August 1964 Radio-Electronics
[Table of Contents]
Wax nostalgic about and learn from the history of early electronics.
See articles from Radio-Electronics,
published 1930-1988. All copyrights hereby acknowledged.
Have you heard of the
term "neutrodon?" Not me, until it appeared in this 1964 issue of
Radio-Electronics magazine's "News Briefs" section. A neutrodon is a
neutralizing capacitor used in vintage tuned radio frequency (TRF) radios based
on triode tubes - called neutrodynes - invented by Dr. Louis Alan Hazeltine. The
capacitors cancel out the Miller capacitance of high gain vacuum tubes. He
Hazeltine Corporation, which is now owned by BAE Systems (British Aerospace
Electronics - it's amazing how many of our technology companies are owned by
foreign entities). Also reported is
de Seversky, designer and manufacturer of World War I combat biplanes and
monoplanes, experimenting with a model "ion-powered craft" - the "Ionocraft" -
that floated on a stream of electrons from an emitter grid located below it.
Although no details were given, he claimed the craft could fly to altitudes of
60 miles. That height would place the Ionocraft within the
ionosphere, where I'm guessing the ambient charges would wreak havoc with
the navigation / propulsion system.
| 8/1958 |
Metal Based Transistor Extends Frequency Range
A new type of silicon transistor, described by Richard R. Garnache of Sprague
Electric Co., is expected to increase the useful frequency range by a factor of
10. Mr. Garnache said the device has a theoretical upper frequency limit of 20,000
mc, but is not likely to exceed 10,000 mc in its present state of development.
The metal-base transistor consists of two layers of single-crystal silicon separated
by a layer of metal no more than 100 angstroms thick. It is an invention of Donovan
V. Geppert of Stanford Research Institute, and is licensed exclusively to Sprague
Inventor of Neutrodyne Dies at 77
Dr. Louis Alan Hazeltine, inventor of the neutrodyne radio receiver, retired
consulting engineer, and former chairman of the physics department at Stevens Institute
of Technology (New Jersey), died at his home in Maplewood, N.J., on May 24th.
Professor Hazeltine was famous chiefly for his invention in 1923 of the neutrodyne
circuit, a means of preventing oscillation in the tuned-radio-frequency receivers
of the period. The effect of tube capacitance was balanced out by small capacitors
(neutrodons), and the radio-frequency transformers were placed at an angle (55-60
degrees from the vertical) to prevent inductive interaction.
Professor Hazeltine sold his patent for $1 million, according to reports - to
a group who organized as the Hazeltine Corp. to license manufacturers under the
In 1944 Professor Hazeltine retired from the faculty of the Stevens Institute
and became a consultant to the Hazeltine Corp. He was also a director of the corporation,
retiring 3 years ago.
Hazeltine was a Fellow of the Institute of Radio Engineers and president of the
institute in 1936. He was also a Fellow of the American Institute of Electrical
Engineers, and a member of the American Physical Society.
Ion-Powered Craft Could Fly at 300,000 Feet
Major de Seversky maneuvering his Ionocraft in the laboratory
model ion-powered craft which can lift itself off the ground and rise to a
height of 20 feet in the laboratory has been demonstrated by Maj. Alexander P.
de Seversky, aircraft designer and inventor. The invention was publicized immediately following issuance of the patent (No. 3,130,945). The Ionocraft,
as de Seversky calls it, keeps itself up by the "ionic wind" given off by a
plane of emitting electrodes in the form of a mesh of hollow, lightweight rods
or crossed wires. Below this plane is another similar one, charged to collect
the ions emitted from the mesh above. Air molecules set in motion by the
movement of the charged ions supply the lifting force. According to Major de Seversky,
the test in an environmental chamber indicates that the lifting force is
sufficient to give the Ionocraft a ceiling of approximately 300,000 feet (60
miles) above sea level. A main application of the Ionocraft would be as an
antenna. Two such antennas sustained approximately 65 miles high at strategic
points in the United States would permit direct TV and radio transmission
between New York and Los Angeles. The lonocraft can be used also as an
intercontinental ballistic missile interceptor, according to its inventor, who
gives a large number of other possible applications.
Now - Computer Makes Movies
Simple animated films can now be made quickly and cheaply with a computer by
a special programming language, according to a report from Bell Telephone Laboratories.
The "movie language" was developed by Kenneth C. Knowlton of the Laboratories. It
includes instructions for drawing pictures consisting of straight lines, arcs, complicated
curves, letters, simple geometric shapes and shaded areas. To make movies by the
computer, each frame is divided into 184 rows of 250 square dots, which may be black,
white or various shades of gray in between. The special computer language (called
BEFLIX, for "Bell Flicks") directs the computer to develop arrays and patterns,
to enlarge, shift or copy from one area onto another, and perform other operations.
The instructions are fed to the computer, an IBM 7094, on IBM cards. It makes a
tape which is fed to a Stromberg-Carlson 4020 microfilm recorder. This contains
a cathode-ray tube similar to a television tube, and a film camera. Each of the
lines is displayed on the tube as it would be on a TV tube. The intensity at any
point depends on the instructions sent from the computer by 6 magnetic tape.
Delegates at the Joint Computer Conference held recently in Washington, D.C.,
saw a 17-minute, movie in which the computer itself demonstrated the technique for
producing animated movies. The new technique, Dr. Knowlton says, can already be
made at a cost that compares favorably with animation by traditional methods. Still
experimental, all its possible applications cannot be foreseen, but it should be
particularly valuable for educational films.
Posted October 17, 2023