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News Briefs
January 1961 Radio-Electronics

January 1961 Radio-Electronics

January 1961 Radio-Electronics Cover - RF Cafe[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.

To show how far in advance of publication date magazines used to need to have their content submitted, this January 1961 issue of Radio-Electronics noted the fortieth anniversary of the country's first commercial radio broadcast by KDKA on November 2, 1920 (two months). KDKA's first daily broadcast began on September 20, 2021. Also reported was a record 100 mile underground communication record. Using a buried antenna, it used a new transmission mode that exploits the interface region between the ground surface and the atmosphere. A new international standard meter was changed to the length of 1,650,763.73 wavelengths of the orange-red line of light given out by krypton 86. Since 2019, the meter is defined as the distance light travels in a vacuum in length of the path travelled by light in vacuum in 1/299792458th of a second, based on a cesium time standard. A color TV standard had not yet been established in 1961, and precise measurements of the ionosphere were beginning to be made with sounding rockets.

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KDKA Broadcast Anniversary - RF CafeBroadcasting 40 Years Old

Pioneer broadcast station KDKA of Pittsburgh celebrated its 40th birthday Nov. 2, 1960. It went on the air officially Nov. 2, 1920, to broadcast the election returns, announcing the victory of Warren Harding. Earlier, it had been operating for some time as an amateur broadcast station in the garage of Westinghouse engineer Frank Conrad. The anniversary was marked with special broadcasts, including one from the building in Westinghouse Electric Corp.'s East Pittsburgh plant from which the first broadcast was sent.

Underground Radio Sets Record

Messages have been sent more than 100 miles from a transmitter buried deep in a California mine shaft, reports Space Electronics Corp., which has been carrying on underground radio experiments for more than a year.

While the idea of underground radio is not entirely new (some work had been done by J. Harris Rogers as early as 1919) , this system appears to work on a new principle. It uses the boundary layer between earth and air as a guide rather than attempting to send the signals directly through the earth.

As explained by its developers, the system works somewhat like this: A transmitting station below the earth sends out signals from a buried antenna pointed in the direction of the receiver. From the buried antenna, electromagnetic waves are generated in the media. These waves can travel in several directions, including an upward path to the earth's floor above.

In view of the discontinuity that exists between the earth - a conducting medium, and the atmosphere - a virtually nonconducting medium, a type of channel is created along the earth's surface. Favoring the direction in which the antenna is aimed, the waves travel along this channel toward the receiving site.

It is the channel formed by the discontinuity between earth and air that enables the effective transmission. This channel roughly extends from a few miles beneath the earth's surface to several miles above it. Both transmitter and receiver, however, can remain safely buried.

In addition to its obvious military applications, Space Electronics sees numerous commercial possibilities for the technique. It can, for example, offer a means of communication immune to ice and snow storms, hurricanes and tornadoes, vandalism and other hazards.

World Has New Length Standard

The international meter is now the length of 1,650,763.73 wavelengths of the orange-red line of light given out by krypton 86. The new standard replaces the platinum-iridium bar which has been kept in France as the standard meter since 1889.

The meter is the base (by Act of Congress) of American linear measurements as well as measurements in all countries using the metric system, and in all scientific laboratories in the world.

The new standard will increase the unification of systems of measurement throughout the world. In the past, it has been necessary to send meter bars to France for calibration against the standard, and it became obvious that - in spite of the care taken in calibration - some of the secondary standards were longer than others. The new standard is immediately accessible anywhere, and therefore will simplify the work of scientists.

No Color for Canada

The Board of Broadcast Governors of the Canadian broadcasting system, in a statement which said in part, "the time has not yet come for color broadcasting in Canada," has declined to authorize color broadcasting in Canada. The board had been urged by the Canadian Association of Broadcasters, the Canadian EIA and individual telecasters to authorize color broadcasting, using US standards.

The board noted that color TV had been "promoted expensively in the US since 1953, but only 500,000 color sets are in operation, compared with 52,000,000 black-and-white receivers.

New Solid-State Device Rivals Tunnel Diode

A device that consists simply of two metallic films separated by an insulating layer may make possible a whole new family of electronic apparatus. The new instrumentality - not yet named - was discovered by Ivar Giaever of the General Electric Research Laboratory. It exhibits the "tunneling" effect of a tunnel diode, at much lower voltages. The device operates at a degree or so Kelvin, at which temperature the metallic films are superconductors.

The device is simple, according to G-E scientist Ivar Giaever:

"First we evaporate or vapor deposit a strip or film of aluminum on a glass slide. We then expose this aluminum film to air for a few minutes, permitting a very thin natural oxide layer to form on the surface of the aluminum film. Finally we evaporate a lead film across the aluminum film. This sandwiches the aluminum oxide layer between the two metal films." The result is seen in the photograph. The active area of the device is the part where the two strips, separated by the insulating aluminum oxide layer, cross.

If the temperature is dropped to 1.2° Kelvin, and a voltage applied across the sandwich formed by the aluminum, lead and lead oxide, a current flows through the insulator. This "tunneling" takes place only if the insulating layer is extremely thin, say 10 atoms thick. Increasing the voltage produces a current curve somewhat like that of the tunnel diode. Between zero and 1 mv, current rises gradually. As voltage is increased further, the current curve drops steeply to about 3 mv, when it again starts to rise very rapidly.

This negative resistance effect, inventor Giaever pointed out, is independent of current direction through the device, whereas the tunnel diode is a one-way device.

While still early to predict exact applications for the device, the negative resistance effect opens possibilities as an amplifier. Since super-conductivity is reduced or negated by a magnetic field, the device could be modulated by a coil wound around the center of the cross, giving a triode effect. According to Dr. Guy Suits, G-E Director of Research:

The new devices that may eventually result from a "marriage" of tunneling and superconductivity should be as different from the transistor as the transistor was from the vacuum tube, and yet they should be able to perform many of the same functions. The discovery, upon which these future devices would be based, is so recent that all of its consequences cannot be fully determined. However, it is already adding to fundamental knowledge of both tunneling and superconductivity and has opened a new approach to the construction of versatile, microminiature electronic components. For example, it may be possible to make - in an entirely new way - a simple device that could function as a switch, diode, negative-resistance diode, triode, resistor or capacitor.

Ionosphere Satellite Up

The most extensive and intensive measurements of ionosphere characteristics and phenomena ever made are being taken by ionosphere satellite Explorer VII. These measurements are expected to increase greatly our knowledge of changes in the ionosphere, including variations due to sunlight and darkness and to solar and geomagnetic storms. The various sensors carried by the satellite are checking the concentration, distribution and temperatures or energies of the ions and electrons that make up the ionospheric belt. The satellite will also measure the quantity, momentum and energy of the particles of cosmic dust, or micro-meteorites, as well as indirectly measuring the density of matter in the space through which it passes.

The satellite, which weighs 90 lbs., is 30 inches in diameter and orbits around the earth, coming as close as 258 miles at its nearest point and reaching out 1,423 miles at its most distant. It makes one revolution every 113 minutes.



Posted June 14, 2024

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