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INTRODUCTION

Your

KENWOOD

Model

TR-7400A

is

a

high-quality

2-meter

transceiver

for

use

in

ama-

teur

radio

mobile

stations

as

well

as

fixed

stations.

It

contains

a

PLL

frequency

syn-

thesizer

developed

and

engineered

through

KENWOOD's

elaborate

VHF

technology

to

provide

high

performance

and

outstanding

technical

characteristics.

The

TR-7400A

is

capable

of

transmitting

or

receiving

F3

FM

signals

on

up

to

800

Chan-

nels

at

intervals

of

5

kHz,

having

25W

RF

output

power.

CONTENTS

SPECIFICATIONS

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

3

SECTION

1

PREPARATION

FOR

USE................

4

1.1

Accessories

1.2

Tone

Squelch

1.3

Antenna

1.4

Installation

Caution

SECTION

2

CONTROLS

AND

WHAT

THEY

DO.........

4

2.1

Front

Panel

2.2

Rear

Panel

2.3

Side

Panel

SECTION

3

GENERAL

TIPS

ON

INSTALLATION........

7

3.1

Mobile

Use

3.2

Fixed-Station

Use

SECTION

4

OPERATION

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

renra

8

4.1

Receiving

4.2

Transmitting

4.3

How

to

Use

the

TX

Offset

Switch

4.4

How

to

Use

the

Hi/Low

Selector

Switch

4.5

How

to

Use

the

Tone

Selector

Switch

4.6

Description

of

“Unlock”

Indicator

4.7

How

to

Use

the

Tone

Pad

SECTION

5

ADDITIONAL

INFORMATION

...........-

12

BLOCK

DIAGRAM

`,

13

TOP

€:

BOTTOM

VIEW

OF

THE

TR-7400A

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

14

SCHEMATIC

DIAGRAM...

1...

eee

ee

ee

ees

15

TTT

AS

AAA

SAS

TR-7400A

SPECIFICATIONS

GENERAL

Semiconductors

Frequency

Range

Frequency

Synthesizer

Synthesizer

Stability

Mode

No.

of

Channel

Operating

Temperature

Power

Voltage

Grounding

Antenna

Impedance

DC

Current

Dimension

Weight

TRANSMIT.

SECTION

RF

Output

Power

Modulation

Max.

Frequency

Deviation

Spurious

Radiation

Touch

Tone

Input

Impedance

Microphone

RECEIVE

SECTION

Circuitry

Intermediate

Frequency

Sensitivity

Squelch

Sensitivity

Pass

Band

Width

Selectivity

(2

Signal)

Image

Rejection

Spurious

Interference

Intermodulation

Audio

Output

OPTION

i)

Tone

Squelch

Tone

Deviation

Encorder

Response

Frequency

Stability

Tone

Squelch

Open

Sensitivity

Tone

Distortion

ii)

Tone

Burst

Burst

Time

ITT

TTT

TTT

TTT

E

TTT

ET

TT

TITTEN

RUND

Transistors

58

FETs

8

ICs

19

Diodes

63

144.00

to

147.995

MHz

Digital

(TTL

Logic)

control

of

phase

locked

VCO

Less

than

+750

Hz

at

25°C

FM

800

—20

to

+50°C

11.5

VDC

to

16.0

VDC

(13.8

VDC

as

reference)

Negative

grounding

50.2

Less

than

1A

in

receive

with

no

input

signal

Less

than

8A

in

transmit

(HI)

Less

than

4.5A

in

transmit

(LOW)

(at

13.8

VDC)

182mm

(7-3/16”

wide

74

mm

(2-7/8)

high

270

mm

(10-5/8”

deep

Approx.

2.8

kg

(6.2

Ibs.)

High

25

watts

(min.)

Low

approx.

5

watts

(adjustable

up

to

15

watts)

Variable

reactance

direct

shift

+5

kHz

Less

than

—60

dB

600

2

Dynamic

microphone

with

PTT

switch,

500

Q

Double

superheterodyne

ist

IF

10.7

MHz

2nd

IF

455 kHz

Less

than

0.4

uV

for

20

dB

quieting

(Less

than

1

uV

for

30

dB

S/N}

Less

than

0.25

uV

More

than

12

kHz

at

6

dB

down

More

than

72

dB

at

30

kHz

of

adjacent

channel

More

than

70

dB

More

than

60

dB

More

than

66

dB

More

than

1.5

watts

across

8

Q

load

(10%

distortion)

+0.5

kHz

(adjusted)

Less

than

0.5

sec.

Less

than

+1%

Less

than

SINAD

10

dB

Less

than

5%

Approx.

0.5

sec.

(adjusted)

NOTE:

The

circuit

and

ratings

may

change

without

notice

due

to

development

in

technology.

SECTION

1.

PREPARATION

FOR

USE

EOS

SAA

SEA

ASA

AUS

A

AS

EA

AS

LAA

EAST

STA

ET

LA

ALA

A

ES

AA

A

AUT

LET

URL

ESTA

ATA

AA

A

AAA

AA

AAA

A

AAA

A

AAA

E

EE

1.1

ACCESSORIES

Carefully

unpack

your

TR-7400A

Transceiver

and

check

that

it

is

supplied

with

the

following

accessories:

(1)

Dynamic

microphone

equipped

with

Apin

plag

ari

a

de

1

piece

(2)

Mounting

bracket

........o.o.ooooo.o..

1

piece

(3)

Mounting

parts

Screws,

6

mm

diameter

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

4

pieces

Plain

washers,

6

mm

diameter

.......

4

pieces

Spring

washers,

6

mm

diameter.......

4

pieces

Nuts,

6

mm

diameter

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

4

pieces

(4)

Stand-off

bracket

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

1

piece

(5)

babel

a

ee

aan

1

sheet

(6)

Spare

fuse,

IDA

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

1

piece

(7)

DC

power

cord

with

plug

and

fuse

......

1

piece

(8)

Miniature

plug

for

external

speaker

......

1

piece

(9)

Miniature

plug

for

touch

tone

pad

......

1

piece

(10)

Plug-equipped

PC

board

for

tonesque!lChy

a

mee

ion

a

ra

a

1

sheet

(11)

Operating

manual

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

1

copy

1.2

TONE

SQUELCH

The

TR-7400A

is

designed

not

only

for

normal

carrier

type

OO

© O

O

00

squeich

operation,

but

also

for

tone

squelch

which

operates

with

the

installation

of

the

optional

tone

module.

If

you

operate

the

TR-7400A

setting

tone

selector

“SQU”

without

the

module,

you

will

it

not

to

be

in

the

normal

receive

mode.

Detail

is

shown

in

page

10.

1.3

ANTENNA

Any

50

ohm

2-meter

antenna

system

may

be

used

with

your

TR-7400A.

The

50

ohm

coaxial

cable

should

be

kept

as

short

as

possible

in

order

to

minimize

line

loss.

Attach

a

UHF

type

connector

(PL-259)

to

the

coaxial

cable

for

easy

connection

to

the

receptable

on

the

transceiver.

1.4

INSTALLATION

CAUTION

Your

TR-7400A

Transceiver

to

be

operated

as

a

mobile

station

should

be

securely

mounted

under

the

dashboard

(or

similar

location)

using

the

accessory

mounting

bracket

and

bolts.

Improper

installation

will

result

in

damage

to

the

transceiver

and

dashboard.

Consideration

must

be

given

to

the

dashboard

material

prior

to

installation.

More

detail-

ed

information

on

installation

will

be

found

in

SECTION

3.1,

the

“MOBILE

USE”,

page

7.

NDARI

NADA

RU

SA

A

A

ULI

UNTRIEDEN

TT

SECTION

2.

CONTROLS

AND

WHAT

THEY

DO

SS

A

SS

ASAS

STAR

UA

UTA

SS

AU

AAA

ESO

SALA

AAA

AAA

SA

ANA

TA

O

®

A

(@

KENWOOD

)

CO

D

n

LI,

L!

L

U

Fig.

1

Front

Panel

View

2.1

FRONT

PANEL

©

®

POWER

Switch

—

Turns

power

on

when

pressed

in.

HI/LOW

pushbutton

Switch

(Refer

to

the

“HOW

TO

USE

THE

HI/LOW

SELECTOR

SWITCH”

section,

page

10).

—

Used

to

select

high

(25W)

or

low

(5W)

RF

output

Power.

TONE

Selector

(Refer

to

the

“HOW

TO

USE

THE

TONE

SELECTOR

SWITCH”

page

10).

—

Four

posi-

tion

switch

used

to

select

type

of

squelch

desired:

SQU:

Continuous

tone

controlled

squelch

(C.T.C.S.)

on

transmit

and

receive

(Optional).

OFF:

Carrier

Squelch

operation.

BUR:

Tone

burst

operation

(Optional).

SUB:

C.T.C.S.

on

transmit

only

(Optional).

Tone

Squelch

Indicator

—

A

light-emitting

diode

(LED)

which

lights

when

the

TONE

Selector

is

set

to

the

SQU

position.

Meter

—

Indicates

signal

strength

as

an

S

meter

during

receive

and

relative

RF

output

power

during

transmit.

The

meter

function

is

automatically

switched

using

the

microphone

push-to-talk

switch.

ON

AIR

Indicator

—

A

light-emitting

diode

which

lights

during

transmit.

Repeater

Indicator

—

A

two-color

light-emitting

diode

which

indicates

the

type

of

repeater

offset.

It

is

red

when

the

TX

OFFSET

Switch

(7)

is

set

to

+600

or

green

when

the

switch

is

set

to

—600.

Digital

Frequency

Display

—

Indicates

receive

frequency

only

in

6

digits

when

the

POWER

Switch

0

is

ON.

The

display

is

covered

with

a

smoked

acrylic

plate.

SQU

Control

(Outer

ring)

—

This

is

a

normal

carrier-

type

squelch

control

which

activates

the

squelch

cir-

cuit

when

turned

clockwise.

VOL

Control

{Inner

knob)

—

An

AF

volume

control

used

in

the

receive

mode

of

operation.

Clockwise

turning

increases

the

AF

volume.

MIC

connector

—

Accepts

the

standard

4-pin

mic.

plug

supplied

with

the

TR-7400A.

MHz

Selector

Switch

—

Used

to

select

the

desired

band.

(144,

145,

146,

147

MHz

indicated

as

4,

5,

6,

and

7

respectively).

100

kHz

Selector

Switch

—

Used

to

select

a

desired

channel

in

units

of

100

kHz,

graduated

in

11

positions:

O

through

9

and

O.

10

kHz

Selector

Switch

—

Used

to

select

a

desired

channel

in

units

of

10

kHz,

graduated

in

11

positions:

0

through

9

and

0.

5

kHz

Offset

Switch

—

Used

to

select

the

least

signifi-

cant

digit,

0

or

5

kHz,

of

the

channel

frequency.

Unlock

Indicator,

(Refer

to

Section

4.6

the

"DESCRIP-

TION

OF

UNLOCK

INDICATOR”,

page

12).—

A

light-

emitting

diode,

indicates

when

the

PLL

circuit

is

in

the

unlock

condition.

There

is

no

synthesizer

output

in

the

unlock

condition.

Note,

however,

that

the

PLL

circuit

is

norma!

if

the

indicator

lights

momentarily

when

a

channel

selector

switch

is

changed.

TX

OFFSET

Switch

(Refer

to

Section

4.3,

the

“HOW

TO

USE

THE

TX

OFFSET

SWITCH”,

page

9).

—

This

switch

selects

the

type

of

frequency

offset

desired.

+600

kHz

switches

the

transmit

frequency

UP

600

kHz

from

the

receive

frequency.

SIMP

stands

for

simplex

operation.

The

receive

and

transmit

frequencies

are

the

-

game.

—600

kHz

automatically

switches

the

trans-

mit

frequency

down

600

kHz

from

the

receive

frequency.

2.2

REAR

PANEL

E

20

DC

Power

Connector

—

Accepts

normal

DC

operating

voltage

through

the

DC

power

cord

supplied

with

the

TR-7400A.

Heat

Sink

—

Radiates

heat

produced

by

the

final

tran-

sistors.

ANT

Connector

—

For

connection

of

any

50

ohm

2-

meter

antenna.

2.3

SIDE

PANEL

20

22

2

EXT

SP

Connector

—

External

AF

output

(8

ohm).

TONE

PAD

Connector

—

A

tone

pad

input

for

“Auto-

patch”

operation

(600

ohm

—

Refer

to

Section

4.7

the

"HOW

TO

USE

THE

TONE

PAD”

on

page

12.)

Mounting

Rail

—

Used

to

install

the

transceiver

on

the

supplied

mounting

bracket.

Snap

Lock

—

Used

to

lock

the

transceiver

body

on

the

supplied

mounting

bracket.

Stand-off

—

Can

be

attached

to

your

TR-7400A

during

operation

to

provide

a

convenient

angle

of

viewing

for

the

operator.

AS

ASA

CEU

NADA

UED

ETIDS

RED

ONE,

SECTION

3.

GENERAL

TIPS

ON

INSTALLATION

EUREN

3.1

MOBILE

USE

1.

Installation

Position

Your

TR-7400A

may

be

installed

under

the

dashboard

of

your

vehicle

for

convenient

operation.

Be

sure

that

its

posi-

tion

does

not

restrict

your

leg

movement

to

the

brake

pedal.

A

typical

installation

is

shown

in

Fig.

4.

2.

How

to

Install

(Fig.

5)

IMPORTANT

The

TR-7400A

is

designed

for

a

negative

ground

installation.

a)

Securely

install

the

mounting

bracket

with

the

suppli-

ed

bolts

and

nuts.

b)

Insert

the

transceiver

into

the

mounting

bracket

using

the

mounting

rails.

c)

Adjust

the

rail

angle

for

the

desired

position

of

the

transceiver.

This

assures

operational

convenience

and

safety

while

driving

the

vehicle.

d)

Unfold

each

snap

lock,

hook

on

the

pawl,

then

clamp

the

snap

lock.

Both

locks

should

be

fully

fastened

to

get

full

effect

of

the

spring

action.

Fig.

4

A

Typical

Installation

CAUTION

Be

sure

that

both

rails

are

fully

seated

in

the

mounting

bracket

before

clamping

the

locks.

B

O

d y

o

IIED.

LLL

LLL

ALA

LLL

LLL

Lah

hbk

LLL

Slide

the

set

into

the

bracket

as

far

as

possible

o

Lock

Pawl

Adjust

the

vertical

angle

of

the

set.

Hook

on

the

pawl

and

fold

forward.

Fig.

5

How

to

Install

3.

Connecting

the

Power

Supply

Connect

the

supplied

power

cable

securely

from

your

trans-

ceiver

to

the

battery/power

supply

posts.

Make

certain

that

the

red

lead

is

placed

to

the

positive

(+)

post

and

the

black

lead

to

the

negative

(—)

post.

If

necessary,

attach

the

power

cable

to

the

vehicle

body

at

the

appropriate

points

to

avoid

dangling.

NOTES

1.

The

power

cable

should

be

as

short

as

possible.

2.

An

alternative

way

of

obtaining

power

is

to

plug

the

cigar

lighter

arranged

in

most

vehicles.

Such

a

plug,

shown

in

Fig.

6,

is

available

at

auto

accessory

shops

or

electronics

parts

stores.

ASA

AA

AAA

AA

AA

ES

STA

A

A

AR

RS

SA

A

SA

AAA

AU

TEL

TEE

TTS

SECTION

4.

OPERATION

SIAM

ADAN

RIDAD

IIA

DUT

A

ADD

4.1

RECEIVING

1.

Connect

the

supplied

power

cable

to

the

DC

power

connector

(Ë

and

the

antenna

cable

to

the

ANT

con-

nector

00.

Select

a

DC

power

supply

or

battery

pack

having

8

to

10A

current

capacity

at

13.8V.

CAUTION

Make

certain

that

connection

of

the

positive

(+)

and

negative

(—)

power

cable

leads

have

been

connected

properly.

2.

Depress

the

POWER

ON

Switch(1)

The

digital

fre-

quency

Display

(8)

will

indicate

the

frequency

and

the

meter(5)will

be

illuminated.

3.

Set

the

TONE

Selector

Switch(@)to

OFF.

"4.

Turn

the

SOU

Control@)fully

counterclockwise.

5.

Turn

the

VOL

Control

clockwise

until

the

noise

comes

up

to

a

comfortable

level.

6.

Set

the

MHz,

100

kHz

and

10

kHz

Selector

Switches

12,

3,

and

5

kHz

Offset

Switch

(3)

to

the

receive

frequency.

If

an

incoming

signal

is

received,

the

Meter

(S)

will

indicate

the

signal

strength.

7.

To

eliminate

the

noise

heard

with

no

input

signal,

grad-

ually

turn

the

SOU

Control

(9)

clockwise

until

the

noise

threshold

is

reached.

3.2

FIXED-STATION

USE

If

you

operate

the

TR-7400A

as

a

fixed

station,

attach

the

supplied

Stand-off

bracket

(25)

to

it

as

illustrated

in

Fig.

6.

The

TR-7400A

is

designed

so

as

to

be

used

with

a

DC

power

supply

having

a

current

capacity

of

around

10A

at

the

rated

operating

voltage

of

13.8V.

Fig.

6

Use

of

Stand-off

Bracket

NOTE

Your

transceiver

is

normal

even

if

the

Unlock

Indicator

(6)

located

on

the

center

of

the

front

panel

lights

momentarily

after

selecting

a

frequency.

For

more

detailed

information,

refer

to

Section

4.6,

the

“DESCRIPTION

OF

UNLOCK

INDICATOR”,

page

12.

4.2

TRANSMITTING

1.

Plug

the

supplied

microphone

cable

plug

into

the

MIC

Connector

OD.

2.

Set

the

TONE

Selector

Switch@)to

OFF.

Set

the

TX

OFFSET

Switch

(7)

to

SIMP.

4.

Set

the

MHz,

100

kHz

and

10

kHz

Selector

Switches

(42,

(9,

(9

and

5

kHz

Offset

Switch

(15)

to

a

desired

channel.

5.

Depress

the

microphone

push-to-talk

switch

to

operate

the

TR-7400A

in

the

transmit

mode.

The

ON

AIR

Indicator

(@)

will

light

and

the

meter

(5)

pointer

will

deflect

to

indicate

the

RF

output

power.

6.

The

best

separation

between

your

mouth

and

micro-

phone

is

5

to

10

cm.

e

NOTE

You

can

check

the

operational

condition

of

the

antenna

system

by

observing

the

reading

on

a

standing-wave

ratio

(SWR)

meter.

It

is

recommended

that

the

antenna

system

SWR

is

1.5

:

1

or

less.

The

transmit

power

will

be

reduced

by

a

protection

circuit

when

the

SWR

is

too

high.

The

TR-7400A

is

designed

so

that

the

Meter

©)

will

read

“8”

when

operating

high

power

(25

watts)

into

a

50

ohm

load.

The

antenna

system,

therefore,

is

acceptable

if

the

meter

reads

around

this

value.

The

meter,

in

this

sense,

acts

as

an

SWR

indicator.

4.3

HOW

TO

USE

THE

TX

OFFSET

SWITCH

The

TX

OFFSET

Switch

D

used

mainly

for

repeater

opera-

tion,

has

three

positions:

SIMP:

Your

TR-7400A

operates

in

the

usual

simplex

mode.

That

is,

the

RF

receive

and

transmit

fre-

quencies

are

the

same.

This

frequency

is

indicated

on

the

Digital

Fre-

quency

Display(8).

+600:

Your

Transceiver

can

be

used

for

repeater

opera-

tion.

The

Repeater

indicator

)

will

light

red.

The

RF

reception

frequency

is

the

same

as

indi-

cated

on

the

Digital

Frequency

Display

,

but

the

RF

transmit

frequency

is

600

kHz

higher

than

indicated.

146.00MHz

146.010MHz

146.400

MHz

FM

REPEATER

147.00MHz

146.610MHz

FM

REPEATER

FM

REPEATER

—600:

Your

Transceiver

can

be

used

for

repeater

opera-

tion.

The

Repeater

indicator

@

will

light

green.

The

RF

receive

frequency

is

the

same

as

indicat-

ed

on

the

Digital

Frequency

Display

,

but

the

RF

transmit

frequency

is

600

kHz

lower

than

indicated.

NOTE

The

TONE

Selector

Switch

(8)

can

also

be

used

for

repeater

operation.

Please

refer

to

Section

4.5,

the

“HOW

TO

USE

THE

TONE

SELECTOR

SWITCH”,

BUR

position,

page

10.

CAUTION

1.

The

TX

OFFSET

Switch

(7),

as

described

above,

shifts

600

kHz

higher

or

lower

only

the

RF

transmit

frequency

of

your

Transceiver

irrespective

of

the

posi-

tions

of

the

MHz,

100

kHz,

and

10

kHz

Selector

Switches

(2,

(3

,

(4

and

5

kHz

Offset

Switch

(5

,

leaving

the

RF

receive

frequency

as

displayed.

In

general,

repeater

operation

is

done

by

setting

the

TX

OFFSET

Switch

(7)

to

+600

for

the

Frequency

range

of

147.000

to

147.390

MHz

and

to

—600

for

146.610

to

147.000

MHz

(see

Fig.

7).

2.

In

using

the

TX

OFFSET

Switch

(7,

particular

care

should

be

observed

not

to

transmit

out

of

the

fre-

quency

band

of

144

to

148

MHz.

148.00MHz

147.39

0MHz

147.600MHz

147.990

MHz

FM

REPEATER

OUTPUT

Yu

EE

——

EEE

OUTPUT

INPUT

AY

TR-7400A

TR-7400A

TR-7400A

TR-7400A

TRANSMIT

RECEIVE

RECEIVE

TRANSMIT

FREQUENCY

FREQUENCY

FREQUENCY

FREQUENCY

<

RANGE

RANGE

x

RANGE

RANGE

Ir

TX

OFFSET

TX

OFFSET

Fig.

7

Layout

of

the

Two

Meter

Band

4.4

HOW

TO

USE

THE

HI/LOW

SELECTOR

SWITCH

Occasionally,

it is

desirable

to

lower

the

RF

transmit

power

to

reduce

battery

drain

or

drive

an

external

amplifier.

Depressing

the

HI/LOW

Selector

Switch

@)to

LOW

will

reduce

the

RF

transmit

power

from

25W

to

5W,

which

is

read

as

“3”

approximately

on

the

Meter

(5).

4.5

HOW

TO

USE

THE

TONE

SELECTOR

SWITCH

The

TONE

Selector

Switch(3)has

four

positions:

SQU:

Sets

your

transceiver

to

the

“tone

squelch”

mode

of

reception

with

the

Tone

Squelch

Indicator

@)

lit

red.

The

tone

squelch

circuit

built

into

the

TR-

74004,

called

the

“CTCS”

(continuous

tone

con-

trolled

squelch)

is

operated

by

the

tone

signal

of

a

specific

frequency

that

has

been

superimposed

with

the

your

voice

signal

onto

the

carrier

in

the

`

TX

unit

and

is

separated

in

the

RX

unit.

You

may

select

any

desired

tone

frequency

by

choosing

one

of

the

tone

squelch

active

filters

listed

as

options

available

for

the

TR-7400A

in

Table

1.

Figure

9

shows

installation

of

the

tone

squeich

active

filter

on

the

PC

board

supplied

with

your

TR-7400A.

Figure

8

shows

installation

of

the

PC

board

in

the

RX

unit

(X55-1150-10).

Frequency

(Hz)

Parts

number

88.5

L79-0408-05

94.8

L.79-0409-05

100.0

L79-0410-05

103.5

L79-041

1-05

107.2

L79-0412-05

110.9

L79-0413-05

114.8

L79-0414-05

118.8

L79-0415-05

123.0

L79-0416-05

127.3

L79-0417-05

131.8

L79-0418-05

136.5

L79-0419-05

141.3

L79-0420-05

146.2

L79-0421-05

151.4

L79-0422-05

156.7

L79-0423-05

Table

1

Tone

Squelch

Active

Filter

List

Bottom

side

Fig.

8

How

to

Install

the

Tone

Unit