Gates Radio Company BC-250GY-1 Instruction Book

INSTRUCTION

BOOK

FOR

TRANSMITTER

GATES'

a

MODEL BC-

250GY

-1

I.B.

#888

0836

001

Gates

Radio

Quincy,

Company

Illinois

Please

modulation

the

MODULATION

read

these

TRANSFORMER

instructions

transformer

in

INSTRUCTIONS

before

this

attempting

transmitter.

to

test

The modulation

type

may be of

in the

ings whereas

may

modulation

order to

In

transmitter

the

a.c. to

half of

ating

equal.

a

primary

indicate

in reality,

transformer

properly

the the

secondary

primary

normally,

transformer

which

windings.

that

will

An ohmmeter

the

this

is

is performing

check

circuit,

merely

winding.

then

these

employed

indicate

in this

unequal

transformer

normal

a

reading

normally.

this

transformer

apply

Check

If the

voltages

transformer

should

check

defective;

is

volts,

117

voltage

the

transmitter

resistance

wind-

the

of

the

and

60

on

is

of

cycle

each

oper-

outside

asproximately

be

Gates

Quincy,

Radio

Company

Illinois

INDEX

Page

SECTION

- INTRODUCTION

I

- BC- 250GY

II

Oscillator

Intermediate Power

Audio

Amplifier

Chassis

Relays 8008

Rectifier

Transformers

Wiring

Detail

Connecting

III -

IV

INITIAL

General

Tuning

Making

- TYPICAL

Operational Procedure Performance

TRANSMITTER

-1

Unit

Amplifier

Tubes

the

TUNE

Load

-UP

VOLTAGE

DETAILS

Procedure

Measurements

AND

CURRENT

e

CONDITIONS

OF BC-

250GY

-1

1

2

3

4 4

5

6

7

8

10

13

16

PARTS LIST

ADDITIONAL

PHOTOGRAPHS

DRAWINGS:

Conclusion

Warranty

INSTRUCTION

M -5422

Helpful

810

.813

813

842

Oscillator

General

4339 001

9110

9191

3887

001

BOOK

Unit

Information

Detail

-

- Frequency

- Transformer

- Overall

Control

Circuit

/Load

Determined

Connections

Schematic

16

17

1

-3

A -

E

Components

9/11/63

-1-

BC-250GY-1

Rated

Power

Output

SPECIFICATIONS

Watts

250

Capable

Power Output

Frequency

R.F.

Output

Frequency

Carrier

Audio

Shift

Distortion

Response

Residual

Audio

Input

Range

Impedance

StTbility

Noise

Impedance

Level

280 Watts

KC

540

-1600

30 -300

+ 5 cycles

3% or

ohms

less

less 50

(as

at 95%

90% modulation

DB

+ 1 -1/2

DB 30 -

+

2

least 55

At

30

12,000

DB below

modulation

500/600

DB

+ 8

ohms

+ 2

DB for

ordered)

modulation

- 7500

10,000

-

cycles

100%

cycles,

cycles

100%

modulation

Primary

Power

Consumption

Size

Weight

Tubes:

Supply

and

Cubage

Volts,

230

KW at 95%

1.6

78

high,

900

pounds

Oscillator

1st

IPA

2nd

IPA

Power

Audio

Amplifier

Driver Modulator Main

L.V.

Rectifier

wire,

2

modulation

wide,

34"

packed;

12BY7A

-

12BY7A

-

813

-

50/60

33"

112

810

-

deep

cubic

6L6G

810

8008

5V4GA

cycles

feet

(2)

-1-

BC-250GY-1

INTRODUCTION

SECTION

The

Gates

BC

transmitter

radio

tained

The

and

Radio

The

540 to

broadcasting

will

it

F.C.C.

is officially

Company

radio

frequency

1600

components frequency

of critical

specified

components

more

one

factory

or

immediately.

-250GY

having

give

rated

power

Model

KC.

are

supplied

antenna

could

circuits

Transmitter

every

station.

years

modern

of

the

of

approved

BC -250GY

of

case

for

ordering.

In

range

each

when

loading,

error,

in

be

not

complete.

modern

a

is

feature

When

properly

trouble

-250GY

BC

records

the

on

Transmitter

the

BC -250GY

specific

operation

the

calculated

making

high

demanded

installed

-free

service.

transmitter

F.C.C.

of

amplitude

for

transmitter

frequency

the

of

In certain

transmitter

frequency

resonance

In such

cases

fidelity

modern

the

by

and

250

is

a

as

modulation.

is

determining

rare

situations

determining

and

/or

loading

advise

main-

watts

Gates

from

the

on

the

of

The

load

radio

from

frequency

30

components.

load

active,

will

The

ation. on

usually

ditional

with

impedance

such

required.

be

radio

Each

plan

the

plans

special

the

Gates

sentative

output

ohms,

300

to

also

is

It

specified.

be

with

as

transmitter

station

operation,

of

the

transmitter

equipment

Sales

factory

the

at

or

be

can

but

can

essential

If this

is

fed

only

own

direct

a

unit

has

its

location,

and

will

Engineering

office.

arranged

so

that

do

in placing

not

load

tower,

one

part

individual

etc.

antenna

desired.

be

Staff,

either

to

with

match

a

single

a

the

impedance

compensating

of

the

station

requirements

The

Consulting

system.

For

the

At

this,

field

resistive

set

is

the

re-

order,

also

components

installdependent Engineer

times,

ad-

consult

repre-

of

-1-

BC-250GY-1

BC-

250GY

TRANSMITTER

-1

SECTION

^AILS

DET

II

The

following

general

the

to

transmitter

the

is best

it

pertaining

as

Oscillator

The oscillator

facing

stage.

vacuum

mounting

The

in a

plate

operation

separate

supply

chassis;

voltage.

M -5422

the

ample

power

to

Unit

back,

the

This

is the

crystals.

screws,

are

a part

A voltage

oscillator

to

information

construction

itself.

the

unit

at

is located

look

to overall

directly

standard

It can

unplugging

and

M -5422

the

of

section

of

obtained

of

this

supply

divider

unit,

drive

the

BC -250GY

the

on

operational

and

modern

all

in

As

transmitter

performance

the

on

below

be

the

Gates

M -5422

readily

the

oscillator

from

instruction

a power

also

this

delivers

with

and

following

transmitter

detail

transmitting

various

its

in

detail.

inside

813

intermediate

left

Oscillator

removed

by

connecting

unit

is

supply

used

is

book.

on

for

approximately

this

813

voltage

stage.

pertains

surrounding

equipment

sections

the

of

amplifier

Unit,

loosening

cable.

explained

The

the

filament

audio

modulator

volts

150

unit

the

cabinet,

using

in

four

detail

and

the

driver

bias

to

delivers

The

on

813

the

ating

stage

813 chassis.

when

structions

This

the

will be

plate

is

the

for

filaments

the

approximately

the

of

characteristics,

normal

tubes

quency

heat

will

having

are

crystals

calibrated

retested

The

been

transmitter.

within

range

of

to

be

reach

to

are

in

It can

a very

few

adjustment

due

equipped

The

maximum

813.

and

The

are

emission.

the

to

stable

a

normally

in a the

M -5422

be

cycles

of

grid

on,

grid

8 -

a

oscillator

can

current

10

with

M -5422

are

vacuum

operable

Any

requirements

heat

level.

received

oscillator

anticipated

of

the

frequency

specified

current

tuned

be

meter

unit,

reading

milliamperes

crystals

frequency

on

delay

There

from

unit

that

have

in

the

of

the

unit,

supplied

the

setting

are

supplier

and

frequency

frequency,

trimmer

condensers.

M8,

which

according

the

on

without

zero

as

temperature

soon

the

frequency

gaps

no

after

before

with

within

mounted

oper-

is

in-

to

meter

M8.

voltage

the

as

fre-

monitor

set.

to

having

shipment

the

will

be

the

on

9/11/63

-2- BC-250GY-1

Intermediate

Amplifier

The 813

oscillator condenser

coil

intermediate

unit (tube

directly

is

center

power amplifier

end.

The

resistors

imately 350

voltage

plate current

M6.

C24,

rent.

On

the

low

of

The intermediate

in

the plate

same

value

extremely

screen

which

volts on

furnishing

and

of

the 813 tank

coil

relative

of capacity

low capacity

amplifier

V6) and

adjacent.

tapped

to

voltage

are normally

to ground

the opposite

is obtained

the

screen,

ample

the

intermediate

amplifier

circuit

L7, the

tap

from

tune

to

is located

The

its associated

intermediate

has

with neutralization

end from

set

at the

allowing

drive

for

amplifier

tunes

and

is tuned

taps (when

the center

should

which

will tend

directly

that of

through

factory

a

the

to

used)

tap.

be

power

resonance

to

should

used,

to

above

coil

and

amplifier

the

of

the

two

voltage

to

margin

grid

obtain

high

for

amplifier.

is indicated

by capacitor

minimum

plate

always

much coil

As

except

result

to

in arcing

the

tuning

tank

final

drive

dividing

approx-

line

The

meter

on

cur-

on

be

and

a point

as

the condenser.

in

In case

of changing

viously supplied

valuable.

will

For 1200

(first

turns)

full coil 650

condenser

be

KC to

from center

tap

will

provide

provides

KC to 720

(C41),

1600

KC requires

Power Amplifier

The power

allel.

inductive harmonic

capacitor

of

capacitor

frequency

amplifier

The

load

branch

radiation.

C33,

C32.

is usually

and

frequency

when

and from

manufactured,

The tuning

KC use

tap).

tuning

a

tuning

15

from

the addition

550

consists

is connected

the

of

and brought

The value

tank

The final

of

properly

to a

ranges

turns

The second

range

KC to

of two

new frequency

the

will

on

from

KC to

720

650

810

through

circuit,

amplifier

exact

to

determined

C33

is

provided

following

be as

each

1500

of

KC, a

side

tap

1100

200

a

from

KC to

KC.

400 mmfd.

tubes

pass

low

a

system

a

resonated

is

frequency

at

from

that

information

follows:

center

of

center

950

Tuning

mmfd.

padding

operating

filter

which

minimizes

by

the

by

time

the

carrier

shipment.

of

pre-

tap

(21

KC.

The

from

padder.

in par-

the

to

means

variable

9/11/63

-3-

BC-250GY-1

In

some

very

ser

amplifier

the antenna

mation

instances of

low

C33,

impedance

may be

as to the

will

immediately

antennas,

affected

not

and

resonate

would only

antenna

supplied

unusual

loading

the

as

applied

with

be

loading

or

the factory.

to

value

to normal

the load

in case

characteristics

conditions,

tank padding

of

charts

applied,

direct coupling,

of

particularly

conden-

the

and

it

if

would

be

infor-

should

be

Audio

The audio

cabinet

Class

on the

oscillator

vacuum

tubes

bottom

Chassis

chassis

facing

A audio

top

of

-bias

type

time

terminates

the

of

approximately

plate

For

sary

back

servicing

bias

the

voltage of

under-

to

chassis

remove the

revealing

where

power

supply

negative

modulators,

the

is

rear

the

driver,

the chassis

supply

delay

modulation

to

cabinet.

volts.

375

main

the

servicing

knurled under-

all

required.

is so

this

side

which

of

individually

is

hinged

and

the push

and

relay

accommodates

-pull

and

The

The modulator

also

its

E6.

plate

power

of

thumb

chassis

It should

constructed

supply

chassis

on

the push

Class

accommodates

associates

The output

transformer

voltage

tubes operate

supply.

the

audio

screws

wiring

that

to provide

deck,

and

and components

noted

be

60

adjustable

right

the

-pull

B 810

5Ú4G

T3, located

to

modulator

the combination

tube

of the

the

6L6G

is only

it

this chassis

that

volts

bias

by

the

is taken

voltage

bias

hand

of

6L6G

tubes

the

and

810

modulator

the

in

tubes

the

at

neces-

hinges

for

fast

oscillator

for

resistors

the

(1622)

is

full

from

the

R4 and

R5.

Relays

The thermal

audio

filaments

delay

a

from

67 and

overloads

the

few

Using

not

emergency

(4/11/63

chassis;

of

relay

temporary

the audio

68.

may

bias

voltage

seconds

transmitter

the

recommended

procedure.

operating

the

6L6G

filament

control

tubes.

by accident

expedient

can

chassis

In

this

trip

after

way there

from

having

not

the

initial

without

the

and

or

be

and

cold

a

above

time

element

In case

failure,

had

by

placing

no time

is

start.

obtained

start

time

the

mentioned

is

-4-

delay

being

to

relay

connected

of breakage

resume

removing

a jumper

delay

This

full

no

value.

trouble

delay

mounted

is

across

of

operation

the

between

time

terminals

action

is usually

By

for

be

of

servicing

will

tube,

only

BC-

on

the

time

delay

and

the

due

tube

to

waiting

encountered

course,

250GY

-1

the

a

is

and

oduïator

filament

the

the current the circuit

contacts

normal

cause

operation,

the overload

contacts

contactor

to chatter,

occurs.

becomes

through

in series

were used

coil,

or

Both overload

resistors for

unshunted

gives a

shorted required

about

at

overload

load

does not trip

ulators,

venting

operating

higher current

out on the

to trip

400 milliamperes, does not trip

the

distortion

and

sower

ampliiier

return circuits.

sufficient,

auxiliary

an

with

the

high

modulation

armature

to operate

these

modulation

possibly

to pull

drop out,

relay coils

setting

the overload

current

rating.

is

resistors

the

respective

heavy

with normal

with

resistors

through

normal program.

also

load the

this

stages

These are normally

the contacts

relay

voltage

may provide

open.

directly

cycles

although

are

current

MA

300

Increasing

R27

and

relay.

enough

tuning

have

with normally

contactor

sufficient

If normally

in series

would

no

shunted

point.

and shunting

the amount

R28, raises

The relays

that

and the

In the

inductance

element.

overload

open.

close,

relays

completing

closed

coil.

current

closed

with

cause

overload

the plate

the

actually

by adjustable

The normal

with

that

the current

should

the power

amplifier

modulator

case

of

of the

the

coil,

in

When

Under

to

contactor

resistors

is

trip

over-

mod-

pre-

8008 The 8008 mercury

ature.

tube has

verse

the

Rectifier

If

a

direction,

transmitter

as-unattended

may become

directly

which

and

minor

Another

replaced

is

modifications

solution

transmitter

furnaces,

certain

adjusted

value

energized.

haust

the

fan

thermostat

around

tifiers

Q /11 /Fiji

could

degrees.

95

is

Tubes

temperature

the

tendency

and

excessive,

not

cabinet

such

Similarly,

operating

NOT recommended

vapor

rectifier

is too

to "arc-

resulting

is

operated

in a unheated

mercury

the

a type

by

nearly

so

by semi

is to

install

with a

that

so

as 75

installed

be

degrees,

if high

when the

Operation

are

too

conduct

voltage

back"

in

a

tubes

high or

or

high

where temperature

building,

vapor

using

xenon

sensitive

-conductor

a heating

thermostat when

the temperature

the heating

to temperature,

or

rectifier

or

rectifiers.

element

control

temperature

top of

the

in

temperature

of

above

this

120

equipment

°F or

below

-5-

temper-

sensitive

low,

current

short

is a

where the

some

other

such

drops

element

is a problem,

the transmitter,

reached

with

45 °F

to

this

in the

circuit.

problem,

tubes

inert

or

inside

as used

below

will be

a

mercury

ambient.

25flGY

Re-

type

temperature

may

with

the

an

value

of

re-

When

such

be

gas

for

a

ex-

with

of

rec-

-1

Transformers

the

Several

of

terminals.

a.c.

line

nects

at the

to

always connects

terminal

specified

connecting

by

terminal

this

Wiring

The power

Most

local

ation

load

This transmitter

source.

#3.

operating

Detail

line connections

wiring

regulations

will

current

It will

modification,

transformers

With

terminal

to

the

Transformer

manual.

regulations

meet

is

but

these

for

#3

load.

line

should

all

8.5

requirements.

amperes.

requires

not

operate

designed

is

are provided

transformers,

terminal

to

normal

The secondary

instead

#2

terminal

to

voltage

of

##4 instead

diagrams

made

are

require

a service

be checked

The wire

volts

230

on a

to

208

operate

voltage

of

The other

one

#1.

with

side

output

voltage

terminal

included

are

directly

may be

#3,

of connecting

to

switch

so that

The maximum

size

a.c.

the

should

single

volt power

either

change

the

on

incoming

side con-

the

secondary

raised

lowered

or

elsewhere

fuse

the

with

fuses.

initial

normal

phase

transmitter

#8

be

power

source

cycles

50

on

by

to

in

block

A7.

The

install-

or #10.

without

or

cycles.

60

The audio

the

rear

should

working may

If

put pad,

having

mitter

of

be

the

be

equally

had

output

a

and

response.

The

frequency

located

modulation

The

Both

will

used.

are

pins not

Sometimes

high

so

9/11/63

input

line

modulator

shielded

a

well

changing

by

amplifier

is advisable

it

5

loss

of

amplifier

monitor

radio

the

on

monitor

are connected

connected

be

audio

that

seldom

connects

panel

pair.

with

primary

to the

to

DB to

6

or

to

and

jack

frequency

connection

together.

wrong.

cable

are the

terminal

the

to

(right

The transmitter

either

side,

ohmage.

taps

on

the

transmitter

fixed

side

is for

a

no

for

panel

insert

assure

introduce

is fitted

This

Small

is tried,

size

results

-6-

board

facing

input

Other

input

from

is

input

transformer

does not

pad,

"H"

reaction

errors

single

a

at the

two

a

insures

-axial

co

the

losses

between

in

bottom

pin connector.

that

cable

and

satisfactory.

at the

rear).

bottom

500/600

impedances

have

an

500/500

trans-

frequency

connector

rear.

the

two

should

capacities

250GY

BC-

This

ohms,

T8.

outohms

lines

be

-1

on

go

transmitter

should

The

the

to

top

the

of

radio

The

itself

lations.

recommended.

down

and connecting

inside

Connecting

the

cabinet

grounded

be

radio

the

frequency

cabinet

system

In some

installations,

transmitter,

strap

a

to

Load

should

cable

by

adjacent

ground.

behind

from

well

be

to

output,

to

least

At

the

there

grounded.

meet

underwriters'

which

feedthru

the

2"

a

this

to

lead

side

the

is

copper

might

panel

system

The

cabinet

bowl,

strap

be

the

to

ground.

regu-

stud

should

is

dressed

base,

The

coaxial

antenna

connects

transmitter.

wire

line that

mitter

be

the

ing

transmission

should

the

ground

cabinet.

brought

up

convenient

engineer's

open

or

to

In the

firmly

be

path

Where

through

locations

eye.

wire

the

case

line,

secured

will

the

transmission

feedthru

of

the

ground

not

desired,

bottom

will

as

insulators

coaxial

the

to

have

the

of

be

line

or

on

transmission

portion

top

travel

to

coaxial

the

quickly

of

the

of

transmission

cabinet

obvious

the

direct

top

line

transmission

the

cabinet

through

any

at

of

or

the

to

coupled

the

open

also,

tríns-

line

number

the

install-

so

may

of

9/11/63

-7- BC-250GY-1

SECTION

III

General

Before

Operational

proceeding

necessary

portion

of the

1 -

2 -

3 - Froper

4 -

5 - A

6 -

7 - Looking

8 -

9 -

with

things

to

transmitter.

Proper

Froper

line

location termination

equipment.

for

of

shipping

Removal used

recheck

have

Complete

and

been

check

wrench

connections

have

been

over

making Making

that

main

sure

certain

ground

the

ground

IMPORTANT.

Making

certain

correction connecting

INITIAL

Procedure

initial

before

be

the

done

voltage

all

of

-down

tie

all

purposes.

be sure

to

installed

the

of

sure

be

to

that

brought

all

that

of

AT

taps

to

could

down

wiring

everything

the

to

the

LEAST

that

have

terminal

TUNE

Briefly,

to

-UP

fuse

tubes

the

any

-up

voltage

tune

check

block

in

antenna

straps

components

properly.

transmitter

bolts,

all

possibly

securely.

broken

for

is

transmitter

the

transmitter

antenna

COPPER

2"

system.

transformers

one

side

#1.

let

the

A?.

the

and

sockets.

or

other

removed

with

screws

work

solder

secure.

well

is

STRAP

with

the

of

recheck

us

applied

is

following

dummy

antenna

materials

for

a

loose

shipment

screwdriver

and

other

shipment

in

connections,

grounded

the

IS

to

VERY

tied

THIS

RECOMMENDED.

voltage

supply

line

the

any

to

list:

and

-

10

In case

the

building,

the

varied

equipment.

ground

formance

With

closed

the

and

"Filament

power

unit

tions

supply

tuned

is

for

9/11/63

Making

and

output

sure

that

wire

the

no

transmitter

particular

Additional

potentials

and

low

noise.

transmitter

power

ON"

supplied

switch

for

the

according

this

unit.

audio

wiring

shields

input

or

wire

power

a

located

is

attention

ground

highly

is

ready

Sl,

M -5422

When

to

lights

oscillator

the

to

the

-8-

the

been

has

have

been

runs

cable.

on

must

in

the

be

busses

important

operate,

transmitter.

tube

the

directions

transmitter

properly

the

same

upper

and

to

elimination

paid

for

the

service

filaments

unit.

given

has

shielded

grounded, cable

floor

of

grounding

good

per-

switch

Pressing

and

The

oscillator

the

in

been

factory

-250GY

BC

an

as

a

of

is

the

instruc-

-1

tested

the

on

current

which

of

should

the tube.

frequency,

on tuning.

The 813 stage

meter, and

8 -

be

this

the

10 milliamperes

should

is provided

oscillator

amount

tuned

with

to

no

more

than

with a convenient

for

no

maximum

voltage

grid

on

check

a

grid

current,

the plate

Before pick -up coil

far

the modulation

stats

clockwise.

applying

L12, for

removed from

monitor

R4

R5

and

Set the

Remove the plate

making

sure

Disconnect

and

2 or

30 seconds,

light

will light.

voltage

close.

contactor

ON condition,

the connector

the

whichever

3

"ON" switch

primary

the

Pressing the

to open.

opening

high voltage,

the

minimum

the

to

tank

input.

maximum

neutralizing

connector

of

is used.

time

delay

With

should

S2

high

With

the

set

coupling,

possible

coil

bias

as

the two

Set

voltage,

condenser

from

is not

the plate

one

grounded.

When

E6 closes

door closed,

the

relay

back

cause

voltage

the contactor

back

"OFF"

door should

modulation

the

right

at

so as

modulator

that

of the

transformer

the filaments

is,

C28

8008

and

at half

rectifier

Tl, terminals

the

pressing

the plate

switch

closed

contactor

should

in

cause

monitor

angles

not

to

bias

fully

capacity.

have

been

"FILAMENT"

the

cause

high

the

contactor

and

as

overload

rheo-

counter-

tubes,

1

on

high

E4 to

this

voltage

open.

to

the

high

insulating

El

and

and cause

Opening

S4,

dowel or

relays

operate

armatures

NEVER

If

be touched

the

control

exists and

voltage

incurred

be

With

transformer

the

control

transformer

adjusted. 9/11/63

door

voltage

then

these

of

should

while

may

and blocking

control

stick,

E2.

the

In each

plate

relays

with the

circuit

be

does

remedied

disconnected,

testing

circuits

reconnected,

be

holding

or

then

can

push

the

case

armatures

contactor

the

in

are

body.

not

operate

before

no damage

the control

functioning

the

and

-9-

the

be

the

to open.

220

as described,

door

closed.

of

auxiliary

volt

circuit

continuing.

equipment

to

circuits.

properly,

ridio

frequency

interlock

With

the

a

overload

relay

CAUTION:

and

some

With

the

high

BC-

switch

wooden

E3 should

The

should

fault

high

should

voltage

circuits

250GY

-1

Gates Radio Company BC-250GY-1 Instruction Book

Specifications and Main Features

Frequently Asked Questions

User Manual