Hammarlund Hx50 Manual

THE

HX-500

TRAN

MITTE

..

2

DESCRIPTION

-

AND

-

The

Hammarlund

Manufacturing

Co.,

Inc.

460

W

••

t

34th

Street,

New

York

1,

N

Y.

Interna

lonal

Dlvl.lon:

13

East

40th

Street.

New

Vork

16,

•

Y.

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

THE

HX-500

TRANSMlTTER

INSTRUCTION

AND

SERVICE

INFORMATION

ESTABLISHED

1910

ISSUE

NO.1

In

order

to

receive

the

full

unconditional

90·day

warranty

against

defective

material

and

workmanship

in

this

receiver,

the

warranty

card

must

be

filled

out

and

mailed

within two

weeks

of

purchase.

Please

refer

to

serial

number of

equipment

in

correspond-

ence,

and refer

to

ins

ide

bock

COver

for

terms

of

warronty.

THE

HAMMARLUND

MANUFACTURING

COMPANY~

INC.

460

West

34th

Street~

New

York

l~

New

York~

U.S.A.

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

INTRODUCTION

The

HX-500

Exciter-Transmitter

is

a

self

con-

tained

unit

designed

with your

present

and

future

requirements

in

mind.

The

transmitter

is

completely

self

contained;

employing

21

tubes

(plus

four

semi-

conductor

diodes),

and

requires

only

the

addition

of

a

suitable

mike,

key,

or

bug

and

suitable

antenna

system

for

immediate"

on

the

air"

operation.

This

Transmitter-Exciter

covers,

80,

40,

20,

15

and 10

meter

amateur

bands

by

means

of

an

eight

position

rotary

bandswitch.

Four

bandswitch

posi-

tions

are

provided

for

complete

coverage

of

the

10

meter

band

and

the

built-in

VFO

covers

a

range

of

500

KC's.

The

eight

crystals

needed

for

complete

band

coverage

are

supplied.

The

rotating

drum, il-

luminated

slide

rule

dial

is

calibrated

to

indicate

better

than

10

KC's

and

the

tuning

knob

skirt

can

be

read

to

better

th an 200

cycles.

One

rotation

of

the

frequency

knob

covers

two

divisions

or 20 KCS on

the

illuminated

dial

drum.

The

unit

is

capabie

of

transmitting

the

following

types

of

signals:

LSB,

USB, DSB,

CW,

FM, and

FSK.

The

power

output

on SSB

is

70-100

watts;

70-100

watts

on

CW,

FSK,

FM

and 17-25

watts

on DSB (AM).

The

carrier

suppression

on

both

USB and

LSB

is

greater

than -50 db and

the

unwanted

sideband

is

rej

ected

by more

than

-50

db.

Spurious

frequencies

generated

within

the

unit

are

suppressed

to

a

level

of

-50

db or more.

The

intermodulation

distortion

products

have

been

suppressed

beyond

the

-30

db

level.

The

transmitter

output

pi-network

has

been

care-

fully

designed

to match a

52

ohm

transmission

cable

impedance

and

suppress

harmonic

TVI.

A

logarithmic

type

of

carrier

level

indicator

pro-

vides

a very

simple

yet

adequate

means

of

tuning

up and

continuously

monitoring

the

transmitter.

The

VOX

circuit

adjustments

(Sensi

tivity,

Delay

and

Anti-Trip)

are

located

on

the

front

panel.

The

single

sideband

signal

is

generated

III

the

HX-500

Transmitter-Exciter

by

means

of

a

highly

stable

60

KC

oscillator

whose

signal

is

fed

into

a

carefully

balan

ced

diode

modul

ator

and

subse-

quently

applied

to a

series

of

cascaded

overcoupled

and

under

coupled

tuned

circuits

(with

carrier

re-

jection

trap) which

provides

the

necessary

unwanted

sideband

rejection.

The

choice

of

LSB,

USB, or

DSB

transmission

is

determined

by

the

position

of

the

function

switch

which

shifts

the

resonant

fre-

quencies

of

the

60

KC

tuned

circuits

to

provide

the

proper

bandwidth

for

the

desired

mode

of

operation.

All

of the

controls

that

are

required

for

proper

tune

up and

operation

of

the

Transmitter-Exciter

are

provided

on

it's

front

panel

and

these

controls

are

logically

grouped

for maximum

operating

ease.

The

HX-500

was

designed

with you in mind. You

will

find

many

hours

of

pleasure

in

operating

this

truly

fine

communications

instrument.

Page

2

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

4 5

flll'l'l.fjlOllfi

t!T~(1iJ

3

2

6

17

18

7

19

20

8 9

10

II

12

Figure

J. The

HX

500

Transmitter

1l0CATION

OF

CONTROLS

I.

R.F.

Output

Level

Meter

II.

Tuning

Dial Drag

or

lock

2.

Calibrate

Level

Control 12.

Frequency

Control

3. Meter

Sensitivity

Control 13.

VOX

Delay

Adjustment

4.

R.F.

Level

Control 14. FSK

-FM

N

Adjustment

5.

Final

Amplifier Tuning Control 15. Anti-Trip

Sensitivity

Adjustment

6.

Function

Switch

Selector

(Type

of

Transmission)

16.

VOX

Sensitivity

Adjustment

7.

Operations

Switch

Selector

17. Key

Jack

(CW

-FSK

40

cycle

Identification)

8. Audio

Level

Control 18. Monitor

Jack

9. Driver

Tuning

Control 19.

Patch

Jack

10. Band

Selector

20.

Microphone

Connector

Page

3

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

..

-----------

-----

------~_

..

m

_---_.-

INSTALLATION

UNPACKING

After

unpa~king

the

transmitter

carefully,

make

sure

that

all

tubes,

associated

tube

shields,

and

pilot

lamps

are

properly

seated

in

their

respective

!!lockets.

Inspect

the

unit

for

any

signs

of

damage

during

shipment

and

carefully

read

all

tags

and

labels

for

any

special

instructions

before

discarding

them.

MONI'TOR

JACK

The

microphone

and

key

connections

to

the

trans-

mitter

are

located

along

the

bottom

edge

of

the

trans-

mitter

panel.

A

standard

microphone

connector

such

as

the

Amphenol

type

75-MCIF

or

equivalent

is

required

to

connect

the

microphone

to

the

transmitter.

Any

high

impedance

microphone,

either

crystal

or

dynamic,

will

give

satisfactory

results

when

used

with

this

transmitter.

The

key

or

"bug"

is

con-

nected

to

the

front

panel

receptacle

by

means

of

a

standard

two

contact

phone

plug.

The

key

or

"bug"

may

be

connected

to

the

remote

control

plug,

lo-

cated

at

the

rear

of

the

chassis,

instead

of

the

front

panel

if

desired.

See

Fig.

2 for

remote

key

connec-

tions

on

the

14

prong

plug

located

at

the

rear

apron

of

chassis.

MICROPHONE

&

KEY

CONNECTIONS

The

monitor

jack

provides

a

means

of

listening

to

the

received

signals.

Any

headset

fitted

with

a

standard

two

conductor

phone

plug

can

be

used.

When

the

phones

are

plugged

into

the

receptacle,

the

communications

receiver

speaker

will

be

disabled,

provided

that

the

receiver

output

and

speaker

are

wired

as

shown

in

Fig.

2.

PHONE

PATCH

The

phone

patch

jack

requires

a

standard

two

conductor

phone

plug.

This

input

receptacle

is

con-

nected

directly

across

the

high

impedance

audio

level

control.

Any of

the

phone

patches

available

should

be

useable

when

the

output

is

fed

into

this

jack

(on

the

assumption

that

sufficient

gain

has

been

provided

in

the

patch).

Page

4

117

VOLT

POWER

CONNECTION

Before

inserting

the

line

cord

plug

into

the

power

outlet,

make

certain

that

the

power

source

is

of

the

proper

voltage

and

frequency.

The

Model HX-500

Transmitter-Exciter

is

designed

to

operate

on

105-125

volts,

50-60

cycles

A.C.

Do

not

under

any

circumstances,

connect

this

unit

to

a

source

of

direct

current

as

doing

so

will

blow

the

fuse.

ANTENINA

CONNECTION

The

output

impedance

of

the

HX-500

is

'50

Ohms.

A

suitable

RF

cable

and

cable

connector

is

RG-8/u

coaxial

cable

with

an

Amphenol

type

83-1SP

or

equivalent

coaxial

cable

connector.

The

selection

of

the

type

of

antenna

and

coupler

will

depend

upon

the

band

of

operation

and

the

ob-

jectives

of

the

user.

The

ARRL

publications

are

an

excellent

source

for

information

on

the

design

and

construction

of

various

types

of

antenna

systems.

ANTENNA

RELAY

The

HX-500

is

equipped

with

an

internal

antenna

changeover

relay.

The

typical

Send-Receive

connec-

tions

are

illustrated

in

Fig.

2.A

stanaard

phonograph

plug

is

required

for

the

receiver

connections

to

the

changeover

relay

contacts.

RECEIVER

AUDIO

CONNECTIONS

In

order

to

have

the

VOX

relay

control

the

signals

from

the

station

receiver's

loud

speaker,

the

HX-500

Transmitter

must

be

connected

to

the

station

receiver

as

shown

in

Fig.

2.

In

many

cases

the

blocking

bias

connections

will

be

needed

to

put

the

receiver

in

standby

in

place

of

the

"make

and

break"

contacts

as

shown

in

the

Figure.

BLOCKIING

BIAS

CONINECTIIONIS

A

high

impedance

bias

source

(-lOOV.)

is

provided

to

silence

the

station

receiver

during

periods

of

transmission.

6 of

the

rear

receptacle

supplies

this

voltage

when

the

VOX

relay

is

energized,

(transmit

position)

and

grounded

in

the

normally

open

position.

7

is

a

suitable

groun?

connection

for

running

a

shielded

lead

to

the

receiver

if

it

be-

comes

necessary

to

minimize

RF

pick

up

in

the

lead.

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

HX-500

TRANSMITTER HQ-170 RECEIVER

--------------_

..

-------

~

EXT,

CONN.

REC.

ANT.

son

ANT.

ALe

ADJ.

SLO-BLO

o e

2 4 6 8

1012

14

0

(;)

0 61{4

AMP.

lei

~J;-

;~

~@

~

0 0 e

~

OIlJOOI/JO

10',£GoOI

~!

~~

" • 1 • II

13

o (;) @

lO1~

~

II

SHIELDED CABLE

~

!ot--GROUND

SIDE

= OF

WINDING

-+

~

1'-. I

0-300

MA

DC

OR

O·3V

METER

METER READINGS

IDUNG

CURRENT

-60

MA.

FULLY

LOADED

-200

TO

230

MA.

(WITH

MATCHED LOAD

AN

0

IN

OSB-MOX

POSITION)

EXTERNAL

~

1,7,13

2

3

4

5

6

8

9

10

II

12

14

WIRING

CONNECTIONS

FUNCTION

GROUND

NORMALLY

OPEN

CONTACT}

CENTER

CONTACT

R:~:Y

NORMALLY

CLOSED

CONTACT

-100

V.

-IOOV.

FOR

RECEIVER

BLOCKING

REMOTE

CW

-

40

CYCLE FS K KEY

RECEIVER OUTPUT TRANSFORMER SECONDARY

STATION

RECEIVER

SPEAKER

FSK

RELAY

CONNECTION

FSK

RELAY

CONNECTION

CATHODE

CURRENT

OF

VI5

S.

VI6

(6146'S)

Figure

2.

Typical

Amateur

Station

Wiring

'l;l

II>

(Jl:l

~

Q1

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

FUNCTION

OF

OPERATING

CONTROLS

FUNCTION

SWITCH

The

Function

Switch

determines

the

type

of

emitted

signal

selected

by

the

station

operator.

The

HX-500

is

capable

of

transmitting

the

following

types

of

signals

as

indicated

on

the

knob:

LSB,

USB,

DSB (AM),

CW,

FSK,

and

FM.

OPERATION

SWITCH

The

five

position

Operations

Switch

turns

the

AC

power

ON

(Standby)

and

OFF,

and

inel

udes

the

MOX,

VOX,

and

Calibrate

positions.

When

manual

control

of

the

transmitter

is

desired,

the

MOX

position

is

used.

In

the

MOX

position,

the

antenna

and

VOX

relays

are

always

energized

and

are

completely

independent

of

control

by

the

VOX

circuit

knobs

(VOX

sensitivity,

VOX

delay

and

anti-trip).

In

the

VOX

position,

the

transmitted

output

is

controlled

by

the

voice

energy

from

the

microphone.

In

this

position,

the

antenna

and

VOX

Relays

are

controlled

by

the

adjustment

of

the

VOX

circuit

controls.

The

proper

setting

of

the

VOX

knobs

is

outlined

in

the

Tuning

Procedure.

In

the

calibrate

position,

the

Antenna

and

VOX

Relays

are

always

in

the

de-energized

position

(receive).

This

position

is

used

to monitor

the

trans-

mitted

signal

in

the

communications

receiver

and

is

also

used

for

zero

beating

the

HX-500

signal

fre-

quency

to

an

incoming

signal

or

desired

frequency.

CALI

BRATE

LEVEL

A

calibrate

level

control

is

included

in

the

trans-

mitter

to

adjust

the

amount

of

signal

fed

into

the

receiver

from

the

transmitter

in

the

Cal

position.

The

Calibrate

Level

knob

is

adjusted

so

that

the

desired

level

of

the

transmitter

output

as

observed

on

"s"

meter

of

Receiver

or

the

loudspeaker,

(or

headset

connected

to

Monitor

Jack)

is

sufficient

for

monitoring.

A

very

limited

amount

of

RF

power

is

"leaked"

from

the

final

amplifier

tank

circuit

to

the

receiver

input

via

the

Antenna

Relay

wiring.

R.F.

LEVEL

The

RF

Level

control

adjusts

the

gain

of

the

5.55

to

6.05

Mcs

broadband

amplifier.

Optimum

RF

output

on

all

bands

is

achieved

with

the

adjustment

of

this

control.

This

is

usually

set

at

4

to

5.

Page

6

AUDIO

LEVEL

The

audio

level

control

adjusts

the

amount

of

audio

gain

required

to

fully

voice

modulate

the

transmitter.

This

is

usually

set

at

5.

DRIVER TUNE

The

Driver

Tune

knob

adjusts

both

the

3rd

mixer

plate

and

driver

plate

tuned

circuits

to

resonance

at

the

frequency

desired.

FINAL

TUNE ,

The

Final

Tune

knob

adjusts

the

output

tank

capacitor

for maximum

RF

output.

The

knob

skirt

is

marked

to

indicate

the

designated

area

on

each

band

w

here

maximum

output

can

be

obtained

as

observed

on

RF

Level

indicator.

BAND

SELECTOR

The

eight

position

Band

Selector

control

selects

the

proper

combination

of

tuned

circuits

and

the

proper

heterodyne

crystal

on

each

band.

The

Band

Selector

shaft

also

indexes

the

direct

reading

dial

drum

which

indicates

the

band

in

use.

METER

SENSITIVITY

The

meter

sensitivity

knob

controls

the

amount of

deflection

of

the

output

level

meter.

Clockwise

rotation

increases

the

sensitivity

of

the

meter

circuit.

The

Output

Level

Meter

is

used

to

tune

up

the

transmitter

to

any

frequency

within

its

range.

The

meter

indication

is

logarithmically

proportional

to

the

RF

voltage

across

the

50

Ohm

output.

This

fea-

ture

gives

the

meter

wider

dynamic

range

of

indi-

cation.

DIAL

DRAG

& LOCK

The

small

knob

adjacent

to

the

Frequency

tuning

knob

has

been

included

in

the

HX-500 for

the

pur-

pose

locking

the

dial

drive

to

a

selected

frequency

and

adjusting

the

tuning

knob

calibration.

Clockwise

rotation

of

this

knob

restrains

the

frequency

knob

from

turning.

It

also

enables

the

adjustment

of

dial

action

or

torque

required

for

personal

preference

of

the

operator.

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

IIi

TUNING

GENERAL

The

HX-500

Transmitter

has

been

designed

to

give

the

utmost

in

quick

and

easy

operation

for

the

radio

amateur

operator.

All

operating

controls

are

clearly

identified.

The

slide-rule

type

of

dial

is

marked

off

to

indi-

cate

every

10

kilocycle

change

in

frequency

on

each

of

the

eight

direct

reading

bands.

In

addition

to

the

10

kcs

markings,

every

band

contains

two

heavy

dot

markings

and

two

heavy

diamond

shaped

markings.

The

dot

markings

indicate

the

outer

limits

of

each

amateur

band

in

which

authorized

amateur

communi-

cation

is

permitted.

The

diamond

shaped

markings

have

been

included

to

show

at

a

glance

the

outer

limits

of

each

amateur

phone

band.

Since

the

10

meter

band

extends

over

foUF

band

change

positions,

the

markings

are

included

only

on

the

first

and

last

of

the

four

segments.

The

frequency

tuning

knob

and

dial

lock

knob

are

connected

to

the

variable

capacitor

located

on

the

VFO

sub-chassis

by

means

of

a

spring

loaded

gear

drive

mechanism.

Twenty

five

revolutions

of

the

tuning

knob

covers

a

SOO

Kcs

band

segment.

The

major

markings

on

the

frequency

tuning

knob

are

calibrated

to

indicate

1

Kcs

changes

in

frequency

and

are

sub-divided

to

indicate

frequency

changes

of

two

hundred

cycles

between

each

small

division.

To

accurately

set

the

transmitter

to

a

specific

frequency;

for

example

3962.4

Kcs.,

turn

the

tuning

knob

until

the

dial

pointer

indicates

the

nearest

10

Kcs

point

below

the

desired

frequency

e.g.,

3960

Kcs

and

add

two

major

divisions

(2

Kcs)

plus

two

sub-divisions

(400

cycles)

as

indicated

on

the

skirt

of

the

tuning

knob.

The

HX-SOO

dial

drive

mechani~m

has

been

machined

to

extremely

close

tolerances

in

manu-

facturing;

however,

there

will

exist

(as

with

all

gear

driv~s)·

a

very

small

error

between

dial

pointer

indication

and

the

tuning

knob

skirt

calibration

when

knob

markings

are

compared

with

the

pointer

indica-

tion

at

various

points

across

the

band.

There

are

several

other

frequency

determining

elements

which

also

contribute

to

the

dial

inaccuracies

such

as:

VFO

tuning

capacitor

and

crystal

tolerances.

As

shipped

from

the

factory

the

"0"

marking

on

the

knob

skirt

has

been

mechanically

aligned

to

the

high

frequency

end

of

all

bands.

Since

most

amateurs

operate

within

a

limited

portion

of a

particular

band,

the

knob

markings

should

be

indexed

for

the

highest

a

ccuracy

possible

in

the

area

of

operation.

To

correct

for

this

knob

runout,

the

knob may

be

PROCE

URE

turned

when

the

pointer

remains

stationary

with

the

aid

of

the

dial

lock.

The

most

accurate

frequency

calibration

means

readily

available

to

the

amateur

is

the

crystal

calibrator

located

in

the

communica-

tions

receiver.

Zero

beat

the

transmitter

as

outlined

below

to

the

nearest

100

Kcs

check

point,

lock

the

dial

by

turning

the

lock

knob

clockwise,

then

turn

tuning

knob

until

"0"

on

the

knob

coincides

with

the

fiducial.

This

will

require

more force or

torque

than

when di

al

is

free running.

CAUTION

The

HX-SOO

Transmitter

has

been

very

conservatively

designed

to

give

reason-

ably

long

vacuum

tube

life.

However,

the

life

expectancy

of

vacuum

tubes

greatly

depends

upon how much

use

and

abuse

they

get.

All

tuning

adjustments

should

be

made

with

the

RF

output

level

meter

indicating

less

than

-10

db

for

conserva-

tive

operation

(with

the

meter

sensitivity

set

at

its

proper

operating

level).

The

final

setting

of

the

RF

level

control

should

be

the

last

tune-up

adjustment

to

be

made.

INITIA

TUNE-UP ADJUSTMENT

The

Operating

controls

should

be

set

as

follows:

FUNCTION:

DSB

OPERATION:

OFF

AUDIO

LEVEL:

o

DRIVER

TUNE:

Set

to

"5"

BAND

SELECTOR:

Set

to

desired

band

FREQUENCY:

Set

to

desired

frequency

CAUBRATE

LEVEL:

Set

to

"s"

METER

SENSITIVITY:

Set

to

"5"

R.F.

LEVEL:

Set

to

"3"

FINAL

TUNE:

Set

to

middle

of

desired

band

segment

VOX

DELAY:

C

ounterc1ockwise

posi-

tion

FSK-FM-~F:

Set

to

middle

of

range

ANTI-TRIP

SENSITIVITY:

C

ounterc1ockwise

posi-

tion

VOX

SENSITIVITY:

Counterclockwise

posi-

tion

ALC

(REAR

APRON):

Clockwise

position

(OFF)

Page

7

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

Turn

the

"Operations"

switch

to

Standby

and

allow

at

least

a one minute vacuum

tube

warm-up.

Turn

the

"Operations"

switch

to

MaX

and

adjust

"Driver

Tune"

for maximum

meter

deflection.

Then

adjust

"Final

Tune"

for the

highest

reading.

Repeat

adjustment

of

both

Driver

and

Final

Tune

until

Meter

deflection

cannot

be improved.

CW

OPERATION

Turn

the

"RF

Level"

control

until

the

"Level

Indicator"

reaches

a maximum

(saturates).

Use

the

lowest

setting

of

the

control

consistent

with

obtain-

ing

maximum

output

(knee

of

curve).

Adjust

"Meter

Sensitivity"

control

to

read

"0"

db.

Turn

the

"Function"

switch

to

CW

and

key

the

transmitter

via

the

"Key"

jack.

SIDEBAND

OPERATION

After

the

transmitter

ha s

been

tuned

up

to

a

de-

sired

frequency

on

CW,

adjust

the

"ALC"

control

(on

the

rear

of

the

chassis)

so

that

the

"Level

Indi-

cator"

drops

to

-1 db or one

half

a

division.

Turn

the

"Function"

switch

to

USB or LSB

and

the

"Audio

Level"

control

knob

until

the

"Level

In-

dicator."

meter

fluctuates

or

averages

around

the

-10

db

marking when

talking

into

the

microphone

at

con-

versational

level.

This

setting

will

usually

be 4

to

5

depending

on

the

mike,

speaking

level

and

distance.

VOX

SENSITIVITY

-

VOX

DElAY

-

ANTI-TRIP

OPERATION

After

the

transmitter

has

been

tuned

up

to

the

desired

frequency

with

all

of

the

larger

sized

knobs

adjusted,

the

VOX

Relay

control

knobs

are

brought

into

adjustment.

Turn

the

"Operations"

switch

to

indicate

VOX

and

turn

the

"VOX

Sensitivity"

knob

clockwise

until

the

VOX

relay

readily

closes

when

talking

into

the

,microphone.

It

is

desirable

to

keep

the

"VOX

Sensi-

tivity"

as

low

as

possible

since

any

undesired

background

noise

in

the

Ham

Shack

will

trigger

the

VOX

relay

and

you

will

be

on-the-air.

Usually

the

"VOX

Sensitivity"

knob

will

be

near

the

center

of

its

range

or

pointer

vertical.

The

de-energizing

time for

the

VOX

Relay

is

controlled

by the

"VOX

Delay"

control.

This

control

is

used

to

keep

the

VOX

Relay

closed

during the

quiet

periods

between

words.

Turn

the

"VOX

Delay"

control

clockwise

until

the

relay

flutter

between

words

is

eliminated

during

the

course

of

conversa-

tional

speech.

Excessive

"VOX

Delay"

should

be

avoided.

Leave

at

CCW

position

to

start.

The

"Anti-Trip"

Control

is

used

when

the

"Oper-

ations"

switch

indicates

VOX

operation.

When

the

Page

8

Station

receiver

and

speaker

are

connected

for

VOX

operation

(see

Figure

2)

the

speaker

"Anti-Trip"

control

is

adjusted

to

a

setting

where

the

audio

'signa~

picked

up by the microphone from

the

re-

ceiver's

speaker

will

not

energize

the

VOX

Relay.

This

feature

prevents

the

retransmitting

of the

in-.

coming

audio

signals

from your

station

receiver.

Excessive

speaker

volume

is

capable

of

disabling

the

VOX

Relay

completely,

therefore,

minimum

re-

quired

gain

should

be

used.

Always

adjust

the

receiver

audio

gain

to

the

desired

level

before

ad-

justing

the

"Anti-Trip"

control.

AM

OPERATI,ON

Turn

the

"Frequency"

and

"Band

Selector"

knobs

to

indicate

anyone

of

the

authorized

amateur

phone

bands.

Tune

the

transmitter

for maximum

out-

put

as

outlined

in

the

general

and

CW

sections

with

switches

on DSB

and

MaX.

Reduce

the

RF

Output

level

to

indicate

-6 db on

the

"Level

Indicator".

Increase

the

audio

level

until

there

is

a

small

fluc-

tuation

or

kick

upward in

the

output

level

meter

pointer

when

talking

into

the

microphone.

The

carrier

reference

level

can

be

established

more

precisely

if

an

oscilloscope

and

audio

oscil-

lator

are

used

to

set

up

and monitor

the

output

signal.

If

the

carrier

level

is

set

too

high,

peak

amplitudes

are

flattened

before 100%

modulation

occurs.

If

the

carrier

level

is

set

too

low

the

maxi-

mum

power

output

capabilities

are

not

attained

at

100%

modulation.

FSK

OPERATION

FSK

Operation

is

accomplished

with

the

aid

of V4

(l2BY7)

Reactance

Tube

Modulator

which

shifts

the

frequency

of

the

60

Kcs

Carrier

Oscillator

by

means

of a

change

in modulator

screen

voltage

(see

Figure

3).

Lowering

the

screen

voltage

lowers

the

frequency

of

the

60

Kcs

Oscillator

and

raises

the

RF

Output

Frequency;

conversely,

raising

the

screen

voltage

raises

the

60

Kcs

Oscillator

frequency

and

lowers

the

RF

Output

Frequency.

The

change

in

screen

voltage

is

controlled

by

the

Polar

Relay

keying

employed for

RTTY.

The

amount of

Frequency

Shift

is

adjusted

by

the

FSK

Deviation

control

R140. When the

Polar

Relay

is

closed

the

screen

voltage

on

the

Reactance

Modu-

lator

may be

raised,

lowered,

or

remain

unchanged

depending

on

the

position

of

the

arm of

FSK

Devia-

tion

Potentiometer.

The

zero

position

is

located

at

(approximately)

the

center

of

its

range.

Clockwise

rotation

from

the

center

position

will

decrease

the

s cre

en

voltage

and lower

the

frequenc

y

of

the

60

Kcs

Oscillator.

Counterclo~kwise

rotation

from the

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

+150V.

FSK

TO

SF-ID

REAR

(FOR

CW

OPERATION)

12

ON

J2

AND

P2

PIN 9

ON

J2

AND

P2

R22

I MEG.

R25

200

R

24

330

middle

position

will

increase

the

screen

voltage

and

raise

the

frequency

of

the

60

Kcs

Oscillator.

The

40

cycle

keyed

identification

frequency

shift

is

accom-

plished

by

closing

the

key

jack

contacts.

Note

that

the

40

cycle

keyed

identification

shift

is

not

adjustable

and

when

the

CW

key

Jack

contacts

are

closed

the

screen

voltage

is

lowered

thereby

lowering

the

60

Kcs

Carrier

Oscillator

by

40

cycles

and

raising

the

RF

Output

Frequency

by

40

cycles.

Tune

up

the

transmitter

as

outlined

on

the

preced-

ing

general

and

CW

sections.

Turn

the

Operation

switch

to

Calibrate.

Zero

beat

the

transmitted

signal

in

the

communications

receiver.

Rotate

the

Function

switch

to

indicate

FSK

and

adjust

the

small

"FM-

FSK~F"

knob for zero

beat

if

necessary.

This

ad-

justment

is

made

with

both

Polar

Relay

Contacts

arid

key

Contacts

Open.

Close

Polar

Relay

Contacts

and

vary

the

FSK

Deviation

Control

for

zero

beat,

then

adjust

in

either

direction

from

this

position

for

the

desired

850

cycle

shift.

FM

OPERATtONI

FM

Operation

is

accomplished

by

Reactance

Tube

V4

(l2BY7)

modulating

the

60

Kcs

Carrier

Oscil-

lator.

In

the

FM

position,

the

audio

amplifier

output

is

fed

to

the

screen

grid

of

the

Reactance

tube

there-

by

translating

audio

variations

to

frequency

devia-

tions

of

the

Carrier

Oscillator.

Tune

up

the

transmitter

as

outlined

in

the

preced-

ing

general

and

CW

sections.

Turn

Operation

Switch

to

Calibrate.

Zero

beat

the

transmitted

signal

in

the

communications

receiver.

Rotate

the

Function

Switch

to

indicate

FM

and adj

ust

the

small

"FM-FSK~F"

knob for zero

beat

if

necessary.

Turn

Operations

Switch

to

MOX

and

raise

Audio

Level

until

a

small

fluctuation

of

the

Output

Level

is

observed

on

the

meter.

BIAS

CONTROL

ADJUSTMENT

The

output

of

the

bias

supply

in

the

transmitter

DEV.

~

FOR REMOTE

KEY-40

CYCLE

FSK

CONNECTION

(OPTIONAL)

L-

has

been

set

at

the

factory

to

-50

volts

d.c.

with

117

volts

a.c.

power

line

input.

If

the

line

voltage

is

subject

to

variations,

it

is

advisable

to

monitor

the

plate

current

of

the

6146

vacuum

tubes

and

make

periodic

adjustments

in

the

bias

voltage

to

keep

the

plate

current

at

its

optimum

value.

Adjustments

of

the

bias

supply

will

result

in

extending

the

life

of

the

vacuum

tubes

and

will

provide

maximum

output

power.

Provision

has

been

made

via

the

"External

Con-

nection"

plug

to

connect

a 0-300

milliampere

d.c.

or

a 0-3

volt

d.c.

voltmeter

to

read

cathode

current

on

the

Final

Amplifier

tubes.

The

0-3

volts

d.c.

meter

will

read

0-300

milliamperes

when

connected.

Con-

nect

the

positive

meter

terminal

to

14 of

the

plug

and

the

other

side

of

the

meter

to

13

of

the

plug.

Rotate

the

"Bias

Adj,."

to

read

60

milliamperes

of

plate

current

when

the

equipment

is

in

the

standby,

LSB

or USB

positions.

MODEL

HX-500

USED

AS

AN

EXCITER-DRIVER

WITH

A

LINEAR

AMPLIFIER

The

model HX-500

output

power

is

more

than

ade-

quate

for

driving

a

high

powered

linear

amplifier.

It

may

be

necessary

to

insert

a

resistive

pad

to

absorb

some

of

the

power

output

and

for

the

pQrpose

of

maintaining

a

50

Ohm

load

to

the

HX-500

Transmit-

ter.

The

amount

of

padding

needed

will

depend

upon

the

circuitry

in

the

linear

amplifier

and

the

tubes

used.

Always

use

the

least

padding

necessary

so

that

the

HX-500

is

working

at

well

below

its

maxi-

mum

output.

This

will

result

in

more

linear

operation

overall

and

extend

the

6146

tube

life.

When

the

HX-500

is

used

as

an

Exciter-Driver,

the

RF

Level

Control

is

adjusted

for optimum

drive

on

the

grid

of

the

high

powered

linear

amplifier

instead

of

the

6146's.

Figure

3.

CI63

l,005uF

Simplified

Schematic

Diagram

showing

RTTY

Operation

EXTERNAL

CONNECTION

PLUG

REG

R139

82K

5%

R

140

50K

R

141

22K

5%

-}TO

POLAR

CoRJr'A~\S

Page

9

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

HAM

MARL

NO

X-SOO

TRANSMITTER

CIRCUIT DESCRIPTIO

AUDIO

AMPLIFIER;

Signals

from

the

microphone

enter

through

the

front

panel

microphone

connector.

These

small

audio

vari-

ations

are

then

amplified

by

means

of

a

three

stage

resistance

coupled

amplifier,

consisting

of

both

sec-

tions

of

a 12AX7 (V-5A-B), and

one

half

of

a 6CM7

(V-6A).

The

amplifier

is

limited

in

response

below

300

cps

by

means

of

appropriate

values

of

coupling

condensers.

This

helps

to improve

the

unwanted

sideband

rejection

in

the

sideband

filter,

and

in ad-

dition

serves

to

prevent

distortion

due to

overloading

of

the

transmitter

by high

energy,

low

frequency

peaks.

Since

all

modulation

in

the

HX-500

is

accomplished

at

low

power

levels,

the audio

amplifier

is

not

re-

quired

to

supply

any

appreciable

amount

of

power

to

the

load,

and

is

consequently

designed

as

a

voltage

amplifier

only.

The

main audio

output

is

directed

to

the

balanced

modulator

for

AM

(DSB)

and

SSB (LSB-

USB)

operation,

or to

the

reactance

tube

modulator

for

FM

operation.

The

audio

amplifier

is

out

of

the

circuit

on

CW

and FSK

positions.

Part

of

the

audio

output

is

routed

to

the

voice

operated

relay

(VOX)

circuits

to

be

described

later.

60

KCS

OSCILLATOR:

A 6AU6

pentode

tube

(V-l),

1S

employed

as

an

electron-coupled

Hartley

oscillator

operating

at

a

frequency

of

60

kcs.

This

low

frequency

allows

the

use

of

a high

CIL

ratio

tank,

thus

providing

a high

degree

of

stability

usually

obtained

only

in a

crystal

osciUator.

At

the

same

time,

it

permits

the

oscillator

frequency

to be

varied

(modulated)

for

FM

and FSK

signals,

by

means

of

a

reactance

tube

modulator

connected

in

parallel

with

the

oscillator

tank

cir-

cuit.

Another

advantage

in

the

use

of

this

low fre-

quency

is

the

excellent

rejection

of

the

unwanted

sideband

in

the

SSB

(ilter.

Temperature

stability

is

enhanced

through

the

use

of

a

special

ferrite

tuning

core.

The

output

of

the

60

kcs

oscillator

feeds

the

bal-

anced

modulator

and

provides

the

fundamental

car-

rier

energy

in all

modes

of

transmission.

REACTANCE

TUBE

MODULATOR:

In

this

circuit

a 12BY7

pentode

(V-4),

is

employed

as

a

reactance

tube

modulator. On

FM

and FSK po-

Page

10

sitions

the

plate

circuit

of

this

tube

is

connected

in

parallel

with

the

60

kcs

oscillator

tank

circuit,

and

acts

as

a

shunt

inductance,

and would

raise

the

resonant

frequency

were

it

not

for

Capacitor

C-110

which

compensates

for

this

added

inductance,

and

maintains

the

60

kcs

oscillator

at

its

center

fre-

quency

under

no

signal

conditions.

R-25, in

the

cathode

circuit

of

the

reactance

tube

provides

com-

pensating

adjustment

for

tube

aging

and

component

tol

erances.

In

the

FM

mode

of

operation,

the

output

of

the

audio

amplifier

is

applied

to

the

screen

of

the

re-

actance

tube~

varying

the

transconductance,

and

thereby

the

effective

inductance

across

the

oscil-

lator

tank

circuit.

This

causes

the

frequency

of

the

60

kcs

oscillator

to

shift

by an amount

proportional

to

the

audio

modulating

voltage.

Circuit

parameters

limit

the

resultant

frequency

deviation

to a maximum

of

about

3

kcs.

On

FSK

position,

the

FSK DEV. control, R-140,

is

placed

in

shunt

with

the

high

impedance

screen

cir-

cuit,

thus

clamping

the

screen

voltage

by

an

amount

determined

by

the

setting

of

R-140.

Depending

on

the

voltage

available

fromR-140,

this

may

either

in-

crease

or

decrease

the

tube

transconductance,

with

a

resultant

shift

in

the

60

kcs

oscillator

frequency.

R-140may

be

adjusted

to

provide

for

varying

amounts

of

deviation

up

to a maximum

of

approximately

2

kcs,

the

standard

for

RTTY

being

850

cps.

rFhe

switching

of

R-140

across

the

screen

circuit

is

controlled

by

the

output

contacts

of

the

teletype

transmitter,

in

association

with a

polar

relay.

Terminals

for con-

necting

this

relay

are

brought

out

to

pins

/;

11

and

#12 on

the

external

connector

J-ll,

located

on

the

rear

apron

of

the

transmitter

chassis.

Forty

cycle

(40

cps)

identification

frequency

shift

is

obtained

on FSK

position

by

means

of

a

small

change

in

screen

voltage

as

a

result

of

the

closing

of

the

tele-

graph

key.

This

small

shift

in

frequency

will

provide

adequate

code

identification

as

required

by

the

FCC

without

causing

operation

of

the

receiver

teleprinter.

During

SSB (LSB-USB),

AM

(DSB), and

CW

opera-

tion,

the

reactance

tube

modulator

is

disconnected

from

the

60

kcs

oscillator

tank

circuit.

BALANCED

MODULATOR:

In

the

SSB mode,

the

output

of

the

audio

amplifier

is

fed in

paranel

to

the

balanced

modulator.

At

the

same

time,

the

R-F

signal

from

the

60

kcs

oscillator

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

lS

applied

in

push-pull.

The

resultant

heterodyne

action

will

produce

sidebands

above and

below

the

carrier

center

frequency

(60

kcs)

by an amount

equal

to

the

modulating

frequency.

As

the

R-F

inputs

to

the

balanced

modulator

are

180

degrees

out

of

phase

and

the

output

is

effectively

in

parallel,

the

60

kcs

carrier

will

be

cancelled.

The

sideband

products

remain

however,

and

are

passed

on to

the

60

kcs

filter

for

rejection

of

the

unwanted

sideband.

Either

the

upper

or

lower

sideband

may

be

selected

by

means

of

the

front

panel

function

switch.

CR-l

and

CR-2,

the

IN634

crystal

diodes,

are employed

as

modulator

elements

because

of

their

good

linearity

and high front to

back

conduction

ratio.

Transformer

T-l

which

couples

the

R-F

signal

from

the

60

kcs

oscillator

is

bifilar

wound to

secure

the

necessary

balanced

feed

to

the

diode

modulators.

On

AM

(DSB)

position,

the

balanced

modulator

is

unbalanced

by

disconnecting

one

of

the

IN634

diodes,

thus

pro-

ducing

a

conventional

AM

signal

with

carrier.

60

KCS

AMPLIFIER

AND

SIDEBAND

FILT

R:

The

low

60

kcs

oscillator

frequency

permits

the

use

of

a highly

efficient

and

unique

tuned

circuit

for

removal

of

the

unwanted

sideband,

and

for

properly

shaping

the

high

side

of

the

desired

sideband.

The

first

group of

filters

consist

of

L-3,

L-4,

and

L-5,

working

into

a 6EW6

pentode

tube

(V-2),

the

output

of

which

is

connected

to

the

second

filter

group

comprised

of

L-6,

L-7,

L-8

and

L-9.

The

amplifi-

cation

obtained

serves

to

compensate

for

the

inser-

tion

loss

the

two

filter

sections,

while

the

amplifier

circuitry

provides

isolation

required

for optimum

operation.

Top

capacity

coupling

is

utilized

within

each

group

of

tuned

circuits.

A

combination

of

overcoupled

and

undercoupl

ed

condi

tions

are

used

to provide an

adequate

bandpass

and

still

retain

the

steep

sided

response

curve

necessary

for

sideband

operation.

A

bifilar

"T"

trap

rejection

filter

consisting

of

T-2

and Z-1

is

used

to improve

the

sharp

cut-off

charac-

teristics

of

the

filter

chain.

The

"T"

rejection

filter

is

adjusted

for maximum

rejection

of

the

unwanted

sideband

at

250

cycles

from

the

carrier

frequency.

It

should

be

noted

that

the

front

panel

function

switch

knob

indicates

the

lower

sideband

position

when

the

sideband

filter

is

actually

passing

the

up-

per

sideband

of

the

60

Kc

oscillator.

This

is

due to

the

fact

that

unlike

the

first

and

second

mixer

whose

heterodyne

oscillators

operate

on

the

low

side

of

the

signal

frequency,

the

third

mixers

heterodyne

oscil-

lator

operates

on

the

high

side

of

the

signal

fre-

quency.

This

effectively

inverts

the

sideband

posi-

tion with

respect

to

the

carrier,

due to

the

subtrac-

tive

action

of

this

type

of

mixer.

The

final

output

from

the

transmitter

agrees

with

the

knob

indication,

but

up to

the

third

mixer

it

should

be

remembered

the

sidebands

are

reversed.

The

sideband

filter

is

aligned

in

the

upper

side-

band

position

(front

panel

knob

indicates

LSB).

When

the

function

switch

knob on the front

panel

indicates

USB

(final

transmission

mode on

the

switch)

the

sideband

filter

is

actually

operating

on

the

lower

sideband

and

a

small

amount of

closely

controlled

fixed

capacity

is

added

to

each

band

pass

tuned

cir-

cuit,

lowering

the

resonant

frequency.

This

sym-

metri

call

y

10

cates

the

passband

below

the

carrier

frequency

instead

of

above.

When

operating

CW,

FM, FSK

or

AM

(DSB),

the

signal

bypasses

the

60

kcs

amplifier

and

sideband

fil

ter

and

passes

dire

cdy

to the

first

mixer.

FI

RST

MI

XER

&

1590

KCS

OSCILLATOR:

The

signal

from

the

balanced

modulator

is

routed

either

directly

to

the

grid of

the

first

mixer

(CW-FM-

FSK-DSB),

or

through

the

60

kcs

amplif'

er

and

filter

(LSB-USB),

and

beats

with

the

signal

from the

first

of

three

heterodyne

oscillators

which

ultimately

produce

the

final

operating

frequency.

The

hetero-

dyne

frequencies

are

carefully

selected

to

keep

spuri-

ous

outputs

to an

exceptionally

low

minimum

value.

In

this

stage,

a 6U8 dual

purpose

pentode

and

triode

combines

the

function

of

both

mixer

and

oscil-

lator.

The

pentode

section,

V-3A,

acts

as

the

mixer,

while

the

triode

section,

V-3B,

is

employed

in a

crystal

controlled

oscillator

circuit

operating

at

a

frequency

of

1590

kcs.

The

resultant

beat

note

be-

tween

the

60

kcs

mixer

and

the

1590

kcs

signal

from

the

oscillator

is

applied

to

the

input

of

a 1650

kcs

filter

which

provides

further

shaping

of

the

sig-

nal

passband

characteristics.

The

plate

voltage

of

the

oscillator

section

is

supplied

by a

regulated

150 vol

ts

to

insure

absolute

stability.

A

special

1590

kcs

trap

is

employed

as

part

of

the

output

filter,

thereby

preventing

any

pos-

sibility

of

the

oscillator

signal

being

passed

on to

subsequent

stages.

Two

sections

of

the

1650

kcs

filter

are

located

on

the

exciter

chassis

and

are

joined

to

the

third

section

on

the

VFO

chassis

by

means

of

a

low

capacity,

shielded,

polyethelene

cable

connected

from

J-1

to

J-6.

The

output

of

the

1650

kcs

filter

is

then

routed

to

the

grid

of

the

second

mixer.

Page

11

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

SECOND

MIXER

& VARIABLE

FREQUENCY OSCILLATOR:

Following

the

1650

kcs

filter,

the

signal

is

fed to

the

grid

of

the

pentode

section

of

a 6U8, V-9A,

where

it

beats

with

the

signal

from

the

variable

frequency

oscillator

(V.F.O.)

comprised

of

the

triode

section

of

the

same

tube,

V-9B,

tunable

over

the

range

of

3.9

MC

to

4.4

MC.

The

second

mixer

and

V.F.O.

are

constructed

on a

separate

sub-chassis

to

provide

the

utmost

in

mechanical

isolation.

The

V.F.O.

employs

a

ceramic

coil

form

and

a

high

stability

tuning

ca-

pacitor.

This

circuit

is

also

temperature

compen-

sated

to minimize warm-up

drift.

The

oscillator

circuit

proper,

is

a

high

C/L

ratio

modified

Colpitts

which

further

improves

the

excel-

lent

frequency

stability

characteristics.

The

variable

tuning

capacitor,

C-91,

is

directly

gear

driven

from

the

FREQUENCY

control

knob on

the

front

panel

to

eliminate

backlash,

and

provide

for a

high

order

of

calibration

accuracy

and

re-setability.

The

output

heterodyne

frequency

of

the

second

m~xer

may

be

anywhere

in

the

range

of

5.55

MC

to

6.05

MC,

depending

on

the

setting

of

the

V.F.O.

tuning

capacitor:

This

signal

is

then

applied

to

three

filter

sections

tuned

to

this

range,

the

first

two

being

located

on

the

V.F.O.

sub-chassis,

link

coupled

to

the

third

section

located

on

the

main

chassis,

by

means

of

a

low

capacity,

polyethelene

cable

connected

between

J-7

and

J-9.

From

the

cen-

ter

tap

of

the

bi-filar

transformer

in

the

first

filter

section

there

are

two

wave

traps

connected

to ground.

These

traps

are

tuned

to

5.5

MC

and

6.15

MC

and

effectively

eliminate

the

possibility

of

any

spurious

radiation

at

or

close

to

these

frequencies.

Connector

J-8

on

the

V.F.O.

sub-chassis

mates

with

the

cable

plug

P-8

from

the

main

chassis,

sup-

plying

filament

voltage

as

well

as

150

volts

(regu-

lated)

and

300

volts

(non-regulated)

for

the

oscil-

lator

and

mixer

sections

respectively.

BROADBAND

(BAND

PASS)

AMPLIFIER:

The

signal

at

this

point

in

the

circuit

may be

anywhere

in

the

frequency

range

of

5.55

MC

to

6.05

MC,requiring

broadband

circuitry

for

further

ampli-

fication.

Two

6CB6

sharp

cut-off

pentodes,

V-I0

and

V-ll,

are

employed

for

reasons

of

excellent

linearity

and

wide

frequency

handling

capabilities.

These

tubes

are

normally

biased

at

a

high

negative

voltage

(50

volts)

so

that

in

the

receive

or

standby

modes

the

signal

does

not

pass

beyond

this

stage.

Closing

the

telegraph

key,

or

operation

of

the

VOX

relay

during

Page

12

vOlce

transmission,

removes

this

negative

bias

and

permits

the

signal

to be

passed

by

the

amplifier.

The

grids

of

the

broadband

amplifier

tubes

are

connected

to

the

automatic

level

control

circuit

(ALC) which

functions

in much

the

same

manner

as

receiver

AGC.

This

is

more fully

explained

in

the

section

devoted

to

this

circuit.

The

R-F

LEVEL

control,

R-57,

is

inserted

as

a

bias

control

in

the

transmit

mode, and

allows

the

gain

of

the

6CB6

broadband

amplifier

tubes

to

be

varied

according

to

output

requirements.

THIRD

MIXER

& FINAL

HETERODYNE OSCILLATOR:

After

amplification

in

the

broadband

amplifier,

the

signal

is

coupled

by

means

of

capacitor

C-110 to

the

grid

of

the

third

mixer.

At

this

point,

the

signal

(5.55

MC

-

6.05

MC)

is

heterodyned

with

the

output

of

the

last

(crystal

controlled)

oscillator

to

produce

the

final

output

frequency

ranging

from

3.5

MC

to 30

MC,

depending

on

the

position

of

the

BAND

SELEC-

TOR

switch,

SB-3.

As

mentioned

previously,

the

sidebands

are

reversed

with

respect

to

the

front

panel

knob

indication

up to

the

third

mixer.

Due to

the

sub-

tractive

action

of

this

type

of

mixer-oscillator

it

is

here

that

the

sidebands

are

reversed

to

agree

with

the

front

panel

knob

indication.

Separate

os

cillator

and

mixer

tubes

are

employed

in

this

stage,

providing

a

high

degree

of

electrical

isolation

and

frequency

stability.

A 6EW6

pentode,

V-12,

is

used

as

the

mixer

tube,

while

a

6C4

triode,

V-13,

is

employed

in

the

crystal

controlled

oscil-

lator

section.

The

proper

crystal

and

tuned

circuit

for

the

oscil-

lator

are

selected

by

the

BAND

SELECTOR

switch.

All

eight

crystals

required

for

complete

coverage

of

the

ham

bands,

including

the

entire

10

meter

band,

are

provided

as

part

of

the

transmitter.

The

tuned

circuits

for

the

output

of

the

mixer

are

also

selected

by

means

of

the

BAND

SELECTOR

switch,

and

couple

the

signal

to

the

grid

of

the

driver

stage

for

further amplifi

cation.

When

not

transmitting,

the

6EW6 third mixer, V-12,

is

also

biased

at

minus

50 vol

ts

along

with

the

broad-

band

amplifier

tubes,

providing

additional

insurance

against

radiation

of

energy.

DRIVER AMPLIFIER:

The

driver

stage

employs

the

high

gain

video

type

pentode,

12BY7 (V-14), to

obtain

sufficient

linear

R-F

energy

to drive

the

final

output

stage.

As

the

final

tubes

are

operated

class

AB-l

there

is

no grid

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

current

drain in

that

stage

under

normal

signal

con-

ditions,

and

the

driver

is

not

required

to

supply

any

power,

being

designed

and

operated

as

a

high

gain

voltage

amplifier

only.

The

proper

tuning

networks

for

the

plate

circuit

of

the

driver

are

selected

by

appropriate

sections

of

the

BAND

SELECTOR

switch,

SB-3.

The

outputs

of

these

tuning

networks

feed

the

signal

from

the

driver

to

the

grids

of

the

final

6146

amplifier

tubes

by

means

of

capacitor

C-136.

Fine

tuning

of

the

driver

stage

is

accomplished

in

both

the

grid

and

plate

circuits

by

means

of

variable

capacitor

C-133,

the

DRIVER

TIJNE

control.

FINAL (POWER) AMPLIFIERS:

The

final

amplifier

employs

a

pair

of

6146

pentode

tubes,

V-16,

connected

in

parallel.

They

provide

a

nominal

power

output

of

100

watts

(PEP)

on

either

upper

or

lower

sideband

and

100

watts

on

CW,

FM,

and FSK, with maximum

linearity

and

minimum

dis-

tortion.

The

power

output

on

AM

(DSB)

is

25

watts.

The

amplifier

is

neutralized

by

means

of

capacitor

C-149 on

the

highest

portio!?

of

the

10

meter

band

and

maintains

its

performance

over

the

entire

range

of

frequencies

transmitted.

R-F

choke

L-34,

in

the

grid

circuit

provides

the

proper

input

impedance

as

well

as

serving

as

a grid

return

for

the

bias

supply.

Chokes

L-27

and

L-28,

together

with

parallel

resistors

R-120

and

R-121,

act

as

low

"'Q"

parasitic

suppressors.

Resistors

R-1l9

and

R-122

in

the

screen

circuits

also

provide

isola-

tion

from

possible

parasi

tic

oscillations.

A

final

tuning

capacitor,

C-150,

controlled

from

the

front

panel,

provides

a

means

of

resonating

the

plate

circuit.

RFC

L-29

serves

to

prevent

R-F

from

returning

to ground through

the

power

supply.

The

output

of

the

parallel

6146'5

feeds

a pi

net-

work

comprised

of

L-31

and

appropriate

values

of

capacity.

Coil

L-30

in

the

plate

circuit

has

taps

which

are

selected

by

means

of

the

BAND

SELEC-

TOR

switch,

providing

optimum

load

impedance

at

all

times.

The

output

impedance

is

fixed

at

50 ohms,

thus

eliminating

mismatch

when

used

with

standard

50 ohm

antenna

systems.

If

antenna

impedances

other

than

50 ohms

are

encountered,

a

simple

external

antenna

coupler

may

be

used

to

provide

the

proper

match.

As

an

added

operating

convenience,

the

HX-500

contains

an

internal

antenna

change-over

relay

with

connections

for

the

receiver

input

by

means

of

ex-

ternal

connector

J-14,

located

on

the

rear

chassis

apron.

AUTOMATIC

LEVEL

CONTROL (ALC)

Part

of

the

output

of

the

final

amplifier

is

coupled

to

the

automatic

level

control

(ALC)

circuit

by

means

of

capacitor

C-170.

This

signal

is

then

recti-

fied by

one

of

the

6AL5

diode

sections,

V-17B, pro-

viding

a

bias

control

voltage

whi ch

is

applied

to

the

grids

of

the

two

6CB6

broadband

amplifier

tubes.,'Tbe

net

result

is

to

limit

the

output

of

the

broadband

amplifier

50

as

to

prevent

overdriving

of

the

subse-

quent

stages

(particularly

the

final)

thus

effectively

eliminating

the

possibility

of

overload

and

resultant

frequency

splatter.

Potentiometer

R-124,

acts

as

a

voltage

divider

across

the

ALC

rectifier

tube,

allowing

the

threshold

level

to be

varied

according

to

operating

require-

ments.

This

has

the

effect

of

delaying

the

action

of

the

ALC

rectifier

until

a

relatively

high

level

of

out-

put

from

the

final

amplifier

is

reached.

In

this

man-

ner,

the

transmitter

is

ab

le

to

operate

with normal

gain

characteristics

under

average

signal

condi-

tions.

When

the

predetermined

output

signal

is

ex-

ceeded,

the

automati

c I

evel

control

circuit

will

then

respond

very

rapidly

to

keep

the

output

to a

safe

value.

VOICE OPERATED RELAY

(VOX)

Part

of

the

output

from

the

second

audio

amplifier

is

fed

through

capacitor

C-49, to the VOX SENSI-

TIVITY

control,

R-43,

in

the

grid

circuit

of

V-6B.

This

half

of

the

6CM7

dual

triode

tube

is

employed

as

the

VOX

amplifier,

serving

to

increase

the

audio

level

forproper

operation

of

the

VOX

diode

rectifier,

V-7A.

This

circuit

contains

the

VOX

DELAY con-

trol,

R-48 which

determines

the

amount

of

delay

time

in

the

operation

of

the

VOX

relay,

K-l,

and

antenna

change-over

relay,

K-2.

The

triode

section

of

the

6U8

tube,

V-8B,

is

used

as

the

anti-trip

relay

tube,

while

the

pentode

section,

V-8A,

serves

as

the

anti-trip

amplifier.

Potentio-

meter

R-53

in

the

grid

circuit

of

the

pentode

section

serves

as

the

ANTI-TRIP

SENSITIVITY

control,

providing

a

means

of

adjusting

the

input

level,

rela-

tive

to

the

audio

output

from

the

station

receiver.

The

output

signal

of

the

anti-trip

amplifier

is

then

rectified

by V-7B,

the

anti-trip

diode.

This

rectified

voltage

is

then

applied

as

a

back-

bias

to

the

plate

of

the

VOX

diode,

V-7A

preventing

the

voltage

developed

by

the

microphone

amplifier

from

causing

relay

K-l

to be

energized.

With

proper

adjustment

of

both

the

VOX

SENSITIVITY

and

the

ANTI-TRIP

controls,

a

condition

of

balance

will

be

attained

which

will

provide

correct

VOX

oper&tion,

yet

prevent

the

relay

from

being

actuated

by

sound

from

the

station

receiver's

speaker.

Page

13

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

OUTPUT

METER

CIRCUIT

The

output

meter

provides

a

means

of

measuring

the

rdative

output

of

the

transmitter

in all

modes

of

transmission.

The

scale

is

semi-logarithmically

calibrated

from 0 to

-60

db.

CR-3, a IN34A

crystal,

diode,

and CR-4, a

spe-

cial

HD6164

silicon

diode

are

employed

in

the

metering

circuit,

performing in

such

a

manner

as

to

cause

the

output

meter

scale

calibration

to

agree

with

the

output

level

from

the

final

amplifier.

CR-3

establishes

the

basic

re1erence

voltage

for

operation

of

the

meter,

while

the

characteristics

of

CR-4

do

not

allow

it

to

conduct

any appreCiable

amount

until

A

pre-determined

voltage

output

from

CR-3

is

reached.

At

this

point

(about

0.6V

or

higher)

the

silicon

di-

ode,

CR-4 will

conduct

heavily,

effectively

swamp-

ing

the

meter

circuit

and

slowing

the

otherwise

fast

rise

of

the

meter

movement

and

pointer.

This

allows

the

meter

to give a

truer

indication

of

relative

output

as

indicated

by

the

meter

scale

calibrations.

Rheo-

stat

R-59

the

METER

SENSITIVITY

control,

is

ad-

justable

from

the

front

panel,

and

provides

a

means

of

varying

the

meter

indication

according

to

specific

requirements.

POWER SUPPLY

The

power

supply

is

located

on

the

main

chassis

of

the

HX-500, and

is

generously

rated

to

provide

aU

. t f

th'

the

power

reqUlremen s 0 e

transml

tter.

··

A h

eavy

duty

power

transformer

supp

1

les

apprOXl-

mately

900V

rms for

each

12AX46T

high

voltage

rectifier

tube

plate,

and

320V rms for

each

plate

section

of

the

6CA4,

the

low vol

tage

re

ctifier

tube.

In

addition,

there

are

separate

windings

which

sup-

ply

12.6V

at

1.2

amps

for

the

12AX46T

rectifier

filaments,

and

6.3V

at

10 amps for

the

6CA4

low

voltage

rectifier

filaments

as

well

as

the

filaments

of

the

tubes

in

the

transmitter

proper.

The

6.3V

wind-

ing

also

powers

the

1147

pilot

lights

DSl,

2, 3

and

4.

One

section

of

a

6AL5,

V-17A,

acts

as

the

bias

rectifier

whose

output

is

controlled

by a

voltage

divider

network

consisting

of

R-134, R-135, and

the

BIAS

ADJUST

rheostat

R-136.

An

OA2

voltage

regulator

tube,

V-21,

operates

off

a vol

tage

di

vider

network from

the

215V

tap

on

the

low

voltage

rectifier

circuit.

This

tap

provides

the

voltage

for

operation

of

the

V-R

tube,

which

provides

a

regulated

150V d. c.

output.

Addi

tional

high

voltage

d. c.

outputs

are

provided

by

the

H.V.

rectifier

(780V),

and

by

the

L.V.

recti-

fier

(215V. + 300V. + 350V.) for

the

operation

of

the

various

transmitter

stages.

Two

bias

voltages

of

-50V

and

-lOOV

are

sup-

plied

by

the

bias

rectifier.

All

rectifier

circuits

are

well

filtered,

insuring

low hum and

distortion

levels.

A

blower

motor

and

fan, for

cooling

of

the

output

tubes

plugs

into

a

receptacle

on

the

power

supply

chassis

and

is

controlled

by

the

main

power

switch

. h .

ill

t e

power

transformer

primary.

TUBE

COMPLEMENT

Symbol

Type

VI

6AU6

V2 6EW6

V3 6U8

V4 12BY7

V5 12AX7

V6

6CM7

V7

6AL5

V8 6U8

V9 6U8

VI0

6CB6

Vll 6CB6

V12 6EW6

V13 6C4

V14 12BY7

V15 6146

V16 6146

VI7

6AL5

V18 12AX4

V19 12AX4

V20

6CA4/EZ81

V21

OA2

Page

14

Tube

Pentode

Triode-Pentode

Pentode

Double

Triode

Double

Triode

Double

Diode

Triode-Pentode

Pentode

Triods

Pentode

Double

Diode

Double

Diode

G

as-

Filled

Diode

Function

60

Kcs

Oscillator

60

Kcs

Amplifier

Crystal

Oscillator

- 1st Mixer

Reactance

Modulator

1st and 2nd Audio Amplifier

3rd Audio Amplifier -

VOX

Amplifier

VOX

Diode

-Anti-Trip

Diode

Anti-Trip Amplifier -

Relay

Amplifier

VFO -2nd Mixer

Bandpass

Amplifier

Bandpass

Amplifier

3rd Mixer

H.F.

Crystal

Oscillator

R.F.

Amplifier -

Driver

Final

R.F.

Power

Amplifier

Final

R.F.

PowerAmplifier

ALC -

Bias

Rectifier

High

Voltage

Rectifier

High

Voltage

Rectifier

Low

Voltage

Rectifier

Voltage

Re

ctifier

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

~---------

--

- - - - - -

--

-

----r--------,--

-

----,

I EXCITER -SIDEBAND GENERATOR SUBCHASSIS I

V.FO.

SUBCHASSIS I MAIN CHASSIS

I LSB

USB

I

TO

RECEIVER

ANT.

ANt

CHANGEOVER

t

RELAY

I

1

I

I I

29.5-30.0

I

L I

-'-

I

-.-J

Figure

4.

Simplified

Slock

Diagram

VI7

6AL50

V21 CDO

OA20

00

0

VI8

IZA

FAN REC.

VI9

o

VI6

6146

81.1®-A~-A-DJ-@-o-""'6V-::C~:-::04,...o-JIZAoX4GTB

VI500

6146

FSK

DEV.

V3

JI

D D

r-IN-P-U-T----------,

TRIM

D

DO

DB~T

IZV~~70

o~

0 ¢

o

DoDO

DO:ie

O

'0

U

00°

V7

V8

OUTPUT 0

RES.8AL

6AL5

6ue

oJ7

I

VI3

D D

~

6~~60

0

6C:~~6

0 00 '210

VIO

VII

0

8B,:1:,0

8J6~DO

o0 0

05

IN~~TO

IZ~~7

12AX7 0

I--.

Figure

5.

Tube

location

Diagram

Page 15

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

HX-500

TRANSMITTER

FIELD

ALIGNMENT

PROCEDURE

EQUIPMENT

REQUIRED:

1.

General

coverage

receiver

covering

600 KCS to

30.5

MCS.

2. 100 KCS

crystal

calibrator.

3.

Audio

generator

-

1%

accuracy.

4.

R-F

Generator

-

1%

accuracy.

5.

VTVM

or

Wattmeter.

(optional)

6.

50

ohm dummy

load

or two

60

watt

bulbs

In

par-

allel.

(optional)

7.

0-300

MA

Milliameter

(optional)

GENERAL

INSTRUCTIONS:

The

alignment

procedure

to

be

described

is

a much

simplified

version

of

the

one

performed

at

the

factory.

It

will

enable

the

operator

in

the

field

to

realign

the

HX-500

transmitter

with

reasonably

good

accuracy

with

a minimum amount

of

test

equipment.

This

pro-

cedure,

together

with

voltage

and

resistance

charts

contained

in

this

manual

will

usually

provide

the

information

necessary

to

restore

the

transmitter

to

peak

operating

efficiency.

If

more

serious

trouble

exists

than

might

normally

be

encountered

the

unit

should

be

returned

to

the

factory

or

to

the

nearest

field

maintenance

station.

If

the

necessary

high

quality

test

equipment

is

available

the

"Comprehensive

Alignment

Procedure"

may

be

followed

and

will

provide

more

precise

and

accurate

adjustments.

In

no

case

should

the

"Com-

prehensive

Alignment

Procedure"

be

followed

with-

out

the

equivalent

test

equipment

of

known

accuracy.

When

using

the

following

"Field

Alignment

Pro-

cedure"

no

attempt

should

be

made

to

align

or

adjust

circuits

or

components

not

specifically

covered

in

the

instructions.

INITIAL

CONTROL

SETTINGS:

1.

"Function"

switch

on

"LSB"

2.

"Operations"

switch

on

"CAL"

3.

"Meter

Sensitivity"

maximum

CW

4.

"Calibrate

Level"

maximum

CW

5.

"R-F

Level"

as

required

ALIGNMENT

PROCEDURE:

1.

Connect

the

60 KCS

oscillator

output

developed

across

R8

(balanced

modulator

circuit)

through

a

.01

or

larger

capacitor

to

the

antenna

input

of

a

receiver

tuned

to 600 KCS.

The

receiver

should

be

accurately

set

on

frequency

with a 100 KCS

crystal

calibrator

that

has

been

checked

against

a known

standard

such

as

station

WWV.

2.

Carefully

adjust

the

60

KCS

oscillator,

Ll,

for

zero

beat

in

the

receiver

(lOth

harmonic).

The

same

BFO

and

dial

setting

employed

with

the

crystal

calibrator

should

be

used.

3.

Feed

a

1300

cycle

±

10

cycle

signal

of

1

volt

to the

"Patch"

input

on

the

transmitter

front

panel.

Rotate

"Audio

Level"

control

to

"7".

Tune

up

transmitter

at

3.75

MCS

(80

M)

adjust-

ing

the

"R-F

Level"

control

so

the

transmitter

level

indicator

meter

M1

reads

about

-10

DB.

Connect

a 10K

Yz

watt

resistor

across

C13

and

another

across

L7.

Adjust

"R-F

Level"

con-

trol

if

necessary.

Peak

L6 for maximum

making

sure

the

adjustment

is

very

precise.

Remove

the

10K

resistors

from

across

C13 and

L7

and con-

ne

ct

them

across

L6

and

L8.

Peak

L7 and

L9

for maximum

on

the

"Level

Indicator

Ml".

Re-

move

resistors

from

across

L6 and

L8

and con-

nect

them

across

L7

and

L9.

Peak

L8

for max-

imum and

then

remove

the

resistors.

4.

Set

audio

generator

to 1250

cycles

±

lO

cycles.

Connect

a 10K

resistor

across

104

and

peak

L3

and

L5

for maximum.

Remove

resistor

from

L4

and

connect

it

across

L5.

Peak

L4 for maximum.

5.

Tune

audio

generator between

300

and 2300

cycles

and

locate

the

frequency

of

maximum

output,

keeping

the

"Level

Indicator"

at

about

-lO

DB

with

the

"R-F

Level"

control.

At

the

frequency

of

maximum

output

use

the

"R-F

Level"

control

to

set

the

"Level

Indicator"

to

exactly

-10

DB.

Note:

The

audio

generator

should

maintain

con-

stant

output

at

least

over

the

range

of

250 to 2500

cycles.

Tune

audio

generator

lower

10

frequency

until

the

"Level

Indicator"

reads

-16

DB.

This

should

be

bet

ween 260 and

340

eye!

es.

Tune

audio

generator

higher

in

frequency

very

slowly

noting

that

the

"Level

Indicator"

does

not

drop

-14

DB

until

between

2200 and 2400

cycles

the

"Level

Indicator"

reads

-16

DB.

Page

16

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

BIAS.'

,..

,

DEV.'

2

,.

'u

T9----:

_.

TI5

10M

RI36

ADJ.

RI40

FSK

TI3

40M

TI2

BOM

'l:l

III

(1l

OQ

Figure

6.

Top

View

of

the

HX-SOO

TransmiHer

Chassis

(H.V.

Cover

Removed)

......

--.l

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

m

6.

Rotate

"Function"

switch

to USB.

Do

not

dis-

turb

HX-500 or

audio

generator

settings.

Tune

audio

generator

for maximum

response

on

the

"Level

Indicator".

This

should

be no more

than

-13 DB on

the

"Level

Indicator".

Adjust

the

"R-F

Level"

control

so

that

the

meter

reads

-10

DB.

The

-16 DB

frequencies

should

be

the

same

as

for

the

"LSB"

position.

7.

Disconnect

cable

from

)6

and

feed

the

output

of

the

"Exciter"

section

into

the

antenna

input

of

the

receiver.

Be

sure

that

the

"Function"

swi

tch

is

on

either

LSB

or USB

and

that

the

"Audio

Level"

control

is

adjusted

maximum

CCW.

Tune

in

the

1590 KCS

signal

for maximum

on

the

receiver

level

indicator

and

adjust

the

top

slug

of

1'3

for Minimum on

receiver

level

indicator.

8.

Reconnect

cable

to J6 and

tune

up

transmitter

in the

80

meter

band.

With

the

transmitter

"Level

Indicator"

adjusted

by

means

of

the

"R-F

Level"

control

to

approximately

-20

DB

or

less,

adjust

the

bottom

slug

of

1'3 and top

and bottom

slugs

of

1'4

and 1'6 for maximum

output

on

the

transmitter

"Level

Indicator".

Be

sure

to

keep

output

below

-10

DB

on

the

meter

by

means

of

the

"R-F

Level"

control.

9.

Tune

transmitter

to 4

MCS.

Set

the

"Frequency

KCS"

dial

to zero with

the

scale

pointer

resting

at

exactly

4

MCS.

Tune

up

transmitter

and

feed

signal

into

the

receiver

(previously

calibrated

with

the

100 KCS

calibrator).

The

receiver

should

be

tuned

to

exactly

4

MCS.

Adjust

L17

for

zero

beat.

Tune

receiver

to

3.5

MCS

with

the

calibrator.

Tune

transmitter

to

3.5

MCS

making

sure

that

the

"Frequency

KCS"

dial

is

on zero when the

dial

scale

pointer

is

on

or

close

to

3.5

MCS.

Adjust

C92

for zero

beat

in

the

receiver.

Repeat

9.

until

no

adjustment

1S

ne

cessary

for zero

beat

at

3.5

and 4

mcs.

10.

Tune

transmi

tter

to

3.75

MCS

making

sure

of

frequency

accuracy

by

first

zero

beating

3.8

MCS

with

the

receiver

calibrator

with

the

"Fre-

quency

KCS"

dial

on

zero.

Place

a

1K

J.'2

watt

resistor

having

as

short

leads

as

possible

across

secondary

of

1'11.

Very

carefully

tune

the

bottom

slug

of

1'11 for maximum on

the

x'mitter

level

indicator.

Remove

resistor

from

secondary

of

1'11 and

connect

across

primary.

Peak

top

slug

of 1'11 for maximum.

Repeat

above

procedure

for 1'10.

Page

18

11.

Tune

up transmi

tter

at

3.775

MCS

and

place

1K

resistor

across

primary

of

1'9.

Adjust

top

slug

of

1'9

and bottom

slug

of

T8

for maximum on

"Level

Indicator".

Remove

resistor

and con-

nect

across

secondary

of

1'9.

Adjust

bottom

slug

of

1'9

for maximum. Remove

resistor.

12.

Be

sure

"Function"

switch

is

on

LSB

and

"Operations"

switch

is

on

"CAL".

Connect

signal

generator

to

junction

of

SB-3C arid

C124

(grid

of

V14).

Set

"Band

Selector"

to

10M

(28.0

-

28.5

MCS).

With

"Driver

Tune"

set

for

maximum

capacity

(CCW) feed in a

27.75

MCS

signal

and

adjust

generator

level

and

"Final

Tune"

so

that

the

"Level

Indicator"

M1

reads

less

than -20 DB.

Peak

bottom

slug

(insert

tool

from top)

of

L26 for maximum on Ml.

Set

gener-

ator

to

30.25

MCS.

Rotate

"Driver

Tune"

and

"Final

Tune"

to minimum

capacity.

Adjust

C143

for maximum

output.

OTE:

If

oscillation

occurs

when

adjustments

are

made

check

to

see

if

C149

(neutraliz-

ing

capacitor)

is

set

at

about

half

capac-

ity.

Repeat

above

step

if

necessary.

If

neutralization

is

required

refer

to

instruc-

tions

under

"Neutralization

Procedure"

Step

25.

13. Remove V13 from

its

socket.

Connect

signal

generator

to pin

11

1

of

V12. Run top

slug

of

1'15

to top

of

can.

Rotate

"Driver

Tune"

to maximum

capacity.

With

a

27.75

MCS

signal

into

V12

rotate

"Final

Tune"

for maximum on Ml.

Adjust

signal

generator

output

to

keep

indication

below

-10

DB.

Peak

bottom

slugs

of

L26

and

1'15 for

maximum on

Ml,

readjusting

signal

generator

level

if

ne

cessary.

14.

Set

signal

generator

to

30.25

MCS.

Rotate

"Driver

Tune"

to minimum

capacity

and

"Final

Tune"

for maximum

indication

on

Ml.

Peak

C143

and C132 for maximum on

M1

keeping

reading

below

-10 DB

by

means

of

signal

in-

put

level.

15.

Set

signal

generator

to 29 MCS.

Peak

"Driver

Tune"

and

"Final

Tune"

for maximum on

Ml.

Adjust

top

slug

of

1'15

for maximum on

Ml.

If

a

dummy

load

is

available,

the

output

may be

checked

by

rotating

"Operations"

switch

to

"MOX"

and

increasing

generator

input

level

until

output

indicator

(wattmeter

or

VTVM)

reads

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

CI49

NEUTRALIZING~

''''\i\

u"a

F'

-

.T~

~=

r

.'~-

iii.

III

".

...

,,,

'

...

i"lffjl'

'~1·.J~.,..~~n:-:j:;;-~--:------

~

.•.

'f"

11

:.... •

~llf~>I!il..

CI40

(40M)

.

,.EW

_

--.'

CI39

(80M)

~-C58

L17

VFO

<i

CI28 (80M)

COIL

'~

CI29 (40M)

CII3 (80M) -CI20 (JaM)

11"".

CI14

(40M)

CI19

(10M)

-,

~'--

~

I

CI15

(20M)

~,.,....,.....,.

.::.:"'~.:,

CI18

(10M)

'-£-

L~

~

_~I

CI16

(15M)

-'-'

CI17

(10M)

~-

'"tJ

III

~

.....

\Q

Figure

7.

Bottom

View

of

the

HX·500

Transmitter Chassis (Covers

Removed)

FREE DOWNLOAD

COURTESY OF N9SOR

WWW.HAMMARLUND.ORG

Hammarlund HX50 Manual

Popular Transmitter manuals by other brands