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lrJi<'(Jl-.)1ATI

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iJC-1T

IN..,TrWCTION

BCOY

-'•

it

!'~S•.

TrF,!t ·,O'

IFli·,D

r·o~

COf'E.LHAD

OP1

'.,h/

,'I'ION 640KC/

,~5rJKC

-

C8-

?':

7

1'hi:-- c•t~nd ·

,rd

RC-1·?·,

1000

.

att

broad

ca.

t · er

nsmittf!'r,

has

b

en

mo<

ified

to

OD~t"Rt

on

th

Conelr

d

requency

of

640

KC. The

rh1nge

from

P'iQ

tr,

thfll

r-e

.~

1

l

larly

used

broad

ca

t,

fre'1ueney,

o

ths

Conelr~d

fr

quency

o

6M) K ·

•,

.srr.omoliRhed

pr&cti

•.

lly

in.

tant

neously

by

the

operat

on

of

e,.

_v

ral

RF

relays

•ithin

the

transmitter.

These

rel

vs

are, . 11 ·~ctu~

ted

h:,

me

.n~

of

r

n~

lever

r-w

itch

located

on

r,

,e

right

.:rn;j

s

de

o

th

,

t:r

n~-

mit

t~r

ad

Jac

~~t

to

th

to

molula~or

Li·s

control•

• A

nee

indicating

l,

.

.u1

,..

lncat-.ed

iust

&

hove

the

swi.

ch

i~

lit

when

the

freou•ncv

r i an,,-e

re-

]

.':t

y

are

in

tEe-

fe

6

ul

!.

·

posi

·ion.

· · 1

!..

.1Sl

:c..

tAl. vPr,n.-d"ING Pk.O(.;""lJUh.l -

..

In

0r

~r

to

1

·t

?.ntan~ou_ly

c

b·,

m

g~

from

one

frequer:cy

,o

an0

·

h,,r,

ne

BG

- " T

tr;;.r.-:;,r,itt"'r

ha

b

e1

~

"'.1~ified

a~

follows

-

-h

gecond

os.iJJ-~tor

ur.it

(:·~422

~icts

\

ef>n

jn-t

Jled..i.

An

ah1~-:i.:.11um

sh

lf

has

t "'en

mount

en

across

the

j n,..j

de

front

of

the

t.ransmi

t,PJ"

nd

on

hie~

shelf

thP.

Conelrad

oscillator

nc

the

re

6

7.1lar

fr•quen.y

orcil-

lator

{d

)O!~

C)

a re

rlac

d.

The

regu

ir

o~cilla

tor

normal

1

y

i::

loc-

....

d

on

th

. c .:s.,iel

an,j

!:'helf

arsl'!rr.lily.

It

has

o~

_n

r

moved

::\nC.

i.

mo1rnted

~

on

the

right

s

ide

of

the

ho~iz01tal

~helf.

The

Conelrad

o~cillator

i

to

t.h

e

lt<>ft

of

t,h

~

rep;ular

oscj

llc1

or,

on

the

same

shel

r.

'I'

.ese

osciJlar,or

make

u

of

cahles

which

are

pl•1gged

into

the

bac

·

side

ot

the

oscillator

cha

sis.

Thh·

makes

for

easy

r~:nov

J.

of

each

oscil

~tor

for

ser

icin~,

if

n~ceesary.

A11

fr-

quency

control

relays

a ·e

ener

izPd

by

th_

two

S"'t.s

of

cont·lct.s

which

:'Art'!

a

pa.rt

of

+..,he

latchinf

r

lay

Kl6.

Thii

late}

L

,?..

relay

L,

locat-ed

on

the

panel

and

she

f

assembl

y ,

on

the

right

hand

sir!e

of

tho

tran.

rr.itter,

ju

t,

below

the

os~illator

shttl.f.

Two

set

of

3inv,1e

,

ol

doubl

throw

contacts

on

this

latchin

g

rely

do

the

energi2ing

of

each

separa

e bank

of

frequency

s~l~ctor

reldy~.

The

coils

of

this

l

tchtng

r~J

y

are

energized

by

230

volts

AC

which

:ivailable

th1

ough

th~

lev

r

s~l~

tor

switch

Dq/,..9Al

if

th

0

filament

circ

1

J;\t

of

the

EC-1T

tran.,rr.it

t

is

de-energiz"d•

. A

pa

rof""norr.1aI!y

c!o-ed

contact"on

the

filam

n€

start

el~y

Kl

re

in

series

with

230

vols

AC,

the

lever

selector

~wi~ch

S9

1

S9A

~nd

the

coils

of

latchi

g

rAlay

Kl6.

If

the

filaments

ar~

off•

the

opera

ion

of

the

sel~ctor

switch

S9/S9A 11 entr-r ,

ize

on~

of

the

coils

of

the

latching

relay

16

{either

for

Coni'!lrad

or

regular

frequ

ncy),

t

lis

in

turn

will

rn~chanically

latch

n a

set

of

ontacts

which

will

cl

ce

th

AC

230

volt

circuit

to

ne

of

the

two

frequency

chan~e

bank

of

RF

relays.

(Thls

ci

cuitry

is

shown

on

overall

~chematic

C7:~o.,O

included

1

.-.1

1-

th!

s

nstruction

book.)

Bear

in

mind

it

is

imno~sj

J

~

to

chan

•

o~

rgti

~

f

enuencv

of

this

r&

emitter

wnile

the

oiat

or

ilam~nt

cir-

c~1

1~

en

r~ized:

This

Proc~dure

was

inco

o

·ated

to

make

the

ooe

a-

tin

fool-?r-oof,

it

cannot

be

swit,chr>d

with

any

h1

,h

voJ

age

apolied

,o

the

vario

cir

uits

of

ne

transmitter.

This

prec

udes

the

cossi-

bili

y

of

a-cin

co~tacts

•

.

,:

)

KC

oneration

th

following

rel

y

will

be

er

t'!r

~ized,

,

O,

'

'-' -

,.,

I

Tne~ r

lays

h

ve

en

~elected

by

the

op

r

tlo~

of

h

t

tr

n

,1

ter

filurn

n.

c

rut

d

-en

r_

z~d

at

~h

i

...

-

www.SteamPoweredRadio.Com

..

S9A

op.rat'on.

The

function

of

each

relay

of

this

group

will

be

d-

cr·ted.

1-lelay

K8

Is

-

used

to

swi

t

ch

the

two

o

ell

la

tor

units

that

are

a

part

f

thi

transmitter

into

the

~rid

circuit

of

the

6BG6G

RF

driver

sta~e.

A

set

of

double

pole,

double

throw

con

actn

perform

two

switchin

functions.

With

K8

nergized,

on1?

iLt

of

contact

connects

the

s:

0

KC

oscillator

unit

output

to

th(:;

i;rid

circuit

of

the

driver

sta

.,

,

as

m.

n-

t

ioned

previously,

the

othE"r

:=:et

of

contacts

switch

the

pla

e

vol

ta

;Je

to

the

850

KC

oscillator

unit.

Physically,

this

relay

is

located

on

th

panel

and

shelf

5

embly,

it

1 on

the

inside

of

the

ri

ht

hq

.

section

of

the

trans

itt

r .

Th

right

side

of

the

cabinet

mus e

remo ed

to

service

this

r

lay.

R

lay

1<9

i

located

just

below

th~

R~'

driver

coil

nd

behind

the

two

RI-,

driver

vari~hle

tank

condenger.

•

This

loc

tion

is

ju

:;t

to

tl.e

right

h nd

side

of

the

oscillator

mounting

shelf,

on

the

inside

o~ he

trans-

mi~ter

car.in~t.

This

relay,

when

ener

ized

or

S50

KC

operation

co -

n

-C

s

the

variable

condenser

C7

and

it

p

dder

corn1ens

r

Cl

5

;_

"'~•c,r.s

th

eoil,

L8

and

when

a.d.'usted,

Will

tune

the

HF

driver

s

a.er@!!

to

~r::')

KC.

Relay

KiO

iR

loc

t

d t

the

1

ft

hand

sid

of

th

P.A.

tank

coil

Ll2

(when

transmitter

i viewed

from

the

rear}.

With

thi~

relay

ener

gir. d

for

850

KC

operation

its

contact

romplete

the

v

riabl

tap

or

rotat

4

n ,

whe

1

circuit

of

th•

PA

tank

coil

Ll2.

This

varia

le

connectj

on

i"

made a a

i

lable

to

the

o

era

or

by

mean~

of

the

un .n.

knob

located

· n

th~

front

panel,

m~rked

P.A.

Tune.

This

control

11~ s

th

P.A.

coil

to

be

tuned

to

r~sonance

at

P50

KC,

th~

re~1lar

operating

frequ~ncy.

Rel

y

Kll

is

locat

d

in

a

row

of

relays

t

the

very

ton

of

Uie

cabinet

and

is

available

for

servicing

by

removing

the

rear

cabinet

cover.

T1is

relay.

when

energized,

compl~tes

the

RF

c

rcuit

bet

·een

th~

output

o

P.A.

t,~1nk

coil

L2

an

the

input

of

load

int

coil

113.

Rely

Kl2

is

located

on

the

in91de

left

hand

ortion

of

he

ca

,

1net,

very

near

the

output

connection

of

coil

Ll4o

Thi~

r~lay,

when

en

r~ized,

completes

the

RF

circuit

between

th

output

of

coil

114

and

the

input

of

modulation

onitor

pickup

coil

Ll5.

en

this

transmitter

is

in

the

S

~orc

''reful"r"

operating

po~it1.on,

the

various

relays

eet

up

the

output

circu

t so

as

to

use

~11

,hen

t-

works ,

hat

are

normally

used

in

the

scanJard

BC-lT

tr4nsmitt

r.

Thi~

network

has

proved

itself

to

t,e

e,ctremely

~atisf

ctory

for

m·

tchin

the

P.A.

tubs

to

he

51.5

ohm

lo~u

and

at

th

same

t1m~

to

di~criminate

~ainst

harmonics

that

might

be

gener

ted

in

the

fin

1

amplifier.

A

small

n

on

indicating

lamp

is

ountPd

irectly

ahov@

the

fre

u~ncy

change

witch

S9/

9A

.

This

neon lamn

is

ener

ized

when

the

witch

·o/

S9A

is

mov!'d o

the

top

nosi

..

ioni

mark

d '

1

Reg.".

Thi-;

indicates

to

h

opera

or

that

the

l

tching

r ,

ay

Kl6

is

in

the

1

51KC

operat

. n

p

sition

and tht'!

transmitter

will

be

ready

to

be

energized

to

produce

]

ro

w·tts

carri

rat

thi

frequoncy.

T .,

no

...

nal

tuning

proc~dure

wi

1 b

followed

s

described

in

the

stan-

~

d

rd

1n

truction

book

for

opP.ration

o

this

transmitter

on

~~O

KC.

or

oper~tion

on 640

KC

the

Con_lr

ft~que

cy,

th

rel1ys

mention

d

abov

d

.-en

rgized.

At

1-,he

s

me

im~

rel

ys

Kl3,

Kl4

and

Kl5

will

n n

.t

1is

c<1rni:ination

of

E!nt'rg·

'."..ed

and

d

-energi

zed

relay

1.,'-2277

www.SteamPoweredRadio.Com

..

w

11

t

natle

h

trans:rit:ter

to

instantan~ouslr

develop

1

r:,,;

(')f

:)lJr:,

,

,ut

c,~r

Gn

6l0

KC

.

In

the

following

pdragrarhs

a

descrip~ion

of

t

~e

elar~

ac~ion

or

640

KC

operation

wtll

be

de·cribcd.

e

Oscill

tor

c

ange-ove

r

relay

K8

i~

de-enerr,izad

.

In

thi~

position

thr-

dou'"1

l e

oole

doubl

throw

set

o.i.

contacts

have

disconnected

the

:~50

KC.·

oscillator

power

nd

output

circuits

and

have

now

set

,rn

th

clrc'..d,t

J

of

the

,.o

KC

oscillator

.

This

6 0 K

outp.1t

ir

heint~

fed

into

thP

~rid

circ·

it

of

the

,

.RF

driv

r

sta~e

.

'

rhe

RF

driv

r

ank

cond

nser

change-over

relay

K9

is

de-energiz

d.

Thi::'

automaticat

1,

cUeconnects

C7 anc

Cl5

and

1

th

ir

plac~

the

V.:iri

nle

condrmser

C26 and

padding

conden

er

G27

havft

been

comP.~teL

Thdse

condensers

will

tun

the

RF

buffer

coil

1$

to

the

Conelr!ld

fr

-

qu

ney

of

640

KC

. Once

these

cori<lensers

a e

')rop(~rly

tune

i

t.

.is,

of

cc

urse

, no

:-,robl

m

to

~wi

td·.

from

850

KC

to

640

KC

im,-n(

dia

·.el

v t

ean

of

relay

K9

.

In

the

power

amplif

i

er

St>

C

tion

of

the

transmitter,

t h

(~

relny

KlO,

Y.ll

and

K12

t,ave

been

de

-

energized

.

A:,

the

sarn.e

time

relays

Kl3

1

Kl4

and

Kl~

have

b en

ene

r

ize

d.

Thi~

relay

act.ion

sets

up

the

am

_

l1fier

for

640

KC

opt-ration.

It

will

't

.

noted

that

f or 640

KC

op,..ration,

the

ot..t

...

rut

circuit

configu

r

ation

has

been

simplif1Pd

to

just

a

common

ttFI•,

3ljpht

tuning

of

this

ci

rcu

i t

is

pos

itle

by means

of'the

s~ries

n-

ductor

Ll6,

the

knob

of

which

js

loc

~

ted

at

the

v ·

ry

top

of

~1e

ca

btnet

nenr

th~

door

~top

.

Rel

y

Kl0

i~

de-energi.zed

.

This

opens

the

variable

coll

:,

r.c.,i't

circuit

and l l ows

the

coil

inductance

to

be

increased

ae

now

thP.

ircuit

mE:Ak

s

u

se

of

th

e

ad

di

ti

on

al

tu

rn

s

which

are

betwe

n

he

var

.

~a

t

l~

wh~,.J I

ap

and

the

C

on

el

rad

f i

xe

d t

ap.

(Late

r

on

,

the

inform

-

3.tton

for

loci:.ting

this

tap

will

be

given

.)

Relays

Kll

and

Kl2

are

de

-

,mere;ized.

This

action

automat1cr1.J

y

dL

-

conn

ct

11'3,

Ll4.

ClJ

and

C_J4

from

the

output

circuit

.

The

~ner~ized

relays

Kl3,

Kl4

anJ

Kl5

now

set

up

the

outru

circ

u

it

for

operation

on

th~

640

Y.C

Con

lrad

fre.quen

Yo

Kl3,

bt!!!ing

P.

er-:;i.1,ed

now

conn<~cts

Cl~

And L16

acros

, e nor-i,a l

P.A.

t,ank

coridens

rn

Cll

"'nd

Cl:2.

Th:is

adds

another

ao,rox1mate

2~0

1nmfd.,

to

the

VrllUEI

of

P.

A.,

t .k

condensers.

As

t.r

1

ere

wer

two

400

mmfd.

conr\('n:.;"!rs u

.:

ed

f'

o 810

KC

1

this

makea

10w

a

to

al

cap

c-i

ta

nee

of

.0010)

mf

d.

used

f

or

,

.,.

.J

KC.

This

approx

:i

r.iate a

,t

c,.

"

of

10

.

or

the

P.

A

..

R

lay

flt

1-

~ne:gized

hich

places

the

loadin~

c~

ndonuer~

Cl6

and

Cl?

into

rne

•>utpit

cjrcuit

.

These

-::ondensers

w r s e

lec

t.

ed

o

.:-·ti

,.,

:·1c

)ri'y

1 ,,d t.r!e

amolifier

into

re

istive

51. 5

ohm

loa

c

l.

If

tL

e ic

tr

l

"orc

,h·

i.·n

oa<i

is

(1iff

rent

than

:;1.5

o

hm

.;

(with

no

ro;:ctanc

t!

v1r

an,

,

!-er-

v-

lu

of

outpu

t

conden

f"

r

":'IU$t

he

H~l,ct

, <l.

PP

· y ¥ l

:"

i.i:-.

ene

gi

ed

which

co

mpl0tes

th

e o,1t

;,

ut

ci

.r<'uit

to

th"'

e..:ter

&

:1

.F.

loH

~.

t'

~~~

comol~t~s

the

~Pqu~nce

of

op~ration

~or t

he

varic

u~

r•l

ye

th

3t

are

u~

j

in

~~i1

tr~nfmitt~r.

C':.;

-

2277

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2t

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his

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in

ut

for

the

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JO

~C

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os

l.;

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adjustm

nt

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varying

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ctor

Ll6.

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s

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ditior.a}

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ljst

that

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p~rt

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this

instn1ction

book.

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s1-i1

p

't

nent

the

v

rious

rel

ys

and

oth

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com

.nent

hav•

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r,

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p_

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te

trana-

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itter

:rnd r move

11

o"

th

mat~rtal..

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thorou~

,

hly

at

the

ve

top

of

the

tran

mitter

i

the

~n

compar

ment.

www.SteamPoweredRadio.Com

ADDENDA

0HEET

BC-1

T

TR,L\JM.ITT

.£R

WITH

CONELRAD

SWITCHING

CS-2277

C28,

P.A.

Padder

for

Conelrad

frequency

has

been

removed

for

shipment.

It

will

be

necessary

to

remove

the

Fan

Assembly

in

the

top

of

the

trans-

mitter

to

install

this

capacitor.

This

transmitter

is

equipped

with

silicon

rectifiers

per

customer's

specification.

2/28/61

GATtS

RAJIO

COMPANY

QUINCY,

ILLINOIS

www.SteamPoweredRadio.Com

•

;1.

DD

EN

DA

,3

H

£~

T

For

BC

lT

:B;or

BC

500T

Reference

833A

Tube

Handling

The

Ga

tes

BC

lT

and

its

compa

n

ion

transmitter

the

BC

500T,

use

83

3A

power

tubes

in

the

modulator

and

power

amplifier

stages.

These

are

of

the

single

wire

or

thread

filament

type,

as

com-

pared

to

othe

r

tubes

that

may

have

the

filam

e

nt

(heater)

con-

tained

in

a

tube,

which

is

com11only

called

the

cathode

assembly

.

Tubes

ha

ving

filam

e

nts

su

pp

orted

by

springs

(such

as

the

833A)

require

more

than

normal

car

e

in

handling.

These

filament

wires

are

easily

broken

by

sudden

he

avy

vibration.

At

all

tim

e s

han-

dle

the

tubes

with

care,

until

they

ar

e

safely

ins

e

rted

in

the

tube

sockets

of

the

transmitter.

At

this

point,

more

car e

is

required

as

the

two

filament

prongs

are

also

the

me

ans

for

securing

the

tubes

in

the

transmitter

.

l"iake

sure

th

e

conn

ec

tions

have

some

"give"

so

that

no

u

..

~

due

strain

is

p

l~ced

on

the

glass

to

metal

seal

. As

these

tubes

do

expand

a

bit

during

op

e

ration,

the

two

securing

filam

e

nt

connec-

tors

must

be

able

to

mov0 a

bit

themselves

.

Tak

e

car

e

when

making

the

grid

and

p

late

conn

e

ctions,

do

not

put

any

undue

strain

on

th

ese

connections

also,

during

tube

installation.

Of

cours

e

the

connections

of

th

e

grid

and

plate

should

b e

fl

e

xibl

e

to

al

low

for

expansion

of

the

tube.

For

shipping

or

storing

it

is

a

dvisable

to

us

e t he

packing

material

and

ca

rton

that

the

tube

was

shi

p

ped

in

from

the

tube

manufac-

turer.

·

Following

th

e

se

reason

a

bl

0

precautions,

ther

e

should

be

no

trouble

in

handling

th

ese

tubes

•

2/17/61

-1-

www.SteamPoweredRadio.Com

I -.

L

.

BC

-IT,

BC500T,

BC250T

A.M.TRANSMITTERS

www.SteamPoweredRadio.Com

•

INDEX

Page

AIR

FILTERS

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

.

..

.

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

;........................

7,

9

ANTENNA

COUPLING

••••......... .

.........

•..•..

..

.....

..

•

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

...

.. ...

••

.••••.

...

.•

.....

..•.•

7

AUDIO

INPUT

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

3

CRYSTALS

AND

ADJUSTMENT

...........

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

...........

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

.

..........

Z,

7

DUMMY

ANTENNA

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

_.

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

4

FEEDBACK.............

.....

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

..

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

3

FILAMENT

RHEOSTAT...............................

..

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

..

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

......

.........

7

FLOOR

WEIGHT

..

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

..

... .

...

...•..

......

..

.•.

..

.

..

.. ...•

..

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

...

..

.

..

...

.....

. l

FREQUENCY

MONITOR

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

•••

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

...

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

....

..

. 3

GROUND

SYSTEM

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

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

Z

INTERMEDIATE

POWER

AMPLIFIER.....

..

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

.

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

3

METERS

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

7

MODULATION

MONITOR

........

.

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

.......

.....

3

MODULATOR

BIAS

,

ADJUSTING

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

..

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

...

........

3,

6

NEUTRALIZING

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

3,

5,

6

PARTS

LIST

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

.....

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

.

........

.....

......

10,

11

PLATE

RHEOSTAT

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

...

....

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

.

....

...

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

..

.. 7

POWER

AMPLIFIER

AND

TUNING

...

..

........

....

..

.

...

....

..

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

...

....

•..

..

.•

....

..

.

3,

6

POWER

SUPPLIES

:

HIGH

VOLTAGE

.........

..

...

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

:

.........

-..

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

.......

....

4

INTERMEDIATE

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

4

MODULATOR

BIAS

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

4

PRIMARY

LINE

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

Z

PROTECTION:

MODULATOR

...

•.

...•..

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

...

........

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

.......

........

..

.

..

.

...

..

3

POWER

AMPLIFIER

..

...

......

..

....

•

..

.

..

....

..

.

..

.

..........

....

.

..

..........

3

RELAYS...............

.

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

.

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

...........

.......

..

......

3,

7

READYING

CHECK

LIST

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

,

..

•

..

4

REMOTE

CONTROL

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

.•

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

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

....

...........

...

..........

.........

1,

4,

8

SPECIFICATIONS,

TYPICAL

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

...........

......

....

.......

.

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

...

..

.....

I

SUCTION

FANS

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

1, 7

TEST

EQUIPMENT

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

7

TRANSMITTER

BASE

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

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

.....

..

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

.

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

Z

TUBES

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

1

TUNE-UP

PROCEDURE

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

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

.....

.•.

...

4,

.

5,

6,

7

VOLTAGES

AND

CURRENTS

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

,........................................................

6,

7,

9

GATES

RADIO

COMPANY

-

Quincy,

Illinois,

U.S.A.

www.SteamPoweredRadio.Com

•

INSTRUCTIONS

FOR

INSTALLING

AND

OPERATING

THE

GATES

MODEL

BC-lT

lKW

BROADCAST

TRANSMITTER,

M5393

IB-869A

In

the

preparation

of

this

instruction

book,

we

have

endeavored

to

be

concise,

yet

thorough.

In

several

places,

symbol

numbers

are

referred

to,

such

as

R 1

or

S 1,

etc.

These

symbol

numbers

will

be

found:

(a)

on

picture

illustrations

in

this

book,

(b)

on

the

wiring

diagrams

in

this

book,

(c)

adjacent

to

or

on

the

part

itself

in

the

equipment,

and

(d)

on

the

Parts

List.

Symbol

numbers

follow

industry

standard

procedure

and

have

a

mean-

ing.

"R"

means

a

resistor

or

rheostat,

"C"

is

always

a

capacitor,

"V"

a

vacuum

tube,

''S"

a

switch,

"K"

is

always

a

relay,

"L"

is

an

inductor,

either

air

or

iron

core,

etc.

As

you

read

this

book

and

it

might

say,

"Adjust

Ll2

to

resonance".

Find

Ll2

on

the

picture,

which

in

this

instance

is

picture

M5393,

and

you

quickly

understand

what

to

adjust

and

also

gain

familiarity

at

the

same

time.

--

You

will

find

this

equipment

a

pleas

-

ure

to

install

and

not

nearly

as

difficult

as

the

length

of

the

instruction

book

might

indicate.

Instruction

books

are

reference

manuals

for

both

installation

and

future

servicing.

IMPORTANT

...

If

this

transmitter

is

to

be

unattended,

i.e.,

operated

by

remote

control,

care

should

be

taken

that

winter

temperatures

inside

the

transmitter

building

do

not

go

below

50°

Fahrenheit.

Mercury

vapor

recti-

fier

tubes

will

arc

back

at

low

temperatures,

often

causing

serious

damage

to

other

expensive

components.

Protective

relays

and

blower

motors

may

also

become

sluggish

under

extreme

cold

conditions.

Failure

to

provide

adequate

winter

minimum

building

temperatures

will

void

the

guarantee.

THE

FOLLOWING

SPECIFICATIONS

ARE

TYPICAL

AND

MAY

VARY

SLIGHTLY

WITH

VARIOUS

MODES

OF

OPERATION:

1.

Rated

power

output

:

1000

watts.

Capable

of

1100

watts

where

directional

systems

induce

losses.

2.

Frequency

range:

1600

Kc

to

540

Kc

at

the

frequency

you

ordered.

3.

Power

input:

230

volts,

single

phase,

either

50

or

60

cycles.

Provide

#4

or

larger

primary

wiring

from

entrance

box

to

transmitter.

Transmitter

will

con-

sume

approximately

4000

watts

at

100%

modulation.

4.

Frequency

stability:

t_

10

cycles.

_

5.

Audio

input:

12

db

f

2

db

for

100%

modulation.

The

output

of

a

Gates

SA-39B

limiter

should

be

correct

for

this.

If

other

limiter

or

audio

amplifier

used,

be

sure

and

check

output

capabilities.

/

6.

Input

audio

impedance:

Ai,

supplied,

600

ohms,

which

will

also

match

500

ohm

impedance.

It

may

be

connected

for

150/250

ohms

if

desired.

7.

Distortion:

Rated

at

3%

from

50

to

10,000

cycles

but

capable

of

much

better

at

many

frequencies.

You

will

be

pleasantly

surprised.

8.

Noise:

60

db

or

better

below

100%

modulation.

9.

Carrier

shift

:

3%

or

less

between

O

and

full

modulation

provided

wire

size

in

Point

3

(above)

is

followed

and

R.F.

load

is

correctly

tuned.

10.

R.F.

output

impedance

:

Will

match

loads

from

50

to

70

ohms.

An

antenna

coupling

unit

ii;

usually

necessary

to

match

the

antenna

tower.

Gates

Radio

Company

OTHER

HELPFUL

DATA:

(a)

Provision

for

2

vacuum

type

crystals

and

holders.

If

you

wish

a

spare,

order

M5602,

giving

your

frequency.

(b)

The

inbuilt

dummy

antenna

will

accept

100%

modu-

lation

and

is

for

51.5

ohms.

See

Par.

4

under

"How

Can

We

Helr,

You?

"

in

the

back

of

this

manual,

entitled

'Computing

Power

Output".

The

dummy

antenna

is

substituted

for

the

tower.

(c)

THE

TWO

TOP

SUCTION

FANS

can

do

their

best

in

cooling

performance

by

periodical

replacement

of

the

removable

air

filters

located

at

the

front

bottom

of

the

transmitter.

Order

Type

M5825

and

two

are

required.

The

time

cycle

in

replacing

filters

depends

on

dust

conditions.

Normally

about

three

times

annually.

(

d)

The

floor

weight

is

800

lbs.,

or

slifhtly

leas

than

100

lbs.

per

square

foot.

Allow

28

'

for

the

front

door

swing.

Size:

78"

high,

36-1/16

."

wide

and

31-7/8"

front

to

back.

(e)

TUBES:

Your

100%

tube

complement

(TK287

if

you

wish

to

reorder)

is:

(2)

(6)

(4)

(2)

( 1)

12BY7A

for

oscill,ator

and

first

intermediate

amplifier.

6BG6G,

of

which

two

are

parallel

operated

as

the

second

intermediate

amplifier,

\wo

are

push-pull

audio

input

amplifiers

and

two

are

cathode

follower

driver

amplifiers.

833A

tubes,

of

which

two

are

R.F.

power

amplifiers

in

parallel

and

two

are

Class

B

modulators.

8008

main

power

supply

rectifiers.

866A

intermediate

power

supply

rectifiers.

5R4GY

bias

supply

rectifier.

I~

you

wish

FCC

spare

tubes,

which

is

-

the

minimum

list

of

spares

acceptable

to

FCC

(TK288

if

you

wish

to

reorder),

these

are:

( 1)

12BY7A;

(3)

6BG6A;

(2)

833A-

( 1)

8008•

( 1)

866A-

and

( 1)

5R4GY.

' ' '

GATES

RADIO

COMPANY

-Quincy,

Illinois,

U.S.A.

Page

1

Gates BC-1T Mode d’emploi

Manuels Émetteur populaires d'autres marques