GE SSB Jr. User Manual

HAM

NEWS

Presenting a

SS

3 -Tube

5 -Watt

rtr"Pir-._ .11

°

.-

- _ . .

°

SSB

-;

,;_.D

&

i

" 43 1-.

.

,

Jr.

Transmitter

..

.i-

`

Y. /

:

with

Superior

Performance

'

wr

Fig. 1. Front

single

trols need be adjusted (except

control).

permits a

obtained.

panel view

-frequency

Front

-panel mounting

compact physical

CONTENTS

SSB Jr.

Designer's Corner (Notes

Sweeping

Technical Information (6A07)

the Spectrum page

of

on

the

the SSB Jr. For

audio gain

the

of the

controls

layout to

of the SSB Jr.

design

operation none of the

con-

be

FEATURES

Simple to

Uses

Has sideband-reversing control

Usable

or home transmitter

rig) page 10

construct

inexpensive

as

emergency,

parts

-

portable

pages 1-9

11

12

page

AUDIO

INPUT

I2AU7GREEN

R2

3

1R3

t /

/

PHASE

I q

R15

BUJE

1. ;O'

R4

SSB,

ELECTRICAL

NETWORK

SHIFT

i

C7 ¡

A'

98 G1G"

J

lo; l

Q l

RED

R5

0B

I

12AT7

18

Jr.

CIRCUIT

13

A.F.

BALANCE

i'

RI!

BLUE

\T EL.:

/+

02B

YEL.E

R12

T2

a

o Cl2

RED

G2A

BLUE RED

'RE

1-4/

Suj

XTAL

OR

V. F.O.

O

RED C3

a WH.

117(

C13T

12ÁU7

2

R14

m.C4

~ G5 ~

041110004X10

1,80e818e081,

6

I

G6 -

L21,

GI,

*L5

RF

OUTPUT

TWIST

0

RFC

C18

1

019

5

G2C

*MOUNTING

C,

Cz

C,,

Cs,

C,:

Cr 2430

C, C,

C,,, 607,5 mmf

Cu,n C,, 0

C

C,,, C2, 0 G,,

J Open

L,,

END

C,2,

C,, Cie,

C,,,

Cl-

4860

G,... 1N52 germanium diode

02, 0,,

L2

20-20-20-20

C,e

mmf

(0.002

mmf

trimmer in

mmf (0.0043 mf

mmf trimmer

1215 mmf

mmf trimmer in Parallel)

350 mmf

(0.001 mf

mmf trimmer in parallel)

(S00 mmf mica

600 volt mica

with

parallel

see

text

turns No. 21 enamel wire

33

on

Millen No. 69046 able hookup

(All

1000

May

mf mica

parallel)

in parallel)

100 mmf)

slug coil form. Link

wire

6AG7

x

6aL4

1

4

RFC

YC2D

Fig. 2. Circuit diagram

capacitors

and

resistors

0.5 mf 200 volt paper

450

mf

mmf

250 mmf

not

be necessary, see text

mica

005 mf mica or

01 mf mica

0

wound on

electrolytic

volt

mica or ceramic

mica X10%

with

*5%a

with

5%

with

*5%

with

X10%

(250

X10%

or ceramic

002 mf mica

or equivalent,

circuit

close

iron core adjust- S

of

6

open end.

L3 Y

g

GI7

K

1

G16

- 300

V.

Circuit Constants

170-780

50-380

ceramic R,

mmf

wound R,6,

turns

*20%

9-180-

in

X10%

jack R,,,

of

tolerance

Ls

L,

Ls

RFC

R, Rº

Rs

R,

Rs

R,,

Rs,

R

R,2 500

R,,

R

T,

Ts,

GI

G20-

021T

G

RFC

10.5 V.

of the SSB

unless specified otherwise)

R,,

R,

R,,

R,; 1000

T,

014>m

G2 R16

a

G3

G15

C+,

B-

Jr.

turns No. 19

16

fill Millen No.

turns. Link

8

turns No. 19

28

open

matches

Radio -frequency

as

Same

end to match

ohm

72

1

430

1600 ohm,

133,300 100,000

510

Stancor

UTC R -38A transformer

RFC

enamel wire spaced

coil

69046

of

L,

enamel wire. Link on

megohm

100 ohm potentiometer

form. Tap at

1 turn

at center.

except no

load.)

choke 0.5

10,000 ohm, %

ohm, 3,1

ohm, ohm,

ohm,

ohm potentiometer

47,000

20,000 ohm,

ohm

DPDT

link

turn

load. (4

millihenry

potentiometer

750

ohm,

%

(*5%)

watt

watt (*5%

A

(*1%0

watt

%

(

watt

A watt

(*5%)

330 ohm, 3.4 watt

ohm,

34

potentiometer

toggle switch

A -53C

transformer

used

watt

1%)

watt

1 watt

to

link

SSB Jr. is a complete

The

mitter-just

on the air. No

are

single-sideband

add

2

microphone and

longer must amateurs

equipment

single-sideband

ís

too

to

feel

trans-

that

under -

antenna and you

complex

too

or

more

complicated

difficult

reach of anyone

stand

no

is

modern 3 -tube transmitter.

SSB within the

to

to build.

build or

This

The

SSB

adjust

rig should

is interested.

that

than

Jr,

bring

rig

any

Further,

be

second

sacrificed in power input, not including

(300

contained crystal oscillator

operation),

chanical

suited

transmitter,

sideband

is

available

adjust

nical

new

Corner

first

speech amplifier channel

network,

trol

input tube, tube.

newly of transformer

shift network

12AT7

transformer

each

diodes.

signals from

half

separate

portions of

plate

work

is link

AB' linear

tank circuit

All

slug -tuned coils wound on Millen

iron

of audio polarity

S).

audio channels,

order

addition,

phase

eliminates

need

modulator balance

resistors manium

to emphasize

from

obtained jointly

transformer

tamed

network by means

formers which

distortion

any amateur can

assured that

to

The

peak

volts at 60

and electrical ruggedness that

as

The

system

signal is

daringly direct and effective.

components

All of

the

details

modulator design are explained

section

With reference to the circuit diagram,

tube,

amplifier

and the

Starting

potentiometer

The

designed

miniature tube.

of

which

The balanced modulators are

of

the

link windings

circuit

into

coupled

This power amplifier works

circuit

forms.

coil

Sideband

Provision

to

-shift

for two

R16

diodes.

The

audio

300

in

his single-sideband

none

in quality.

interest

the

power output

ma.). The

40 db. sideband suppression,

a complete

or

as an exciter for a

used in

a simplified phasing

information

Jr.

SSB

on

the

of this

12AU7, is

a

oscillator. A 12AT7 serves

in

final is

with the audio

is one-half

which

output of

audio phase -shift

T1. The

feed

coupled to two

employs a pair

crystal oscillator, which is

the

12AU7. These r -f

a 90 degree r -f phase

of

oscillator. The

the

a balanced load circuit (L:,,

to the grid

power amplifier

(LU, Cm)

tuning

switching is

in

is

made for

this equalization

achieve

a semi

normal

-fixed

network

need

the

non-standard

R17 in

and

characteristic of the SSB

the

3000

to

caused by

T1. Low

audio

cycles

by

circuits

are shunt

build the SSB

Performance has not

of

simplification.

is 5 watts and

filament power, is 18

Jr. rig features

SSB

(or

portable,

mobile,

the generation

Inexpensive

are used throughout.

necessary to

rig

appears

new

issue.

the

feeds

this tube

separate triode

on L1 and

in this

phase -shift

-triode,

a twin

output of

a 6AG7 pentode.

circuit,

an

grid

the

the 12AU7 miniature

of

is coupled

network by means

outputs

These two tube

balanced modulators

of germanium

also supplied

signals

L2,

-shift network

balanced

circuit (L4, C17) of

a 6AG7.

tube,

into

is link coupled

that

is accomplished by

accomplished

one of

control

adjustment. Use of

for a special transformer,

is

achieved

No. 69046

audio channels

the

equalization

sideband cancellation. In

(R7) is

precision

by

conjunction with

intelligence -bearing

per second.

the action

differential

of lightly

direct

of

phase -shift is

following the phase -shift

loaded

to

-fed

current

Jr.

rig

will

and

be

signal

been

the total

watts

buffer

make

home

network

in

the phase -shift

input

of

the

a self-

for VFO

and

it ideally

emergency

transmitter.

of

the single-

method

and easily

construct

Tech-

article.

and

Designer's

the

Fig.

2,

combination

as a twin

gain con-

self -biased

me-

that

and

the

into

of

the phase

sections

of the

sections

are

crystal

r -f

by

the other

are picked

which comprise

by

up

in the

modulators

C21) which

C21,

the class

a conventional

to the load.

adjustable

powdered -

by

the reversal

(switch

of gain

being

resistors.

the balance/buffer

in the

necessary in

provided

this

control

or the

Stable

for

the ger-

Jr.

is

designed

frequencies

This

C1 and the audio

feature

main

output

reduce

in

their windings.

trans-

harmonic

A

5 by

with good

as

shown, may be used, although

It is

recommended sketches Obviously other

shown has

problems have been eliminated.

and

Before

advisable to

board. This is

-

terial may be thin bakelite or

The

dimensions are 4

corner

one

tube. This board uses

which

are padded with four adjustable mica

and four

X-3 ,

plus or minus

shown R,

Continental

ever, the

two

resistors and paralleling each of them with

watt

resistor. Careful selection of

-

will

133,300

znegohm resistors is to

body of

on three

a

directly

dress the leads

-

the chassis

will

as the

in Figs. 3A and 3B.

be

procedure described

nections

is

-

Fig.

shift network.

133,300

150,000 ohm

1.2 megohm (plus

permit close

ohms. A convenient

the precision

The

phase

below transformers T1 and

be saved by

last

Mount

omitted initially, since

will

21x4 K4"

I

pa

7:

3. (A) Mechanical

inch

by 2

7

access,

the

been carefully

starting work

make

cut

is

chassis

for all component

that parts

photographs

layouts

diagrammed in Fig. 3. The

off

will work,

made and many

ón

the audio phase -shift network

inches

by 2% inches.

permit access

to

four fixed mica condensers

precision resistors (Continental

R9 are

and

Nobleloy 100,000 ohm

1% tolerance).

as specified, that is,

ohm resistors were made

precision

or minus

adjustment

slip them

-shift network

half

to

step

the

TExT

.

150,000

-inch long

from these

clear the phase -shift

installing

in the construction.

phase -shift

be made

.ITE

sub -assembly

spacers

transformers

the

network

The

dashed

the

later presumes

at the proper time only.

THICK

C7 -

0.002

TRIMMER. (2430

0.0043

8 -

TRIMMER.

9- 0.001

TRIMMER. (121S

500 NNW MICA

C10-

MME

TOTAL)

A

5

- +7 ' ;

B

arrangement

(B)

Detail view of the audio

network

provides ample

parts. A cabinet,

is not

this

layout

be

followed

but

main

the

insulating

any

resistors. How-

Continental Nobleloy

10%

1.2

the

to

way

ohm

megohm

the

desired value

to mount

inside

resistors.

under

T2. It

network. Time

network sub -assembly

elements as

connections detailed

that these

MICA

WITH 170-780 MME

MICA

WITH

(4860

MME TOTAL)

MICA

WITH 50-380

MME

WITH

TRIMMER.

(607.5

_`

y

.

of the audio

space,

essential.

shown in

exactly.

the layout

layout

chassis it is

base ma-

material.

Note

to the 12AU7

In

that

trimmers,

Nobleloy

the unit

they

by

taking

one-half

a

tolerance)

units

the 1.2

the hollow

is

mounted

the chassis

is best

flat

against

shown

should

alignment

MME

TOTAL)

170.780

MME

TOTAL)

9 T0(80

MME

(

phase

-shift

the

are

of

to

con-

-

3

A word of caution about

hot

the

diagram-the

the mounting

cold

and

asterisk indicates end, that

ends are

the coils. Make sure

as specified on the circuit

the

is,

the end with the

end

that

which is

long

tuning screw.

The links

indicated in Fig. 11. As a suggestion, wind the

as

links

of wire nice

running from one coil to

connection

placed under L,

point for the

to the

The

nect

form terminals.

and L2 (C6) is shown

since

this point the particular

will be given on this

Note

above the panel from

hole in

grid

of

terminals 1, 3 and 5 of

desirable to ensure stable

also that

is placed between coils L2

The unused

to the winding and

ings of T2 and Ta have several

are are fed through small rubber

circuits on

to

secondary leads from T3 which

Twist

sideband

Do not

as you may wish to use

or perhaps run your automobile engine while trans-

mitting

Ample mounting

near

reference

C2n,

may

T1, T2, T3.

The

handling. Do

unit itself. The

leads

propriate ends

diodes from heat

with cold

where only

joint.

A four -wire

power supply

the

nected

end of power supply.

The

Any

or more

electronic bias plying 10.5 volts may be used for bias.

on

coils

the

with solid insulated

is

convenient,

looking

job. Twist the

are

holds on well,

another

point. A small terminal

serve

to

links

balanced modulators.

small

across

amount of

the

coming

fixed mica tuning condensers that con-

L1, L2

will

depend

unit

L3 are

and

The

coupling

dotted

actual

on stray coupling

you

later.

that the grid connection

the

chassis right

the

terminal) of the 6AG7

a 2 by 2)4 inch brass or

transformer

not

All leads from the

used.

the

leads

these

reversing switch on the

ground either

if

the rig

C2, the four -section electrolytic condenser. With

C2, one

to

etc. The

be cabled

heater

together

germanium

not bend the

between

as

negative

diodes the coil

of

pliers between the

the soldering

much

heat

shielded

to the exciter.

plate supply

to chassis ground. A male

the cable makes

power supply

source of power supplying

may

be used.

either,

and L; below deck.

forgotten.

underside.

together

is

121,

while soldering by holding

before

heater lead in

an

for mobile

used

for C1 and R3

space

mf section is

20

leads that run from

with

diodes deserve

mounted by means

are

terminals

R77. Protect

and

taking place. Further,

is

necessary

as is

cable

convenient connection

a

not unusual in

is

It is not necessary

and a standard battery sup-

over the

wound

hookup

wire.

cold end,

This

and makes a

wires together when

coil, or to another

as

convenient junction

a

L,

from

and

mounted

capacitor between

in

the

capacitance

More information

build.

to

socket.

of the 6AG7

pin number

Direct

hot end of

may be

strip

L2

and going

on the coil

circuit diagram,

needed at

effects in

La

through a

strapping

amplifier operation.

aluminum shield

may

leads

grommets

All, that

a -c

be cut off close

The secondary wind-

intermediate taps that

three transformers

in

the chassis

is,

remain above chassis.

running

front

heater power supply

except the

them to the

panel.

the

work.

will be

another is

C2A,

the 12AU7

other leads

the

leads

lead

special

close to the diode

of L3 and

the germanium

itself

diode

make

to

brings power

The

shield serves

and should

plug

volts

300

the

and

from

at the other

any respect.

and

type

4 (the

Note

chassis,

found

from

care

of

their

the ap-

lead

the end

use

a good

the

be con-

to the

mils

60

to use

The

power supply used

tured is shown in Fig.

given in Fig.

section filter

acts as a bias

R1 adjusts

The

main a -c switch is

is

Note

S2.

bleeder

when

the

employed

arrangement

tact.

There

layout,

your convenience.

L1

The

SSB Jr.

output

microphone

carbon microphone,

is quite adequate,

is

contemplated.

On

the other hand, low-level microphones,

as

the usual

may

is

in

be used if

A

suggested

amplifier may

porated into

shown

or the single -button carbon

provide in excess of required as a minimum input

is

As

are some

must

that

cision resistors specified

resistors are not available-although you

get

try to

precision resistors

good resistance bridge.

resistors

for

used

use precision resistors initially.

The

adjustable mica

phase

-shift

trimmer. Those actually used are El-Menco

trimmers-T52910

T52510 for

9

the

to

Resistors

minus 5%

required,

are

tolerance series.

The

diodes. Other

may

as

I measurement.

I

be used instead. If possible,

which have

forward

on an

ohmmeter.

it is, measure

reverse

different. The lower

Make

this measurement

intend to

of any one

average resistance of the group.

The

diodes used

proximately

when the analyzer

A

6.

5V4 -G rectifier tube

to supply 300

rectifier

the bias voltage

that resistor

drop

to

and

the positive

rig

is turned off. A double -pole

with

the

gives the effect

nothing

is

any arrangement

rig as

even desirable,

type of crystal or dynamic

a one -tube preamplifier is provided.

circuit is shown

be built as a

the SSB Jr. rig.

true with many transmitter

component parts used

be chosen carefully.

them if at all

will change value

a while, and that is

network

the 50 to 380

180

mmf range.

R4, Rs

tolerance. This is

and

these

germanium

types, such

about the same forward resistance.

resistance is

the leads

use to

of

the

250

To

to the diode

The

make sure

diodes

ohms on

with

7 and the circuit

volts,

supply 10.5 volts. Resistor

to

obtainable.

and the stand-by

S1,

R2

acts

voltage

switch

arms

of a

critical about the power supply

designed

circuit be

used.

connected

in Fig.

separate

Either

2 volt (RMS) signal level

the

signal

important.

are

possible-you may

have

which

may

for

and R11

diodes

the

determine approximately

resistance

two readings should

resistance

in

was

may

You

after

why it is

trimmers used in

any

be

170 to

the

mmf range;

are

because the

values only

are

1N48,

as

low resistance

in

the four diodes you

on

the

that

is

within

the rig

a Weston

set

the

to

the

as

tied

Jr.

SSB

and a

a

together, as this

feeds

low

to zero

rig pic-

diagram

a single

6H6 tube

switch

resistance

quickly

switch is

double break con-

may

be used

requires

A single

as shown in Fig.

if mobile

to

that a high -

-button

operation

microphone,

This

8A.

unit or incor-

the preámplifier

mike

circuit

to the SSB Jr.

designs,

in

the SSB

Obviously,

Jr.

the pre-

If precision

should

been

they have been

good

780

specified

select four

one direction,

and make

is

the one of interest.

forward

ten per cent of

shown measured

RX10

use

checked

find

that

desirable

the audio

grade

mmf

T52310

and

as plus

values

come in

as

1N51

and 1N63

as checked

a second

be

resistance

772 analyzer

scale. (Dif-

of mica

range;

the 5%

diodes

suit

8B

such

pre-

will

there

rig

non

on

these

to

mica

for

or

stated

1N52

The

what

then

quite

the

ap-

-

a

4

_1_

.

111,

í

.9

.

411.

N1

f.

3"

SHIFT NETWORK

PHASE

(BELOW

ON I/2" SPACERS)

Ti

STANCOR

e No 3c

Fig. 4.

Rear view

R5

(USE SHAFT

r-----,

II

-----J

I

i 12AT7 i

of

--- --__

the

55B Jr.

LOCK)

C2

a,b,c,d

-1'

1

- 1---.\

CABLE OUTLET

-c+

2"

5"X 7"X

CHASSIS

i`

// \

AG7

KEEE

\

\\ /

/

Sill

L----

r-

1

i i

L___ ----J;

R1 AUDIO GAIN

____

----

,/

/

_,

.T I

i'

I '\I2AU7

r.-'-1.1

n'

XTAL

SOCKET

Fig. 5. Chassis layout for the 55B Jr. (top view)

xi,

i

-4 --'-'-ii

LI

(BELOW)

¡

t

1/2"

+

FRONT

.1

L2 L3

(BELOW)

(ABOVE)

L4

L5 (BELOW)

5

ELECTRICAL

CIRCUIT

C,

C:, C,

J Closed

L

R,

ferent ohmmeters

diodes are

the

It is recommended

be as specified.

T3

less you wish

determine

indicated

to procure.

on

It

if the substitutes

are standard parts,

Observe that the

the circuit diagram by their

is

further recommended

No. 69046 coil

not critical, they

distributed capacitance,

and

specifications

difficulty

no

The

adjustment

is most

circuits

assembly out

R10

(and

and Ro) should

permit

7

may

non-linear in

Do

not

to duplicate

forms as specified.

must have a certain

you should

given

-wise.

coil

of the

easily done with the phase

the

of

chassis.

7.

Fig.

Co 5.0V

T

(All resistor,

circuit jack

metering

henry

choke,

different

give

nature.)

that transformers

make any substitution

a

connections

-G

5V4

Fig. 6. Circuit

and capacitors

40 mf 450

volt electrolytic Rx volt electrolytic S,

mf 50

50

or

terminal posts

with 0-100

160 mils (UTC

ohm potentiometer

100

readings,

long series

suitable.

are

inexpensive,

color code.

you

that

While

if

and

you adhere

encounter

audio phase

-shift

The resistors

the

ratio of

bear

-.

Jr. Power

SSB

supply

-O

L,

diagram of the SSB Jr. power

Circuit Constants

*20% tolerance

to S. DPDT

mil meter

T2

T1,

of tests

The

and

indicated

are

use Millen

the coils

inductance

to

absolutely

R-20)

since

and

types

easy

un-

to

are

the

T

100,000, that is, 4

mined. If in

you used,

bridge. The now

through C10)

can be used. The most accurate will be described.

An audio

to 2750

is required,

be carefully calibrated by the method

later.

through a step-down

will serve

tiometer

Adjust

posite) voltages

tiometer. A steady

network

-shift sub-

R7

and

133,333 to

convenient frequency

acting

the

R.

potentiometer

obtain equal

temporary

12AT7

and connect to

ends

in

the rig as

ily short

respective center tap

Be sure to remove

time,

12AT7.

deflection

loscope

chassis.

First

shift

1

and

nections

J 300V.

-300V.

10.5V.

V.

-10.5

6.3

V.

6.3V.

supply

unless specified otherwise)

1000 ohm

..

SPST toggle

Power transformer, 350-0-350 at

volts at

6.3

amperes (UTC R-11)

to

doubt as

double-check

adjustment

consists only of

to their

oscillator

per second (with

cycles

plus an oscilloscope.

Connect

nicely)

the output

to a 1000 ohm

with the arm

the

a

as

vertical

with 500

provide leads

to facilitate checking.) One

position so

arm

appear

convenient

deflection

to the other and

voltages

double cathode

ohms

as shown

M, N, and

the double

circuiting

and

of course supply

Pins

amplifiers in the

common connection

connect

unit, and lead N to terminal A'. Connect leads

2

to terminal

are missing at this stage

the

3 and 8

lead M

amperes,

3

3, as closely as can be

to the ratio of

their value

of

the phase -shift network

setting

the four capacitors (C7

values.

proper

capable of

operation from 225

The

of

transformer

grounded.

audio frequency

may be used

voltmeter

(a

from each

in Fig.

cathode

the plate

of

the UTC R -38A

12AU7

should

the audio

(the

or

that equal (but

on each

with

lead

from

true center

-follower

9. (It

1

and 2

may use

follower

of

and

operating

connect to

oscilloscope,

for this

adjust

should be made

to terminal A

M. (Note

that

1

watt

switch

toggle

switch

75 mils,

volts

at

5.0

the resistors

on an accurate

methods

Several

good

waveform)

oscillator

described

oscillator

Stancor A -53C

2000

ohm poten-

half of

the poten-

signal

of

an

oscilloscope

job.

one end

the arm to

tap).

Set

circuit

cathode

will

with

each tube

the 6AG7

the dashed con-

of

using

to ground

be

convenient

clips at the

the

by

temporar-

transformers.

voltages

H

the

and

the oscil-

on the phase -

adjustment.)

12AT7

at this

for

3

l

deter-

should

op-

any

Swing

the

of

up

to its

the

and V

to

the

I

4

a

6

It

ELECTRICAL

CIRCUIT

HIGH

IMPEDANCE

MIKE

Fig.

(All

Cz, Cs

Cs,

Cs

Ca,

Rs

R2 R3 0

Adjust the

oscilloscope

slanted

frequency frequency

negligible

has

a straight

If the

the oscilloscope

adjustable

tiometer)

input

necessary.

At any

straight

capacitor

correction. shift

shifter.

on the

justment

"leaning" to

axes parallel

which

the appropriate

be

changed

ellipse

After

check

the oscilloscope

A, and then

on terminal

In general, always make certain

scope is used

double-check

scope are

terminal

readjust C7

the ellipse

circle.

should

when C7

horizontal and

to

produce

degrees when

at 45

of 490

will be

internal

line instead of a

display appears

latter

series

mounted at either the

terminal,

rate,

line at

may be needed to provide

Try values from

lead 1

from

Adjust the trimmer

oscilloscope. It

is made the display

one

to the

leans

the other way.

so that a

is

obtained

changing

(and

correct,

repeat

B.

in

(if the deflection

skewed, for

A'. If the circle changes

to

produce

(obtained by switching

Changing

give equal

is set correctly.

a line

CPS (an exact

described

phase shift

resistance (a

depending

the objective

CPS.

490

terminal

A

will be

side through

deflection

gain control

circle

at the point

the gain

if necessary)

by moving lead

the setting

a phase -corrected

instance) connect

an ellipse

lead 2 from

and

opposite

the

later).

to

control

Failure

R2

M

2

S. B.

CARBON

MIKE

B

8. Suggested

resistors

0.05 mf 400 volt paper R,

mf

8

450

2 megohm,

0 1

5

vertical gains on

about

oscillator

method

If the oscilloscope

the

narrow slanting ellipse.

is necessary to correct

it

externally

50,000

vertical

on what correction

is

here

In some cases a series

0.05 to

terminal B on the phase

to

of C7

noted that as this ad-

will shift from an ellipse

a circle or ellipse (with

axes) to an ellipse

desired

If

on the oscilloscope

instead of a "right"

of

correct

on

the phase

1

back to terminal

of C, with

4.5T06V. DC

microphone circuits for use

and capacitors

megohm, Mj watt

WI inches

display

to

0.0005 mf. Now

Circuit Constants

*20%

volt electrolytic R7 47,000

megohm, 1 watt T

by using an

or

3

is set to a

setting

of

will be

poten-

ohm

horizontal

watt Re

the

long

get a single

necessary

the

obtain a circle

necessary,

or

may

adjustment.

the oscilloscope,

shift

lead 1

back

that the oscillo-

manner. As

in

A'

plates

to

"half

to A

skew to

the oscillo-

lead 2

slanting ellipse,

a

-way" between

lead

and back again

the display

to

2) and a

to get symmetrical

12AT1

5

TC5

,(C4

6.3V.

T

AUD0

OUTPUT

with the SSB

tolerance unless specified otherwise)

ellipses (egg

tortion, either in the oscilloscope,

transformer, test

tortion.

lator

shift

for a circle as was done for

C10

outlined for that

is

Now connect lead M

to terminal set the oscillator

oscilloscope phase

to the junction

on the oscilloscope,

Repeat the

R -C

and set

except for a final

shift network. Connect

G, and

short circuiting

plates

If the

ternal compensation

in

an over-all

on the

1

to point

A, A',

the arm appears on the oscilloscope

a

250 CPS.

from 250

little

perfect

The audio band over which the

a plus or

is

225 to

that when

-shaped,

at

frequency

as

connect

before,

F.

a signal

leads

1960

to

and

case.

Connect leads

the

or

as low

of

above

Rs

pair,

the

C,.

and

oscillator for

check the

A to E.

and

T2, T3.

Be

connections

oscilloscope

frequency

-shift network.

phase

B,

C, lead 2

E, E',

and

of the potentiometer

Then,

as the

CPS

from

circular display at

2500 CPS,

to

one side to the

minus 1.3 degree

2750 CPS, or

other circuits are properly

move lead

frequency

shift

R9

300

AUDIO

OUTPUT

Jr.

470

Microphone

or other

cathode follower.

M

as before.

Use terminals

certain to remove

33,000 ohm,

to grid

display)

the

level

as possible

N

and

to terminals E and

and 2 to E,

CPS,

correct oscilloscope phase

1

to terminal G.

C7, using

to

terminal D,

1

and 2

at 1307

as before,

and

C,.

procedure

326.7 CPS. This

A to A',

and move

Adjust

for

D

adjustment

E to

between

did not

over the four

lead

require

check

can

To

do

to point

F,

N to

point

toward M

screen

oscillator

this

other,

440, 1225 and

deviation from 90

12

in

to 1

now

this,

G,

at a frequency of

frequency

circle will wobble a

passing

range. This means

ohm,

watt

3

ohm,

watt

M

watt

M

transformer

is due to dis-

oscillator, the

Conduct

to avoid

the

dis-

E',

the

set

oscil-

Adjust

the precautions

lead N

and

to terminal D,

CPS, correct

lead

C9

for a circle

the remaining

this

and C

time

completes

the phase -

of

E', B to C,

the

changes

frequencies used

be made easily

lead

D. Now shift

wobble

F

temporary

the

connect

M

to

12AT7

in

ex-

lead

to point

until a circle

is varied

through a

CPS.

2500

indicates

degrees

adjusted, a

1

7

AUDIO

Om

IWO

The

frequency ratios (just

PASSE

SHIFT

NET-

WORK

N

POT

previously

the

actual

mentioned)

values of

are far more important

frequency

resistance

as the

(or resistance)

ratio

than

used.

9. Audio

Fig.

sideband

worst points within

sion

network operation

performance,

explained The phase shift

justment, so

adjustment you

that the

monic of 490

CPS are all the

CPS,

3920

audio oscillator)

of

half, one-third,

both oscillators

Lissajous

assures

even though

suppression

will

ratio

It will

namely, 3920 CPS.

CPS frequency

the test oscillator

Use of

be

so the

great detail as an aid toward this goal.

in

network should

that

may seal the trimmers with

noted

be

12th harmonic

CPS and the 3rd

be

etc., of

feed

figures

observed.

a calibrating

that the

exact frequencies

the

R12

+

phase -shift network test

ratio of 39

range. The average

this

about 45

is necessary to obtain this

adjustment

you

when

that the

same as the

used

frequency

326.7

of

Thus, if a stable source

(such as a thoroughly

a

as

can be set

this reference frequency

an oscilloscope

frequency

AUD.

BAL.

¡t

/

is

possible at the

db

Proper phase

db.

procedures

never

satisfied with the

are

ratios are such

CPS,

harmonic

2nd harmonic of 1963

very

used

the

closely

and the

in

reference,

ratios used are correct,

DPDT

SWITCH

Iá (SB-REV.)

A.F.

INPUT

JACK

layout

suppres-

-shift

class of

have

been

require read-

cement.

the 8th

this

are

har-

of 1306.7

warm

frequency

to one-

resulting

manner

unknown.

/ \RI6

7 MOD.

3"\

4

Install the

remove

(3850

to 4000 KC) or

socket from

level,

set

counterclockwise)

out, drain should be about 35 to 40 under

this

current

the

power, adjust LI, reapply

oscillates. This may be

ceiver tuned to the

advance

oscillation ceases.

r

to assure stable crystal

simply adjust L1

Apply

jack of

flection

12AT7,

(pin

of

if

8) after making

phase -compensated at

Adjust

R12

to about

reasonably

lower the

Now

of about

bias

link

put

(no amplifier

I

\

' BAL.

1

phase -shift

the 6AG7

a VFO

L1 and L2 for minimum

condition with

drain is

the slug in

an audio signal

the

of the oscilloscope to

and the vertical deflection

RS

plug

on

Then

for

exciter and

produce

to

mid

-range.

low

audio signal

better).

in

the 6AG7, after

101..f,

L;

to the

used).

/ MOD.

/ LOAD

/ I

1---i-

\L3

R17

+ `

MOD.II

BAL

,

-

5x7"X2"

CHASSIS

network

output

tube,

a

supply

at not less

and

over

crystal

LI

with the

back

minimum total

certain

the

a

This test

volts is supplied.

vertical plates

Deliberately

3"

38

signal to

than a

apply

oscillator

the

45 MA,

power,

etc.,

checked by

frequency. Continue

crystal

the slug out

operation.

1225

of

connect the

a cathode (pin

to

that the

frequency of 1225 CPS.

circle on

should be made at a

level

checking

unbalance one

--+

/L4

7"

116

in

plug in

inductance

power.

MA at 300

turn off the B+

until

For

current.

CPS

the other cathode

the

(in general,

Connect

of the oscilloscope

P. A.

chassis,

the

crystal

a

crystal

the

10

volt (RMS)

(slug

The

current

volts

operating. If

the crystal

means

of a re-

operating

horizontal

oscilloscope

screen. Adjust

a few

VFO

to the

3) of

see that

to

until

turns

input

the out-

of

12

to

de-

the

is

the

a

the

1

L

8

2

8

/

GAIN\\

RI

+-IO\

i l

Í

I'

IPLATE

I +

I

l ) XTALOR

Am,/

3

4 16

15"

I I

L-+-

OSC.

.L.,/

SOCKET

Fig.

10.

1r12AU7

SOCKET

PHASE

2

1

4

" /

4 1

VFO

I"

18--I8

SSB

panel

Jr.

layout

R. F.

I"

(front view)

I

SHIELD

12"X2!"

I1,7

I

2

I"

I16 ~

P.A.

PLATE

IÍ6

I"

1"

1

--i

modulators by setting

Adjust

convenient

small

Adjust L3 for

and

this tuning

modulator unbalance

output

L4, in that order.

turning

adjustments

for zero output

noted that as

mum point

control.

Next apply

citer by

velope

in

such a

appearing on

modulator balance

adjustment

oscillation

between

L1 until stable

the 1225 CPS

adjust

the envelope,

cally. still

reduction,

play is seen.

With

ages applied

the audio

plate of

keep the

grounded

check

manner.

voltage (on

(C6)

Usually

can be provided

of two

half an

clipping off equalize

R16

adjustment

change.) Connect

from L6 as

Apply the

adjustment

ripple -free display

pacitor

tone

This completes

load may

drive a

Note

and L5 should be

constitute

principal effect of

lower

tuning

It

carefully.

signals are applied,

There first

is harmonic

assumed that a pure

for maximum

L6

first since other circuits are

at

finally

then

stage. Check

R1 to

advancing

be

will

direction

during

L2

L2 for

When a

further

etc.

L2 tuned

tone

the

common

to

the

If this

necessary

is

very little

pieces

inch or

the

R17. (Note:

and

before, and

necessary)

(if

check

and

now be

high power

that when

output

L2

quite important,

is

It

are two possible

carrier unbalance

is

speed. This deflection may

sweep

further increase

tune

is done it

may be necessary

the

Next remove

zero, and, by

R16 and

of

seen on the oscilloscope.

as

correct points are

the

becomes

1225 CPS audio tone

some

R1.

Adjust L2 (the

seen.

as

the output.

(R16

The crystal (if

of L2.

this

L1 tuning. If so, back out the

and

crystal operation

audio

minimum

checking

minimum

this

reduce

until

it is now

modulators. Temporarily remove

the

to

and connect

oscilloscope

connection of

chassis.

voltage

1225 CPS

on

is appreciably

arm of

the

between

conveniently

insulated wire twisted together for

of

so. Adjust

bit at

little

a

RF

signals appearing on

capacity, since both

of

the oscilloscope to

necessary

is

obtained before

modulator balance

the adjustment of

connected,

linear

changing frequency,

readjusted,

tuning adjustments of the

the

mistuning L3, L4, and L; will

efficiency. The

or

will be

degraded

may be noticed that when

the

distortion

R16

appreciably off

vertical deflection

deflection

of

L, for maximum

keep

to

successively

from overloading

tuning

again on

all

1247, balance the

Undoubtedly

to

successive alternate

reached the

sharper on each

RF phase control) the "modulation"

reduce

Remove

and R17), and repeat

the

used)

operation due to

signal still applied continue

"modulation" or ripple

modulator balance periodi-

point

ripple,

substantially ripple -free

a

to

Note

the arm of

R16)

L1

capacity is required, and

check

then

tone

in

installed.

was

therefore,

envelope develops

causes for

(carrier shift),

in

sine

is

is reached, adjust

adjust

then

to check

time

vertical deflection

the

arm of

the

the oscilloscope

the deflection

R17

lower than

more coupling capacity

and L2.

by making a

amount of

the

and

to approximately

a time

voltages

both

modulator balance.

check

make

L2 tuning to obtain the

the coupling

Remove the audio

SSB, Jr. A

the output used

or

amplifier.

since

principal

sideband

to adjust L2

this action. The

audio

the

wave

1225 CPS

of

-center.

at any

not

yet tuned.

(maximize),

output.

reduce

to

L5, L3, and

input

audio

modulators

It will be

mini-

to the

RF

some

tone,

check

may stop

interaction

slug

obtained. With

R12

L2

for more

the

r -f

R16.

Always

and then

in

similar

a

the

condenser

capacity

the

arms

after each

voltages

read r -f

output

whatever

(Ri6 and

dummy

Ll,

L2, L3,

these circuits

rig.

effect of mis -

suppression.

large audio

some ripple.

and the other

circuits. (It is

is

be

As

the

by

ex-

en-

the

on

to

on

to

dis-

volt-

first

this

by

of

will

slight

ca-

R1 ).

to

L4

The

be

very

used

_- o

Z.®

'11._

r

4

r

?..

..i'r

..

..-

Fig 11.

as the

by setting

effects

operation

pronounced) to

ripple (which is easily

balance controls

out, adjust

minimum envelope

should

probably

audio source or

observing

In

chronized

quency of

carrier ripple.

of

twice as

audio distortion.

show three

will

all these

simultaneously, so a

vised. In the

distortion is the principal

audio

identified

easily

When

rise to about 80 MA at

input. labically from

around 70

an oscilloscope to determine

use

levels. Overload

suppression, and so is to be avoided.

band cancellation

level are

peak

balance

level is

Peak

flattening of

higher

load, but the

making adjustments and later,

while

ing

the

The

sideband

which

out

sideband by tuning the

receiver with

talk test and

output.

frequency. If

is being generated.

band

accordingly.

It takes about 15 minutes

make

all the

experience

single-sideband

adjustment

the

simple to

actually

for not being frightened away

is that extremely modest equipment

reliable

Under

input

signal.) One

carrier

(where

reduce

R16

L2

slightly

be less

than

caused

by audio distortion, either in the

in

the audio

ripple,

from

the

about 122.5

Unwanted

many peaks,

times

distortions (and

sample SSB Jrs. tested,

at

feeding a load

speech

With

resting value of about

a

MA,

depending on the

will

adjustments performed

probably the

is best

made with

the audio

the

peaks

level

input

overload

rig.

sideband selector switch is

(upper or

switch

BFO supplying

its

tune

Then

tune the

the

adjustments described

is gained. Do not be frightened

because of a

procedure,

do,

and you

very

detailed and

'phone

communication

..

chassis view of the SSB Jr.

may isolate

balance

R17

generally

are

The

display

these effects

the "ripple."

identified when

and

(in conjunction

ripple.

5% of the

system

the oscilloscope

1225 CPS audio

to show

CPS

sideband ripple

so will second harmonic

and

Third harmonic audio

many peaks,

as

maladjustments) may

little

care

levels.

high

the

full level

input the

total

current

maximum

cause degradation

most reliable

little

signal

due

amplifier

to

used

can

be

when

condition should

lower) is

position corresponds

exciter

the receiver

receiver

voice

rises,

pitch

Identify switch positions

from

lengthy

since the

find

will

that the description is

complete.

from

yet

.

;0.

.

at

and

component,

or no

level

output

to

these two

high-level

With

moved)

remaining

of

the transmitter.

should

signal at a

ten cycles or so

etc.

thought

third

input

with a

waveform. Always

at about half

working

too,

used

generated.

carrier.

for normal

a

the

a "cold"

here after a

audio

most

are

the

carrier

the carrier

balanced

with RIO

ripple

is most

and

be syn-

show

will

distortion

Of course,

occur

is ad-

harmonic

and

current will

single

will rise syl-

MA to

60

operating

of the side -

Sideband

ones. Carrier

input.

audio

which causes

overload.

into a

be avoided

when operat-

to control

Find

upper

to

signal

on

Conduct a

speech

slightly

description of

lower

upper

side -

start

little

away from

adjustments

the

reason

most

Another

single-sideband

affords

developed.

for

fre-

is

tone

A

a

to

are

9

NOTES ON THE DESIGN

THE SSB, JR. RIG

Because the

new

by a

style modulator, it seemed designer, W2KUJ,

for

detail

readers of

The SSB Jr. is

just don't happen by

the design

space and

performance in any way. Easy adjustment for

optimum performance

The

phase -shift

this

tion of

culations were

The result is

tion.

has

only eight parts and

properly.

The

first (and

plained

put

done.

needed (absolute sistance

nature.

resistance

conjunction with a single reference frequency,

all

the preferred

wasted,

stable enough to hold

is a small

mer

circuit elements to change. In this

is

the phase

high

ance should be

must be minus 0.2857 equal to

matter

the two

CPS. curve

within

indicated in Fig 12.

in detail.

in

accurately

The

By making adjustments which involve both

sources

however, if

why precision

range

capacitors, since the trimmers are

obtained.

A

word

impedance

D. Incidentally,

of

networks

The differential

is

1.3

SSB

type of phase -shift network, and a new

the benefit

Ham News.-Lighthouse Larry

many

reduce complication

sort.

Two

problem

and capacity are obviously

and

of

method is

Jr. rig

explain these units

of the technically

a superbly simple rig. Such

accident,

new ideas

was a

network is

Literally hundreds of

made

along

a better

methods of adjustment are possible.

preferred

The

other one

measured values and call

here is

accuracy) since

capacitance values simultaneously

error are eliminated.

preferred.

the components used

their

resistors

of adjustment is provided by

about operating conditions necessary

-shift networks. The outputs must feed

circuits.

low,

and the voltage supplied

times the

voltage

the

the voltage

megacycles. The

symmetrical

degrees from

A,E

at

(yes, there

phase

about

A

slight error in setting

OF

is made

design

desirable to

however. Throughout

were employed

while not sacrificing

foremost

an example of simplifica-

the way

performing

is really very

has already been ex-

one)

is

to obtain the accuracy

All

values after selection. This

specified,

are

The

effective source

voltage supplied to

output of each section

from zero frequency to a

center frequency for

design

are actually two)

-shift

point

this

225 CPS to 2750

possible

have the

in

further

minded

to

point of

to

design.

laborious cal-

the final

network that

easy to adjust

obvious. Merely

the

standards

of

a different

And

this accuracy

almost

that is why

are

and why only

the

most

the

good stability

way

imped-

to

versus

frequency

and

holds

CPS,

the

things

of

likely

is

refer -

save

solu-

job

re-

not

trim-

for

very

A,E

800

ence frequency

band up

this

operating

voice communication.

poor quality

Another

the balanced modulator used

moments

few

cuit. Fig. 13

two germanium

cuits. First, suppose a high

volts is

signal,

resonant

tapped

same

direction. Point T naturally

because of

onant circuit,

G1. One half

the source, tending

direction. But at

positive potential

resonant circuit. The net

G, and G2 to cause current

cuit is a draw. No net voltage

circuit

at the source

in

balancing resistor

the

we have

its operating frequency.

go to get

Now, let

voltage at U

resonant

the

This, in effect,

frequency

cuit, with point S

bias voltage at U

the

current

direction. Under

other

will be

voltage at U is an audio frequency cuit is

unbalanced

frequency

audio

quency

to

as

in

is

sets

two

pair of diodes (such as G3 and G, of Fig.

feed currents into

to

frequency

audio tively 90° out of phase with the first, sideband cur-

rents caused by these signals flow

circuit in such a manner

onant

sidebands

of

single-sideband suppressed

a

case of SSB

The

Fig.

1217

of

characteristics of the diodes and to

couplings.

necessarily

modulators

such

complete

What

or at other frequencies, in general?

bands

radio

the

(3960 CPS)

or

down

band is

using

when

simplification

to consider what

shows just one modulator

diodes,

applied at point R. On

current passes

circuit

the phase

but, of course, no current flows

cycle later current

this time point T would be

currents

in the resonant

nothing,

but

imagine a

us

is

positive, G2

circuit,

unbalances the circuit and a

voltage

will appear across the

in phase

than G2, and the circuit is

in phase with

in

voltage

rate)

across the

of sidebands with

and

will result only in

by

the same

adequate-even

One need

this rig.

which

G1

and G2

frequency signal

through G2

and tends

inverting

pull point

to

because

of

result

to

frequency

and in G1

This

wait.

bias applied at U. If

will

and G1 will pass

with the

is negative, G1 passes more

this condition the voltage

that at

one direction or the other

and the resulting radio fre-

resonant circuit is

no

resonant

the

radio

frequency

percentage. The

not fear

deserves comment is

in SSB

Jr.

takes

place

with

the positive crest of

into

pull

to

tends

properties

passes through G, from

T in the negative

the "inertia" of the

of the

flow

in

the

appears

and

energy

and

circuit,

seems

like a long

pass

more

voltage

unbalanced

R.

Obviously,

voltage,

carrier.

circuit from related

through the

cancel

and to

is

Jr., it

function of the balancing resistors (R,;

2) is to equalize minor

Thus,

perfectly

composite

really

a

any one balanced modulator is

balanced, but

fed

with

balance.

as to reinforce one set

the other set.

carrier

high grade one.

differences

balance

polyphase signals

the

about operating SSB Jr. in other

frequency circuit

(Continued

design is for the

on page 12)

GI

shifting

desirable-for

reports of

Let's

take a

in

the

consisting

associated cir-

of a

the center

point

S in

to go negative

of the

through

at a

battle

between

resonant

across

this

is

dissipated

G2. Thus

but

none

way

current

current.

at

in the

if

the cir-

(at

actually

another

is

connected

respec-

result

In

in

out stray

of two

allows a

amateur

described,

meter

75

into

radio

R.

at

less

resonant

When

2)

sources

The

signal.

action

As

cir-

of

few

the

res-

cir-

far,

at

to

the

cir-

If

T

the

an

res-

the

and

the

not

is

10

Fig.

12.

200

Audio

USEFUL ~WC

300

500 E00

rnEOUENCT

1250

2000 3000

M O.P.S.

phase -shift network performance

Fig. 13. SSB

modulator

Jr.

circuit

s.

.!

tr.

F

Well,

volume

solved.

hundred

presented

maybe a

thing

that the bound volume

sent in "yes" votes will be

Evansville

Radio Engineers.

described

Norgaard,

this group, but

wire

we

so

inverted speech is that

hear on the

munication systems.

be

systems

an

low frequency side of a

receiver by

so-called

pitched

should hear the wolf

verted speech!

recognize it.

speech it is

thing.

Company" into

comes out sounds

kino."

inverted

the problem

Ham News

of

At the time this

you had sent

of

this evidence

bound

goes

along as expected I'll

recently had

I

-Owensboro

in

W2KUJ,

recording of

Whenever

like

easy to produce

Don or

demonstrate

to

short-wave

used a great deal,

At any rate, you produce

In fact,

upper

For

scrambling

of

sideband,

tuning

upper

sounds

until

practically

example,

Conversely, if you say the

speech

my boss had

is

well on its way to

column was

in

volume was a good idea. So,

this

he

sideband.

high in pitch and vice versa. You

I

to the

is

available.

notified

pleasure of

the

Section

subject

My

issue of the Ham

had

also

unable

was

Don's talk and

I give talks on

inverted speech, because it is

SSB equipment. As

with

strange sounding stuff that you

bands

least, inverted speech

At

although

are employed.

say, and

let

us

carrier.

it

the

on

The

-whistle coming through

guarantee that

can

become familiar

you

impossible to

if you say "General Electric

inverted

an

like

"Gwunree Oyucktruck Krin-

system, what comes out sounds like

"General Electric Company."

In other

if

speak

you

system, what comes out

As

example,

an

and

"eee wye"

further,

be nice

as

to be able to

you can

words,

new

this

"metz

says "oh

Don and I did.

form a new language,

language

is

wee"

pee

yeah."

We decided

recite the poem

about the

over two

written

"yes" votes, and

boss he

be notifying you

Those

personally.

of the

was the

been invited to talk to

to appear, so I

took it along with

when I

agreed that

if

you who

of

addressing the

Institute of

SSB Jr.

News. D.

made

single-sideband

you know

on transoceanic

now more complicated

inverted speech

placing

This

can

high

frequency side of a

effect

you would

speech

latter

into

an

understandable

means

But

you

used to

by taking

it

on

be

done on a

is

make low

to

inverted

with

recognize

system, phrase into

inverted speech

English.

"nuts to you"

go

can

it

that

Mary Had A

bound

being

every-

soon

rig

E.

me.

com-

the

in-

on

never

any-

what

an

and

even

would

Little

intense

job.

We

"Sweeping

in inverted

Lamb

concentration we succeeded

thought you would

the

Naarow hod Uts feeious yiz yelt

Arnd I view

No

yarng

A word of

inverted speech language,

alone. People

as it is!

It doesn't

realize

a

Even

happens readers are product -conscious.

had

a question

News (page

fluorescent lamps. I

length, and

might be

connected

Just

pointed out

such a

just

which contains

densers.

pany,

-37.

IF

This same

the

other

Electric

surround myself with

unit,

The reason this

thicker or

This News from

SSB

Jr.

formation as

velopments. may

it.

caution. When

have strange enough ideas

take

he has a bunch

that

I

though

by the

do

makes

that

in

5) regarding radio interference

referred to a

made, consisting of

in delta.

other

the

that two

special condenser, that is,

such concern

One

their

and

person continues,

company

Company!

way, carries the

heavier is that

not

is

going

now on, but

I

rig,

deemed

possible

It is possible

be twelve

speech,

and after

in

the decoding

like

see

to

Spectrum,"

yiz sla

so

O yutty

hair

bop naarow

pee bay.

uz

practising

make sure

an editor

know this,

me realize

of a

of sharp-eyed readers.

every so

For

September

the

answered

the

home-made

three

day one of my readers

manufacturing

0.07

three

interference filter

mf

is

Sprague Electric

making such

Oh well, looks like

more

G -E catalogs.

number

issue of the G -E Ham News

to

pages

it

be the standard

contains twelve pages.

in

this

it desirable

newest

on this

that one or two

long, if

the

this poem in

here it

is:

yarng,

snee,

this

that you

magazine

often

that the

example, VE1WM

-October, 1950 question

0.07

mf wrote

concerns

a single

delta -connected

has

and points

filters

is

25F214.

size of

case, because

to give as

of amateur de-

issues

material

an hour

of

yump,

poem in

of amateurs

Ham

are

long to

something

News

Ham

from

at some

filter

which

condensers

me,

and

make

unit

con-

Com-

number

the

out, that

the General I'll have

The

G -E

feels

Ham

the

of the

much in-

a year

warrants

to

--L'iyh

toserle

Jc 44,

1 1

GENERAL DESCRIPTION

Principal

vacuum

for

amplifiers.

Cathode: Heater Voltage

Heater

Envelope:

Base: B8-21

Base

Application:

type

in

use

Current

Material:

power

output stage of television

the

(A -C or

PHYSICAL DIMENSIONS

MAX

NIA

8-6

TECHNICAL

The 6AG7 is a metal

amplifier pentode

Unipotential

Coated

D -C)

Small Wafer Octal

Metal

0

65

Shell,

high

designed

video

3 Volts

6

Ampere

MT -8

8 -Pin

Phenolic

INFORMATION

6AG7

The

-

rent levels

Direct

DESIGNER'S CORNER

band, 3850 to 4000

to

not be obtained on

160. It's simply a matter of

the second

solder joint had cooled down, the rig

adjusted and

75 ohm dummy

procedures

some

than

procedure

the operating

using

ever had

is

tube

capable of

and

operating

features a high

Interelectrode Capacitances:

Plate

Grid to

Input 13 µµf

Output 7.5 µµf

Grid

Screen (Approx)

to

Grid to

The

Cathode

Heater

to Cathode (Approx) 10.7

that equally successful performance

think

unit

described in

people

for me

it

did

really does the

instructions,

If you

get

SSB Jr.

it,

you

in ham radio.-W2KUJ

(Approx) 5.2 µµf

(Cont.)

KC.

20

or

pictured in

one ever built. Ten minutes

was delivering 5

load-and I followed

a little longer

(after

either.

-tenth the fun out of building and

one

as I did in designing, building and

in for

are

the most

at high

transconductance.

is

There

this issue

10,

or

coil

no reason,

even

design.

watts peak power

article. Maybe it

the

read

to

all, I

wrote

job. I didn't

enjoyment you have

plate cur-

0.06 µµf

5.8 µµf

µµf

however,

on what is left

of

Ham News

the

them), but.1, 2, 3

would

after

the last

was perfectly

adjustment

will

instructions

peek ahead in

of

was

to

take

a

FROM:

HAM NEWS

1