April 1936 Radio-Craft
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Craft,
published 1929 - 1953. All copyrights are hereby acknowledged.
Did you know that some radio service
equipment can be financed by the Federal Housing Administration (FHA)? That's right,
if your business needs a new tube tester or maybe an oscilloscope, Uncle Sam is
there to help. That was in 1936, anyway, per this Radio-Craft magazine
news blurb. Today, of course, the FHA no longer makes loans for business equipment
- the Small Business Administration (SBA) takes care of that. Nowadays the FHA restricts
itself to home loans - including to illegal residents, those with no money for a
down payment, and otherwise traditionally unqualified. Also reported, among lots
of other interesting stuff, is some early instances of RFI (radio frequency interference)
emanating from hospital equipment. Oh, and an anecdote regarding a Babe Ruth run-in
with the coppers. Note the
gun (aka Tommy gun) pointed at him in the drawing.
The Radio Month in Review
Two radio devices used to track-down the "shadow" - the direction
finder and the oscilloscope.
Radio is now such a vast and diversified art it becomes necessary to make a general
survey of important monthly developments. Radio-Craft analyzes these developments
and presents a review of those items which interest all.
Radio "Shadow" Unmasked at Last
Last month the answer was found to a question which for some time has stumped
radio operators, short-wave listeners and the entire radio profession.
As some readers may know, a mysterious type of radio interference in the form
of a low-pitched hum similar to a 60-cycle line hum has been interrupting radio
communication on certain short wavelengths, especially between the frequencies of
11,000 and 20,000 kilocycles. The hum has been heard irregularly and it apparently
changed in frequency from time to time.
This mysterious "shadow" as it has been affectionately (or not so affectionately)
called, has puzzled some of the best-known engineers in the radio industry and become
so important during the past 6 months that RCA Communications, Inc., spent many
hours making "fingerprints" of its tone, wavelength, waveform, and direction of
Finally, the "shadow" was unmasked, last month (after many possible sources were
tracked down) by the U.S. Navy!
The mysterious hum which was reported from all parts of the U.S., Honolulu, Nova
Scotia, Puerto Rico and the Canal Zone has been traced to the high-frequency vacuum
tubes used by hospitals and doctors in certain medical treatments. The findings
were turned over to the F.C.C. for further consideration. It is stated that proper
shielding will eliminate the "shadow."
Photo-Cells Give Telephone Time Service
The Post Office Department in Berlin, Germany, made known last month that it
is testing a new apparatus which automatically announces the time to all telephone
subscribers. The device consists of a drum on which narrow tone-film strips are
placed so that they cover one-half of the drum. Twenty-four tonebands are recorded,
one for each hour of the day, and 6 strips are recorded for the minutes. The tonebands
are scanned by 2 photoelectric cells (one for the hours, and the other for the minutes)
so that every reporting of the minute is preceded by a reporting of the hour. The
time is announced once every 4 seconds, thus 14 times in each minute. A few seconds
before the minute is over the machine is cut off and a buzzer switched on for 3
seconds, so that the end of a minute can be marked exactly.
This represents a new service and a unique application of electronic devices.
Some radio service equipment can be financed under the F.H.A.
Service Equipment Approved for F.H.A. Loans
Service Men will be interested to learn that certain types of servicing equipment
were approved, last month, for financing by the Federal Housing Administration!
The Precision Apparatus Co. was among the first to have its units approved for
financing under the above plan. Analyzers and tube testers made by this company
are among the servicing components included.
Under this plan, dealers and Service Men can buy their equipment and pay for
it over an extended period, just as repairs on homes, buildings, etc., are being
financed by this Federal Administration.
Verifications to be Discontinued
Of interest to the DX fan is the decision made last month, by two well-known
operators of radio broadcast transmitters, to discontinue sending out the usual
verifications of reception.
It is to be regretted that the Westinghouse Company which operates W8XK and W1XK
short-wave stations, and the British Broadcasting Co. which operates the short-wave
transmitters in England, found it necessary to discontinue this service to their
listeners in far-off lands.
The announcement of the Westinghouse Co., explained that newspapers and magazines
now carry listings of short-wave transmitters, their frequencies, and program schedules.
The increasing volume of mail, it added, also makes acknowledgment impracticable.
Amateur Radio Saves Infant
Amateur radio maintained its reputation of helping in time of
Amateur radio again came through nobly last month, in an emergency. On a small
island in the Pacific Ocean, 75 miles out from Los Angeles, a tiny four-months-old
girl was ill and in need of medical aid. The only communication from the island,
which is known as San Nicolas Island, to the mainland is by means of an amateur
radio station - W6JLF - operated by I. P. Elliot.
Elliot made contact with another amateur at Redondo Beach who called the local
police. The latter notified the Los Angeles police and the Coast Guard-and by the
time the police reached a doctor, a Coast Guard Patrol Boat was ready to sail.
Before morning, the boat, carrying the doctor, hove-to on the lee side of desolate
San Nicolas Island and another mark was chalked up on the already enviable record
established by amateurs.
"Radio Fading" and Sun Glow
Bright hydrogen eruptions from the sun corresponded with the major radio fade-outs
during this past year, according to a statement made last month by Dr. R. S. Richardson
of the Mount Wilson Observatory.
Four remarkable fade-outs of radio transmission were noticed at intervals of
about 54 days and it was suggested by Dr. Richardson that some form of unusual solar
activity might be responsible. Spectro-heliograms (in other words - special photos)
of the last two fading periods which lasted about 15 minutes each, showed in each
case a strong eruption of glowing hydrogen - known as a "flocculus." Dr. Richardson
based his statement on these records.
The careful study of such phenomena will eventually result in much better knowledge
of radio transmission.
Radio Reports Aerial Maneuvers
Major Williams uses short-wave radio for announcing how to "loop
The short-range characteristics of ultra-high frequencies in the neighborhood
of 35 mcs. have just been put to a new and interesting use by the well-known flier,
Major Al Williams.
The installation, which was completed last month, is the first of its kind to
be used in an airplane. It consists of a 5-watt transmitter and receiver installed
in the plane, with similar equipment located on the ground.
Major Williams uses this set-up to demonstrate difficult aerial maneuvers to
aviation students and spectators, at various air fields. He converses continually
with an announcer on the ground, explaining his movements.
Insull Buying Radio Stations?
According to a report received last month, Samuel Insull - one- time utilities
magnate - is starting a new venture called the Affiliated Broadcasting Co. with
which he hopes to band together some 26 low-power broadcast stations in Illinois,
Wisconsin and Indiana.
Mr. Insull is convinced and has convinced many of the small-station owners that
there is a real field for additional revenue by banding together.
However, an inquiry addressed to the Federal Communications Commission was answered
very definitely that they (the F.C.C.) had no such information! /p>
Among stations known to have been approached by the ABC are WCLS in Joliet and
WWAE in Hammond - both have a power of 100 watts.
Radio "Signal 32" Nabs Babe Ruth
Babe Ruth was greeted by police guns!
The "Pack" radio transmitter used to announce the results of
An amusing incident - and one which shows just how efficient the police-radio
systems in large cities can be - took place last month, and involved no less a celebrity
than Babe Ruth, baseball's "King of the Swat."
It seems that the Babe struck another car while driving home from Long Island,
N.Y.; the damage was slight and he decided to proceed on his way.
However, the owner of the car which was hit thought differently, and before Mr.
Ruth had crossed the Queensboro Bridge across the East River, he was greeted by
an officer with a high-powered rifle. It seems that the police, not knowing who
they were chasing sent out signal "32" meaning that the quarry might be dangerous!
The incident was settled peacefully.
"Pack" Transmitter Reports Ballot
The engineering staff of station WLW found a new use for the portable "pack"
transmitter which they designed and built a short time ago, in the experiment conducted
last month in Cincinnati with the "proportional representation" method of balloting.
This suggests a new use to which such short-range transmitters will, no doubt,
be put (F.C.C. permitting!) by other broadcast stations on similar occasions.
The transmitter, carried on the back of an announcer can be taken anywhere (where
it is not possible to move the ordinary "mike" and line amplifier) thus facilitating
the reporting of such events. The signals from the pack transmitter can be picked
up at any convenient location by a receiver and then carried over land lines to
the station. While the use of portable transmitters is not new, this application
is certainly a new and novel one!
"Check Valve" Reduces "Static"
Late last month, the American Radio Relay League announced a new radio device,
which could be attached to the intermediate-frequency amplifier of any broadcast
or short-wave superhet.
This device, which was described as a "balancer circuit," reduces to a great
extent the interference caused by auto ignition systems, refrigerators and other
forms of man-made static and will, to some extent reduce natural static, though
it is not a "static eliminator."
Mr. James J. Lamb who designed the new unit stated: "The general principle comprises
one tube paralleling a tube in the receiver's I.F. amplifier, followed by a rectifier.
The rectified noise currents are fed back through a circuit and applied to a previous
tube in the receiver to block or render that tube inoperative for the duration of
the noise impulse.
"The period the device is active may be so small that the ear does not perceive
any change in the program quality."
In other words, this device is a special type of automatic volume control!
Posted December 28, 2023
(updated from original
post on 6/28/2015)