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September 1930 Radio-Craft
 [Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
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Superheterodyne receivers were
originally the sole domain of the Radio Corporation of America (RCA), which owned
the patents and refused to license them until around 1930. Hugo Gernsback, a contemporary
editor of the era, provides a little insight into superregenerative receiver
(an Edwin
Armstrong invention in 1912) circuits which superheterodyne was about to replace,
and why it was an important improvement in technology. This appeared in a 1930
issue of Radio-Craft magazine. Sidebar: The question often arises regarding the difference
between a "heterodyne" circuit and a "superheterodyne" circuit. The most popular
answer is that "super" (meaning "over") refers to the
intermediate frequency (IF) being located above the
range of human hearing, which peaks at about 15 kHz. Doing so assured that
any IF leakage into the audio circuits would not be discernable by the radio listener.
Seems reasonable.
The Superheterodyne Cycle
 By Hugo Gernsback
Radio, as I have said often before, is known to go through certain evolutionary
cycles. It has done so from the start, and it can be expected to go on indefinitely
in this manner. The radio industry has always been progressive enough to take hold
of that instrumentality which it thought would give the best results. It was so,
beginning with the coherer-spark-gap cycle; it was so during the crystal-detector
cycle, the regenerative "blooper" cycle and, of late, in the so-called tuned-radio-frequency
cycle.
Practically all sets in use today use some sort of tuned-radio-frequency circuit,
or a modification of the principle. Regeneration has been severely left alone; because
in the modern set, the old shrieking and whistling has been completely tabooed by
radio engineers and the quiet set is the order of the day. During the last few years,
few changes in the average radio set have been noted and, while we have changed
our tubes from the old-fashioned "triodes" to "screen-grids," the circuits still
remain fundamentally the same.
The superheterodyne cycle, into which we are now about to be launched, promises
to change radio conditions enormously. It is true that the superheterodyne has been
known for many years, and has been valued as one of the best and most sensitive
circuits known. It has been, however, because of basic patents, the sole property
of the Radio Corporation. This company steadfastly refused to license anyone else
to use the superheterodyne patents until, very recently, the announcement was made
that the R.C.A. will now license a number of companies to build superheterodynes
for themselves.
This announcement is an important one and, in a way, it has created a sensation
in the radio industry; particularly as the announcement of the decision was made
so late in the season that it probably will affect few of the models that will come
out during the remainder of 1930.
During 1931, however, the situation will be vastly different. There is not the
slightest doubt in our minds, that practically every radio set manufacturer will
immediately turn to superheterodynes, for a number of reasons. In the first place,
there is no question but that the superheterodyne circuit is the best and most efficient
circuit known to the radio art today. If one or two radio set manufacturers start
to bring out superheterodynes, the rest of the industry must of necessity follow,
or be left behind.
Of course, we will have many new variations of the superheterodyne and we may
confidently expect that, if the entire radio industry is to stand behind the circuit,
it will be greatly improved as time goes on. We will have screen-grid superheterodynes;
we will have pentode superheterodynes; we will have all sorts of combinations of
the circuit or adaptations of it; and there is little doubt that even the still
more mysterious superregenerative circuit will also, in the near future, be heard
from.
In the past, there was one slight disadvantage in using a superheterodyne set,
and that was the necessity of using two tuning controls. The modern radio set buyer
demands a single tuning control; and the R.C.A. has finally produced one good model
in which a single tuning control is used. There is no question in our minds that
the standard commercial superheterodyne set, which will be put out by the radio
industry during the coming year, is to be of the single-control variety.
Of course, one of the various advantages of the superheterodyne is that it requires
no aerial. Under modern conditions, with a broadcasting system of the power we have
today, much better reception can be obtained by means of a superheterodyne than
with practically any other set. The reason is, that the superheterodyne tunes much
sharper, and it is much easier to tune out an interfering station with a loop than
with a set that uses an aerial.
The sales arguments, when recommending a superheterodyne to the prospective customer,
are of course much stronger; because he need incur neither expense or worry about
an aerial. Then there are still in this world some people who think of an aerial
as a lightning danger; these people will naturally prefer a superheterodyne, which
has no "aerial complex."
We, personally, welcome the idea that the superheterodyne is now to come into
its own. We urge every reader of Radio-Craft to brush-up on superheterodyne literature;
and Radio-Craft, during the coming months, will do its share by publishing every
month superheterodyne data which in time will be most valuable, not only to the
general reader, but to the Service Man, the radiotrician and the professional radio
man as well.
It is certain that the superheterodyne will stimulate the radio trade to a marked
extent during the next few years.
It will have a great and lasting effect on automotive radio; as the superheterodyne
is certainly a most efficient set for use in a car.
The superheterodyne will also encourage the long-neglected radio experimenter;
who will again be able, we hope, to buy low-priced kits for experimental purposes.
From whatever angle you look at the situation, the superheterodyne cycle looks
distinctly hopeful for the radio industry during the next few years.
Posted on July 26, 2023
(updated from original post on 9/28/2015)
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