Copyright
Hugo Gernsback.

Radio for all online

. (page 1 of 15)
Online LibraryHugo GernsbackRadio for all → online text (page 1 of 15)
Font size
QR-code for this ebook


THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

LOS ANGELES



RADIO FOR ALL



THE FUTURE OF RADIO

IN this illustration are shown some of the future wonders of Radio. Several
of the ideas are already in use, in an experimental way, and it should not be
thought that the entire conception is fantastic.

The illustration shows a business man, let us say, fifty years hence. To the
right is a television and automatic radiophone. By means of the plug shown
to the right of the machine, the man can plug in any city in the United States
he desires ; then, by means of this automatic control board he can select anv
number in that city he wishes, merely by consulting his automatic telephone
directory. As soon as he has obtained his number, a connection is made auto-
matically and he not only can talk, but he can see the party whom he calls. At
the top of the instrument is a loud-talker which projects the voices of the people,
while on a ground-glass in front of him the distant party is made visible. This
idea is already in use, experimentally.

Directly in front of the man, we see the "radio business control." By means of
another television scheme, right in back of the dial, the man, if he chooses to do
so, can load and unload a steamer, all by radio telemechanics, or throw a distant
switch, or if a storm comes up, look into the interior of his apartment and then,
merely by pressing a key, pull down the windows; all of which can be accom-
plished by radio telemechanics, a science already well known.

His business correspondence comes in entirely by radio. There is a tele-
radio-typewriter. This electro-magnetic typewriter can be actuated by any one
who chooses to do so. For instance, if we wish to write a letter to Jones &
Company, Chicago, Illinois, we call up by radio, that station, and tell the operator that
we wish to write a letter to the Company. Once the connection is established,
the letter is written in New York, let us say, on a typewriter, and automatically
sent out through space by radio; letter for letter, word for word being written
by the other typewriter in Chicago. The letter when finished falls into a basket.
Instead of sending our correspondence by mail we shall then do our letter-writing
by radio. There is nothing difficult about this scheme, and as a matter of fact, it can
be put into use today, if so desired. We have all the instrumentalities ready.

Going further, we find the Radio Power Distributor Station that sends out
power over a radius of 100 miles or more. This radio power may be used for
lighting, and other purposes.

In front of the bridge we see a number of people who are propelled by
Radio Power Roller Skates. On their heads we see curious 3-prong metallic
affairs. These collect the radio power from a nearby railing, which, however, is
not in view, and which they do not touch. The power is sent through space from
the rail to the 3-pronged affair and then is conveyed to the skates, which are
operated by small electric motors. The<e roll at the rate of 15 to 20 miles an
hour, and there is no visible connection between the wearer and the Radio
Power Distributor.

We next see the crewless ships controlled by radio. This has been made pos-
sible today. Indeed, several U. S. battleships have already been manoeuvred over



a considerable distance by radio. The time will come when we can direct a ship
across the ocean without a human being on board. Future freight will be sent
in this manner. The ship, every ten minutes, gives its location by radio, so that
the land dispatcher will know at any time where the ship is located. Collisions
are avoided by a number of instruments into details of which we need not go here,
but which have already been perfected. Collision with icebergs also is avoided
by thermo-couples which divert the ship away from the iceberg as soon as it
enters water which has been cooled below a certain degree.

The radio-controlled airplane works similarly to the radio-controlled ship,
and it will be possible to control such airships very readily in the future. As a
matter of fact, John Hays Hammond, Jr., in this country, has done this very
thing. Radio-controlled airplanes will play a great role in the next war.

It is a mistake to think that radio is only good for the distribution of intel-
ligence. As the illustration shows, the great uses of radio have not been touched
upon as yet.

THE AUTHOR.



RADIO FOR ALL



BY

H. GERNSBACK

EDITOR OF "RADIO NEWS"



WITH 13 HALFTONES AND 138 ILLUSTRATIONS




PHILADELPHIA & LONDON
J. B. LIPPINCOTT COMPANY

1922



COPYRIGHT, 1923, BY J. B. LIPPINCOTT COMPANY



PRINTED BY J. B. LIPPINCOTT COMPANY

AT THE WASHINGTON SQUARE PRESS

PHILADELPHIA, U, S, A,



TK



PREFACE

IN writing the present volume the author has
continually had in mind a book for the public at
large, not acquainted as yet with the radio art.
After having reviewed nearly all the recent books
on radio that have appeared since radio took
the public's fancy, the author believes that the
present volume covers ground not touched upon by
other writers.

The keynote of the book has been simplicity in
language, and simplicity in radio. This book,
therefore, is not a technical volume, and wherever
possible all technicalities, all mathematics, and all
abstruse subjects have been left out entirely. It will
also be noted that the author has not made
use of the word "ether" in this book; for the
reason that modern scientists are no longer
in sympathy with the ether theory. The vacuum
tube, it will be noted, has been touched upon very
lightly and only where it was absolutely necessary.
The reason is that the vacuum tube is a highly tech-
nical subject, and therefore does not belong in this
book. It is a science by itself.

The author has always been a great believer in
analogies to drive a point home ; and for this reason
analogies have been made use of freely wherever
possible in this volume.



12755CO



6 PREFACE

His experience in editing the first radio
journal in the United States, Modern Electrics,
in 1908, then later, Electrical Experimenter, (now
Science and Invention), and, still more recently, as
editor of Radio News, has given him the opportunity
to view the radio problem through the eyes of the
"man in the street." He hopes that he has suc-
ceeded in conveying a technical message into
plain English.

If the present volume is the means of converting
a fair percentage of the public at large to radio,
the labor expended has been well worth while.

H. GERNSBACK
New York, June, 1922



CONTENTS



CHAPTER PAGE

I. HISTORIC 11

II. WAVE ANALOGIES 15

III. TRANSMITTING (GENERAL) 30

IV. RECEIVING (GENERAL) 42

V. RECEIVING INSTRUMENTS 51

VI. TUNING 101

VII. AERIALS, LOOP AERIALS, GROUNDS 108

VIII. RADIO DIAGRAMS AND How TO READ THEM 149

IX. RADIO TELEPHONY 164

X. How TO MAKE SIMPLE RECEIVING OUTFITS 180

XI. THE FUTURE OF RADIO 229

XH. RADIO ACT pyj912.... 239

.. 283



LIST OF ILLUSTRATIONS

The Future of Radio Frontispiece

Transmitting President Harding's Arlington Address 42

Amplifiers Used to Receive the Speech 42

Motorbus Equipped With Radio 70

Two Portraits Transmitted by Radio 101

The Author's Radiotrola 127

Mme. Olga Petrova Singing for Radio 149

Mme. Gadski Singing Tannhauser Aria 164

Broadcasting Station Power Plant 173

Author Delivering Lecture From Newark 229

Power Plant of Newark Broadcasting Station 239

Map U. S. Radio Broadcasting Stations 282



RADIO FOR ALL

CHAPTER I
HISTORIC

LET us begin at the beginning. There are so
many misconceptions in radio today that it is best
that the reader should know just how the art of
radio came into existence. The true art of radio
was unquestionably discovered by Heinrich Hertz,
a German professor, living at Frankfort. His first
technical papers on his epoch-making invention were
published in 1887. Hertz's experiments were chiefly
made in the laboratory. Years before, Maxwell had
made the statement that light waves and electric
waves were all of the same order. There had,
however, before Hertz's time never been any experi-
ments of electric waves in free space. Hertz was
the first to send electric waves through space
by means of an electric spark. His appara-
tus was simple; he had an electric spark coil that
made intermittent sparks, and by proper arrange-
ment of this station, he could receive sparks at a
distance by the simple arrangement of cutting a
single wire hoop and leaving a small gap. Between
the two free ends, small sparks jumped whenever
sparks were made to jump on his spark coil a few
yards away. In other words, every time he pressed

11



13 RADIO FOR ALL

the key at his sending station, a spark would jump
at the small gap at his receiving station, which was
composed of nothing but a wire hoop. This con-
clusively proved that electric or, better, electro-
magnetic waves had been sent through free space.
His were only laboratory experiments, and while
he described the phenomenon correctly in scientific
papers, and while it was even in these days consid-
ered an epoch-making discovery, no one thought
of using the invention for practical purposes.

However, Guglielmo Marconi, an Italian youth
had read of these experiments, and being gifted
along these lines, he duplicated Hertz's experiments.
Soon his mind conceived the idea of using the inven-
tion for transmitting intelligence over a distance.
He endeavored to send a message without wires over
miles where Hertz used yards. Instead of the wire
hoop, Marconi devised and used a more sensitive ap-
paratus. He found that an instrument called the
coherer was enormously sensitive to the new electric
waves, and he soon was transmitting signals for
many hundreds of yards on the estate of his father
in Italy. By diligent labor he increased this dis-
tance, and shortly was telegraphing without wires
across the English channel, and not many years
later, he transmitted the letter "S" in telegraphic
code across the Atlantic by means of wireless.

To Marconi, therefore, belongs the honor of
having perfected the wonderful invention of radio,
first discovered by Hertz. Radio telephony, con-



HISTORIC 13

trary to popular opinion, is not a new invention
either. It has now been known for over two dec-
ades. Radio telephony, as we know it today, was
first invented by Valdemar Poulsen, the Danish
Edison. Instead of using a crashing spark at his
sending station, he used a silent electric arc with
certain adjuncts. This was not only entirely noise-
less, but it gave rise to something new, viz., Contin-
uous Waves. Heretofore, radio engineers had al-
ways used the electric spark which produced inter-
rupted waves. With these sparks, we could not
transmit the human voice because the interrupted
waves would break up the words in such a way
that nothing intelligible could be heard at the re-
ceiving station. It is as if you were trying to talk
and somebody was vibrating the hand to and from
the mouth rapidly. Naturally, no intelligible
words can be heard when this is done. Since
Poulsen's time, radio telephony has been well known
to the radio fraternity and many messages have been
sent. Thus for instance, in 1915, words spoken at
the Eiffel tower station, Paris, were distinctly heard
in Arlington, which is on the outskirts of Washing-
ton, D. C. At another time, the human voice flung
out into space at Arlington, was heard distinctly
at Honolulu, a distance of over 5000 miles. So
you see, the art of radio telephony is not of recent
origin, as people still believe. Not only is it possi-
ble to send the human voice from one radio trans-
mitting station to a radio receiving station, but in



14 RADIO FOR ALL

1916, an experiment was made whereby people sit-
ting in the dining room of the Waldorf Astoria
could hear the sound of the surf of the Pacific Ocean
at San Francisco, a distance of over 3000 miles.
This was accomplished by hooking up the radio sta-
tion to the ordinary land station, while the radio re-
ceiving station was at Arlington, Va. Then the radio
waves were conducted along an ordinary telephone
wire stretched between Washington and New York,
and the roar of the ocean was heard through the
ordinary telephone receivers connected to the tele-
phone switchboard in the Waldorf Astoria. The
public for many years refused to be interested in
radio telephony until very recently, when our broad-
casting stations began to send out regular enter-
tainment by radio. Then the newspapers began to
take it up, and today radio is a household word in
every American home, be it located in the city, the
suburbs or in the country.



CHAPTER II
WAVE ANALOGIES

FIRST of all it is necessary that you implant
thoroughly into your mind the fact that there is
nothing mysterious about radio; it is subject to
natural laws the same as other phenomena.




What is a radio wave? It is not any different
physically than a sound wave or a wave in the ocean.
If we throw a heavy stone in a still lake, it makes
what we call a splash. This wave rapidly extends in
the form of circles, as shown in Fig. 1. The heavier
the stone and the higher it falls, the greater the
splash, and the higher the waves. It is exactly so in

15



16 RADIO FOR ALL

radio. If by means of certain electrical apparatus
connected to an serial, we excite this serial electri-
cally, waves are set up in the space exactly as water
waves are set up on the lake. Radio waves, just as
do the water waves, branch out in all directions.
With the water waves this is not so true. A true




Fro. 2.

water wave, as we know, is carried along only upon
the surface of the water. A few feet below the water
and immediately above the water, no water waves
are had. A more strict analogy would be
sound waves. Take for instance, a church bell.
By giving it a blow with a hammer, we excite this
bell. What happens? Sound waves are set up
in the air in all directions from the bell. Whether
you are on the street level, 100 feet below, whether



WAVE ANALOGIES



17



you are 100 feet above in an airplane, whether you
are in a building where it is on the same level as
you are in all these positions you will clearly hear
the ringing of the bell. (Fig. 2.) What does this
mean? Just this. The sound waves are propagated
in every direction in
the form of waves,
invisible to the
eye, but "visible"
to the ear. These
waves are exactly
of the same shape
as are the ocean
waves or water
waves with the
difference that the
sound waves go
out in the air in
the form of
spheres. In other
words, the first
sound wave leav-
ing the bell F '-

would be a sort of invisible globe all around it. The
wave rapidly branches out, becoming larger and
larger, always remaining, however, in the form of a
sphere, as seen in Fig. 3. If the sound waves do not
go out in the form of spheres, it would not be possi-
ble for us to hear them in all directions as we have
seen in Fig. 2. We, therefore, come to the conclusion




18 RADIO FOR ALL

that sound waves that leave a bell branch out,
above, below, sideways, in fact in all directions.
It is exactly so in radio. The serial of the
broadcasting station, or other radio transmit-
ting station radiates exactly as does a bell. Both
are transmitters of waves. The radio waves go
out in the form of spheres as well, branching out
in every direction of the compass, as well as below
and above. Not only do the radio waves pass
through the air the same as the sound waves, but
radio waves pass through solid objects also, in an
easier manner than sound waves.

We all know that we can hear a bell even if
windows are closed. In other words, the invisible
sound waves pass through the window panes al-
though we cannot see the sound waves. Radio
waves do exactly the same thing, with the exception
that they pass through solids far better than do
sound waves. If we are far down in a basement, and
providing it is sound proof, we no longer hear the
bell, but radio waves go through solid stone walls
with great facility, and are, therefore, not stopped
by such obstacles. Radio waves even pass through
mountains, providing these mountains do not con-
tain ores or other metallic substances. Radio
waves also pass through the water just as sound
waves do. We all know that if we suspend a bell
below water, it may be heard if we sink a tube into
the water and apply our ear to it. Thus radio
waves may be received in submarines totally sub-



WAVE ANALOGIES 19

merged in water. Radio waves also pass through
the earth with great facility. As a matter of fact,
it is possible to receive radio messages readily, as
we will see in a later chapter, by burying an insu-
lated wire in the ground. Such a wire, though
deeply buried, readily intercepts radio messages.

We therefore have learned here that there is
nothing mysterious about the radio waves any more
than sound waves. Both are subject to similar
natural laws. Not only this, but as we all know
the farther away we go from a ringing bell, the more
difficult it is to hear it. The greater the distance
the less able we are to hear the bell. The reason is
of course, that the original wave, as we increase the
distance between ourselves and the bell, becomes
larger and larger and soon covers a tremendous dis-
tance. Finally there comes a point where we no
longer can hear the bell. This may be a distance of a
mile or less, that is if we have ordinary hearing.
There are, however, persons and animals whose
hearing is so acute that they can hear the same
bell much further by reason of their being
more sensitive.

If we were to take two horns and point them in
the direction of the bell, as shown in Fig. 4, and
apply the ear pieces to our ears, we would be able
to hear the bell again, although without these appli-
ances, we would not be able to hear it at all. Why is
this so? The reason is that the vibrations that
reach our ears normally are too weak to be inter-



20



RADIO FOR ALL



cepted by our small ears. By enlarging our ears,
as shown in Fig. 4, we intercept many more weak
sound waves, and these waves, all being collected
into our ears bunched together, so to speak are
sufficient to again impress the diaphragm in the ear,




FIG. 4.



and we are thus again enabled to hear the sound.
We merely cite this interesting experiment because
it holds true in radio as well. If we have a
transmitting station, or a broadcasting station, we
can hear it only up to a certain distance with a given
apparatus. If we take a small aerial, which we can
liken to a normal ear, we can use it only for a given
distance, let us say 25 miles. If we move this aerial 30
miles away from the radio broadcasting station, we
can no longer hear it. The case here is exactly as
with the sound waves. The radio waves have now to
cover enormous areas, and there are not enough



WAVE ANALOGIES 21

waves, so to speak, to leave any impression upon
our small serial. If, however, we were to double or
triple the size of the serial, we would do physically
the same thing as we were doing when we attached
the two horns to our ears. By having a larger
increased serial with more wires, we would, by
means of this, intercept more waves than we could
with a small normal serial; consequently with such
an serial we could hear the broadcasting station
again, even though we were removed 35 miles from
it. You see that the analogy between the sound
wave and the radio wave holds pretty true, all the
way through. Of course, in radio we have other
means to bring in the signals even if we are removed
still greater distances. It would not always be
practical to make the serial tremendously large in
order to hear greater distances, also we would not
expect to hear our bell 20 miles away by means of
even large horns. We would have to devise some
other more sensitive means to hear the bell, and
there are such means at hand today in super-
sensitive electrical microphones which magnify the
very weakest sounds. So too in radio it is not
necessary to build a larger and larger serial, the
more we remove ourselves from the broadcasting or
transmitting station. Instead, we use more sensi-
tive apparatus which will magnify the sounds in an
electrical manner, so that we can hear the station
even though we are removed thousands of miles
from it.



22



RADIO FOR ALL



WAVE LENGTH

What do we mean by wave length? We often
hear in radio that a certain station transmits at a
given wave length, say 360 meters. What does
this mean? First we might state that a meter is a
measurement the same as the yard. A meter,
roughly speaking, measures 40 inches. All Euro-
pean countries instead of yard, foot and inch use the







meter, centimeter and millimeter. The meter has
one hundred centimeters and one thousand milli-
meters. Let us now return to our stone which we
dropped into the water. If we were to place our
eye on a level with the water, and someone was to
throw a stone into a quiet surface of water, what
would we see? Fig. 5 shows this. We would see
a wave coming out, as shown in our illustration.
Any water wave is composed of two distinct parts,
the crest and the trough. In other words, the water
first comes up then dips below the original surface,
then up again above the original surface, etc. In our
illustration, we have shown in dotted lines the orig-



WAVE ANALOGIES 23

inal surface of the water. The disturbance of the
stone has caused the water to expand into waves.
Now then, the wave length is that portion which ex-
tends from crest to crest. In Fig. 5 we see what a
wave length consists of. It starts at the top of the
crest, covers the trough and again up to the crest.
This is exactly one wave length, because it embraces
the total make-up of one complete wave.

By throwing an ordinary stone into the water,
such a wave length may be anywhere from one foot
upwards. Out on the ocean where we have very
large waves, so called swells, such ocean waves may
reach the length of about 300 yards or 100 meters
or more. We might, therefore, say that an ocean
wave has a wave length of 100 meters.

In radio we have the same sort of waves, and
these waves go out into space in all directions, as
we have learned before. In radio we can make a
wave length from a few yards or a few meters up
to several thousand meters and over. This all de-
pends upon the apparatus we use. It would be
the same with our bell. A very small bell, only a
few inches high, would give very small sound waves,
while one of the big church bells would give a much
bigger sound wave. In radio too we have the same
thing, and we can change from a short to a long
wave length.

What are the different wave lengths used in
radio? It has been found that short waves do not
travel over such great distances as long waves do.



24 RADIO FOR ALL

Using receiving instruments of an ordinary sensitiv-
ity, it has been found that it is better to use a wave
of 2000 meters or more, if we wish to transmit mes-
sages over several thousand miles, as for instance
across the ocean. A small wave length does not
pass as readily over such great distances.

RADIO TELEGRAPH AND RADIO TELEPHONE WAVES
How do the waves in radio telegraphy and radio
telephony differ? In radio telegraphy we simply
hear the plain wave in our telephone receivers, if
thus we may term it. If the operator in the trans-
mitting station presses his key, groups of waves are
sent out into space as long as the key is depressed.
At the receiving side we hear the waves making a
buzzing sound for the length of time that the key is
depressed at the sending station. If the key is
pressed down for a second, we .hear a buzz for a se-
cond. If the key is depressed for two seconds we
hear the buzz for two seconds, and by means of this
buzzing sound the telegraphic signals are repro-
duced^ Usually a code such as the Morse or the
Continental is used. For instance, a short buzz will
be the letter "E" while "SOS" would stand for
the following (a short dash be-
ing a short buzz, a long dash being a long buzz).
In radio telephony, however, we have a different
and more complicated action. In the first place,
we hear sounds, words, and music exactly as they
are produced at the broadcasting or transmitting
station. Two distinct things happen. The aerial



WAVE ANALOGIES 25

is made to send out a radio wave that is continuous.
This wave cannot be heard by the human ear with
ordinary receiving apparatus. It is what is techni-
cally called C.W. or Continuous Wave. It is also
used to carry along the human speech. At this point


1 3 4 5 6 7 8 9 10 11 12 13 14 15

Online LibraryHugo GernsbackRadio for all → online text (page 1 of 15)