Moseley Pcl-303/c User manual

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INSTRUCTION

MANUAL

MODEL

PCL-303/C

STUDIO-TRANSMITTER

LINK

www.SteamPoweredRadio.Com

I

INSTRUCTION

MANUAL

I

MODEL

PCL-303/C

STUDIO-TRANSMITTER

LINK

I

I-

I

MOSELEY

ASSOCIATES,

INC.

I

Santa

Barbara

Research

Park

111

Castilian

Drive

I

Goleta,

California

93017

I

Revised

I

October,

1972

I

www.SteamPoweredRadio.Com

I

I.

II.

III.

IV.

V.

VI.

VII.

VIII.

IX.

PCL-303/C

TABLE

OF

CONTENTS

Introduction

·

Specifications

A.

Overall

System

Specifications

Page

B.

Receiver

Performance

Specifications

1

4

C.

Transmitter

Performance

Specifications

Unpacking

and

Initial

Checkout

Installation

Antenna

Detailed

Description

of

Transmitter

A.

B.

C.

Transmitter

Operation

Transmitter

Circuit

Description

Transmitter

Remote

Control

D.

Transmitter

Adjustments

and

Alignments

Detailed

Description

of

Receiver

A.

Receiver

Operation

B.

Receiver

Circuit

Description

C.

Receiver

Adjustments

and

Alignments

Shipping

Instructions

Final

Te

st

Data

-i-

5

6

7

8

9

10

12

14

15

17

19

20

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I

INSTRUCTION

MANUAL

MODEL

PCL-303/C

STUDIO-TRANSMITTER

LINK

I.

INTRODUCTION

The

Model

PCL-303/C

Composite

Aural

Studio-Transmitter

Link

(ST

L)

is

a

wide-

band

system

de

signed

for

the

transmission

of

a

composite

FM

stereophonic

signal

between

a

broadcast

studio

and

a

remotely

located

FM

transmitter.

Ruggedly

built,

compact,

and

rated

for

continuous

duty,

the

Model

PCL-303/C

is

an

all

solid-

state

unit

employing

only

silicon

s

em'iconductor

s.

There

are

several

advantages

to

the

transmission

of

a

composite

·

FM

stereo

signal.

Some

of

these

are:

1.

Only

one

basic

RF

link

is

utilized

to

transmit

the

com-

posite

stereo

waveform,

including

the

19

kHz

pilot

sub-

carrier.

This

is

in

contrast

to

the

utilization

of

two

aural

ST

L

systems

to

convey

the

unmatrixed

LEFT

and

RIGHT

audio

signal.

This

results

in

an

equipment

cost

savings.

It

should

also

be

noted

that

a

67

kHz

SCA

subcarrier

can

also

be

applied

to

the

ST

L

for

direct

rebroadcast

_

by

the

FM

transmitter.

2.

The

stereo

generator

is

located

at

the

studio

site

where

adjustments,

if

required,

can

be

made

away

from

the

strong

RF

fields

found

near

large

FM

broadcast

trans-

mitters.

These

high

RF

fields

can

have

deleterious

effects

on

the

instrumentation

employed

to

properly

align

the

stereophonic

generation

equipment.

The

Model

PCL-303/C

Composite

Aural

STL

is

basically

the

same

as

the

·

Model

PCL-303

except

that

the

75

µsecond

pre-emphasis/

de-emphasis

networks

and

15

kHz

600

n

low-pass

filters

have

been

removed

from

the

transmitter

and

receiver,

respectively.

The

basic

modulation

response

capability

of

the

direct

FM

oscil-

lator

employed

in

the

Model

PCL-303/C

is

sufficent

to

accept

PCL-303/C

-1-

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and

faithfully

transmit

the

frequency

spectrum

required

for

FM

stereophonic

broadcasting.

Further,

the

bandwidth

of

the

10.

7

MHz

I.

F.

amplifier

of

the

composite-

system

receiver

has

been

increased

and

adjusted

to

follow

a

curve

which

yields

a

linear

phase

characteristic.

The

detected

composite

waveform

in

the

Model

PCL-303/C

receiver

is

passed

tprough

a

low-pass

filter

which

does

not

significantly

alter

the

phase

relationship

of

the

composite

signal

(does

not

degrade

separation).

This

low-pass

filter

will

attenuate

any

remote

control

or

secondary

program

subcarriers

multiplexed

above

the

composite

signal

(,

far

in

excess

of

the

requirements

of

FCC

Rule

73.

317(a).

The

Model

PCL-303/C

STL

consists

of

a

transmitter

and

a

re-

ceiver

each

mounted

on

a

standard

5¼" x

19

11

rack

panel

with

slide-out

provisions.

The

ST

L

receiver

is

a

crystal-controlled,

double-conversion,

super

heterodyne

type.

A

relay

is

included

in

the

receiver

to

mute

the

composite

output

should

the

incom-

ing

carrier

fall

below

a

given

preset

value.

In

addition,

Form

C

contacts

of

this

relay

are

terminated

on

the

rear

apron

for

use

by

external

alarm

or

control

circuits.

The

transmitter

incorporates

a

direct

FM

basic

oscillator

to

achieve

flat

response

and

uniformly

low

distortion

over

a

wide

modulation

frequency

range.

Provisions

are

included

on

the

transmitter

to

multiplex

two

~ubcarriers

for

remote

control

and

auxiliary

service.

A

special

extended-life,

quiet

fan

provides

cooling

for

the

final

power

amplifier

chain.

The

basic

direct

FM

oscillator

is

phase

locked

to

a

temperature-controlled,

low-

frequency,

reference

crystal

oscillator.

Also

included

in

the

transmitter

are

two

frequency-doubler

stages,

one

3-stage

Class

C

RF

power

amplifier,

and

a

parametric

·

multiplying

power

diode.

A

3-section

bandpass

filter

is

incorporated

in

the

STL

trans-

mitter

RF

output

circuitry.

A

sampling

diode

is

included

in

this

assembly

to

indicate

relative

RF

power

output

of

the

transmitter.

All

transistors

and

IC'

s

in

the

Model

PCL-303/C,

other

than

the

transistors

on

the

AFC

board

in

the

transmitter,

are

socket

mounted.

Both

transmitter

arid

receiver

units

are

fully

shielded.

PCL-303/C

-2-

I

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I

It

should

be

noted

that

the

Model

PCL-303/C

Composite

Aural

STL

can

only

be

used

with

those

types

of

FM

exciters

employing

a

direct

FM

oscillator.

Further,

the

unit

is

designed

basically

to

operate

with

the

Moseley

Model

SCG-3T

Stereo

Generator.

However,

it

is

possible

to

apply

a

signal

from

other

stereo-

phonic

generators

meeting

th~

requirements

of

FCC

Rule

73.

322.

The

input

level

requirements

of

the

PC

L-

303

/ C

transmitter

must

be

observed

to

obtain

satisfactory

results.

PCL-303/C

-3-

.

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II.

SPECIFICATIONS

Model

PCL-303/C

Composite

Aural

Studio-

Transmitter

Link

A.

Overall

System

Specifications

L+R

Frequency

Response

L+R

Distortion

L+R

SNR

Stereo

Separation

±0.

5

db,

50

Hz

to

15

kHz

Less

than

0.

75%,

50

Hz

to

15

kHz

65

db

for

35

µv

input

signal

Greater

than

35

db,

5.0

Hz

to

15

kHz

(assuming

that

input

stereo

signal

has

separation

1n

ex

c

es

s

of

38

db)

B.

Receiver

Performance

Specifications

Frequency

Sensitivity

RF

Input

Modulation

Acceptance

Intermediate

Frequencies

Spurious

Response

Stability

Maximum

Available

Composite

Output

Signal

Metering

Operating

Temperature

Range

Dimensions

Weight

Power

Requirement

Mounting

PCL-303/C

-4-

890

MHz

to

960

MHz,

crystal

controlled

Less

than

8.0

µvotts

for

20

db

quieting

50

n,

Type

N

female

connector

±200

kHz

1st

I.

F.

72

MHz;

2nd

I.

F.

10.

7

MHz

Spurious

and

image

responses

attenuated

more

than

60

db

Maintained

to

within

±0.

001

%

of

assigned

frequency

over

ambient

range

of

0°C

to

55°C

6

volts

peak-to-peak,

1000

n

minimum

load

impedance,

unbalance

Single

multimeter

for

monitor-

ing

essential

operating

parameters

0°c

to

55°C

5¼"

X

19"

X

14

11

17

lbs.

120/240

VAC,±10%,

50-60

Hz

Standard

19"

rack

I

www.SteamPoweredRadio.Com

I

C.

Transmitter

Performance

Specifications

Type

Direct

FM

RF

Output

Frequency

Stability

Multiplication

AM

Noise

Deviation

Spurious

Emissions

Emission

Symbols

Stereo

only

Stereo

and

67

kHz

SCA

Composite

Input

Multiplex

Inputs

Operating

Temperature

Range

Power

Supply

Power

Requirement

Cooling

Dimensions

Mounting

PCL-303/C

7

watts

nominal;

8

watts

maxi-

mum

into

nominal

50

!J

load.

Type

N

female

connector

Better

than

0.

001%

(0°C

to

60°C;

crystals

mounted

in

temperature-

controlled

oven

12

times

basic

oscillator

frequency

Better

than

75

db

below

carrier

reference

±70

kHz

for

l

00%

modulation

More

than

60

db

below

carrier

246F9,

255

kHz

B.

W.

290F9,

300

kHz

B.

W.

10,000

!J

unbalanced,

approxi-

mately

3.

5

volts

peak-to-peak

for

1

00%

modulation

Two

BNC

connectors

are

pro-

vided

for

subcarrier

channels

in

110-200

kHz

spectrum;

ap-

proximately

1.

0

volt

rms

for

20%

deviation

0°C

to

55

°C

Fully

regulated,

self-

contained

120/240

VAC,

±10%,

50-60

Hz

Convection

and

forced;

fan

has

long-life

bearings

5¼"

X

19

11

X

16

11

Standard

19"

rack

-5-

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III.

UNPACKING

AND

INITIAL

CHECKOUT

The

Model

PCL-303/C

transmitter

and

receiver

should

be

care-

fully

unpacked

and

inspected

for

concealed

shipping

damages

upon

receipt

of

the

equipment.

Retain

all

boxes

and

spacers

in

case

a

claim

is

to

be

made

against

the

carrier

for

damages.

Should

the

equipment

be

damaged,

IMMEDIATELY

file

a

claim

with

the

carrier.

The

top-shield

cover

of

the

STL

transmitter

should

be

removed

so

that

the

shipping

spacers

which

have

been

used

to

secure

the

various

shock-mounted

subas

semblies

can

be

removed.

It

is

also

recommended

that

the

receiver

top-shield

cover

be

removed

to

confirm

that

the

muting

relay

and

all

tran-

sistors

are

properly

seated

in

their

sockets.

This

visual

inspec-

tion

will

also

acquaint

the

user

with

the

location

of

the

key

components

in

the

equipment.

CAUTION:

Do

not

attempt

any

tuning

adjustments

on

the

receiver

or

transmitter

at

this

time.

All

tuned

circuits

have

been

pre-aligned

at

the

factory

and

should

not

be

adjusted

unless

proper

test

equipment

is

available

and

then

only

after

reading

the

Tuning

and

Alignment

Procedure

outlined

elsewhere

in

this

manual.

If

a

10

watt

50

n

RF

termination

capable

of

operation

at

950

MHz

is

available,

with

or

without

a

calibrated

wattmeter,

the

STL

transmitter

can

be

bench

checked.

With

the

RF

load

connected

to

the

output

of

the

ST

L

transmitter

and

the

line

cord

plugged

into

a

source

of

117

VAC,

50-60

Hz

power,

the

front-panel

RADIATE

switch

can

be

turned

on.

The

RF

wattmeter,

if

used,

will

immediately

indicate

between

6

watts

and

8

watts

of

output

power.

The

RF

output

meter

on

the

front

panel

of

the

PCL-

303/C

will

indicate

between

50

and

55

divisions.

The

receiver

should

be

placed

oil

an

adjacent

bench

and,

after

the

power

plug

has

been

connected

to

the

power

source,

the

power

switch

can

be

turned

o~.

It

may

be

necessary

to

care-

fully

insert

a

small

wire

into

the

Type

N

RF

input

fitting

on

the

rear

of

the

receiver

chassis

to

minimize

multipathing

effects.

Do

not

attempt

to

adjust

the

input

or

output

cavities

of

the

ST

L

receiver

and

transmitter

under

these

test

conditions.

These

are

PCL-303/C

-6-

I

www.SteamPoweredRadio.Com

I

preliminary

tests

and

should

be

conducted

to

become

familiar

with

the

basic

operation

of

the

system.

An

audio

test

signal

of

3.

5

volts

peak-to-peak

may

be

applied

to

the

Type

BNC

modulation

input

connector

on

the

rear

of

the

ST

L

trans

-

mitter

for

the

initial

transmitter

check.

This

signal

can

be

.

derived

from

a

standard

audio

oscillator

or

Model

SCG-3T

FM

Stereo

Generator.

An

oscilloscope

or

VTVM

should

be

connected

to

the

Type

BNC

output

connector

located

on

the

rear

of

the

ST

L

receiver

to

confirm

the

presence

of

the

test

signal.

Bear

in

mind

that

multipathing

conditions

can

exist

under

these

initial

checks

and

will

affe

.

ct

the

measurements

made.

Since

the

STL

transmitter

does

not

employ

pre-emphasis,

it

is

not

necessary

to

reduce

the

amplitude

of

the

input

'

signal

source

when

making

frequency

response

measurements.

(This,

of

course,

will

not

be

true

if

the

test

signal

source

is

derived

from

a

stereo

generator.)

IV.

INSTALLATION

The

Model

PCL-303/C

transmitter

and

receiver

can

be

mounted

in

a

standard

19"

wide

rack

using

the

slides

provided.

For

max-

imum

mounting

stability,

the

rear

of

these

slides

should

be

secured

to

the

rear

rails

(or

to

the

cabinet

walls)

with

the

brackets

provided.

The

external

connections

which

must

be

made

for

both

units

include

the

3-wire

power

cord,

RF

input

and

out-

put

cables,

unbalanced

shielded

composite

program

line

and,

if

used,

coaxial

cables

for

multiplex

subcarriers.

The

transmitter

should

be

installed

in

such

a

manner

as

to

allow

air

to

freely

circulate

around

the

equipment.

Transmission

line

considerations

will

determine

to

some

extent

the

placement

of

the

equipment.

As

lengthy

transmission

line

will

introduce

undesirable

amounts

of

attenuatio~

of

the

transmitter

output,

it

is

always

good

practice

to

place

the

STL

transmitter

as

close

·

as

possible

to

the

antenna.

If

a

long

length

of

transmission

line

is

required,

use

the

lowest

loss

line

possible

consistent

with

mechanical

and

economical

con-

siderations.

The

same

precautions

should

be

followed

in

locating

the

receiver.

Because

of

the

use

of

slide-mounting

rails,

it

is

preferable

to

use

a

short

length

of

RG

...

8A/U

coaxial

cable

to

con-

nect

the

RF

fittings

on

the

rear

of

the

ST

L

transmitter

and

re-

ceiver

to

the

actual

transmission

line.

This

prevents

damage

to

the

equipment

and

eases

use

of

the

·

slide-rail

mounting

technique.

In

all

cases,

constant

impedance

RF

fittings

should

be

used,

such

as

a

Type

N

connector,

on

the

transmission

line.

PCL-303/C

(Rev.

10/72)

-7-

Moseley PCL-303/C User manual

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