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News Briefs: Sferics
July 1961 Radio-Electronics

July 1961 Radio-Electronics

July 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.

Ever heard of "sferics?" That's a new word in my technical lexicon as of right now. Sferics (aka spherics), is a contraction, derived from "atmospheric" phenomena, specifically referring to the electromagnetic signals generated by natural events in the atmosphere, such as lightning discharges. Over time, its use has become specialized in the field of meteorology, physics, and certain branches of electrical engineering, where it is used to describe specific types of electromagnetic emissions. It was mentioned in this "News Briefs" column in a 1961 issue of Radio Electronics magazine. Also in the news was the decreasing conductivity of the atmosphere due to low sunspot activity. The sun goes through a roughly 11 year cycle of high and low numbers of sunspots. Ham DX'ers love sunspots since by charging the upper atmosphere, it facilitates long distance communications. Japanese color TV sets were deemed "impressive." Much more.

News Briefs: 11/57 | 8/58 | 11/59 | 2/60 | 4/60 | 8/60 | 9/60 | 10/60 | 12/60 | 1/61 | 3/61 | 5/61 | 6/61 | 7/61 | 8/61 | 9/61 | 10/61 | 11/61 | 12/61 | 1/62 | 2/62 | 3/62 | 4/62 | 5/62 | 7/62 | 8/62 | 9/62 | 10/62 | 11/62 | 3/63 | 4/63 | 6/63 | 8/63 | 9/63 | 3/64 | 7/64 | 8/64 | 12/64 | 8/64 | 9/64 | 1/66 | 3/66 | 8/66 | 9/66 | 1/67 | 3/67 | 4/67 | 5/67 | 6/67 | 9/67 | 3/68 | 4/68 | 5/68 | 8/68 | 9/68 | 1/69 | 11/69

News Briefs

Sferics System May Track Tornados - RF CafeNew System May Track Tornados

A new technique originated by the Boulder (Colo.) Laboratories of the Bureau of Standards for investigating static disturbances (sferics) may have value in tracking tornados and hurricanes. The system, called "Ephi," uses three 125-foot towers spaced about 4 miles apart and forming the vertices of an equilateral triangle. These towers pick up signals that originate from lightning discharges and feed them over coaxial cables to a central station. Electronic equipment then determines the relative difference in time of arrival of the sferic signal from each antenna. From this information, the direction of the lightning source is determined automatically, and with greater accuracy than with direction-finding systems used in the past. Ephi also has potential value as a tracker of severe weather phenomena, since tornados and intense storms are usually accompanied by high-intensity sferics, Two stations located a few hundred miles apart could fix the position of a storm, even though it might be hundreds of miles from either station.

Plenty of FM Multiplexing

Forty-five per cent of all FM stations intend to add stereo service via FM multiplex, according to a recent survey by Motorola. This means that about 370 FM stations will have stereo programs on the air by the end of 1963. Ninety-two expect to be on before the end of this year. With replies in from 204 stations (25% of those polled), the totals show that 27% intend to start stereo broadcasting before the end of the year; 9% during 1962, and 9% in 1963.

Communications Channels Shrinking

Decreasing sunspot activity bids fair to crowd present short-wave activities into a little less than half of the present available spectrum within the next year or two. During periods of intense sunspot activity increasingly higher frequencies are usable, and, as the number of sun-spots fall off, one after another of the higher bands drops off.

As an example, George Jacobs, head of the frequency division of the Voice of America, speaking to the IRE convention, reported that during sunspot minimum only the 6- and 9-mc bands are usable more than one half the time, while during sun-spot maximum the 11-, 15- and 17- mc bands are also usable more than half the time. The coming minimum is expected in 1964, with a maximum again in 1970. Experts believe, however, that the next few sunspot maxima will fall considerably below the 1958-59 sunspot peak.

Satellites, greater development of tower-to-tower microwave systems, and even optical masers have been suggested as possibilities of relieving the congestion when present communications facilities will be squeezed into half the present available spectrum space.

Radio's Heaters Don't Turn Off

The tube heaters in two new AM-FM receivers, the Westinghouse H-761-N7 and the 762 in the same series, light when the set is plugged in and remain lighted during the life of the set. While presumably the main reason for including this feature was to eliminate drift; during warm-up periods, it has long been considered a theoretically good idea to keep heaters burning constantly. Tubes are supposed to have a longer life when heating and cooling cycles are eliminated. The surges that occur when current is turned into cold filaments or the high voltages which are sometimes due to rectifier tubes delivering plate voltage before amplifier tubes are warm enough to pass current may also damage other parts of the receiver.

In spite of the theoretical advantages, Westinghouse is the first to put the system into practice, though it is likely to be followed by others, particularly in equipment where reduction of drift is important.

AIEE Honors Dr. Allen B. Du Mont - RF CafeAIEE Honors Dr. Du Mont

Dr. Allen B. Du Mont has been named an honorary member of the American Institute of Electrical Engineers, an honor extended to only 48 persons since the institute was founded in 1884, and the highest honor awarded by the society. Dr. Du Mont, born in Brooklyn in 1901, was operating his own wireless transmitter and receiver in 1912. Obtaining his first-class operator's license in 1915, he worked as "Sparks" on ocean vessels during his high school and college vacations. After a period with Westinghouse, he became vice president and chief engineer of the de Forest Radio Co. In 1931, he struck out on his own to develop cathode-ray tubes for oscilloscopes and TV use. He invented the electron-ray tuning indicator and sold it to RCA, who made it famous as the Magic Eye. The money obtained from that invention was invested in a factory for the production of C-R tubes. Du Mont's inventions also included one for locating objects, in 1933, but his patent application was withdrawn at the request of the Army Signal Corps, for security reasons.

New Light on Earth's Field

Data obtained from the satellite Explorer X, which was launched to study the plasma (ionized gas) and magnetic fields in interplanetary space, indicates that the sun's magnetic field may extend well beyond the earth. A preliminary analysis of these data give strong support to the theory that the magnetic field around the earth is mainly an extension of the sun's magnetic field. According to this theory, the sun's magnetic field is stretched out by the magnetic pressure of charged particles blown out by the sun.

During periods of stable, strong magnetic fields in space, the lines of force were found to extend nearly radially from the sun. This was the crucial piece of evidence supporting the theory that the solar winds stretch the solar magnetic field.

On the basis of normal magnetic behavior, the lines of force could have been expected to loop around the sun in the same manner that iron filings line up around a bar magnet.

During other periods of the flight, the magnetic field was violently disturbed, fluctuating in intensity between 5 and 40 gammas, and reversing direction rapidly.

The satellite also made the first direct measurements of the density and energy of plasma in interplanetary space.

Jap Color TV Good, Say Visitors

Japanese color television is "impressive," according to visitors to the International Trade Fair at Tokyo this spring. Twelve television manufacturers showed color TV sets at the fair, though some of them were said not to be ready to mass-produce receivers at once. The visitors, mostly Government or commercial electronics men, classed them from "good" to "excellent."

Visitors also expressed surprise at the advances in the field of thermo-electric devices, but stated that the development of electroluminescence lags far behind the United States.

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