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News Briefs
July 1964 Radio-Electronics

November 1961 Radio-Electronics

November 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.

sink-me

 

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News Briefs

News Briefs, November 1964 Radio-Electronics - RF CafeA person using AT&T's new Picturephone can push buttons to control whether he wants to be seen, see himself, see the other person, or nothing at all. Vidicon lens is small circle at upper left of screen. Speaker is behind grill to right. Control set uses no dial, but new "Touch-Tone" pushbutton calling system.

New York to California "Picturephone" Scores Hit at World's Fair

"See-as-you-talk" telephone was demonstrated publicly across the country for the first time at the opening of the New York World's Fair. West Coast reporters at Disneyland in southern California participated in a coast-to-coast press conference, asking questions of Bell System executives in New York via "Picturephone" hookup.

The installation in the American Telephone & Telegraph pavilion at the fair has been drawing great crowds. Soundproofed booths equipped with Picturephones have been set up, allowing visitors to talk with each other and with a telephone operator nearby. At occasional intervals throughout the day, a long-distance Picturephone call is placed to a waiting participant at Disneyland.

Callers sit about 3 feet from the instrument's screen, housed in a compact desktop set. Normal room illumination is sufficient for the tiny vidicon tube, next to the receiving screen, to generate a good picture. The caller has his choice of a view of himself, or of the party he's talking with or no picture at all.

Picture size is 4 3/8 x 5 3/4 inches, with a scanning rate of 275 lines per frame, 30 frames (60 fields) per second. The bandwidth required is about 500 kc (equivalent to about 125 telephone circuits). Each Picturephone set has three pairs of wires - one for the audio signal and two for the four-wire video transmission.

Vlf Signal Puzzle Near Solution

The strange behavior of very-low-frequency (vlf ) radio signals, which may be received better in one direction than in the other when transmitted between two points, may be near explanation, according to Douglass D. Crombie of the National Bureau of Standards.

Radio signals do not travel equally well in opposite directions, and a number of theories have been proposed to explain this anomaly. Crombie believes that the cause may be magnetically caused changes in the radio waves' coefficients of reflection or transmission at the ionosphere. In other words, the difference is due to the earth's magnetic field. Greater signal loss on reflection in one direction is probably due to increased transmission out through the ionosphere.

National Bureau of Standards Broadcast Changes

Transmitting clocks for stations WWV, WWVH, WWVB (and also Navy stations) were retarded 100 milliseconds April 1 because of change in the speed of the earth's rotation.

As of April 1 , WWVB and WWVL began broadcasting continuously from 1630 UT (Universal Time) Wednesdays to 2230 Fridays. Saturday, Sunday and Monday they broadcast from 1630 to 2230 UT; they alternate on successive Tuesdays.

Geophysical alerts are broadcast on WWV and WWVH in International Morse code (7 words per minute) during the first half of the 19th minute on WWV, and on WWVH during the first half of the 49th minute past each hour:

GEO-MMMMM (Magnetic storm)

GEO-NNNNN (Magnetic quiet)

GEO-CCCCC (Cosmic ray event)

GEO-SSSSS (Solar activity)

GEO-QQQQQ (Solar quiet)

GEO-WWWWW (Stratospheric warning)

GEO-EEEEE (No geoalert issued)

By agreement with the Naval Observatory, WWV and WWVH started broadcasting on May 1 daily corrections to the regular time signals to enable users to obtain a very accurate value of UT2. During the last half of the 19th minute of each hour on WWV and the last half of the 49th minute of each hour on WWVH, code signals will be broadcast as follows: UT2 (space) AD or SU (space) three digits. UT2 is obtained by adding or subtracting (as indicated) the number of milliseconds indicated by the last 3 digits to the time as broadcast. The symbols will be revised on a daily basis, the new value appearing for the first time during the hour after midnight UT, and continuing for the following 24-hour period,

Trans-Moon Communications

Lunar communications over 600 miles or more with frequencies around 350 kc may be possible, according to Prof. Newbern Smith of the University of Michigan.

Speaking at the US National Committee of the International Scientific Radio Union, Professor Smith suggested that a "solar wind" consisting of electrons and protons constantly streaming from the sun would create the equivalent of a lunar ionosphere. This would refract or bend radio waves in the same way that our ionosphere bends waves on the earth. Thus radio waves could be received at greater ranges over the moon's surface than previously thought possible.

Range and quality would, of course, be sensitive to variations in the ionosphere, which depends on solar activity, as well as the time of the lunar day. Communications over distances even greater than 600 miles may be possible with elevated antennas, Smith stated.

Satellite Discovers Huge Ray Zone

An 188-pound paddle-wheel satellite called Imp (for Interplanetary Monitoring Platform), launched Nov. 26 from Cape Kennedy, has discovered an energetic radiation zone that engulfs the Van Allen belt. It also confirmed that the earth is enveloped in a turbulent shock wave of streams of energetic particles from the sun traveling at speeds up to 300 miles a second, giving a new clue to the source of the particles making up the Van Allen belt.

When the sunlit side of the earth collides with this shock wave (as close as 40,000 miles from the earth), it creates an ever-broadening wake that stretches as far as the moon.

Sunspot Cycle Nearly Over

The present sunspot cycle No. 19 (the heavy solid curve on the chart) is approaching its end. Current estimates are that cycle 19 will bottom out somewhere between November, 1964 and April, 1965. (The curve is dashed from November 1963 on since exact information is not available beyond that date). The two previous sunspot cycles (17 and 18) are shown for comparison. The peaks of cycles 18 and 19 were the highest measured in the nearly 200 years of recorded sunspot history.

Chart courtesy of the BBC.

 

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