Mfj Versa tuner ii mfj-941d User manual

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MFJ

VERSA TUNER

II

M1OD1EL

MFJ

'

941

D

OWNER'1S

MANUAL

. I

CAUTION:

Read

All Instructions

Before

Operating

Equipment.

: .

MFJ

ENTERPRISES,

INC.

P.

0.

BOX

494,

MISSISSIP

1

PI

STATE,

MS.

3978•2,

USA

'

www.SteamPoweredRadio.Com

MFJ-941D

VERSA

TUNER

II

INSTRUCTIONS

Thank

you

for

purchasing

the

MFJ-941D

VERSA

TUNER

II.

The

MFJ-941D

is

designed

to

match

vees,

verticals,

mobile

whips,

beams,

random

wires,

and

others

fed

by

coax

lines,

balanced

lines

,

or

a

single

wire.

A

1:4

balun

is

built

in

for

connection

to

balanced

lines.

This

unit

will

handle

up

to

300

watts

of

RF

output

power

from

the

transmitter

from

160

through

10

meters.

The

MFJ-941D

will

monitor

either

SWR

or

RF

transmitter

power

in

two

ranges,

30W

or

300W .

The

antenna

selector

switch

allows

switching

to

one

of

the

two

coax

fed

antennas

(direct

or

through

tuner)

and

either

a

balanced

line

antenna

or

random

wire

antenna.

A

bypass

position

allows

switching

to

a dummy

load

or

a

direct

coax

antenna

.

The

tuner

is

bypassed

but

not

the

meter

ciruit

when

the

ANTENNA

SELECTOR

switch

is

switched

to

BYPASS, DIRECT

COAX

1,

or

DIRECT

COAX

2

positions.

CAUTION:

Do

not

use

the

MFJ-941D

for

over

300

watts

of

RF

output

power,

even

in

the

bypass

or

direct

positions.

Do

not

operate

the

antenna

selector

while

transmitting.

INSTALLATION

1.

Install

the

MFJ-941D

between

the

transmitter

and

the

antennas.

A

coax

line

is

connected

between

the

transmitter

and

the

S0-239

coax

connector

marked

TRANSMITTER

on

the

tuner.

2.

One

or

two

coax

fed

antennas

may

be

connected

to

the

S0-239

coax

connectors

marked

COAX

1

and

COAX

2.

NOTE:

Coax

1

and

coax

2

antennas

can

be

connected

directly

to

the

transmitter

by

turning

the

antenna

selector

to

COAX

1 DIRECT

or

COAX

2 DIRECT .

3.

A

random

wire

antenna

may

be

connected

to

the

five-way

binding

post

marked

WIRE.

The

random

wire

antenna

should

be

long,

high,

and

as

clear

of

surrounding

objects

as

possible.

Do

not

ground

the

random

wire

antenna

but

make

sure

that

the

tuner

is

well

grounded

to

the

transmitter.

A

five-way

binding

post,

marked

GND,

is

provided

for

the

ground

connection.

4.

A

balanced

line

fed

antenna

may

be

connected

to

the

two

five-way

binding

posts

marked

BALANCED

LINE,

along

with

a

jumper

wire

from

the

WIRE

binding

post

to

the

adjacent

BALANCED

LINE

binding

post,

as

indicated

by

a

dotted

line

on

the

HFJ-941D.

This

couples

the

MFJ-941D

to

the

balanced

line

through

a

1:4

balun

.

NOTE:

Either

a

balanced

line

or

random

wire

antenna

can

be

connected

at

one

time.

If

a

random

wire

antenna

is

used,

make

sure

that

there

is

not

a

jumper

wire

between

WIRE

and

BALANCED

LINE.

5.

An

antenna

or

dummy

load

may

be

connected

to

the

S0-239

coax

connector

marked

BYPASS

COAX.

The

antenna

switch

on

the

BYPASS

position

will

bypass

the

tuner

and

allow

the

MFJ-941D

to

be

used

as

an

SWR

meter

or

a

wattmeter

.

PA

GE

1

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THE

SWR/WATTHETER

The

SWR/WATTMETER

of

the

MFJ-941D

can

be

used

with

the

tuner

or

by

itself

.

The

SWR/WATTHETTER

is

between

the

transmitter

and

the

tuner

when

the

antenna

switch

is

in

the

COAX

1,

COAX

2,

or

WIRE/BAL

positions.

The

SWR

meter

is

sensitive

down

to

approximately

5

watts

RF

output

.

The

SWR

reading

will

not

be

accurate

for

a

transmitter

power

of

less

than

5

watts

.

FORWARD

AND

REFLECTED

POWER

1.

Set

the

POWER/SWR

switch

to

POWER.

2.

Set

the

300/30

watt

switch

for

the

desired

range

.

3.

Set

the

FWD/REF

switch

in

for

forward,

out

for

reflected

power

.

4.

Transmit

a

steady

carrier

and

read

the

power.

SWR

MEASUREMENT

1.

Set

the

POWER/SWR

switch

out.

2.

Set

the

FWD/REF

switch

in.

NOTE

:

It

does

not

matter

which

position

the

3JJ/3J

watt

switch

is

in

for

measuring

SWR.

3.

Transmit

and

adjust

the

SWR

SENSITIVITY

control

for

fu

l l

scale

reading.

4.

Set

the

FWD/REF

switch

out

and

read

the

SWR.

OPERATION

OF

THE

TUNING

SECTION

The

INDUCTANCE

switch

on

the

HFJ-94

1D

presents

a

minimum

of

inductace

at

position

"A"

and

a maximum

of

inductance

at

position

"

L".

Less

inductance

is

needed

at

high

frequencies

for

the

same

impedance.

The

TRANSMITTER

and

ANTENNA

controls

both

present

a maximum

of

capacitance

at

position

1.

For

optimum

operation

of

the

MFJ-941D,

the

transmitter

must

be

tuned

for

a

5J

ohm

output

impedance

for

the

frequency

band

in

operation

. The

transmitter

can

be

tuned

with

the

MFJ-941D

connected

by

connecting

the

50

ohm

load

to

the

BYPASS

COAX

connector

and

turning

the

antenna

switch

to

the

BYPASS

position.

The

HFJ-941D

is

then

used

only

as

an

SWR

meter

or

a

wattmeter

.

NOTE:

Always

tune

the

transmitter

at

a

lo

w

outEut

power.

After

properly

tuning

the

transmitter,

turn

the

antenna

switch

to

the

desired

antenna

and

tune

the

tuner

for

minimum

SWR

as

described

below

.

Do

not

readjust

tht

transmitter

setting

after

loading

it

to

the

50

ohm

load.

1.

Set

the

TRANSMITTER

and

ANTENNA

controls

to

3.5.

are

half

opened).

(The

capacitors

2.

Rotate

the

INDUCTANCE

control

until

maximum

noise

is

obtained

in

the

receiving

mode.

3.

Set

the

POWER/SWR

switch

to

SWR

and

the

FWD/REF sw

itch

to

FWD.

It

does

not

matter

which

position

the

3JJ/3J

watt

switch

is

in

PAGE

2

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for

measuring

SWR.

Set

the

transmitter

to

the

tune

position

and

transmit.

4.

Turn

the

SWR

SENSITIVITY

control

clockwise

unt

i l a

full-scale

deflection

is

obtained.

If

a

full-scale

deflection

cannot

be

obtained,

increase

the

output

power

from

the

transmitter.

5.

Set

the

FWD/REF

switch

to

the

REF

for

the

SWR

reading.

6.

If

the

SWR

is

not

1: 1,

then

tune

the

MFJ

-941D

for

a

minimum

SWR

.

7 .

While

transmitting

,

and

with

the

I N

DUCTANCE

control

set

the

same

as

for

Step

2 ,

alternately

adjust

the

TRANSMITTER

and

ANTENNA

controls

for

a

minimum

SWR

.

Sice

the

TRANSMITTER

and

ANTENNA

control,

interact,

the

two

controls

can

best

be

adjusted

b y

turning

the

.TRANSMITTER

control

at

a

small

increment

at

a

time

and

t

hen

rotating

the

ANTENNA

control

for

the

minimum

SWR

.

Repeat

this

until

a

minimum

SWR

is

obtained

.

8.

If

a

SWR

reading

of

1: 1

is

not

achieved

,

increase

or

decrease

the

INDUCTANCE

control

one

position

and

repeat

STEP

7.

N

OTE

:

If

a

SWR

cannot

be

achieved

at

this

point,

repeat

Step

7

for

each

INDUCATNCE

contro

l

position

.

Again,

do

this

in

the

tune

mode

or

at

a

low

transmitting

power.

9.

After

a

minimum

SWR

is

achieved,

readjust

the

SWR

sensitivity

(to

get

a

more

accurate

reading

of

the

SWR)

by

pushing

the

FWD/R

EF

switch

in

to

FWD

and

adjust

the

SWR

SENSITIVITY

control

for

a

full

scale

meter

deflection.

Switch

the

FWD/REF

switch

to

the

REF

position

for

the

SWR

reading

.

The

transmitted

power

may now

be

sw

itched

to

3JJ

watts.

The

SWR

sensitivity

must

be

re,et

again

after

full

power

is

applied

.

The

ANTENNA

and

TRANSMITTER

controls

may

need

fine

adjustment

if

the

SWR

is

not

1:1

at

hig~

pow~r .

NOTE:

On

the

16J

meter

band

,

excessive

heatin~

or

arching

may

occur

.

Reduce

the

transmitter

output

power

u~

til

it

stops

.

1J.

To

read

the

transmitt

~

po

w

er

,

pus

r

the

POWER/SWP

switch

i ~

to

POWER

and

the

3JJ/3J

watt

switch

to

~

~ichever

powe

scale

you

~ant.

To

read

reflected

power,

put

the

FWD/REF

switch

in

the

REF

position.

11

. A

SWR

of

1:1

can

occur

from

more

than

one

set

of

control

settings

on

the

MFJ-941D

. When a

SWR

of

1: 1

is

obtained

,

be

sure

to

chec

k

transmitter

power

and

make

sure

that

the

transmitter

power

is

relatively

high

.

If

the

transmitter

power

has

decreased

substantially

,

try

another

INDUCTANCE

control

setting

and

repeat

Step

7 .

'

12.

When

using

the

NFJ-941D

for

receiving

only

,

tune

the

MFJ

-941D

as

described

in

Step

1

and

Step

2.

PAGE

3

www.SteamPoweredRadio.Com

ADDITIONAL

NOTES

AND

CA

UTI

ONS

1,

Do

no

t

use

the

MFJ-941D

for

over

300

watts

of

RF

o

utput

po

we

r .

even

in

the

BYPASS

or

the

DIRECT

COAX

p

osi

tions

.

2.

Do

not

op

erate

the

antenna

switch

wh

ile

transmitting.

3.

For

recalibrating

the

power

scale

settings.

use

the

trim

pots

just

behind

the

meter

. Loo

king

f

ro

m

the

f

ront

.

the

left

trimpot

adjusts

the

300

w

at

t

sca

le

and

the

right

adjusts

the

30

watt

scale

.

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MPJ-9410

SCHEMATIC

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PAGE

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BALANCED

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www.SteamPoweredRadio.Com

I

MFJ Enterprises,

Inc

. warrants

to

the

original

owner

of

this product,

if

manufactured by

MFJ Enterprises, Inc. and purchased from an authorized dealer

or

directly from MFJ

Enterprises,

Inc

.

to

be

free

of

defects

In material and workmanship

for

a period

of

12

months from date

of

purchase provided the following tenns

of

this warranty are satisfied.

1. The purchaser must retain the dated proof-of-purchase (bill

of

sale, canceled check,

credit card

or

money order receipt,

etc

.) describing the product to

establish

the

va-

lidity

of

warranty claim and must submit the original

or

a machine-reproduction

of

such proof-of-purchase

to

MFJ Enterprises,

Inc

.

at

the time

of

warranty service.

MFJ Enterprises,

Inc

. shall have the discretion

to

deny

warranty without dated

proof-of-purchase. Any evidence

of

alteration, erasure,

or

forgery

of

proof-of-purchase

shall

be

cause

to

void any and all warranty terms immediately.

2.

MFJ

Enterprises, Inc. agrees to repair

or

replace

at

MFJ's option without charge to

the original

owner

any defective product provided the product is returned postage

prepaid

to

MFJ Enterprises, Inc. with a personal check, cashier's c

heck

or

money

order

for

$4.00

covering postage and handling.

3.

MFJ Enterprises, Inc. will supply replacement parts free

of

cha{ge for any MFJ pro-

duct under warranty upon reQuest. A dated proof-of-purchase and a

$4.00

personal

check, cashier's

check

or

money

order

must

be

provided to

cover

postage and

handling.

4 . This warranty is

NOT

void

for

owners

who

attempt to repair defective units. Techni-

cal consultation is available

by

calling

(601)

323-5869.

5.

This warranty

does

not

apply

to

kits sold

or

manufactured by MFJ Enterprises,

Inc

.

6. Wired and tested

PC

board products are covered

by

this warranty provided

only

the

wired and teated

PC

board la returned. Wired and tested

PC

boards installed in

the

owner's cabinet

or

connected to switches, jacks, cables,

etc

. sent to MFJ Enter-

prises,

Inc

. will be returned

at

the

owner's

exr,,..

-1nrepaired.

7.

under

no circumstances is MFJ Enterprises,

1,

1.

"'

for

consequential damages to

person

or

property by the

use

of

any MFJ

pro

,

t.

8. Out-of-W1rr1nty Service: MFJ Enterprises, Inc. will repair any out-of-warranty pro-

duct

provi

ded

the

unit is delivered prepaid. All charges will

be

shipped COD

to

the

owner

.

9.

This

warranty

Is

given in lieu

of

any other warranty

express

or

implied.

10. MFJ Enterprises, Inc. reserves

the

right

to

make changes or improvement in design

or

manufacture

without incurring any obligation

to

install

such

changes upon any

of

the

products previously manufactured.

11.

All

MFJ products

to

be

serviced

in-Wm1W1ty

or

out-of-warranty should be addressed

to

MFJ

EnterprlHa, Inc.,

t21A

Loulmtle

Road,

Starttvllle,

Mlnlulppl

39759,

USA

and must be accompanied

by

a

letter

describing the problem in detail along with a

copy

of

your

dated proof-of-purchase.

12. This warranty gives

you

specific rights, and

you

may also have other rights which

vary from state

to

state.

MFJ VERSA TUNER II MFJ-941D User manual

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