March 1936 Radio-Craft
People old and young enjoy waxing nostalgic about and learning some of the history of early electronics.
Radio-Craft was published from 1929 through 1953. All copyrights are hereby acknowledged. See all articles
This is an all-star cast of radio pioneers if there ever was one. It's
not comprehensive by any means, but most of the first-string players
are here in this 1936 Radio-Craft article. One thing I like
about reading these old pieces is that they, for the most part, are
reporting on contemporary events; they are not merely a historian's
interpretation of what the original witnesses recorded. That is not
to say early writers did not editorialize, err, or outright lie about
content, but I give these guys the benefit of the doubt based on the
sources. You have certainly heard of people like Hertz, deForest, and
Marconi, but what about coherer (early detector)
inventor Edouard Branly and ground-breaking commercial radio broadcast
engineer Frank Conrad? Magazine editor, publisher, and inventor Hugo
Gernsback properly give a short run-down on the "Famous Radio Beginners"
of his day.
Famous Radio Beginners
An Editorial by Hugo Gernsback
The beginner in radio always is interested in what other radio beginners
did before his time, and he particularly wants to know what made radio
the great art which it is today. In all arts there have been famous
beginnings that eventually assumed great proportions. While these beginnings
at the time may have seemed unimportant, when looked at from a distance
of 20 to 50 years they now assume tremendous importance.
present art of radio, as most of us know, dates back to the brilliant
and practical researches of that most famous of all radio beginners,
Heinrich Hertz, a famous German research scientist, who did most of
his work in electromagnetic radiations about the year 1887 at Karlsruhe,
Germany. We have him to thank for the brilliant research work which
laid the foundations of modern radio, for his was an effort to experimentally
prove the existence of the very waves predicted in 1864 by James Clerk
Maxwell of Scotland in a series of masterful theoretical researches.
It was Hertz, incidentally, who was the first to transmit power by "wireless,"
(radio) which he did by observing small sparks from a single metal wire
loop not connected to his transmitter by any intervening wires. It was
also Hertz who demonstrated that the new wavelengths could be refracted
similarly to light, an experiment that lay dormant for several decades
- or until Marconi later on made use of Hertz's discovery.
famous radio beginner was the Frenchman, Doctor Edouard Branly, who
invented the coherer - merely a glass tube containing two metal plugs
and, between them, metal filings. Branly observed that when the tube
was placed in a strong electric field produced by a spark coil (while
sparks jumped between the two electrodes of the coil) these filings
became highly conductive.
Marconi, another famous radio beginner, had by this time read about
Hertz's discovery and Branly's coherer. He put two and two together,
added a few ideas of his own, and pretty soon, on his father's estate
in Italy, he was able to send and receive "wireless" (radio) impulses
over considerable distances by means of improved types of Hertz's spark
coil and a spark gap transmitter and Branly's coherer receiver. In due
time, Marconi made other notable beginnings. He invented the aerial,
and the use of a ground connection, both of which are used in modern
radio. Still later he invented the magnetic detector, discarding Branly's
coherer. He is responsible also for the tuning coil which was used for
many years, and which in one form or another still is used in radio.
Our own Reginald Fessenden, another famous early radio beginner,
is responsible for many radio devices that have stood the test of time.
It was he who gave us the electrolytic detector which he patented in
1903. This detector was far more sensitive than any that Marconi and
other radio beginners had used up to that time. Because of its great
sensitivity it was used for many years. Fessenden also invented the
high-frequency alternator, which was used (and still is used today)
for certain types of long-wave commercial transmission.
famous American beginner was Greenleaf W. Pickard. It was he who experimented
with all sorts of substances for use as detectors, and it was he who
gave us the silicon detector, the galena detector, the famous perikon
detector, and many others.
before this there was still another famous beginner in radio, none other
than Thomas A. Edison. It was he who really was responsible for the
present-day vacuum tube. 'Way back in the 80s, Edison discovered what
is now known as the Edison effect. He found that if you sealed within
a glass bulb two independent filaments which do not touch anywhere,
you could make an electrical current jump the space between the two
glowing filaments, by electronic emission. However, Edison did not do
much with this important invention-he had many more important ones to
play with-until the English scientist Ambrose Fleming came along and
used the idea (with some modifications) as a wireless (radio) detector.
used a heated filament and a cold plate. This became known as the two-element
Fleming valve, because it acted exactly as a valve, wholly in an electrical
own Dr. Lee deForest who had heard about this valve began to experiment
with it, and he soon found that in many respects it was a very unsatisfactory
device. He, in turn, made a new "valve" by adding a third element
the so-called grid-between the filament and the plate. From this early
beginning the modern radio vacuum tube evolved. Because of its extreme
sensitivity the deForest vacuum tube as a detector reigned supreme over
the radio world for several decades; in fact, due to this, and its ability
to function as an R.F. and A.F. amplifier and oscillator, the entire
radio industry has been reared upon the vacuum tube.
Soon deForest made another notable and perhaps the most notable radio
beginning, when he discovered regeneration. This immediately made the
vacuum. tube circuit so tremendously sensitive (responsive) that it
was possible, and is possible today, with a single tube to bridge distances
of 3,000 miles, and more, in radio reception!
in 1909 deForest using the vacuum tube as transmitter began sending
out radio telephone impulses through space. One of the first emissions
was a [Enrico] Caruso phonograph record, which was thus broadcast for
the first time. Astonished radio amateurs from New York City almost
fainted when they first heard clear music in their ear phones, where
heretofore there had only been dots and dashes. But broadcasting did'
not begin in earnest until Westinghouse station KDKA at Pittsburgh through
the endeavors of one of its engineers, Dr. Frank Conrad, another famous
radio beginner, started broadcasting in the Pittsburgh area. In a few
months, hundreds of broadcast stations sprang up over the entire country,
and the radio age had really begun.
what was badly needed were better and more sensitive radio circuits,
so a number of other "radio beginners" started to improve these circuits
or hookups; particularly outstanding among these men were Dr. Hazeltine
in this country and Marius Latour of France, both of whom became responsible
for tuned radio frequency circuits.
But still more important radio circuits were yet to come. Pretty
soon the superheterodyne was invented; this hookup, one of the most
famous in radio, is used today to the exclusion of almost all others.
This circuit was invented in France by Levy; but Latour, already mentioned,
also did valiant work on this circuit.
Another famous beginner is our own Professor Edwin H. Armstrong,
to whom we are indebted for many brilliant circuits; including improved
superheterodynes, as well as one circuit which, being extremely efficient
on short wavelengths, is coming into great prominence, namely - superregeneration.
Posted July 21, 2015