Swann 400 Operation And Maintenance

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OPERATION

AND MAINTENANCE

S\^'AN

MODEL

40()

Osrrr

ELECTRONICS

Oceanside,

Ca

ilornia

OPERATION and MAINTENANCE

MODEL 4OO SERIES

S]NGLE SIDEBAND TRANSCEIVER

INTRODUCTION

The

Swan

Model 400

Single Sideband

Transceiver, together with its acces-

sorre6 and

optional

equiprnent, is

designed to be used in either

CW

or

SSB

mode6 on all

portionB

of the

80-,

40-,

20-,

l5-, and I0-meter

amateur

radio bands. Operation on

AM

(Single

Sidebaltd

rrith

Carrie!) is

possible

by

zero-beating the !eceived signal.

The Swan 400

generates

the single side-

band

signal by mean6 of a crystal lattice

filter,

and the

tran6ceive

op€ration auto-

matically

tunes the transmitter to the

receivedfrequency.

Provi6ions a!e

included

in the transceiver Jor ope!a-

tion on either

upper or

lower sideband,

and

provisiong for cohplete band

coveraSe are

included within the basic

Ba6ic

circuitry

of the single conversion

de6ign

has

been

proven

in thouaands of

hours

ot

opeiation of the very

popular

Swan 240

and 350 series

of transceivers.

Mechanical,

electrical, and thermal

stability

are exceptionally high, and all

oscillators

are voltage

legulated

and

ternperature

cornpensated.

PuBh-to-

talk opeiation

is

po6sible in

aU

installa-

tiolrs,

and

operation with a tv,/o-contact

microphone

is

possible

by use of the

FuDction Switch or the VOX acces sory.

The basic tlansceive! iB deBigncd

for

use

with

either the

Model 410 Frequency

Control Unit, which

provides

full covei-

age

of

all

portions

o{ the amateur

bandd,

or

with the Model 4068

Frequency Colttlol

Unit which providea coveiage of

all

phone

portiona of

the 80

throrrgh

l5 rneter bandE

and a 500 kc

portion

of the

l0-meter

band, With

a

suitable power

6upply,

operation may be

fixed,

portabl€

or hobile.

Power input on

all banda exceeds

400

Watts, PEP, on single sideband,

and

320 Watts DC input on

CW. The baaic

t

ranac e ive r includeB autoDatic gain

control,

(AGC)

automatic lirniting

control,

(ALC),

a electable

sideband,

grid-block

keying, calibrator, and speaker

Part

I

of

this Manual

covers

the basic

transceiver. Parts II and lfl cover the

Models 4068 and 410 Frequency Conttol

Unita,

!e6pectively. Part

IV

covers

the

recohEended

power

Bupplies, Model

ff7-XB or ll?-XC lor

ac

operation

and

Model

l4-ll7 for l2

volt dc

operation.

Models a!e

also available

for

230 volt

AC

oDeration.

O.cmr

ELECTRONICS

CORP.

I

MODEL 4OO

TRANSCEIVER

SPECIFICATIONS

FREOUENCY RANGES

Foll frequency coverage of 80, 40, 20,

I5,

and

l0 meter amateur radio bands

in

8

ranges oJ 500 kc each, as Iollows:

3,5-4.0, 7. 0

-7.

5, t3.85-14.35, 21.0-

2r, 5,

28. 0-28. 5, 28. 5

-29.

0, 29. 0

-

29.5, 29.2-?9.1rnc.

Model 4068

Frequercy Contlol Unit

Full

phone band coverage of 80, 40,

20,

and l5 meters,

plus

a 500

kc

segment of l0 lneters, as

follows:

3

.

8

-4.

0, 7

.

r

-7

.

3

,

14. r5

-r4.35,

21.25

-21.45,

28. 5

-29,

0 rnc.

POWER INPUT

bands.

cw

-320

Watts DC input

on

all

bands,

AM

(Sinsle

Sideband

With Carrier)

IZ5 Watts

DC input

on

all

bands.

DISTORTION

Distortion

products

downat

least30 db.

UNWANTED

SIDEBAND SUPPRESSION

Unwanted

sidebaDd downat

least40 db.

CARRIER SUPPRESSION

Carr:ier

suppression at Ieast 50 db,

RECEIVER SENSITIVITY

Less

than 0.5

Inicrovolt at 50 ohms

irnpedanc

e for 6ignal-plus-noise

to

noise ratio

of I0 db.

AUDIO

OUTPUT

AND RESPONSE

Audio

output through

built-in speaker

approx.

3 watts

to

3,2

ohrn load.

Response

essentially

flat 300 to 3000

cps

on both teceive and

transmit.

METERING

PA Cathode

current, 0-800

rrla on

tran6mit

S-Meter, 0-?0

db over 59

FRONT

PANEL CONTROLS

Function Switch,

Sideband Selector,

Phone-CW, AF

Gain, Bandswitch'

Mic. Gain,

Carrier

Balance,

PA

Plate

Tune,

PA Grid

Tune, PA Load Coarse,

PA

Load Fine, VOX-PTT

REAR

PANEL CONTROLS

AND

CONNECTORS

Bias Potentiometer,

Grid

-Block

CW

key

jack,

Jones

plug powe!

connecto!,

VOX

Connector,

F requency Control

Unit Connecto!,

Antenna, S-Meter

Zero,

SPDT

Relay

Terrninal.

FREOUENCY

CONTROL

UNIT CONTROLS

Bardswitch,

Main

Tuning, RF Gain

2

VACUUM

TUBE COMPLEMENT

Vl

-

6EW6 VFO Amplifier

YZ

-

IZBE6 Transrnitter

Mixer

vJ

-

ou.t\.o.urrver

V4

-

6HF5 Power Amplilier

v)

-

bill

)

rowe r Arnprlri

e r

V6

-

IZBZ6 Receiver

RF Amplifier

Y?

-

IZBE6 Receiver

Mixer

V8

-

6EW6 First IF Amplifier

V9

-

l28.q.6 Second

IF AmPlifier

Vl0

-

IzAX7 Product

Detector/Receiver

Audio

6BN8 AGC Amplifie

r/ Detector

6GK6 Audio Output

l2I}A6

I00 KC Cryslal Calibrator

7360

Balanc€d Modulator

12I}A6 Carlier O scillator

I ZAXT Mic.

Amplifier

/

Transrnit

Vl?-

OAZ

Voltage

Regulator

DIODE AND TRANSISTOR

COMPLEMENT

QI,i

2N70

6 Oscillator

QZ*

2N706

Emitte r Follower

D40l TS

-2

ALC

Diode

D4oz TS

-2

ALC Diode

D60l TS

-2

S-Meter

Delay

Dl?01

IN29?4A Zener Voltage Regulator

i.

Transistor

cornplement identical for

eithei Model

4I0 or Model 4068

Frequency Control

Unit.

TRANSMITTER

OUTPUT IMPEDANCE

Wide

-

range Pi-network

output matche8

antennas

e6sentially resistive at 20

to

300

ohms impedance with

provision8

for

both coarse and fine adju6t,

POWER REOUIREMENTS

vtr-

ylz-

vl3-

vl4

-

vl5-

vl6-

Filarnents

ReIay

Bias

Medium Voltage

High Voltage

DIMENSIONS

12.

6 volts, 5.5 amp

12 volt6

dc, 250 ma

-

I l 0 volts dc, 100 rna

2?5 volts dc, 150

ma

800 volts

dc, 500 rna

Model 400 Transceiver

5-l/2

ir'. high, l3

in. wide, IL in. deep

Model 410

Frequencv Control

Unit

5-l

lZ

A,

t^rgn, 6-l/2 in. wide, I I

in.

deep

Control Unit

3

in, high, 1-3/4ir,.

wide, 5 in. deep.

WEIGHT

Mode] 400

Transceiver:

Model 410

Frequency Control

Unit

Model 4068

Frequency Control

Unit

t7lb,

'-

91b.

3 lb.

Sinele Sideband

Su

Car!ie!

400 Watts

PEP,

PART I MODEL 4OO

TRANSCEIVER

CIRCUlT

THEORY

GENERAL

DISCUSSION

The Sr

ran

400 Transceiver

plovides siagle

sideband,

Buppressed

ca!rier

tran€ceive

operation; and

generates the Bingle

side-

band eignal

by mean6

of a crystal

lattice

filte!.

To

permlt

a

logical diEcussion

of

thi6 lnode

of

operation, certain

definitions

ate

nece€5aly,

In a

normal AM signal

(double

dideband

with

carrier), a

radio

frequency

i6 modulated with

an audio Jre-

quency

signal. This

is considered

by

many

to be merely

a ca8e of varying

the

amplitude

of the carlie!

at an audi.o

rate.

In fact,

howeve!,

there are actual.ly

side-

band

frequencies

generated

which

ale the

!eBults

of mlxing

the RI. and A!' 6ignal3.

These

sideband3 are

the suh ot, and

the

difference

between

the two hetelodyned

6ignals. For

detection by means

of

conventional

diode detectols,

the two

sidebands are

mixed with

the carlier to

detect

aDd to

demodulate

the

audio

intelligence.

This inef{icient hean€

of

transrnis

sion

p€rrnits

only approximately

25

per cent

of the full tlanahitted

power

to

b€ used

to tras6lnit intelligence.

There

are

other attendant

drawbacks,

also.

The

bandwidth

of the transmitted

6igna1 is

on the order

of 6 kc, while

the

actual

dehodulated audio

is 1e66 than

3 kc. The

lesult i. very

limited use

of

the band, and

over half

of the allotted

frequency

range iB unuaable

becauge oI

heterodyne6, ioterference,

and congestion.

In

the single sideband,

suppressed carlier

rrode of transhioeion,

only ono sideband

of the Rr. and AF heterodyned

signal is

tranBmitted,

the other sideband and

the

carrier being Buppressed

to a level which

effectively

permits using only the audio

intelligence bandwidth.

This results in

increasing the transrnission

efficiency

many times

ove!,

and

pellnits

an effec

-

tive doubling

of the use of the allocated

frequenciea.

It

rnust be

remerrlbered that in the single

aideband,

suppresned calrier mode

of

transhission, both

the unn,anted side-

band and

the calrier ale

oaly

Buppressed,

not entile1y eliminated. Thu6, with a

transmitted sigDal frorn a

transmittei

with

40 db sideband

6uppression, the

other,

or unwanted sideband is

pleBent,

and it i6 transrnitted,

but its leve1 is

40 db below the'wanted

sideband.

When

3

I MODEL,lOO

TRANSCEIVER

A.

Circuit Theory (cont)

BLOCK

DIACRAM, RECFJIVE

B],OCK

DIACRAM,

TRANSMIT

FIGURE

3

CRYSTAL FTLTER,

TYPTCAL

CHARACTERISTIC

I

MODEL 4OO

TRANSCEIVER

A. Circuit

Theoiy

(Cont)

this

signal is

leceived at a

level of 20 db

over 59. the

unwanted sideband

will be

pre6ent

at a

leve1 oI approximately

55.

The sahe

is true of carrie!

guPPression.

With carrier

suppression

of 50

db, and

a

signal

level of 50

db over 59,

carlier

will

be

present at a level

of

approxirnately

53

to 54.

In

the

Model 400

Transceiver,

the

single

sideband,

suppressed

carrie!

signal is

generated

by the crystal

lattice

filter

method.

Refer

to

the schematic

diagram'

and

to FiSule6

I and 2,

Block

Diagrams

SIGNAL

CENERATION

In

the TRANSMIT

position

(i.

e.,

when the

pu6h-to-talk switch on

the lnicroPhone

i3

pressed ot when the

Function Switch

is

moved to TRANSMIT),

the transmitter

portion of the

transceivel

is

activated,

and

generates a sinSle

sideband,

suppressed

ca!!ier

signal

in the follow_

ing manner:

Carrier

is

Senerated

by

Vl5,

Carrier

Oscillator,

which

is a Pierce

oscillator, with

the

crystal oPerating

in

parallel

resonance.

This stage

operates

in both th€

ttansoit

and leceive

rnodes.

When

transmitting,

the RF

outPut oJ the

oscillator

is injected

into

the control

grid

of the

Balanced

Modulator, VI4.

This

balanced

modulato!

is

a beam deflection

type, and

opeiates

5imila!

to a

cathode

ray

tube

in that

the elect!on bearn

frorn

the

cathode

i6 deflected

to one

outPut

plate or the

other by

the charge

aPPear_

ing

on the deflection

Plates.

The

RF

energy

fed to

the cootrol

Srid

of the

balanced

modulator appeals

on both

plates

oI the

output, in

the absence

of

signals

to the

deflection

plates.

The

two

output

plates feed

the carrier

to

Trans_

forrner

Zl40I

in

push

PuU,

and the

two

RF

signals

cancel

each other

out in the

output

ot the

transforn:rer.

The

defl€c

-

tion

plate reference voltages

are

adjusted

bv

means

of

the ca!rier

balance

control

60

that

with

no audio,

the

RF being

Ied

to

the output

plates will cancel

out' and

the

output lror'j.

Zl40l

will be

zero,

Audio

from

Microphone

Amplifier

Vl6

is superilnposed

on one deflection

Plate,

thereby

unbalancinS

lhe

modulator,

and

the

two sideba$ds

resulting

froh

the 3uln

and

diff€rence

frequencies

of the audio

and carrier

appear

as

a double

sideband,

suppressed

carrier

si8na1

in the

outPut

o{ Translormer

Zl40l.

The catrier

suppression

is aPproximately

50 db.

The

double

sideband,

suPPressed

carrier

siSnal is

then couPled

to

the crystal filter'

which

euppreeees

one sideband,

and

permit6 the

other sideband

to be

fed to

the

First IF

Amplifier,

V8.

The carrie!

frequency

crystal

alrd

the filte!

crystalg

are

selected

so that

in the LSB

poBition

on 4O and

8O hete!s,

the

sideband

siSnal

is

Senelated

with

a calrier

frequency

of

5l?2. 8

kc, and

this siSnal

\till

fall

within

the

bandpass

of the filt€r

6uch that the

lower

6ideband

will be attenuated

by at

least 40

db. See Figure

3.

On the USB

positron of 40 and

80 meiers,

the carrier

clystal

is 5I?6.8

kc, which

positiond

the

double

6ideband

signal

on the

other side

of

the response

culve

oJ the filter,

attenuating

the upper

sideband

by at

Ieast 40

db. In

lhe single

conversion

mixing

proces6, these

sidebands

become

inverted.

OnZ0, 15, and

l0 meters,

where

oPera-

tion

i6

generally on upPer

sideband,

the

siBnaI

i6

generated with

the same

carrier

crystal

used in

generating

the lower side-

band

on 40 and 80

meters.

The five

crystal

filter used

in the

tranaceive!

results

in an

improved

reaPonae

characteristic

on

the low frequency

end

of the bandpass,

and

advantage

is

taken

of this

eflect to

provide better sideband

suppression

on the lnost

used 6ideband

for

each

frequency

band,

I IV{'IEL

4OO TRANSCEIVER

A. C

i.cuit Theory

(Cont)

The single sideband, suppressed carrier At the sarne tirne,

one d€flection

plate of

signal Jrom the First IF Amplilier

is fed the balanced rnodulator is grounded, un-

to

the Transmitter Mixer, V2, u'here balancing

the modulator and allowing full

signals

Irom the VFO Amplifier are

carrier input for tuning

puiposes,

A

mixed,

and the resultant signal

at

the

similar

procedure

is followed in the CW

final

transmitted frequency is alnplified

position

of the Phone

-CW

switch,

to

allow

through

the Transrnitter

Mixer,

the

full carrier

output

duiing

CW operation.

Driver,

V3, and

the Power Amplifiers,

During

CW

operation the cathode of V168

V4 and V5.

The signal from the

VFO

i6 opened from grotrnd, cuttrng ofI the

Amplifier iE initiated in the

particular

tube.

This

allows CW

operation with no

Frequency Control Unit being

used. The danger

of pickup of

audio

through an open

signal frorn the Frequency Control Unit

microphone, Attempts to operate

on

CW

is routed to the VfO Amplilier, and

on by keying the lnicrophone

jack,

and

insert-

40 and 80 rneteis,

is

subtractively

ing

carrier,

are

not recommended.

mixed with the single sideband signal

from

the

IF

AmpliIier. On

20,

15, and RECEM

l0 meters, the frequencies are additively

mixed, resulting in

output on the opposite In RECEIVE

position, or

at

any time when

sideband,

the transrnitter is not in TRANSMIT

or

STANDBY, all

circuits used in transmitting

When in TRANSMIT,

thc

gain

oI the First

are disabled throrgh the

relay controlled

II Amplifier

is controlled

through the

circuits, thc relays being energized Ior

Automatic

Limiting Control network

transmitting, and de-energrzcd

for receiv-

D40l-402,

etc., to control the

gain of ing. Rclay K2, when de-energized, allows

the stage in response

to the

average

in- signals

frorn the transrnitting tank circuit

put power to the

power

amplifiers. This and

antenna to be ted to the Receiver RF

ALC system will

cornpensat€ {or any Amplifier, V6,

where thcy are amplilied,

extremely strong

input signaLs, but does

and then {ed to the control

giid

oI

the

not completely

eliminate the necessity

of

Receiver

Mixer,

V?.

The local

oscillator

proper

adjustrnent

ol the Mic. Gain

signal from the

VFO

Amplifier is

now

Control.

Although

this feature wil] used

to heterodyne the received frequency

prevent the transmitter Jroln flat-topping

to the IF frequency,

either upper or

lower

and spurious

ernissions, considerable sideband.

A11 IF arnplification is

distortion

may

occur if the Mic.

Gain

accomplished at this Jrequency, nominally

control

is not

properly

adjusted. Refei 5l?4.5

kc,

and

in the Product Detector

to Operating Instructions.

Vl0A, the IF lrequency is heterodyned

with

carrier frequency

generated

by

TUNE AND CW OPERATION

Carrier Oscillator, VI5, to

res$lt

in

detection of the sarne sideband used to

Normally,

the Jrequency oJ the carrier

generate the transmitted signal. It i6

oscillator

is approximately 300 cps out- thus

not possible {or the transceiver to

side the

passband of the crystal lattice receive a 6ignal on any frequency

other

filter. In TUNE

position,

to enable the than that to which the trarlsrnitter is tuned,

transmitter

to be tun€d to the maximum nor to detect the wrong sideband. This

power output condition,

the frequency of simple single conversion de6ign results

the carrier

oscillator is moved approxi- in an extrelnely

stable signal, and an

mately 500

cps to

place

it well within image

response down more than 80 db.

the

passband ofthe

cry6tal lattice filter,

Since

the

VFO

frequency from the

1 MODEL 4OO

TRANSCEIVER

A. Circuit

Theory

(Cont)

Frequency Control Unit is deterrnined by

circuit elements which are far removed

frorn

any heat source,

and

the

voltage

regulation

is very

precise

to

the transis-

tor oBcillator,

frequency

stability is

extiemely

good.

Automatic Cain Control,

(AGC)

is

pro-

vided by the AGC Amplrfier/Detector,

VlI, which

provides an AGC signal for

control of

the

gain of

V6,

Receiver RF

Amplifier, V7, Receiver Mixer, and V9,

TRANSM]T AND RECEIVE SWITCH]NC

AII

transmit and receive ewitchrng

i6

performed by relays Kl and K2. In

TRANSMIT

position, only those tubes

that opelate

in the transmit mode a!e

operative, aU

others being biased to cut-

off through the relay contacts, In

the

RECEM

position, with the relay

de-

energlzed, the

tubes that are norhally

used

only in tran3mittiDg are

cut oft in

the sarne

manner. Relay K2, which

when de-energized

feeds signals

frorn

the output

pi-network to the receiver,

and

is used also

to

control

any external

switching.

In the TRANSMIT

po3ition,

the meter

indicates the

cornbined cathode

current

oI the two Power Amplifiers.

In

the RECEM

po6ition, it indicates the

voltage

acro6s R902 in the

cathode of the

Second

IF

Amplifier, V9,

which is

iDversely

proportional to the AGC volt-

age

used to control

the gain of the tube.

Thus the S-Meter

reads le{t to right on

transmit, and

right to left on receive.

POWER RATING

The Swan

400 is capable

of

400

watts,

PEP

input under steady

two-tone te6t

.onditions,

when operated with any of

the

recommended

power

supplies. The

peak envelope

power,

when voice modu-

lated,

i5 considerably

more, tyPically

500

\ratts,

or rnore,

Recommended

power

supPlies

produce

a

no-load

plate voltage

ol approximately

925

volts. Under

TUNE conditions,

or

CW

operation,

this voltage

rnay drop to

as Iow as

?20 volts.

Under steady state

two-tone

modulation,

the voltage will

drop

to apploxirnately

750 volt3, If

Power

Amplifier

idling current

is 50 rna, and

two tone

plate current,

ju8t

before

flat-

topping, is

3?5 ma, the

peak two

-tone

cullent will

be 560 rna.

The PEP input

wiu then be

?50 volts x 560

ma

=

420 watts,

Under voice modulatio!,

beca[rBe

average

power i6 considerably

Iess' the Pow€r

Amplifier

plate

and screen

voltages

will

be mainta)ned

hiSher, even during

voice

peaks, by the

power supply

filter capaci-

tors. Peak voice

plate

cu!rent

will thele-

fole

also be higher

than with two-tone

test

conditions. Under

typical

operatinS

conditions,

peak

plate current befole

flat-topping

will

be 625 lna at 800 volts,

to

result in a

peak envelope

power inPut

of 500

watt8.

Reading6

ol cathode current

would not

reflect this 500 watt

power inPut' how-

ever, because

oI the dampiDg

in the

cathode current

meter. The

meter damp-

ing

i6 such that

the rneter i3

unable to

respond to variations

oJ

cathode

current

in the audible

range.

Cathode current

readings under

normal voice

input, should

not

exce€d approximately

I50 to 175

rna.

POWER

AMPLIF]ER

PLATE DISSIPATION

There

is olten a mi

s und€ r standing about

the

plate dissipation

of tubes

operated as

AB

ampliliers

under voice modulation,

In

the Swan 400,

while in the

transmit

position, and with

no

modulation'

the plate

voltage will

be 890 vo1te,

the

plate current

50 rna, and

the

power

input

will be 50 watts.

I

MODEL

4OO TRANSCEIVER

A, C ircuit

Theory

(Cont)

Authorities

agree that the

average voice

power

is l0 to

20 db below peak

vorce

power.

Normally

some

peak

clipprng in

the Power

Amplilier

(

an be tolerated,

and a

peak-to-average

ratio oJ

only 6 db

rray

sometimeg

occur. unde!

such a

condition,

the

average

power

input

will

be

125 \ratts,

and

plate

current will be

about 156 rna.

With an average Po'\r/er

Amplilier

efficiency of

55

per

cent,

plate

dissipation

wilt be

57 watts, or 28,

5

watts

per

tube. The 6HF5

is rated at

28 watt6 continuous duty

cycle in normal

TV service.

Thus it can be

seen that

under normal

operating conditions

th€

PA tubes in

the Swan 400

are

not

being

driven

very

hard.

Only dLrring

the tune

up is

there any need

to exercise caution

by lirniting

the length of

time the unit

is

held

in the TUNE position

to about

30

seconds

at a time,

B.

INSTALLATION

CENERAL

The

Swan 400 traogceiver has

been

designed to

provide

the

utmost in ease

of

operation, stability, versatility,

arld

enjoyment.

Maximum enjoyment Irorn

your

Swan

will depend to

a

great

extent

on the installation. For

fixed station or

portable

use, operation

with the

Model

I I?XB or I t?XC power

supply

provides

a

(

ompa( t dr rdngement with

maxrrnum

ease oI

op< ration.

AII swrt( hrn8 is

performed in the transceiver.

For

mobile installations, the Model

l4-I1?

supply

provides switching

ar rangements,

and speaker

output rnay be

fed through

the car broadcast receiver 6peaker,

POWER SUPPLY

The

Swan

Models II?XB or

ll?XC

power

Eupplies

provide

aU neces6ary

voltages

required by the transceiver.

The

supplies corne equipped

with a

pre-wired

plug

and

cable,

all !eady for plu8ging

into the transceiver, The

Model l4-II7

supply lor mobile operation

includes

all

necessary

cables,

conn€ctor plug,

luses,

and installation

hardwa!e.

The

Jones

plug

lor connection to the transcervet

ts

furnished with

the unit.

8

Power requirements for the

Swan 400

are shown

in

the

following table. Pin

connections

to the Jones type power

connector

are also listed as an aid in

connecting

other brands or horne-brew

power

eupplies.

+AC

or

DC

EXTERNAL

SPEAKER CONNECTIONS

Audio output from the transceiver is

pro-

vided

at

12 of the

Jones

plug.

The

other speaker lead

goes

to the common

chassis ground

at

pin 6. Output impedance

is between 3 and 4 ohms. For mobile

installations, the car broadcast speaker

rnay be used, in ]vhich case a DPDT

Pin Nornrnal

Minirnum Maximurn

High

Voltage

8

800 vDc

5OO

MA

600 VDC

1000 vDc

lli. Powe r

Mediurn

Voltage

t0

z? 5 vDc

I50MA

225 VDC

325

VDC

Bias

Voltage

3

-

110 vDc

IOO MA

-100

vDc

-I30

VDC

Filament

Voltage

4

12.6 Y'N

5.5 alnp.

II.5V

t4.5 v

Relay

Voltage

5

r2 VDC

250 MA

IO

VDC

14. 5

VDC

I

MODEL 4OO

TRANSCEIVER

B. Installation

(Cont)

seLector

s\ritch should

be installed

to

select

either the broadcast

receiver

or

tranaceiver

output.

MICROPHONE

The rnicrophone input

is designed lor

high impedance

rnicrophones

only. The

choice

oI microphone

is imporlant,

for

good speech

quality, and ehould

be

given

serious

consideration.

Th€ crystal

lattice filter in the

transceive!

provides

all the

restriction necessary

on audio

response, and

fr.rrther

restriction in the

microphone

is not required.

lt is more

irnportant

to have a mic

rophone with

a

smooth,

flat response

throughout

the

speech

range.

The microPhone

PIug

should

be

a

standard

l/4 in. diamete!

three-contact

type. The tiP

connection

is for

push-to-talk

relay

control, the

ring connector

is for

the microphone

terminal,

and the

sleeve is for

the com-

rnon chassis

ground. The manufactu!elis

instructions

should be

followed in

connect-

ing

the lnicrophone

cable to the

Plug.

With

many

microphone6,

the

push-to-talk

button

rnust be

pressed to make

the

rnicrophone

operative,

even

though

the

panel function

switch

i5 in the transmit

position.

This leatule

rnay be

disabled,

iJ desired,

by opening

the microphone

case

and

permanently

connecting

the

contacts

which

control the microPhone.

ANTENNA

Any

of the

common antenna

systems

de-

signed

for uEe

on the high frequency

amateur

bands may

be used with

th€

Swan

transceiver,

provided the input

impedance

of the transmission

line

is not

outside

the capability

ol the

pi-output

matching

network, An antenna

which

reflects

a standing wave

!atio on 50

or

?5

ohm

rransmiss;on

line, below aPproxi

-

matety

4:

I at the

proposed

oPerating fre

-

quency,

or a

system

tha! results

in a

transmission

line iiput

impedance

that

is essentially

resistive

and

between l5

and 500

ohlns

will take

power from

the

transceiver

with

little ditficulty.

If

tuned

open-wire

trallslnission

line

is used to

excite the antenna,

a suitable

antenna

tuner should

be used

between the

trans

-

ceiver and

the antenna

to

Provide

a

reasonable

irnpedance

match

between the

unbalanced

coaxial

output and

the balanced

open-wire

line. Methods

oI constructing

and

operating such

tuners ale described

in detail

in the ARRL

Antenna Handbook,

and sihilar

publications. Fo! oPeration

on the 75- and

40-meter

bands, a simPle

dipole antenna,

cut

to resonate in the

rnost

used

poltion oI the

band' will

Per-

forrn satisfactorily.

For operation

on

the

10, I5, and

20 meter

bands, the

efficiency

of the station will

be

Sreatly

increased

if a

good di!ectional

rotary

antenna is

uBed.

MOBILE

ANTENNA

Mobrle

antenna

rnstallations are

critical,

since any

mobile antenna

fo! use

on the

high frequency

bands

repre6enta a

num_

ber

oI cornpromiBe6.

Many alnateurs

Iose the

ef{iciency

oJ their antenna

through

improper

tuning.

Points to remernber

about the

rnobile antenna

used with the

Swan

400 are:

I, The

rO"

o{ the antenna

loading coil

BhoIrId

be a6

high as

possible. There

are several

comme rcial

models

available

which

use high

"Q"

coils,

including

the Swan

Model 45 and

Model

55 5

band

"Swantennas.'

2.

The loading

coil must be

caPable oJ

handling

the

power of the Model 400

without

overheating.

In TUNE

position, the

power outPut of the

transceiver Inay

exceed 250

watts.

wide spaced,

heavy

wire loading

coils are

e s sential,

9

I

MODEL

4OO

TRANSCEIVER

B. Installation

(Cont)

3.

4.

The

SWR

bridge

is a

useful in6tru-

ment,

but unfortunately

it is

quite

often

mis

unde rstood

and

overrated

in

importance.

Basically,

the SWR

bridge

wil.l

indicate

how closely

the

antenna

load imPedance

matches

the

transmis

sion line,

With

long

transrnission

lines,

such

as

will be

used

in many

fixed

station

installa_

tions,

:t

rs desirable

!o

keeP

tle

impedance

match

fairly

close

i.n

order

10 limit

power loss.

This

is

particularly

true at

the higher

fre-

quencies.

The

longer

the llne,

and

the

higher

the frequeDcy,

the rnore

important

SWR

becornes,

However,

in mobile

Installations

the trans-

rnission

line seldom

exceeds

20

feet

in length,

and an SWR

oI even 4

to I

adds

very

little

to

Power

loss'

The

only time

SWR

will

indicate a

low

figure

is when

the

antenna

presents

a

toad

close

to 50

ohrns,

bot nany

mobile

antennas

will

have a

base

impedancc

as

low as

l5 or 20

ohrns

at

their !esonant

frequencY.

In

euch

a

case, SWR

wiU

indicate

3

or 4

to I, and

yet the system

will

be

radiating

efticiently'

The

really

important

tactor

in

your

mobile

antenna

i5 that

it shoold

be

carefully

tuned to

resonance

at the

desired

frequency.

The JallacY

ln

using

an SWR

b!idge

lie6

in the

{act

that

it is sometimes

Pos

sible

to

reduce

the SWR

readin8

bY detuning

the antenna.

Field strength

may

actually

be

reduced

in an effort

to

bring

SWR

down, Since

tield

strength

is the

Prirnary

Soal'

we

recornmend

a

FieId Strength

Meter

Ior

antenna

tuning.

I'or antenna

aajustments,

the Swan

400

rnay

be loaded

lightlY

to about

lO0 !na.

cathode

current

in6tead

of

the

us\ral 500

rna. This

wiU

limit

tube dis

sipation

duling adjrstrnents,

and

wilt also

help

reduce

interler-

ence

on the frequency.

In

any case,

do not

leave

the transrnitter

on

for

very

long

at one

time. Turn

it on

just

long

enough to

tune and

load,

and

get a Jield strength

reading.

Start

o\rt with

the antenna

whiP at

about

the center

of its adjustment

range,

Set the

VFO

to the desired

operating

Irequency

and

then adjust

P.

A, TUNc

Jor

diP, and

P. A'

LOAD

for

I00 ma,

Then

observe

the

tield strength

reading.

The

Field Strength

Meter

rnay

be set

on top oI

the dash,

on the hood,

or

at

an elevated

location

sorne

distance

from

the car.

Change

the whip

length a

half

inch,

or so, at a

time,

retune th€

P.A.

for

I00 rna.

loading

each time, and

check

field strength.

Continue

this

proL edurc

until the

point of maxirnum

Iield

strength

is found.

This

adjust-

ment will

be Inost

critical

on

75

rneters,

somewhat

le66

critical

on

40,

etc., until

on

l0 rneters

the

adjustment

will

be

quite broad.

AJter

tuning

the antenna

to

resonance'

load

the P. A.

to IuIl

Power'

5.

t0

I

MODEL

4OO TRANSCE]VER

B. Installatiob

(Cont)

CONTROL

FUNCT]ONS

Functions

of the

ON.OFF

SWITCH

FUNC TION

SWITCH

Standby

Calib!ate

Rec eive

Transrnit

T une

Contlols

the varioLls

modes

of operation

of

the tran6ceiver.

DC

Supply

-

Power

to the

transceiver

is disabled.

AC

Supply

-

All voltages

except medium

voltage

are

suPplied.

AC

Supply

-

Plate

and

RF CAIN

(In

F

requency

Control

Unit)

MAIN

TUNING

PA GRID

various

contlols

are as

follows:

Controls

main

po\rer

to

CARRIER

the transceive

!.

BALANCE

Controls

potentiohete!

R1405

in the

balanced

modulator

defl

ection

Plate

circuit, and

pe rmitg

balancing

of the carrier.

Controls

variable

!esistor

Rl80l

which

is cornrnon

itr

the

cathodes

of

V6,

RF

AmpliJie

!, V8

l st IF Am

-

plifier and V9,

znd IF

Am-

plifier, controlling

gain

of

these

stages.

Controls

potentiomete!

Rl20l

in gtid circuit

oI

vI2 AF

Output, and

varies

the

gain ot the final

audio

output amplifie

r,

Controls C

I804 in frequency

deterrnining

tank circuit

oI

!. !equency

Control

Unit.

Controls

CIA and CIB

in

plate tankE

of transmitte!

Inix€! and driver.

Controls

C4l

? in pi-network

to tune

linal

power

arnpli-

tier

plate to

resonance.

Controls

C420 in

pi

-network

to match

impedance

of out-

put

load.

TuneE input

to

Receiver

RF

Arnplifi€ r.

Switches

in

progres

sively

more

capacitance

in

Paral-

lel with

PA Load, Fine.

Switche

6,

plate coi1s, and

associated

caPacitors

of

VFO

Amplifier, VI,

Tran8

-

mitter Mixer,

V2,

and Dri-

ver,

V3,

Also switches

tank

coil of

pi-coupling

system and

associated

capacitor

s in PA

outPut

ll

scleen

voltage are

aPPlied

AF

GAIN

to Vl3,

DC

Supply

-

12

volts dc

is

provided

to

the

relay ci !cuit,

high and

mediurn

voltages supPlied

to

the

plate

circuits

and

bias voltage is

proviced

to

the relay controlled

Same

a6 for Calibrate

but voltaSe

to Vl3

re-

12 volt

dc circuit

through

relay Kl and

KZ i3 corn-

pleted, and all tubes

us€d

only

in rec€ive are

biased

to cutoJf.

AII circuits for

transmit

are

energized, as above,

but only deflection

plate

of the

balanced modula-

tor is

grounded, capaci

-

tor C1504 in the

carrier

oscillator

ie removed

frorn ground, C 1503

is

grounded.

Control6

potentiometer

R1603

in the

grid

Vl68

and controls

amount o{

audio to the balanced

modulato

r.

PA TUNE

PA

LOAD,

r.ine

PA LOAD,

Coarse

MAIN

BANDSWITCH

MICROPHONE

GAIN

M.DEL 4oo r^lo*r"rrut*

ll

C. OPERATION

WARNING

DANGEROUS

ruGH VOLTAGE IS

PRESENT

ON THE PLATE OF

THE

POWER

AMPLIFIER WHENEVER

THE POWER SUPPLY IS ENER.

GIZED. NEVER TURN POWER ON

WHEN THE POWER AMPLIFIER

COVER IS REMOVED.

HIGH

VOLT-

ACE

IS ALSO

PRESENT AT PIN

EIGHT

OF TIIE POWER

PLUG.

The

Swan Model 400 may

be operated

with either the Model 4068

or

Model

410

I.requency Control Unit, and may

be

operated lrom lI7 volts, ac, 50 to

60

cycle

power

with

the Model I l?XB

powe!

6upply

or the Model Il?XC

powe!

eupply.

The Model 400 may be

operated flom a

12,6 volt dc

source with the Swan

Model l4-l

l? power supply.

Before connecting any cableE

to the

Swan 400,

perforrn th€ foilowing stepB:

l Rotate

the PA Bias control on the

rear chassis apron,

fuUy counter

c loc kwi s

e.

2. Rotate

the Function Switch located

on the lower IeJt

of the front panel

counter

clockwi6e to STBY.

3. Rotate

the AF Gain Control

countei

clockwise to

operate the

power

switch

to OFF.

POWER SUPPLY AND

ANTENNA

CONNEC TIONS

l. Connect

either

the

Swan 4068

or

410

Frequency Control Unit

to the

9

connector near the center

of

the

rear chassis apron.

2. Connect

a 50

to 75 ohln antenna to

the coaxial

connector on the rear

chassis

pane1.

3. Connect

the

power

supply cable to

the Jones

connector on the rear

chas sis

apron.

t2

4. Connect

the power supply

to the

proper

voltaSe

solrlce.

RECEIVE

OPERATION

L Rotate

the AF Gain Control

clock

-

wise

to about

the

3

orclock

poBition.

The

po*er switch will opelate

applying

filament, relay, bias, and

800 volt

high

voltage

to the tran8-

2. Wait approximately

one minute

to

allow the tube

filaments to reach

operating

lernperatu!e. DurinB

this

period, perlorm the followrng

steps:

(a)

Rotate the Sideband Selector

to

the c

ounte r

-clockwise

position,

providing lower sideband on 40

and 80 meters. and

uDDer side-

band olr 20,

15,

and

I0 meters.

The

oppo6ite 6ideband will

be

selected when the

6witch is in

the clockwise

position,

(b)

Rotate

the Phone-CW switch to

Phone,

(c)

Rotate the Bandswitch

to desired

band.

(d)

Rotate

Mic. Gain fully counter-

clockwis e.

(e)

Rotate Car.

Bal. control to the

midscale

position, with

\rhite

dot on

knob

aligned

with the

rndex mark on the

panel.

(f)

Preset

PA Plate control to

rnid-position.

(g)

Pre set PA

posrrlon,

(h)

Preset

PA

po

sition,

Glid Control

to rnid-

Load Fine

to rnid-

1 MODEL 4OO TRANSCEIVER

C. Operation

(Cont)

(i)

Rotate PA Load Coarse to

position

6.

(j

)

Rotate Bandswitch on

Fre

-

quency

Control Unit to

desired band,

(k)

Set !'requency Control Unit

tuning dial to desired operat-

ing f!equency.

(l

)

Set R!. Gain Contlol to

approximately

3

o'clock

position.

3. Rotate the Function

Switch

clock-

wise to the REC

position.

4. Care{ully adju6t the PA Glid and

th€ PA Plate controls for maxi-

rnudr receive!

noi3e.

Note:

The

PA Grid Control

resonates

the

transmitter driver stages and the

receive! RF amplifie!

plate

cilcuit.

The PA Plate ard PA Load con-

trols adjust the input and output

capacitors

in the transmitter

power

arnplifier

final

plate

circuit, as

well as the receiver RF ahplilier

grid

circuit.

Prope r adju6tment

of these controls in the receive

position

will re6ult in approximately

resonant

conditions in the trans-

rnitter stage6.

RECEIVER

TUNING

-

IMPORTANT,

READ CAREFULLY.

Precise

tuning of

a Bingle Bideband

signal

is

very

important. Do not be

€atisfied

to merely tune unti.l the voice

can be understood, but take the extra

care of settiDg the dial to the exact

€pot

where

the

voice

sounds natural.

Above all,

avoid the habit of tuning so

that

the voice

is

pitched

higher than

norrnal.

This is an untortunate

habit

practiced by

quite

a

nuhber ot oPera-

tois, The following

points help to

explain

the effects o{ rnistuning:

I. If

you tune so the received voice 1s

higher than normal

pitch,

you will

then transmit ofI frequency, and

your Yirce will sound lower than

nor't[.]

pitch

to the other station,

He

wlll

probably

retune hi8 dial to

mak€

/,rrr

sound right. If

fou

keep

this up,

you'Il gladoally

waltz one

another across the

band,

If both

of

you

are rnistuning to an unnatural

higher

pitch,

your11 waltz

across

the

band twice as fast.

(And

someone

will

no

doubt

be

accused of fre-

quency

drift),

2.

Mistuniog !esult€ in

serious har-

.

monic distortion on

the

voice, and

ghould

be quite noticeable to the

average ear.

Some

will claim that

if

they

donrt know how the other

personrs

voice actually sounds,

they

canrt tune hiln in

propelly,

but this

i6 not true. With a little

practice,

it wiU be Iailly easy to tell. Sorne

voices are relatively rich in

ha.-

monics, and

ale easier to tune iD

rhan a

person

v,/ith a

r'Ilat"

voice.

AIso, a

transmitter \rhich is being

operated

properly

with low diBtor-

tion will be eaEier to

tune

in

than

one which i€ being

over-driven and

is

generating excessive distortion,

There is no lnistaking

when you

have a station tuned right on the

nose,

It wil.l

sound

ju6t

like

I'AM, r'

so to speak. Mainly, avoid

the

habit

of tuning 6o everyone sounds

higher than rormal

pitch, or like

Donald Duck. This i6 incorrect,

unneceaaary and sounds

terrible.

3. A vernier

control for receive fre-

quency, sometime6 reterred to as

!'incremental

tuning,rt

is not

avail-

able on the S\ran 400.

Such

a

device

is not necessary if

proper

tuning

habits are

exercised.

t3

I MODEL

4OO

TRANSCEIVER

C. Ope

ration

{Cont)

4. Your Swan

400

will automatic ally

transmit on

exactly the same {!e-

quency

as

the one to which

you are

Iistening. There

is no adjustment

Jor rnaking them

the sarne, since,

by using

the 6alne oscillato!

for

both send

and receive, it

happens

automatically.

If separation

of re-

ceive and

transmit frequency

con-

trol is

desired, the

Model

22

dual

VFO adaptor

rnay

be installed

in

the

VFO

socket

on back

of the 400,

and a

pair

of 410's

or 4068's

may

then be

p)ugged into

lhe adaptor'

CALIBRATE

To calibrate

the Model 410

Frequency

Control

Unit dial,

tollow

these four

steps:

l.

Rotate the

function

switch to CAL.

Z, Rotate

th€

Kilocycles

dial to the

100

kc increment

neare6t the

d€

si red operating

frequency.

3,

An audio

beat note

will be heard

in the

6peaker.

4,

Adjust

the

Dial Set knob

for zero

TRANSMITTER

TUNING

Tuning

of the transmitter

is

not com-

plicated,

providing the lew

simPle steps

are followed

in the co!rect

order.

Do

not attempt

ini.tial

tuneup without

first

performing

the

ptocedures for Receive

operation

described

above.

The louow-

ing

procedures

assurne

that

the

unit has

been

checked

out in Receive

Position,

and

that the

powe! suPPIy

and Frequency

Codtrol

Unit are adjrsted

and

oPerating

properly.

t. Rotate

the Fonction

S]vitch

to

TRANSMIT,

read

the cathode

current

on

the front

Pane1

meter.

l4

Ouickly

rotate the

CAR

BAL con-

trol

on the lront

Panel

until

the

mete!

reads

rninimurn

cathode

Next, adjust

the PA

Bias control

on

the rear

ol the

chassis until

the

mete!

reads 50 !na.

3.

4. If thi€

is the

first time the

trans-

ceiver

is being

tuned on this

band,

set

the PA LOAD

switch

to

Position

l. Afte!

experience

ir tuning

uP,

the control

rnay

be set

to whatever

po6ition has

been found

to be

optimum

on each

respective

band.

Now, in

rapid succession:

(a)

Turn the CAR.

BAL.

control

clockwise

until a 51i8ht

increase

in meter

reading

is obtained.

(b)

Rotate

the PA GRID

control

for

maximurn

meter

!eading.

(c)

Rotate

the PA

PLATE

control

for minimurn

meter leading.

(d)

Adjust

car. bal.

for a leading

oI

150

rna.

IMPORTANT

-

Tuning

the PA

PLATE

for minimum,

or

"dip,

"

i3 known

ag

i

resonatingri

the

power

amplifiel

plate circuit,

and i3 vety

ilnportant

to

preserving tube

life. If the

transceive!

is held in

Tran8rnit

or

TUNE

position

for more

than

a few

seconds

while

out

of resonance and

with sorne

glid drive,

the

6HF5

tubes rnay

be severely

damaged.

For

this reason we

tepeat:

CAUTION

-

Do

not hold

the transceiver

in Trans-

mit

or TUNE

position for

any length

of

time without

rrdiPPingri

the PA

PLATE control.

The

PA GRID

rnust

first

be

Ipeakedrr

as in

(b),

above,

and

this requires

some carrier

supplied

as described

in

(a),

so it

can

be seen that

these stePs

rnust

be

p€rformed

quicklY. If the

PA

LOAI)

control

is too far

clockwise,

it lnay

I MODEL 4OO TRANSCEIVER

C.

Ope ration

(C

ont)

not be possible to find

arrdip| with

the

PA

PLATE control. r.or this

reason,

be sure to ob6erve the first

sentence

in this section,

Step

4.

5,

Rotate the REC. TUNE

switch

to

TUNE position.

Ouickly

check

the

PA PLATE control for

|dip|

o!

minimom leading. If the meter

dips

to

lesB than 500 ma,, inclease

loading by rotating the PA I.OAD

controls

clockwise, After each

in-

crease in PA LOAD,

resonate

the

PA PLATE again; that is, adjust it

for dip. Continue increasing PA

LOAD until the PA PLATE dips to

450-500 ma. Then switch back to

RECEIVE.

CAUTION: Do lrot hold the tlans-

ceiver in TUNE

position

Jor more

than 30 seconds at a time, even

though

PA PLATE is re€onated,

With fuu

grid

drive

to

the

6H!'5 PA

tubes, which

you

have in TUNE

position, they

are

dis6ipating

con8iderably more

powe!

than they

do durinB

normal voice transrnis-

sion, 60 a short

tuning

period

lnu6t

be observed-

A--,4.,.1t*La''.a?,:!a,a;aa'.-J.aI.A

aLLI.L..

/^

l.

.-..2

o

'.I

-4,

6. Under some conditions, it may

nor

be possible to load up to 500 ma,

This fnay occur with lowe! than

norhal line

voltage

or tubes not

quite up to par, particularly on l0

rneteis, The curlent increase when

tuning the

plate

circuit ofl resonance

will

provide

a

clue

as

to how {ar the

power ampli{ier can be loaded.

Il

the meter s\rings up to 600 or ?00

ma. on either side of resonance, it

will be easy to load up to 500 or even

more,

But, if the tubes

dra\r

ju6t

500 ma.

off resonance,

you

can only

load

to 400 or 450 rna. This is

not

necessarily a sign

that

you

have

a

problem, Peak input

power

with

voice

modulation will still

be

400

watts

when you

load

lo

400

ma. in

TUNE

position. A new pair of PA

tubes may allow

yor.1 to Load higher,

o! possibly

a

new drivet tube will

help. Plirnalily, the level

to

which

you can load will serve as an indica-

tion

of

when

tubes are deteriorating.

If

you can load to 500 ma. when the

set

is new, and after a few monthg

of operating you cannot

get

above

400 ma., or so, it is

plobably

time

to leplace the 6HF5 tubes, and

possibly

tbe

6GK6

driver. The

other

tubes should also be checked at that

time.

AVERAGE PA LOAD SWITCH POSI-

TIONS. The

{oUowinS

po6itionB

are

{or a 50

ohrn non-inductive load,

and indicate approximately

lphere

the PA LOAD srritch will end if the

antenna and coaxial cable are well

matched.

BAND PA LOAD SWITCH

'7.

80

40

20

IO

POS. 7

8

9

l0

A large

deviation from theBe po6ition8

indicates a

possible

matching

problem,

althouSh

operation may 6till be

quite

Batisfactory.

PA LOAD switch

posi-

tions below 5 will

generauy

be

needed only with very low impedance

loadB, such as a 75 rneter rnobile

antenna with

center loading coil.

VOICE TRANSMISSION.

After tuning

up

as

outlined above,

piess

the Push-

to-Talk button on the mike and care-

fully set the CAR,

BAL. control for

minirnum

meter readin8, While

speaking into the

mike, slowly rotate

7.

I MODEL

4OO TRANSCEIVER

C, Operation

(Cont)

the MIC. GAIN control

until occa-

sional

peak reading oI l?5 to

200

ma. are obtained.

With

most

rnicrophones, the MIC.

GAIN

con-

trol will be set

between

9

and

l2

orclock, but it rnay

vary

consider-

abry. The ALC circuit will help

limit cathode current to about 200

rna., but

turning the MIC. GAIN

{rp too high will still

produce

flat-

topping and 6purious

siBnals,

so

it

is important to hold it down. The

meter is

quite heavily damped, and

its reading *ith average

voice modu-

lation may nol look

very impressive,

but the

voice

peak6

are

going

well

ower the 400

$att

Po\"er

rating of

your Swan tlan6ceiver, and

signal

reports

will verify this fa(t.

8.

TRANSMITTER

TUNING WITH

SWR

BRIDGE

OR FIELD STRENGTH

METER.

lf either oI the6e instru-

ments is available,

they

are

highly

recommended

as a better method

o{

tuning

the PA AmpliJier, since

they

provide

a

direct indication

of rela-

tive

output. With the SWR

Bridge

in Forward

position, or

with

the

Fie]d Strength

Meter 5et to

pick up

a

portion of the radiated

power,

simply

adjust the PA TUNE

and PA

LOAD

controls for rnaxirnurn

output.

This

rnust be done

quickly, limited

to about

30 seconds,

to limit tube

di6sipation as

previously

mentioned.

This method will

result in rrraxr-

lnum

possible output

and

efficiency,

as well as

rnaxirnum linearity.

You

witl

probably find that cathode

current

readings

end uP somewhat

less than 500

ma. on l0 meters

becau6e

grid

drive is

the

least

on

this

band.

On

80

rneters where

grid

drive

i6 the

greatest, rnaxinurn out-

put will

be reached at rnore than

500

rna. These are

a normal condi-

tion.

16

NOTE

-

The cathode

cur.ent level

to which

the PA

is loaded will

have

no bealing

on tube life, When

transmitting

with nolrnal voice

modu_

lation, average

Povwer

inPut

rrill

be

the sarne

regardless

of how high

or

1ow

the PA was loaded

while

tuning.

Peak output,

Iinearity, and lowe8t

distortion

will

go along with maxi-

mum

loading. In

other words,

You

will

not extend

tube life by loading

to a lesser

degree, The

secret to

long

tobe life

is simply to keep

TUNE-up

periods short and

not too

frequent.

AM

OPERATION

(Single

Sideband

with Carrier)

L

Tune up

transmitter

to full output

on single

sideband on desired

fre-

quency band as described

above,

2,

Rotate MIC GAIN

contlol to

lull

counter-clockwiae

Position.

3. With

Function Switch

in TRANSMIT,

rotate CAR BAL

control until

cathode current

rs apptoximately

150 ma.

4. While

talking

in a nollnal

tone oI

vorce into the

rnicrophone,

increa6e

MIC GAIN setting

until variation

is

just

discernible

on meter.

This

setting

will result

in adequate hodu-

lation with

one sideband.

CW OPERATION

l. Tune transmitter

to

firll output a6

described

above.

2.

Insert CW

key in

the key

iack Pro-

vided

on

the back of the 400.

Use

a standard

I/4 inch diamete!

2

circuit

phone plL1g.

1 MODEL 4OO TRANSCEIVER

C, Operation

(Cont)

3.

4.

Add a

.4T

or

.

5MF.

,

200 volt

caPacitor

across

the

key. This

capacitor rnay

be added internally

if

desired,

Switch the PHONE

-CW

control owe!

to

CW

position.

Then switch

the

Function Switch

to TRANS. to

transmit, and REC.

to receive.

5. In{ormation

on

a

sidetone

modifi-

cation for the 400 iB available on

request.

GENERAL

The

following

proceduies

are

given in

the order performed

during the

factory

alignrnent fo! the transceiver, For

home servicing only

partial

alignment

may be necessary. Read all

procedures

carefully

before commenc ing either

partial or complete

aliSnment. See

Figures 4 and

5Ior component

place-

rnent.

Equiplnent Requi!ed

L Caliblated

audio freqqency signal

generator, range

200 to 5000

cps.

2. 500 watt dummy load with output

3. Vacuum

tube voltmeter,

4, Walsco 2543

coil

adjustbent

tool.

5, Field

str€ngth meter

6. Calibrated RF Signal

Generator.

P!e

-Alignment

Conditions

l. Neutralizing

capacitorB

C4l3 aet

to rnid-point

and C3l6 Bet

to

approxirnately 3/4

turn lrom futl

cornpres 6ion.

2.

Peak lF transformers for maxi-

rnurn background noise

with

AF

and

RF

gain

Iull clockwi8e

(eithe!

bottom

or

top

core

adjustrnent).

3,

Loosely,

couple field strength

rn€ter to C3l?

(off

9

of

V4)

with

alligator clip

on

cerahlc

capacitor

body.

TROUBLESHOOTING

4.

Transmit bias

potentiometer full

counter-clockwise

(maximurn

bias).

VFO AMPLIFIER

PLATE

CIRCUIT

ALIGNMENT

With VTVM from

pin I of

V7,

Receiver

Mixer, to

ground,

on

-15

volt

scale,

and

using

a

Model 410 or 4068 Frequency

Control

Unit, adjust Vr'O Amplifier

Plate coils {or

peak

VTVM

heading

as

followB:

D.

ALIGNMENT AND

Band

VFO Fle

-

VFO

Dial

Reading

Frequency

(kc)

Coil

80 3,800

Lt 04

40

12,300 7,125 L 103

l5

r 6, 050 Lt 0z

lo

28,500 Ll0l

TRANSMITTER

MIXER AND DRIVER

PLN,TE

CIRCUIT

ALIGNME NT

1,. Rernove

screen

voltage

florn

V4

and

V5 by disconnecting

orange

wire

to

telrninal strip irnrnediately

adjacent

to

V5

baBe.

(Pt.

A in Fig. 5.

)

2. Connect VTVM

across P.412, 4.7K

resistor

bet$/een

pins

I and 2 of

terminal strip irnmediately behind

bifilar coil

in cry6tal filter, !ange

-I5

volt scale,

(Points

B and C in

Fig.5).

t7

I MODEL 4OO

TRANSCEIVER

FIGURE

4

[-a.f

TOP

VIEW,

MODEL 400 TRANSCIEVER.

18

FIGURE 5

BOTTOM

VIEW, MODEL 400 TRANSCEIVER

I

MODEL

4OO

TRANSCEIVER

D, Alignment

and

Troubleshooting

(Cont)

3. Set

PA

grid tuning

Iully clockwise,

phone

-cw

switch

in

Phone

Position,

sideband

selector

in USB

Position.

Procedure:

Adjust bandswitch

to

band shown

and

adjust

coils for

Peak

VTVM

!eading

as

follows:

Function

Switch

Band

vFo

F req,

(t.)

Adjust

Tune*

80 4,O25

LZO',

L305,

cI507,

zL40l

Tune

40 7,

350 L204,

L304

Tune

zo

r4,500

LZ03, L303

Tune

21,500

LZ|Z, L30Z

Tune

IO

29,?00

L20r,

!301

*

Note: I{

VTVM and

field

strength

meter

exceed

ful1 scale

readinS,

gwitch

to

transmit

posltron and

insert

carrier

with carrie!

balance

control to

keep

reading

on scale.

Fietd

Btlength

meter

and VTVM

must both

Peak

at

same

time

since

it is

possible

to t|.1ne

the coils

to

the VFO

lrequency

on l0 meters.

Care

rnust

be

taken that

the coils

be hrned

pro

pe

rly.

Following

the above

Procedures,

replace

orange

wire

to

I of

terminal slriP

adjac

ent

to V5.

ALIGNMENT

OF 5T?5

KC

TILTER

TRAP

With

RF

and

AF gain at

midscale,

feed

5I?5kc

signaf

to antenna

connector

and

adj\rst

L60Z

until

heterodyne

di€aPPea!8

o! S

-meter

reads

zero'

ADJUSTMENT

OT CARR]ER

FREOUENCY

A. With

dummy

load

and

outPut meter

attached,

tun€

transceiver

for

lnaxi-

rnurn

otrtput.

B. Null

out carrier

with

PTT

Pressed

and

set

reBting

Plate

current

to 50

ma

wlth

bias

Pot.

C,

Connect

AF

generator

to MIC JACK

'

adjust

MIC,

GAIN

full CCW-

Proced|1!e:

With

AF

generator

at

1500

cP3,

increaee

MIC.

CAIN

to

P!oduce

a

100

ma,

reading

on the

meter.

Adjust

2801

for rnaxirnuln

meter

reading.

L

z.

3. Adjust

both toP and

bottom

corea

of

Zl40l for

maxirnlrm

rnetei

reading.

4. Adjust

MIC.

GAIN for

t'teter

read-

ing of 300

rna.

5.

Set AF

generator

to 300

cPs. Adjust

C1507

Ior

meter

reading

of 75 ma.

6. Repeat

stePs

I through

5 for

USB

operation,

adju6ting

C 1506.

PA NEUTRALIZATION

With

P. A.

coatse

load in

po6ition

I, set

{req.

to 14. 150,

PA

Plate

control at

9

orclock,

insert

carrier

and

peak P. A.

Crid

control,

adj\rsting

Car.

Bal.

con-

trol for 200

MA,

Turn

PA control

slowly

thlough

iesonance.

Cathode

current should

diP

srnoothly

and

rise to

2OO MA

on

the 1oll caPacitY

side of

re6onance.

If,

instead,

there

i6

a

peak

above ZOO

MA

either

side

of the dlP'

stop

rotation

of the

PA

plate control

at

t9

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Swann 400 Operation And Maintenance

Swann 400 Operation And Maintenance

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