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RADIO
BROADCAST
WILLIS KINGSLEY
WING,
Editor
JANUARY,
1929
KEITH
HENNEY
Director
of
the
Laboratory
EDGAR
H.
FELIX
HOWARD
E.
RHODES
Vol.
XIV.
No.
3
Contributing
Editor
Technical
Editor
AMONG
OTHER
Cover
Design
Frontispiece
-
THINGS.
RADIO
BROADCAST
.
.
-
-
From
a
Design
Antenna
Used
by
Harvey
Hopkins
Dunn
1
THE
appear
at
next
the
February
issue
of
clothes.
will
is
-
A
Kite
Unscrambling
Television
All
......
-
-
in
Early
Radio
Experiments
Boyd
Phelps
Joseph
56
work
BROADCAST
more
figuratively
in
on
an
attractive
new
new
A
famous
designer
try
to pick
cover
which
will
make
RADIO
easily
recognizable
when
you
it
157
About
the
-
Dynamic Loud
Speaker
-
-
Morgan
159
162
163
Book
Review
-
-
-
Carl
Dreher
The
March
of
Radio
WGY'S
Attack on
Ira E.
-
An
With
Editorial
Interpretation
the
Allocation
Plan
the
Broadcasting
Stations
Robinson
Stands
Firm
Decision
The
Regenerative
Commercial
Radio
Telegraphy
With
the
Radio
Manufacturer
-
out
of the
mass
of
others
on
the
newsstands.
The
text
will
be
set
in
a
type
which
is
easier
to
read
and
which
presents
a
more
attractive
appearance
than
the
type
we
now
use.
For
those
who
are
interested
in
such
things,
the
present
type
face
is
Cadmus
and
the
new
RADIO
BROADCAST
will
be
set
in
Bodoni.
Bodoni
is
a
decorative
type
also
notable
because
it
is
"easy
on
the
eyes."
The
contents
is
in
for
some
improving
at
the
same
time
and
we
shall
ask
you
to
await
the
February
issue
for
a
com-
plete
announcement
of
that.
occupies
a
good
part
of
radio
discussion
want
to
be
sure that
our
attitude
on
A
Few
Radio
Questions
Answered
-
166
167
TELEVISION
we
these
days
and
Measuring
a
Receiver's
Performance
"Strays"
from
the
Laboratory
How
Much
Power
Is
Needed?
What
Some
is
a
Dynamic
Speaker
Interesting
Formulas
Kenneth
C
Bias
W.
Jarvis
Keith
Henney
Obtaining
169
The
Task
of
Editing
Empirical
Rules
and
Formulas
-
-
A
Loop-Operated
Browning'Drake
Receiver
A
Simple
A.C.
Operated
Tube
Tester
-
/.
H.
Gocfyl
Staff
171
the
subject
is
clear.
"Television,"
unfortunately,
means
one
thing
to
one
man
and
something
altogether
different
to
the
next.
Television,
like
radio
broadcasting,
may
be
considered
experi-
something
mentally
or
in
respect
to
its
entertainment
value
the
general
public
will
find
satisfactory.
Television
of
entertain-
ment
value
is
certainly
not
here
and
is
not
in
prospect
for
some
little
time.
Articles
in
this
magazine
have
outlined
the
difficulties
to
be
overcome
before
"program
television"
can
be
attained.
the
other
hand,
experimental
television
is
here.
What
most
people
mean
when
they
say
the
word
now
is
merely
experimen-
do
not
intend
to
fill
this
magazine
with
arti-
tal
television.
cles
on
the
subject
when
there
isn't
much
to
say,
but
we
shall
not
fail
to
give
those
who
are
interested
in
experimenting
with
it
as
much
useful
information
as
we
can.
certainly
do
not
discourage
experimenting,
but
in
television
it
should be
made
scale.
perfectly
clear
that
such
it
now
is,
and
that
on
a
limited
-
The
Laboratory
173
On
The
Isotone
Screen-Grid
"Super"-
-
-
-
Dudley
Walford
-
174
We
"Radio
Broadcast's"
Service
Data
Sheets
No.
15.
-
-
-
177
179
181
The
Bremer-Tully
8-10
Receiver
No.
16.
-
The
Freshman
Model
-
Q
Receiver
A/corn
We
Servicing
Home-Made
Radio
Man's
Corner
The
Service
Sound
Motion
Pictures
"Radio
Broadcast's"
No.
13.
Calibrating
a
Radio
.............
........
Sheets
No.
-
-
-
-
-
Receivers
-
-
B.
B.
Carl
Dreher
-
-
182
183
NO
NEW
Home
Study
Wavemeter
As
the
Broadcaster
Sees
It
.......
-
14.
Plotting
Power
Tube
Characteristics
Carl
Dreher
An
Inexpensive
Audio
Oscillator
.....
-
-
-
185
feature
we
have
added
to
RADIO
BROADCAST
in
the
six
years
of
its
history
has
created
anything
like
the
favorable
response
that
the
special
pages
for
the
radio
service
man
have
produced.
Many
interesting
manuscripts
have
been
received
and
we
hope
that
others
who
also
have
ideas
which
should
be
set
down
on
paper
and
sent
on
for
our
consideration
will
become
suddenly
ambitious
and
send
us
their
contributions.
Edward
Stan^o
James
Robert
B.
Friauf
S.
186
188
189
192
A
Chart
for
Making
DX
Measurements
Armchair
Chats
on
Short-
Wave
Subjects
"Our
Readers
Suggest
"
.............
-
Kruse
Apparatus
and
Its
Applications
More
Data
on
the
Sargent-Rayment
Manufacturer's
Booklets
New
-
194
197
-
-
-
........
Howard
wide
selection
of
articles
of
on
"Unscrambling
Television,"
Phelps
Joseph
Morgan
on dynamic
speakers,
K.
W.
Jarvis
on
receiver
an
a.c.
operated
tube
performance,
the
Laboratory
Staff
on
tester,
"The
Service
Man's
Corner,"
Carl
Dreher
on
"Sound
Motion
Pictures,"
and
"Photographic
Data
for
Broadcasters,"
Kruse
on
short-wave
topics,
the push-pull
a.c.
P.
A.
amplifier,
are
some
of
the
most
important.
We
are
proud
to
offer
these
articles
for
they
are
all
exclusive,
interesting,
and
accurate
to
THE
present
Boyd
interest:
issue
contains
a
Barclay
the
last
degree.
"Radio
Broadcast's"
Laboratory
Information
Sheets
No.
149.
A
Resistance-Coupled
Amplifier
No.
150.
A
Resistance-Coupled
Amplifier
No.
ji.
Moving-Coil
Loud
Speakers
No.
aji.
Audio
Amplifiers
.....
109
202
No.
153.
Shielding
No.
154.
A.C.
Tubes
No.
jj.
Band-Pass
Circuits
No.
356.
Power
Output
is
The
contents
of
to
Periodical
this
magazine
indexed
in
The
Redden'
Guide
is
Literature,
which
on
file
at
all
public
libraries.
RADIO
BROADCAST
will
contain,
among
other
an
article
by
Dr.
L.
M.
Hull
on
"Overall
Measure-
things,
ments
on
Broadcast
Receivers,"
a
striking
story
by
Boyd
Phelps
on
how
amateur
television
has
been
accomplished,
a
remarkable
in
audio
am-
story
by
the
Labaratory
on
the value of
filtering
several
valuable
experimental
articles
on
short-wave
plifiers,
work
and
a
host
of
other
features.
WILLIS
KINGSLEY
WING.
TJEBRUARY
17
OOUBLEDAT,
MAGAZINES
COUNTRY
LIFE
WORLD'S
Won*
OORAN
(Book,
of
&
COMPACT,
GARDEN
INC.,
Garden
OFFICES
CITY,
N. Y.
Qixy,
OFFICERS
F.
BOOK
SHOPS
I
all
Publisher,)
THE
AMERICAN
HOME
RADIO
BROADCAST
SHORT
STORIES
LE
PETIT
JOURNAL
EL
Eco
FRONTIER
STORIES
WBrr
THE
AMERICAN
SKETCH
LORD
it
TAYLOR;
JAMES
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CLEVELAND:
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SPRINGFIELD,
MASS:
MEEKINS,
PACKARD
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DOUBLEDAY,
Chairman
of
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the
Board
NEW
YORK:
244
MADISON
AVENUE
NELSON
DOUBLEDAY,
GEORGE
H.
DORAN,
I'
ice-President
S.
A.
BOSTON:
PARK
SQUARE
BUILDING
EVERITT,
Vice-President
Secretary
CHICAGO:
PEOPLES
GAS
BUILDING
RUSSELL
DOUBLEDAY,
SANTA
BARBARA,
CAL.
JOHN
GUNDY,
LTD.
L.
J.
Inc.
J.
HESSIAN,
Treasurer
Atstt
Treasurer
LONDON:
WM.
HEINEMANN,
LTD.
LILLIAN
A.
COMSTOCK,
Aisft
Secretary
TORONTO.
DOUBLEDAY.
DORAN
MCNAUGHTON,
CopTfigkl,
1929,
m
the
United
Stata,
Newfoundland,
Great
Britain,
Canada,
and
other
countries
by
Doubleday,
Doran
&
Company,
All
righli
reiervcd.
TERMS:
$4.00
a
year;
single
copies J5
cents.
154
KADIU
BROADCAST
AJJVJbit
I
listi,H
155
Buy
Now!,
On
Every
thins
In
Allied
has
cut
prices
to
the
bone
your
big
profits
in
radio
can
now
be
bigger
-no
need
to
wait
RADIO
any
longer.
This
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the
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JPti"
^fe
R
Brand
New
Catalog
for
1929
A
pre-inventory
sale
that
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featuring
some
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reductions
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radio.
Everything
in
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offered
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this
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and
this
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catalog
has
been
prepared
to
bring
before
you
this
tremendous
array
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radio
values.
Every
branch
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radio
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is
represented
appealing
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builders
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parts
and
kits
to
dealers
interested
in
the
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and
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accessories
as
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tieing
up
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one
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A.C.
andD.C.
receivers.
Wholesale
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we
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on
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exclusively
wholesale
the
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we now
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you
are
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basis,
ing
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radio
values
new
A.C.
sets
as
low
as
$32.95
attractively
designed
consoles
for
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low
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$16.25.
Corresponding
values are
offered
in
kits,
parts
and
accessories
in
nation-
ally-advertised,
quality
merchandise
the
prod-
ucts
of
the
country's
foremost
radio
manufacturers.
Selling
as
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Send
for
Your
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Now
Knight
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andD.C.
operation
ettablislud
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See
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in
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new
large
catalog.
Allied/Radio
CORPORATION
71
1W.
LAKE
ST.
Dept.A-4
CHICAGO
A
Kite
Antenna
Used
in
Early
Radio
Experiments
elevate
the
long
receiving
antenna
which
was
used
at
Signal
Hill,
Newfoundland.
The
signals
which
were
received
during
this
experiment
were
sent
from
a
station
installed
at
Poldhu
and
was
an
event
of
the
greatest
historical
importance.
This
picture
shows
an
unusual
piece
of
radio
apparatus
which
was
used
by
(luglielmo
Marconi
during
his
trans-Atlan-
tic
radio
tests
in
December
1901,
The
large
kite
which
is
held
by G.
S.
Kemp,
Marconi's
first
assistant,
was
employed
to
156
the
radio
lis-
RECENTLY
sounds
peculiar
loud
tener
has
heard
many
his
quency
the
amplifier
has
a
sharp
low-fre-
cut-off
above
120
cycles,
the
interference
caused
by
the
a.c.
is
eliminated.
The
only
ex-
from
speaker,
and,
if
he
plays
around
on
short
waves,
he
prob-
hum
ably
noise
a
is
familiar
with
an
unusual
identified
as
ception
to
this
statement
would
be
a
case
where
the
a.c.
modula-
tion
varies
which
may
be
signal.
the
overall
if
efficiency
off
television
To
the
un-
all
of
the
amplifier,
for
signal
frequencies
are
the
desired
trained
ear
these
transmissions
choked
60
sound
alike
a
terrible
racket;
to
the
experienced
television
experi-
menter
the
sounds
often
give
a
fair
idea of
the
picture,
even
to
permit
recognizing
the
"sound"
of
faces
of the
immediate
labor-
times
per
second
a
high-pass
filter
will
not
help
this.
An
example
would
be
low-current
filaments
op-
erated
on
a.c.
much
below
their
correct
temperature
where
the
emission
varies
rapidly
with
small
changes
in
filament
voltage.
But
For
the
somewhat
less
experienced,
a
little
practice
with
the
speaker
and
televisor
operat-
ing
simultaneously
will
enable
him
to
pick
out
important
characteris-
atory
staff.
a
good
amplifier
underloaded
should
amplify
weak
or
strong
signals
proportionately,
whereas
example,
tone
quality
when
the picture
contains
two
fig-
ures,
as
two
individuals
side
by
side.
tics
of
the,
signal,
as,
for
an
abrupt
change
in
picked
up
in
any
if
passed
to
the
next
tube
at
stage,
high
loss,
does
not
assume
great
magnitude
or
appreciable
nuisance
in
stray
a.c.
hum
The
experimenter
who
inter-
ered
above.
the
television
amplifier consid-
The
writer
has
recently
cepts
a
television
program
of
un-
known
origin
has
before
him
the
interesting
problem
of
deciphering
these
signals
and
de-
thrown
together
a
transformer-coupled
intensely
termining
the
number
of
scanning
holes
and
the
speed
of
the
disc,
for
this
may
be
obtained
from
labor-
atory
tests.
In
this
connection
this
article
relates
the
author's
ex-
perience
in
unscrambling
mysteri-
ous
television
signals
which
were
heard
regularly
on
Long
Island.
PHELPS-
EXPERIMENTAL
TELEVISOR
which
practically
all
the
cores
has
been
removed
and
the
fiat
section
of
the
curve
moved
up
considerably,
which
seems
promising
although
curves
have
not
been
run
as
yet.
to
the
complex
picture
frequencies
of
a
television
signal
which
are the
result
of
the
detail
three-stage
amplifier
in
the
iron
in
We
now
come
Unscrambliii
By
of
the
image.
If
the
pic-
lowest
frequency
in
a
tele-
vision signal
cannot
be
classed
as
a
musical
tone;
it
is
The
ture
were
divided
one
light
and
one
vertically
into
dark
section
of
75,
thumps
coming
10,
a
rapid
series
at
the
rate of
we know
the
frequency
would
be
720
cycles
in
the
case
of
the
or
20
times
per
sec-
ond.
This
represents
the
number
of
complete
pictures
per
second.
15
better
forms
of
therefore,
it
common
television,
does
not
take
much
A
picture
rate
below
1
5
generally
causes
a
noticeable
flicker
to
the
eye,
like
BOYD
PHELPS
imagination
to
appreciate
the
fact
that
the
details
of
a
face
eyes,
nose,
moustache,
etc.
may
pro-
duce
frequencies
that
will
run
well
into
the
thou-
sands
of
cycles
For
example,
impulses
crosswise
of
the
picture,
equivalent
to
the
none-too-good
detail
represented
by
48
vertical
lines,
at
speed
near
the
flicker
point
would
be
represented
by
a
frequency
of
48
x
48 x
15
which
works
out
to
be
34,560.
Although
decently
recognizable
faces
can
be
produced
without
such
high
frequencies,
the
change
from
light
to
dark
at
the
sharp
contrast
points,
as
the
pupils
of
the
eyes or
sleeve,
is
moving
pictures
projected
at
a
slower
speed
than
normal.
THE
SCAN
FREQUENCY
THE
single
audio
tone
which
seems
to
be
the loudest
frequency
in
a
signal
represents
the
scan
frequency
complex
television
which
is
the
mathematical
product
obtained
by
multiplying
the
number
of
holes
or
scan
lines
by
the
number
of
complete
pictures
per
second.
This
product
is
usually
360,
450,
480
or
720
cycles
per
second,
or
intermediate
values.
This
pitch
seems
es-
pecially
loud
because
it is
in
a
sensitive
range
of
the
ordinary
amplifier
and
speaker,
and
be-
cause
it
is
pure,
regular
and
continuous.
It
corre-
sponds
to
a
musical
note
near
the
middle
of
the
piano
key-board
somewhat
above
middle
C.
In
television
amplifiers,
contrary
to
speech
and
music
amplifiers,
all
audio
tones
below
the
scan
frequency can
be
eliminated
in
many
cases
and
quite
good
quality
will
remain.
This
feature
is
useful
if
a
B-power
unit
is
used
to
supply
plate
power
for
the
amplifier,
as
a
scarcely
noticeable
power-frequency
hum
in
the
speaker
manifests
itself
on
the
picture as
light
and
dark
bands.
When
a
power
frequency
of
60
cycles
is
used,
four
light
bands
appear
if
the
disc
is
running
900
r.p.m.
(15
pictures
per
second)
and
eight
bands
edge
of
coat
450
r.p.m. (7^
pictures
per
second)
the
disc
speed,
for
example,
with
JXK
and
WRNY,
respectively.
If
these
bands
creep
slowly
up
or
down
while
the picture
is
held
correctly
appear
is
if
framed
an
indication
that
synchronizing
by
mounting
of
the
disc
on
a
synchronous
motor
would
not
be
feasible,
as
was
discussed
in
it is
quite
a
ways
from
instantaneous,
and
in
the
received
image
the
shaded
gray
area
at
these
points
may
be
several
scan
holes
in
width,
al-
though
the
photo-electric
cell
at
the
transmitter
may
be
making
its
maximum
change
in
a one-
hole
width
of
the
picture.
But,
in
photography,
portraits
usually
have
their
sharp
harshness
re-
the
direct
last
month's
article
by
the
'57
writer.
Therefore,
if
moved
by
an
intentional
diffusion.
Television
158
limited
to
frequencies
below
5000
cycles
far
from
hope-
is,
in
the
writer's
opinion,
ruin
a
picture
It
is
far easier
to
less.
with
adjustments
of
the
amp-
RADIO
BROADCAST
nearest
drill
JANUARY,
size
1929
was
No.
50
having
a
diameter
of
0.0700."
THE
RESULTS
the
morning
of
the
third
day
the
disc
was
tried
out
and
the
interesting
pictures
watched
with
a
thrill
improper
lifiers
at
the
transmitter
or
receiver.
WAS
IT
when
THE
PROBLEM
out
transmitting
station
is
using
by
listening
to
it,
and
the writer
has
had
some
exper-
iences
along
this
line
that
may
be
of
in-
terest
to
recount.
This
form
of
"radio
sleuthing"
originated
early
in
March,
1928,
when
an
attempt
was
made
to
unscram-
ble
the
signals
sent
by
the
Baird
Labora-
tories
in
London
to
the
Berengaria
in
mid-Atlantic.
The
details
of
this
adven-
NOW
ing
we
come
to
the
problem
of
figur-
what
kind
of
a
disc
the
of
one
eavesdropping
in
on
something
un-
usual
like
watching
the
antics
of
a
com-
edian
practicing
in
supposed
solitude.
This
key-holing
being
absolutely
a
one-way
affair
added
to
the
charm,
due
to secur-
from
detection.
The
question
now
saw
would
arises,
if
I
describe
what
be
violating
my
oath
of
secrecy
sworn
to
on
the
back
of
my
operator's
license
and
the
law
not
to
divulge
or
publish
the
ity
1
1
ture
were
in
the
newspapers
at
the
time
and
included
such
features
as
banging
the
characteristic
notes
on
a
piano
and
line
to
a
sending
them
over
a
telephone
called
out
of
bed
to
piano
tuner
who
was
sound
his
tuning
forks
on
the
other
end
of
the
line
to
determine
the
absolute
scan
frequency.
W2BUO,
who
escapade,
procured
a
fairly
flat
square
brass
disc
of
power-house
flywheel
pro-
to get
the
apparatus
portions.
In
the
haste
next
nightly
schedule,
the
operating
before
the
corners
were
not
even
cut
off.
No
further
signals
assisted
in
this
contents
of
any
message
not
addressed
to
me
or
which
1
am
not
the
authorized
agent
to
forward?
It
was
quite
obviously
not
broadcast
for
public
consumption,
has
had
no
advertising
or
publicity,
and
was
preceded
by
a
weak
announcement,
REAR VIEW
OF TELEVISOR
"Station
2X?
conducting
a
test."
The
days
of
only
a
code
operator
being
able
to receive
and
divulge
a
radio
message
are
over.
Perhaps
the
oath
of
secrecy
should
be
administered
to
the
whole
public
and
thereafter
to
all
infants
within
90
days
of
birth.
The
pictures
on
these
pages
show
the
ap-
described
paratus
used
in
the
experiments
article.
The
front
view
of
the
televisor
in
this
reveals
that
the
container
was
once
a
phonograph
pioneering
now
in
television
as
in
broadcasting
at
9
ZT,
when
the
writer
sent
cabinet
it
were
transmitted,
was
never
learned
how
accurately
the
number
of holes
and
revolutions
were
calculated.
A
phonograph
rec-
ord
was
made
of
the
signals
as
it
is
possible
to
this
way.
preserve
moving
pictures
send-
Recently
a
near-by
station
was
secretly
however,
so
it
of
the
most
ingenious
experimenters
n
radio
to-day
is
Boyd
Phelps.
His
work
represents
in
our
mind
a
proper
exam-
ple
of
genuine
"amateur"
experimenting.
i
did
its
describing
experiments
in
sorting
out
television
signals
in
which
every
factor
but
This
article,
transmission
frequency
was unknown,
will
be
music
to
Minneapolis
amateurs
in
the
speed-control
knob
and
shaft
1921.
Below
may
be
seen
that
have
been
ing
short
television
schedules
shrouded
in
a
similar
deep
mystery.
Trial
on
all
discs
and
speeds
produced
nothing
intelligible,
were
genuine
and
had
yet the
sounds
apparently
variations
of
a
person
moving
the
characteristic
around
or
the
scene
shifting.
The
characteristic
scan
frequency
was
quickly
found
to
be
B
above
middle
C
on
the
piano,
which,
according
to
international
pitch
scale,
would
be
488
cycles.
found
worthy
of
the
reader's
attention
not
extraor-
only
because
the
work
represents
an
but
because
it
dinarily
ingenious
procedure
indicates
very
definitely
the
difficulties
of
achieving
results
of
any
account
at
all
in
television
experimenting.
the
bias
resistor
for
the
power
tube.
This
resistor,
which
is
common
to
the
plate
supply
and
the.
bril-
returns,
is
employed
to
regulate
the
grid
tube
which
is
liancy
of
the
picture
on
the
neon
connected
directly
in
series
with
the
plate
circuit
of
the
2io-type
power
tube.
The
double-throw
switch
behind
the
bias
resistor
makes
possible
"
a
change
from
ear
to
eye
entertainment."
An
interesting
feature
of
the
televisor
is
the
which
is
mounted
on
the
flivver
THE
EDITOR.
The
is
according
to
pitch
of
the
piano
in
question
assume
that
have
not
been
standards
that
pianos
speedometer
tuned
became
popular
usually
lower.
However
WRNY
"tuned
in"
on
G
above
middle
C
and
their
scan
frequency
is
close
to
like
a
log
of
Who's
360
cycles.
(The
keys
now
look
Dust
was
blown
off
the old
Who
in
Television.)
the
ratio
of
the
two
college
physics
book
and
to
5.
The
two
musical
notes
was
found
to
be
4
since
radio
consisted
of
a
hand
drill,
a
saucer
and
a
bent
nail.
The
gear
ratio
of
the
hand
drill
was
such
that
the
bent
nail in
the
chuck
made
four
taps
on
the
saucer
for
every
turn
of
pose.
The
device
front
panel.
This
instrument,
having
been
taken
as
a
apart
and
calibrated
in
r.
p.
m.,
is
employed
tachometer.
The
second
mechanical
picture
shows
the
of
the
scanning
disc
assembly.
A
arrangement
is
synchronous
motor
providing
uniform
speed
friction
belt
connected
to a
countershaft
having
drive
to
the
back
face of
the
scanning
disc.
The
knob
to
the
left
turns
a
threaded
brass
rod
the
handle.
The
handle
was
turned
at
such
speed
notes
on
the
piano
still
being
good
chords,
both
the
ratio
was
having
lowered
the
same
amount,
of
450
determined.
applied
and
a
scan
frequency
as
the
scan
frequency
is
the
product
of
Now,
the
number
of holes
and
the
speed
of
rotation
per
second,
and
neither
of
these
factors
were
known,
the
problem
was
still
quite
a
way
from
complete
solution.
as to
have
the
taps
on
the
saucer
in
step
with
the
of
the
handle
picture
frequency,
and
the
counting
turns
was
easy.
Thus,
in
a
ten-second
run
a
count
of
handle
turns
of
22$,
25 or
37$
would
establish
that
moves
the
countershaft
assembly
radially
10
or
15
whether
the
picture
frequency
was
9,
be
per
second
or
if
not
it
would
probably
the
signals
were
heard
this
a
near-by
value.
The
second
time
was
tried
computations
reduced
the
unlimited
possibilities
to
the
following
proba-
bilities:
60
holes
at
7^
r.
p.
s.,
50
holes
at
9
r.
p.
s.,
Some
slide-rule
and
every
trial
turned
out
very
close
to
374
so
it
was
a
safe
enough
assumption
that
the
transmitter
was
using
30
holes
in
a
disc
running
1
to
frame
accurately
the
picture
and
compensate
differences
in
scanning
speeds
of
various
trans-
mitters.
The
pulleys
have
additional
small
take
a
shorter
flanges
(not
shown)
which
quickly
tube
is
shown
belt
for
slower
speeds.
The
neon
opposite
article,
the
it
3O-hole
spiral
described
in
this
but
can
be
raised
easily
to
the
level
5
r.
p.
s.
(900
r.
p.
m.)
A
vibrating
45
holes
at
10
r.
p.
s.
or
30
holes at
15
r.
p.
s.
Any
of
these cases
would
give
the
characteristic
It
was
assumed
450-cycle
scan-frequency
note.
that
even
speeds
were
used
with
no
"fractional"
holes
or
trick
arrangement
of
holes.
A
NOVEL
FREQUENCY
COUNTER
next
step
was
to
measure
the
picture
an
frequency
which
is
strong
in
cases
where
of
scan
lines
exist,
as
for
unmodulated
series
of
an
indi-
example,
the
margin
above
the
head
vidual
being
scanned,
or
other
irregularities
reed
was
used,
and
a
variable-speed
48-hole
disc
at
5
r.
p.
produced
stationary specs
of
the
image
observation
closely.
s.; all
checked
the
bent
nail
1
of
the
48-hole
spiral.
Many
methods
of
speed
has
control
have
been
tried
but
this
system
results.
provided
the
best
Much
has
been
written
concerning
the
design
of
television discs
so
only
the
final
data
will
be
an
existing
48-hole
given
here.
A
spiral
inside
was
laid
out.
In a
3o-hole
disc
a
maximum
spiral
Middle)
c
)
THE
radius
of
slightly
over
7"
gives
an
image
ii"
wide
at
the
top.
A
picture
height
of
\\"
was
con-
venient
as
this
gave
exactly
20
scan
lines
per
inch.
These
scan
lines,
while
0.05"
wide
in
theory,
CDEFGABc
Pitch
o>
\.
writer
Piano)
appearing
once
in
each
complete
picture.
In
the
case
of
the
unknown
signals
in
question
they
were
too
fast
to
count
one
can
count
to
almost
12
in
a
second
so a
device
was
invented
for
the
pur-
were
made
with
a
round
drill
of
larger
size
calcu-
lated
on
circle
overlap
such
that
inscribed
The
sides
of
the
squares
would
be
edge
to
edge.
theoretical
square
being
0.05",
the
diagonal
and
the
(also
circle
diameter)
figured
0.0706"
S
FIG.
I
How
Television
Signals
"tune-in"
on
the
writer's
piano

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