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September 1935 Short Wave Craft
 [Table of Contents]
Wax nostalgic about and learn from the history of early electronics. See articles
from Short Wave Craft,
published 1930 - 1936. All copyrights hereby acknowledged.
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Germans have long been
on the cutting edge of technology, medicine, and the fine arts. Much of the world's best music,
art, timepieces, engines, aircraft, guns, and other devices have emanated from there.
Notables like Einstein, von Braun, Heisenberg, Planck, Gauss, Kepler, Helmholtz,
Kirchhoff, Hertz, and Fraunhofer - all German - are almost certainly familiar to
all RF Cafe visitors. This 1935 Short Wave Craft magazine article demonstrates the voraciousness with which the
Germans sought to engage in science exploration. It is very unfortunate for the
German people that a couple maniacs like
Wilhelm II and
Adolph Hitler
were permitted to launch their country into wars that both times ultimately ended
in defeat and humiliation. Nowadays it seems, IMHO, the country is attempting to
atone for past behavior in the form of self-flagellation by inviting an overwhelming
number of unvetted, unskilled
foreigners to overrun the country. Japan is not committing national
hara-kiri;
neither should Germany.
1-Watt Short-Wave Transmitters Used in Germany
15-watt short-wave station, transmitter and receiver with pedal-driven
dynamo for exciting the transmitter.
Portable short-wave transmitter carried on the back with a special
harness.
Among the European nations, Germany is at present the most air-conscious one;
German boys of today desire to fly as eagerly as they wanted to be a treasure-hunter,
or a cowboy and trapper 20 years ago. Since motor-driven planes are not cheaper
in Germany than elsewhere the boys construct their planes. These planes are, of
course, only motorless ones - so-called gliders - which are built in the school
machine-shop with the help of an air-minded teacher.
Each of the boys contributes as much money as his parents can afford. This money
is used by the teacher to buy the raw material for the glider-plane to be constructed,
and if the plane is ready the students have a chance to enjoy the thrill of flying
by taking a so-called "Gleitflug-Kursts" (Lessons on how to pilot a glider-plane).
Since such a glider-plane is not able to carry two persons, the instructor -
often an army pilot - is able to communicate with the student-pilot, high up in
the air, only by means of yelling and gestures, an instruction method which is of
course not sufficient to prevent bad crashes, sometimes ending with the destruction
of the glider.
To avoid these unwanted accidents the instructors are now using small portable
telephone transmitters to communicate with the student-pilot. Despite the fact that
the output of these transmitters does not exceed more than 1 (one) watt, and only
a small telescopic antenna is used, these transmitters operating on a wavelength
between 60 and 100 meters often bridge remarkably long distances.
1-watt short-wave set and battery container at the right.
Short-wave portable transmitter for use on small airships.
10-watt portable transmitter and receiver.
The student-pilot receives the telephone signals by means of a small 4-tube receiver,
which is battery-operated. These receivers are not only of very small size but also
extremely light. The entire weight, including batteries, is about 7 to 8 .pounds.
Headphones installed in the pilot's cap, serve as the sound reproducers. A horizontal
hanging wire about 18 feet long is used as the antenna. Sometimes the guy wires
of the plane do the trick as antenna.
While these transmitters of 1-watt output are used by small glider-schools only,
the larger training camps have transmitters of about 15-watt output. The instructor
then has the opportunity of contacting the student under all circumstances. Each
of the glider-planes has for that reason a certain number, and interested short-wave
listeners often have a chance to hear the instructor calling for example a certain
plane: "Glider No. 567, do so and so," or if the weather conditions are not favorable:
"Calling all gliders, calling all gliders, to go down!"
These 15-watt transmitters are divided into three handy boxes, which are carried
by the students like knapsacks on the back. One box contains the transmitter. The
second one the aerial supports and the antenna wires, and the third one the power
source, the pedal-operated generator, used like a bicycle. The pedal generator is
so designed that it may be folded up in a few minutes. Each of the boxes has a weight
of about 50 pounds. As experience shows such a station may be put in operation in
a time not exceeding two minutes after arriving at a certain place, this time includes
the erection of the aerial supports and the antenna wires.
Similar transportable transmitters completed by a fitting transportable receiver
are often used for communication purposes in case of sport events and political
demonstrations. Telephony and code traffic is used in all such cases. Such a station
is very often installed in a small dirigible to supervise traffic regulations, etc.,
from above.
The German Broadcasting Co. is using portable 10-watt transmitters for reports
about interesting events direct from the spot. Often a special communication car,
furnished with several short-wave transmitters is in use. However, in all cases
where such a large car cannot be used, a small 10-watt transmitter, divided into
three or four boxes, is employed for the transmission. These transmitters are of
a relatively light weight and easily bridge distances of 10 to 15 miles.
Another very interesting type of portable short-wave station, also operating
on a wavelength of 60 to 100 meters, but often furnished with a continuously variable
wave range from 40 to 2,000 meters, is used by the German army. These very small
stations, having an output only of one watt, may be used alternately for telephony
and code transmission. If the code-key is touched, a small buzzer operating as a
tone generator, modulates the transmitter. A very sensitive 5-tube superhet, with
seven tuned circuits, gives a selectivity so high that many stations operating in
near-by channels may be used at the same time without any danger of mutual disturbances.
These small army stations are, despite their small output of one watt, very efficient.
Despite the fact that a very simple "L" antenna is used, 20 miles are easily bridged
where code is transmitted. Telephony is transmitted over distances of 10 to 12 miles
easily. The operator has a normal French-type telephone for telephone transmission.
Since these stations are working in two-way traffic, a very interesting trick has
been used to cut-off the receiver when the transmitter is used to radiate the telephone
signals. The microphone currents are fed into a rectifier, which operates as a kind
of combination between a squelch-circuit and an A.V.C. system. If the microphone
is in operation, the bias voltage of the receiver is automatically changed and the
entire receiver is cut off. Since the time-constant of this cut-off system is very
short, a regular two-way conversation can be carried on.
The entire station is divided into three small portable boxes of about 25-pound
weight for each part, and a small hand-driven generator is used as power source.
Posted January 19, 2024
(updated from original
post on 3/28/2017)
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