B51514 B50760 B51581

B5

0756 B51518 B51554 A50206-1

[-lh NCL

C50527-8

20

20 20

57

RH

UJ

NCL R33

24

COILS

AND

CHOKES

(Cont)

SHAFTS,

COUPLINGS,

DRIVE

TRAIN

(Cont)

L22 L24, L25 L26 L27 L28 Choke

Choke 4.7 Choke, Parasitic B51545 Choke, Antenna Coil

VFO

!lh

3.3

SWITCHES

S1-A

S1-BC

S1-DE S1-FG Bandswitch, Driver S1-HI

S1

S2 S3-AB Function Switch, S3-CDE

S4

S5 S6

S7

S8

Bandswitch,

VFO

Bandswitch,

Carrier

Bandswitch, Mixer

PA Bandswitch Detent Shaft Sideband Selector

Function Switch,

10

Meter Rocker Rocker Part

of Gain Controls

Part

of Transcei\'e Vernier

SB

Osc.

Switch

MOX-OFF

VOX-PTT

KNOBS

Function, Sideband Selector,

Bandswitch

PA

Load

, Exciter 'Tune, Transceive

Vernier

PA

Tune

Main

Tuning

Audio Gain

RF

Gain,

10

Lever,

SHAFTS,

Shaft, Function Switch Shaft, PA Shaft, Exciter Shaft, PA Load

Meter Switch

COUPLINGS,

Tune

C50523-5

C50523-3

B51520

!lh

Interlock, A51524

Interlock, A51522

Output

Front Rear

DRIVE

R1550-19

A51521 A51525

A51523 B51558 A50854 B51526 B51527 B51541 B51549 B51548-2 B51548-1 B51550 B50986-2

NPS-7K2LA

NPS-7F2LA NPS-7::\!LC NPS-17D2LA NPS-7:\3LC A51399

TRAIN

A51551 A51561-1 A50818-2 A50818-3

Coup-Link B25000 Bushing, Panel

Palnut 3/8-32 Coupling, Function Coupling, Bandswitch

Drive

Train,

VFO,

Counter, Without

COVERS

Cover, PA Cover, Cover, Cover,

VFO

Top

VFO

Bottom

Second Mixer

MISCELLANEOUS

Front

Panel Bushing, Nuts for Above Lockwasher for Above Han Hanger Hanger Cabinet Foot, Rubber, Extension Foot, Cabinet Cover

Hanger

ger Bracket

Screws

Pins

Rubber

MISCELLANEOUS

M F-1 Filter, D-2 Diode, Varactor X1 Xtal, 6.0200 X2 X3 X4 X5 X6

X7

X8

Rel

Meter

Xtal Xtal Xtal Xtal Xtal Xtal Xtal Relay

Xtal

6.0234

11.000

18.000

25.000

26.000

25.500

24.5

Me

6PDT

Me Me Me Me Me Me Me

8000 ohms A50798

A50840-0 B19322-8

Switch

With

Gang

J654-2

A12611 A51681

C50815 B51560 B51587 C51505

PARTS

E51502-5 A50817 A50117-7

5j 8

B50836 B50835 A50860-1 E51580-2 A50850 A50851 D51579-3

ELECTRICAL

C50833

A51557 A51307-9 A51546-1 A51546-2 A51555-1 A51555-2

A51555-4

A51555-6 A51555-5

A51555-3

KCE

25

SECTION 7

THE

FOLLOWING GREATER INPUT. AND

*AC

TRANSMIT

FUNCTION

Tube

V-1

V-2

V-3 12BE6

V-4

V-5 6GK6

V-6

OR

Type

6GJ5

6KE8

12AT7

DC

THAN

DC

10 SWITCH

AMPLIFIER

TRANSMIT

OSCILLATOR

AND

TRANSMIT

AMPLIFIER

DEPENDING

VOLTAGE

MEGOHMS.

VOLTAGES

DRIVER

S-METER

IN

Function

FINAL

FIRST

MIXER

LOCAL

SECOND

MIXER

SPEECH

AND

ON

AND

MEASUREMENTS

RECEIVE

ARE

TAKEN

THE

SSB

Pin Resistance

1 10 k 0 2 3 4 5 6 20 k 7 10 k 8

9 0 0 0

1 2 3 4 5 6 20 k 7 10 k 0 8 0

9

1 2 0 3 4 5 6 7

1 2 3 4 0 0 0 5 6 15 k 7 8

9

1 2 3 0 4

5

6

7

8

9

1 2

3 1 k 1

4 0 0

5

6

7

8 0 3

9

SUPPLY

RESISTANCE

VOLTAGES

POSITION.

-

20 k

ARE

WITH

20

k

3.2

0

10 k 10 k 270

3.2

ARE

CARRIER

n

fl

MEASUREMENTS

TAKEN

-45

BALANCE

to

WITH A VTVM

AT

Receive

-65

V ADJUSTABLE 0

12.6*

6.3* 6.3*

-65 V ADJUSTABLE 0 0

-65 V ADJUSTABLE 0

6.3*

MAXIMUM

WITH

TUNED

Voltage

RF

FOR

- 0 0

-45

to

-65 V ADJUSTABLE

0 0 0

100 k

0 0 0

-

30 k

100 k

10 k 150 200 k 100 k

-

470

fl

0 0 0

47 k

1so

n 0 8

200 k

- 6.3*

- 12.6*

INF

. 0 0 10 k 300 10 k 250

0 0

20 k 75 30 n

0 0 0 35 k 56 k .2

-

0

-40 0 0

12.

6* 240 270 240 30

-40

-40 270

6.3* 6.3*

270 260

0 2

-1

-40

0 0

250

6.3* 6.3*

AN

INPUT

GAIN

WITH

MINIMUM

Transmit

WITH

+250

BIAS

+250

BIAS

WITH

RESISTANCE

NO

INDICATION

CONTROL

.3 v

12.6

CONTROL

0

CONTROL

0

6.3 *

CONTROL

270

0

12.6*

0

150

0

170

-1

0

6.3*

12.6*

300

270

0

85

1 0

0 6 0

SIGNAL

26

VOLTAGE

AND

RESISTANCE

MEASUREMENTS

(Cont)

Tube

V-7 12AU7

V-8

V-9

V-10 7360

V-11

V-12

V-13 12BE6

*AC

**+20

***0

Type

6GH8

12AU7

6BZ6 1st

12BE6

OR

TO

ON

TUNE

OSCILLATOR

MICROPHONE

P

REAMPLIFIER

MODULATOR

2nd

DC

DEPENDING

+30

VOLTS

FUNCTION.

Function

CARRIER

AND

RELAY

CONTROL

vox

AMPLIFIER

BALANCED

RF

STAGE

RF

STAGE

1st

RECEIV

ER

MIXER

DEPENDING

ON

+20

1 20 k 2 300 k 3 0 4 5 6

7

8 0 9 -

1 20 k 2 3

4

·5 6 7 8 0 0 0 9

1 100 k

2 800 k 0 0

3 1.5 k 4 5 6 100 k 35 40 7

8

9 1

2

3 500 k

4 5 6 7 8

9

1

2 220

3 4 5 6 80 k 150 0

7

1 470 k

2 0 0 0

3 4 5 15 k 6 7 270

1 150 k 2 0 3 4 5 10 k 250 6 7

SUPPLY

TO

Resistance

-

0

20 k

300 k

meg

1

600 k 35 35

-

- 12.6*

100 k

0

meg

1.5

0

-

10

meg

0 0

2.5 k

150 k

Receive

100

0 LSB,

0 USB,

-60

USB

0 0

12.6* 0

100

-60

0 0

6.3*

150 300

-1

6.3*

100

0 0

0

70

3 3

0 0

12.6* 12.6*

-.

7

6.3* 0 4

0

-40

0 0 0

15 k 15 k 50 k 50 k

meg

1

fl

- 6.

-

10 k 300 300

0

-

82 k

fl

0 0 0

-

56 k 10

fl

ON

+30

CARRIER

DEPENDI

BALANCE

NG

ON

CARRIER

6.3* 250 250 250 250

25** 25** 25**

0

+1

3*

12.6* 12.6*

0 0 0

0 0

12.

6* 270 130

2.7

-.5 0

12.6*

200

0

BALANCE

Voltage

0 USB,

LSB 0 USB,

Transmit

100

-60

12.6* 0

100

-60

6.3*

-1

6.

3*

12.6*

-.9

-40 80

-.7 0

6.3*

200

0

6.3*

25***

0

6.

3*

0

12.6*

250

0 0

-40 0

12.6*

250

0 0

LSB

27

VOLTAGE

AND

RESISTANCE

MEASUREMENTS

(Cont)

OR

Type

12BA6

12AX7

6AQ5

OA2

DC

Tube

V-14 12BE6

V-15 12BA6

V-16 12BA6

V-17

V-18

V-19

V-20

*AC

Function

2nd

RECEIVER

MIXER

1st

IF

2nd

IF

3rd

IF

PRODUCT

DETECTOR

AND

AUDIO

AMPLIFIER

AUDIO

AMPLIFIER

VR

DEPENDING

Pin Resistance

1 120 k 0 2 0 0 0 3 0 0 0 4 5 6 56 k 7

1 2 0 0 0

STAGE

1st 4 -

TUBE

ON

3 4 5 6 7

1 2 0 3 0 0 4 5 6 7

1 2 0 0 3 4 5 6 7

1 2 3

5 0 6 300 k 7

1 2 3 0 4 5 6 7 800 k

1 2 3 4 5 6 7 0

SUPPLY

Voltage

Receive

-

10

k 250 250

120 k 0

40 k 0

0 0

10

k

40

k

120

n 2 2

180

k

12.6*

25

12.

6*

240

150 150

.2 0

Transmit

-40

12.6*

-40

12.6*

260

- 12.6* 12.

30

k

15 k 65 65

120 n 150 k 0 0

0 0 0

-

100

k 240 0

150 k 110 150 n

100

k

40

k

Sk

10

meg

800 k

470 n 15

- 6.3*

10 k 300 10

k 250

8k 0

INF.

0

8k

INF.

240 260

1 1

12.6* 12.6*

2 0

200 260

0

2.8 0

12.6* 0 0

100

-.6 0 0

0

150

0 0 0

150

0 0

-45

12.6*

250

-23

300

250

150

0

0 0

0

6*

0

6.3*

0

0 0

0

28

CAPACITORSI IN pF. IF POINT(.) PRECEDES DIG1TS:fiF.

RESIST0RS:IN OHMS: K=KILOHMS. M=MEGOHMS.

SWITCHES:

SYMBOLS:

20UUNLESS OTHERWISE SPECIFIED.

POUUNLESS OTHERWISE SPECIFIED.

ALL

SHOWN

FULL

CLOCKWISE ROTATION WILL RESULT AS FOLLOWS: SI-BANDSWITCH 28-21-14-7-3.5 Mc. S2SlMBAND LSB-USE.

s3-FUNCTION

SM METER 29.5-29.0-28.5-28.0

f

VARlA8LE COMPONENT

/

ADJUSTABLE COMPONENT

LGROUND. CHASSIS

CCW,FRO~

OFF-SSB-AM-CW-TUNE

THIS

POSITION

;

R33

,

SSK

10%

0

CAL SOCKET.J7--D

NCTION SW.S34

RECEIVER BIAS4

>OC FROM FINAL

C FROM AGC DET.4

--TO

FINAL GRID COUPLING

V3 AND BIAS CONTROL-

>FROM MlC KE

TO

PTT

DIODE

04 BIAS

>-RF GAl

CONTROL-

S3:OFF-SSB-AM-

r

RECEIVE

3

BlAS TO VFO-

BIAS FROM St-C-<

+TO ANTENNA JACK

+TO RELAY

TO

BAL

MOD. VIO

National NCX-5 User manual

Specifications and Main Features

Frequently Asked Questions

User Manual