June/July 1940 National Radio News
of Contents] These articles are scanned and OCRed from old editions of the
National Radio News magazine. Here is a list of the
National Radio News articles I have already posted. All copyrights are hereby acknowledged.
Both funny and ridiculous I thought as I read this article from
a 1940 edition of National Radio News where author Julius
Aceves, a consulting radio engineer, makes the case for not buying
a newfangled, cheap radio that is supplied with a built-in antenna
when using a good old-fashioned outdoor antenna is the better option.
It's not that he doesn't have a valid point about the larger, obstruction-free
outdoor antenna providing superior signal strength and a greater
signal-to-noise ratio; it's that part of his argument is that in
doing so you are denying the outdoor radio antenna companies revenue.
That mindset is akin to telling people they should not buy notebook
computers because in doing so you are denying computer monitor and
keyboard manufacturers their rightful sales volumes. He does, to
admit that there are "a few well-engineered antenna kits" that are
worth consideration if
insist on taking food from the mouths of antenna salesmen's children.
As you probably know, it is rare to find a radio today that does
not have at least an internal AM antenna, often with no provision
for any type of external antenna connection. Most radios do offer
a connection point for an external FM antenna, however. A common
method for effecting a cheap FM antenna is to use the AC line cord
as the antenna or, in the case of a portable device like a smartphone,
the ear bud wires from the antenna. Higher end models, like my nifty
Tesslor R601S vacuum tube radio and my
Sangean WR-2, are supplied with internal antennas and connection
points for both AM and FM external antennas.
Advantages of Outdoor Antennas
Loops and indoor antennas have a definite place in the radio
industry, but a good outdoor antenna system is still tops when it
comes to picking up distant stations and keeping noise interference
at an absolute minimum.
By Julius G. Aceves,
Amy, Aceves & King, Inc., Consulting
11 West 42nd St., New York, N. Y.
To one who has specialized for years in signal pick-up and interference
elimination technique, the recent attempts to do away with outdoor
antennas are something truly to cry about. Indeed, we are going
backwards in our radio reception when we get away from noise-reducing
outdoor antennas in favor of loops and built-in antennas for operation
of moderate-priced and high-fidelity receivers. Convenient and cheap
as these antenna substitutes may be, they cannot and do not take
the place of the noise-reducing outdoor antenna, in providing for
optimum performance from a broadcast receiver. To prove that point
is the purpose of the following dissertation.
Also, from your standpoint as a Radiotrician this antenna-substitute
trend is far more than an academic question. It means dollars and
cents out of your pocket. For every time a set with loop or indoor
antenna is sold, it means the elimination of one more revenue-producer
for the service trade. Antenna installations, check-up and repair
jobs are "gone with the wind" when antenna-less sets sweep into
popularity. Hence it's your concern, too, that the public be educated
with regard to the superior results which an outdoor antenna will
First, let's be perfectly frank about this whole matter. We'll
concede at the start that there is a definite place for the loop
and built-in antenna. Technically, the self-contained signal interceptor
is perfectly legitimate for portable sets. Also for tiny midgets
that may be transported from room to room, or that may be used in
temporary quarters such as hotel room, school dormitory or hospital.
Economically, in the face of midgets selling for $10 or less,
the built-in signal interceptor is again legitimate and even essential.
No midget-set buyer is going to spend a few dollars extra for an
outdoor antenna, especially in metropolitan areas close to powerful
broadcast stations. Meanwhile, the limited tone quality of these
bargain-basement sets is such that one or two more handicaps don't
mean much, anyway.
Turning to better-grade radio sets, the self-contained interceptor
is quite another matter. Technically, the loop, built-in antenna
or indoor antenna decidedly handicaps set performance, as we shall
presently prove. Economically, such a set owner can well afford
another few dollars if much superior results can be obtained. So
our interest is primarily in better-grade sets.
Now just a few elementary principles to refresh our memories
and pave the way for the reasoning to follow:
Fig. 1. Signal strength of tuned and untuned antenna compared
with a tuned loop.
Fig. 2. Comparison of performance of a noise-reducing system
with conventional antenna of same dimensions.
Radio waves have two components: electrostatic and electromagnetic.
The device picking up these waves may be actuated mainly by one
or the other. Accordingly, we have a collector of the open antenna
or the shielded loop type.
The loop being a directional device, we can get maxima or minima
by rotating it in space. Thus, we can differentiate between two
waves coming from different directions. One wave may be that of
a desired station; the other, a source of interference. Better reception
is obtained by turning the loop against the interference source
rather than for maximum signal reception. By shielding the loop,
we practically eliminate the electrostatic component and receive
by means of the electromagnetic, with maximum directional effect.
All of this sounds ideal. In localities where radiated interference
is very low and signal strength fair, the loop may be satisfactory
at least in the broadcast band. Foreign stations in the short-wave
bands from 49 meters down to 16, cannot be received with the same
broadcast loop because of tuning-range difficulties. Also, since
the field strength of overseas stations is usually low, they cannot
be heard well even on a special short-wave loop under normal circumstances.
The same applies to ultra-high-frequency reception. Television reception
is out of the question. For signal pick-up, the loop is no better
than an indoor antenna. A shielded loop, however, gives better
discrimination against noise than an indoor antenna.
Most horn are none too happily situated with regard to low interference
level and high signal level. The radio set may be surrounded by
inductive interference or so-called "man-made static." There are
motors with sparking brushes, interrupters in thermostatic controls,
electric bells, dial telephones, contactors for elevators, and so
on. There may be that arch terror of radio noises, diathermy apparatus.
Outside, there may be neon or other gaseous-tube type electric signs,
or even incandescent lamp signs with motor-driven contactors. A
trolley line nearby doesn't help matters. Neither does a high-tension
transmission line with leaky insulators or transformers.
How can the loop take care of this situation? If oriented for
a minimum (or even a "null") for one source, it is not going to
help noises from other directions. Moreover, it is well known that
the induced voltage in a loop is very weak in comparison with the
electromotive force from an open antenna, even of the indoor type.
Therefore, when receiving from stations other than locals, we are
going to get tube noises; unless the receiver is extremely sensitive,
the automatic volume control cannot take care of fading.
What to do? Can a well-designed outdoor antenna system really
reduce background noises and increase signal strength in a typically
poor radio location? The answer is decidedly yes.
You may be skeptical. Other servicemen have become skeptical.
During the last half-dozen years, the market has been flooded with
so-called "noiseless antenna kits." Fantastic claims of noise-reducing
properties have been made without proper foundation. It is a safe
guess to say that more than 75% of such kits failed to reduce noise
as compared with ordinary antenna wire, in any worth while degree
to justify the claims. Frankly speaking, there have been many "phonies"
marketed, which have given a big shiny black eye to this antenna-kit
Nevertheless, there are a few well-engineered antenna kits - and
master antenna systems which are the product of years of study and
specialization. These kits really do the job. All they require,
from an installation standpoint, is to have the actual pick-up structure
(be it a doublet, "T", or vertical rod of proper height) in a noise-free
location, equipped with suitable couplers and transmission line
and a good quiet ground, in order to effect an amazingly high degree
of interference reduction. This is done in a two-fold manner:
1. Neutralizing the interference pick-up from the line connecting
the antenna proper with the radio receiver, and preventing the passage
of spurious currents from the power line into the input circuit
of the radio receiver.
2. Increasing the signal strength by maximum pick-up of the intercepted
In order to illustrate these principles, measurements were made
of signal and interference pick-up on typical loops and antennas
with and without noise-reducing equipment. The results are shown
in graphical form as follows:
Figure 1 shows a typical instance of relative signal levels from
a tuned loop vs. an outdoor antenna of the tuned and untuned types.
From these graphs, the superiority of the antenna over the loop
for signal strength alone is apparent.
Curves A, Band C in Fig. 2 represent: A, the signal-level difference;
B, the noise-level difference; C, the signal-to-noise logarithmic
ratio (curve A minus curve B), for a certain noise-reducing antenna
kit on the market, as compared to an ordinary outdoor antenna and
downlead of same dimensions. Curve C gives the resultant noise reduction
for a given signal loudness, and represents the improvement in reception,
which is as high as 40 decibels in some instances.
Do you realize what this means? Well, it corresponds approximately
to the adding or suppressing of a stage of audio amplification.
In other words, it corresponds to raising or lowering the volume
of an orchestra from piano to forte, or in piano playing, from mezzoforte
to fortissimo. This represents the effect of an increase of about
100 times in signal voltage, as a reduction in the noise has the
same effect as such a signal increase.
How would you like to soften the interference in your radio receiver
from an annoying forte to a tolerable piano level when listening
to the New York Philharmonic Symphony on a Sunday afternoon, if
you are a music lover? This would certainly justify the additional
expense of a noise-reducing antenna. That is the argument to pass
on to your customers.
And so in conclusion: There's no substitute for the properly
designed, perfected, noise-reducing antenna system, correctly installed.
You can readily demonstrate the practical gain in signal strength
and reduction of background noise by installing such a system in
your own home or shop, and having set-owners come to hear the results
for themselves. You can safely install such a system on a money-back-if-not-satisfied
basis, for it does prove itself. In this manner, you can show that
antenna-less receivers, threatening to become universal, cannot
give the best possible reception. Remember also that antenna-less
receivers cut down service revenue.
Editor's Note: The foregoing article represents the views of
the writer, a well-known antenna engineer, and was prepared especially
by him for the National Radio News.
Most of the loop-equipped sets have provisions for outdoor aerials.
By connecting a good aerial to such a set when it is tuned to a
distant station, you can demonstrate that signal level noticeably
rises and noise goes down. Even holding a finger on the antenna
post of many of these sets, while tuned to a distant station, will
sometimes prove effective as a demonstration of the need for a good
aerial when DX reception is desired. In a noisy location, only a
noise-reducing antenna of good quality should be considered.
Although the author made no mention of a specific antenna system
in giving performance curves, we presume he is referring to one
of the types manufactured under patents held by Amy, Aceves &
King. The antenna kits sold by the Technical Appliance Corp., 17
East 16th Street, New York City, using the trade name Taco, are
so licensed. Information on these kits may be obtained by writing
directly to the manufacturer.
Undoubtedly, there are other concerns making kits that will also
perform satisfactorily in giving a good signal-to-noise ratio. A
trial of several types should be made if possible, at your shop,
to determine the best type for your particular location.
Posted April 22, 2014