NAB reports (Jan-Dec 1946)

Justin Miller, President A. D. Willard, Jr., Exec. Vice-Pres. C. E. Arney, Jr., Sec.-Treas. Robert T. Bartley, Director of Government Relations ; John Morgan Davis, General Counsel; Willard D. Egolf, Special Counsel; Howard S. Frazier, Acting Director of Engineering ; Dorothy Lewis, Coordi¬ nator of Listener Activity; Frank E. Pellegrin, Director of Broadcast Advertising ; Harlan Bruce Starkey, Chief, News Bureau; Arthur C. Stringer, Director of Promotion. Travel at Speed of Light The chief signal officer explained that radar pulses, like radio waves, travel at the speed of light — 186,000 miles per second — and that a transit time of about 2% seconds was required for the pulses to surge from the earth to the moon and for the echoes to travel back. The mean (average) distance between the moon and the earth is calculated by astronomers to be about 238,857 miles, but this figure varies as the moon revolves and moves in an orbit around the earth, and both move around the sun. General Ingles recalled that Sir Edward Appleton, prominent British physicist, recently predicted that scien¬ tists ultimately might be able to map the surface of the moon very accurately with the aid of radar. Other au¬ thorities, however, believed that considerable improve¬ ments in radar technique would be necessary before this could be done. Complicated Problem The problem of detecting radar echoes from the moon was complicated by the fact that scientists had never before been certain they could project radio waves beyond the earth’s atmosphere, nor had they ever succeeded in generating sufficient energy in the very high frequency band of radio to attain this range of nearly half a million miles. The Signal Corps experiments have valuable peacetime as well as wartime applications, although it is impossible at this stage to predict with certainty what these will be. One obvious possibility is the radio control of long-range jet — or rocket-propelled missiles, circling the earth above the stratosphere. The German V-2 missiles already are believed to have reached an altitude of 60 miles. The primary significance of the Signal Corps achieve¬ ment, General Ingles said, is that this is the first time scientists have known with certainty that a very high fre¬ quency radio wave sent out from the earth can penetrate the electrically charged ionosphere which encircles the earth and stratosphere. The several layers of the iono¬ sphere start about 36 miles above the surface of the earth and extend to approximately 250 miles. On this basis, the V-2 projectiles already have risen above the lower ionosphere levels, and it is now known that radio waves can completely penetrate the ionosphere. Check on Astronomers The new technique will also be valuable for studying the effects of the ionosphere upon radio waves. Scientists already have learned that low and medium frequency waves are reflected by the ionosphere, and these reflec¬ tions form the “skywaves” used for long-distance broad¬ casting. The ionized layers also sometimes distort and bend radio waves, much as a prism distorts light waves. By checking radar data against visual data provided by astronomers, it will be possible to compute accurately the effects of this distortion. Another valuable application may be the provision of new astronomical information. Not only may it be pos¬ sible to construct detailed topographical maps of distant planets with the aid of radar data, but scientists may be able to determine the composition and atmospheidc char¬ acteristics of other celestial bodies by this means. A less likely application of the new technique will be the possibility of radio control from the earth’s surface of “space ships” venturing thousands of miles from the earth, and the radio reporting of astronomical data elec¬ tronically computed aboard such vessels. The equipment used by the Signal Corps for this experi¬ ment comprised extensive adaptations to a standard war¬ time Signal Corps radar known as radio set Scr-271, originally designed in 1937 for long-range early warning against enemy air attack. It was an early model of this set which detected Japanese planes approaching Pearl Harbor on December 7, 1941, while they were 132 miles distant. The radar was operated at its standard frequency of 112 megacycles — its alternating-current radio waves made 112 million complete cycles per second — but the pulse repe¬ tition rate and pulse width were extended beyond the usual standards. Instead of sending out several thousand spaced pulses each second, the modified radar transmitted a pulse only every five seconds. The pulse width was in¬ creased from a few billionths of a second to as much as one-half second. This equipment, therefore, sent out a half-second pulse of radio energy every five seconds. A specially designed high persistency oscilloscope, comparable to the “A-scope” used on wartime radars, was constructed to present visual evidence of the moon echoes. When the radar was operating, a line across the face of the tube represented the transit of the successive pulses. As each pulse left the transmitter, a tall “pip” appeared at one end of this line. A smaller pip, toward the other end of the line, represented the pulse echo re¬ ceived from the moon. A double-sized antenna with 64 instead of the standard 32 dipoles was mounted on a 100-foot tower within the heavily guarded confines of the signal laboratory for this experiment. The antenna was “aimed” at the moon opti¬ cally by means of a specially constructed peep-sight. OPA PRICING CLOSES BATTERY PLANTS Companies that manufacture batteries for battery oper¬ ated home radio sets are experiencing OPA troubles. Immediate result for one producer has been the closing of four plants. Though an industry advisory meeting has been set for next Tuesday (29), the manufacturers are said to antici¬ pate no action which would permit production at a profit. “The facts are simple,” one executive told NAB. “Em¬ ployee straight-time wages have risen more than 35 per cent since 1940-41, and cost of materials has increased, but the price of the product remains the same as in October, 1941. “Most of those usually employed in four plants,” the spokesman stated, “are now unemployed. With full em¬ ployment and 1941 prices, the company lost over $100,000 in December. It is not in a position to continue such losses.” WALTER C. EVANS AND OTHERS HONORED BY I.R.E. Walter C. Evans, Vice-President of Westinghouse Elec¬ tric Company and in charge of Radio, was awarded a fellowship by the I.R.E. at its winter meeting held at the Hotel Astor, January 24. In addition Ralph Vinton Lyon Hartley, Belle Telephone Laboratory Engineer, and Dr. Peter C. Goldmark, Engineer of the Columbia Broad¬ casting System, also were honored. The fellowship was awarded Mr. Evans “in recognition of his past contribution to radio and his present active participation in the affairs of the Institute.” Mr. Hartley’s citation reads “. . . for his early work on oscillating circuits employing triode tubes and likewise for his early recognition and clear exposition of the funda ( Continued on next page) JANUARY 28, 1946-54