Circular-Type Radio Antenna

Designed for mobile use, this General Electric “doughnut” antenna shown at the recent convention of the Institute of Radio Engineers, can be installed directly above the roof of an automobile and is claimed to give the same results as the tall whip-type (vertical) antennas commonly seen on police squad cars. Efficient for both receiving and transmitting, it provides equal radiation of radio waves in all directions horizontally. The demonstration model was mounted on a toy train.

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Signals from the Stars

EVER since it was first indicated that the static present in the output of radio receivers was due in part to physical disturbances on the sun a new field of research has attracted popular scientific interest. It is radio astronomy, whose equipment and observers listen not to man made responses, but instead to continuous “static” from the stars. That cosmic radio noise exists was realized as far back as 1931. Early records proved it to be most intense when receivers probed toward the Milky Way, or lengthwise through our enormous watch-shaped galaxy. By contrast, the sun emits very weak signals, principally from its chromosphere and corona, although at longer wavelengths these show tremendous variations up to several thousand per cent. It is easy to imagine the annihilating results such changes would have on the earth were they at the visible portion of the spectrum. Yet in terms of total solar radiant energy, the effect of radio waves is insignificant.

Radio astronomy differs from the visual in two principal ways. First, of course, is the fact that we are studying unseen phenomena—radiation at wavelengths much longer than that detectable by the eye. And, second, instead of lens systems and photographic plates, very sensitive radio receivers teamed with high resolution antennas are used to make the observations. Current television stations operate from 1.39 to 1.75, and 3.4 to 5.5 meters (the latter, channels 2 to 6). The FM radio band lies in between, covering 2.8 to 3.4 m. But standard AM broadcasting transmits from 180 up to 550 meters. For example, WNBC New York, at 660 kilocycles on the dial, has successive wave crests separated by approximately 1,500 feet, nearly as high as the Empire State Building, all racing toward listeners with the speed of light. Up to the present time radio astronomy investigations have been confined to measurements at wavelengths between 3 mm. and 20 meters. At the shortest wavelength the successive wave crests are separated in space by about twice the thickness of a penny.

The instruments used for celestial microwave study, while resembling reflector type telescopes in appearance, differ considerably in operation. Moreover, weather clouds which prevent optical work will not appreciably interfere with the collection of stellar radio data. This was vividly demonstrated at Attu, Alaska, on September 12, 1950, when the Naval Research Laboratory’s expedition successfully recorded a total eclipse of the sun during a rainstorm. But in resolving power, radio telescopes cannot equal conventional ones because of the much longer wavelengths used.

Since radio astronomy itself is a comparatively new field, where the tools and observing techniques are still undergoing modification, definite conclusions regarding the cause of noises heard from out in space would be premature. Interesting is the fact that none of the brighter stars we see in our sky contributes much in the range of radio waves.

Just as advances in terrestrial nuclear _ physics have explained the heat and behavior of stars, they also aid scientists in formulating theories on the origin of cosmic rays. Some years ago, it appeared plausible that loose electrons in interstellar space sent out radiations as they sped past protons or other heavier particles. The more modern idea, however, proposes that some unusual stars of lower than naked eye luminosity and temperature may be responsible. Stronger emissions from the summer constellation of Sagittarius, toward the center of our galaxy, suggests a concentration there.

Exploration of the universe has thus been vastly expanded with the growth of radio astronomical apparatus permitting study of celestial radiation at frequencies never before investigated. Who can predict what great and hitherto “invisible” objects will be discovered?

—P. A. Leavens

WINDOW WASHERS TALK IN BROADCAST
Perched on ledges high above the street, two window washers, one in New York and the other in Chicago, communicated by radio recently in a novel broadcast sent out over a nationwide hook-up. With portable transmitters strapped to their backs, the workmen carried on a lively conversation about their work for the entertainment of the listening audience scattered all over the United States.

The idea that your calls are safe from eavesdropping because you have a specially tuned radio is also incredibly naive. All you’d need was a general radio with a tuner and you could listen to all the calls.

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NOW — POWER IS BROADCAST!

by Thomas J. Naughton

The Klystron, greatest radio advance, transmits energy without use of wires!

LIKE schoolboys in a classroom, more than 100 deans and professors of Eastern universities stood in a laboratory of the Westing-house plant at Bloomfield, N. J. Each of the learned gentlemen held in his hand a light-bulb with a few inches of bare wire attached; all of them expectantly watched the Westing-house engineer who was tinkering with two small doughnut-shaped, contraptions, connected to a six-foot loudspeaker-like horn, at the front of the room. The engineer straightened up.

“All right, gentlemen. Ready!”

At the words, the savants, like Statues of Liberty, raised their light-bulbs overhead and held them there. The engineer flicked a switch, swung the big horn to point toward them; pivoting smoothly, the big horn came to rest focused on the cluster of bulbs. And as it did so, every one of the bulbs lit up.

No wires, except for the little tail-like antenna, were attached to those lamps. They contained no batteries, they were entirely unconnected to any source of power. Yet they were alight. How?

The answer to that question records the achievement of a goal, a Promised Land of Science that has been sought for 40 years. It is something new under the sun. For those lamps were receiving power from the big horn, through the air. Power, in that laboratory, was being broadcast.

Those little lights, shining in a prosaic laboratory, marked the coastline of a new land. No powerlines march Indian-file over the hills and through the valleys of that land; no wirepacked conduits lie buried under the streets of the cities; no third-rails or overhead wires parallel the railroad tracks. The people there do not need those things, for they can tune in a supply of power as easily as we tune in a radio program.

There are no gas stations in that land. Automobiles have no gas tanks, no batteries; driven by electric motors, they draw their power from the airwaves. Airplanes are free from the leash of limited fuel capacities, for they carry no fuel; they can fly from New York to Hawaii, to Hong Kong, to India, with never a stop.

Houses have no furnaces, no oil burners, no steam pipes or radiators; they are heated by electrically-activated coils set in the walls. Power is everywhere, in the air itself, always available, waiting only to be funneled out through a strand of wire and put to work in a thousand ways.

That is the land whose first dim outlines were picked out by the light of the little lamps in that laboratory. It is the El Dorado for which cranks, dreamers and geniuses alike have been looking for two generations.

Our passport to it is the pair of doughnut-shaped copper containers manipulated by that Westinghouse engineer. Separately, the containers are called rhumbatrons; together, with a copper pipe connecting them, they form an invention which has been authoritatively described as “the most important advance in radio since the invention of the audion in 1906″: the Klystron.

For the Klystron, newborn though it is, has already proved itself the wonder-child of electrical technology. Probably no other invention of recent years has been the master-key to so many doors, has swept away obstacles from so many different paths of progress. Broadcast power is only one of the great vistas opened up by the Klystron; other fields in which advances are already being made with it are airplane travel, telephony, and television; and it is an important new tool for national defense.

Yet for all its versatility the Klystron, like most great inventions, is essentially simple; , it consists chiefly of nothing more complicated than two oscillating magnetic fields. Through the first field, in rhumbatron No. 1— called the “buncher”—a stream of electrons is squirted from a cathode; the field, shuttling rapidly back and forth, alternately speeds up and slows down the electrons passing through it so that they emerge from it not in a steady stream, but in bunches, with empty spaces i between. These bunches of electrons, traveling at a clip of 25,000 miles a second, shoot through a copper pipe to the second rhumbatron, the “catcher”; there they hit the ; second, or backstop, magnetic field, which absorbs their motion -energy and converts it into high-frequency radio waves. These are the waves of power.

The whole process -takes place inside a space no larger than that occupied by a portable radio. A Klystron, complete, weighs only about five pounds. Even the name of it and its parts are, as scientific names go, compact and simple; the rhumbatron is so called because of the rhythmic motion of the magnetic field inside it; “Klystron,” derived from Greek, signifies “waves breaking on a beach”—a phrase which pictures very aptly what happens in the “catcher” rhumbatron.

But the waves produced by the Klystron are different from any ever known before. The Klystron waveband is narrow—the wavelength is from one centimetre to one metre—but there is room in it for about 500,000 separate signals, as compared to about 100 separate signals possible in the standard 200 to 450 metre band. Also, the Klystron wave travels through air in a straight line; it does not follow the curvature of the earth, and it goes through the Heaviside Layer, that mysterious ionized stratum which serves so usefully as a backboard for all other radio waves, like a bullet through cardboard. If directed into a copper pipe, however, it will flow in that pipe like water, even around turns.

These characteristics cause communications engineers to regard the Klystron as being little short of a gift from heaven. Because of the enormous multiplicity of its signals, they believe it will soon enable them to transmit as many as 500,000 telephone messages at once on a single cable. Then all the long-distance telephone calls in the country could be handled by one or two main trunk lines with comparatively short tributary branches. Messages from New York to Pittsburgh, Chicago, Denver, and San Francisco, for ex- ample, could all be poured into the same cable; those bound for the inland cities could be unerringly picked out of the crowd at the right time and shunted off to their proper destinations while the others shoot through. Television engineers expect to use the Klystron similarly, so that the cost of television networks—up to now so huge that no such network has ever been formed—can be cut to a fraction of its present figure by transmitting many programs through a single copper pipe.

In short-distance communication the possibilities opened up by the Klystron are even greater, for it may in most places actually eliminate wires altogether. Wires are not needed in this age of radio for transmitting messages; that is being done without wires all the time. Where there are a great many messages, however, wires are necessary to keep them separated, because without wires only as many different messages could be in transit at any one time and place as there are distinguishable wavelengths available— under present circumstances, a few hundred. But the Klystron makes possible half a million simultaneous messages, each distinct from all the others, without wires. That is to say the Klystron makes possible, for all except the very largest cities, radio telephone.

Your radio telephone will have two parts: a receiver, set at a fixed wavelength which will be your telephone number; and a transmitter, ajustable by a dial to whatever wavelength you want to call. You won’t have to worry about eavesdroppers, because no receiver will be able to pick up any messages not tuned to its own built-in wavelength, and all the receiver wavelengths in any one community will be different. One city’s system will not cut in on that of any other city, as long as the two are at least 200 miles apart, because the Klystron wave travels in a straight line in air, and therefore cannot be tuned in beyond the horizon as seen from the transmitter. The short-range receivability of the Klystron wave, which appears at first glance to be a limitation, is actually an advantage.

Nor is its straight-line travel an advantage only for radio telephony; it combines perfectly with two other characteristics of the Klystron wave to make the instrument a powerful tool both for safety in air travel and for national defense. One of these characteristics is so remarkable that, if the Klystron had nothing else to recommend it, it alone would be enough to ensure the invention an important place in engineering history. It is that Klystron waves can be focused with precision on an objective—not merely directed in a general way, like present-day airlane “beams,” but aimed at a point. The airlane “beam” is a cone, fanning out from the source; the Klystron beam is extremely narrow and can be shot out like the ray of a searchlight.

Already that controllable precision has been put to use where it was badly needed. The Klystron is the heart of a new blind-landing system for airplanes, a system as superior to all previous ones as a modern pursuit ship is to a jenny. For even the best of the older systems had serious faults; they were not thoroughly reliable under all conditions and, even under the best conditions, most of them were fantastically complicated. The Klystron beam system, simple, boring through static like a high-speed drill, has solved the problem. Army and Civil Aeronautics Authority planes, using it, have made more than 1000 blind landings in all kinds of weather, and every one of them has been perfect.

Although the Klystron beam penetrates electrical disturbances and the Heaviside Layer with undeviating ease, however, it will not go through any substance which is not a good conductor of electricity. Whenever it hits an electrically-resistant surface, it bounces back from it like light from a mirror. This is another apparent liability which is in fact a considerable asset.

For because of it the pilot aloft in dirty weather can use the Klystron to shoot a beam downward and, by measuring the time it takes to rebound, determine a vital fact no altimeter can tell him: his exact distance from the ground. Over rough country he can shoot a Klystron beam ahead, and with it feel his way past shrouded mountain peaks.

And if he can see mountains, he can see other planes. Reports of R.A.F.’s new radio-rebound device to increase the effectiveness of fighter planes against night bombers indicate that the Klystron is doing its part to keep the Luftwaffe out of English skies!

In the improvement of ground defenses against aircraft, the Klystron is proving invaluable. Antiaircraft watchers probing opaque skies with its far-reaching, invisible finger can spot approaching planes long before any sound of motors could be picked up by even the most sensitive microphones. The Klystron can aim and fire guns automatically in pitch darkness with greater accuracy than human gunners can achieve on a clear day!

In that field the Klystron jumped to maturity almost as soon as it was born. But in other fields, in which it remains still an infant, it will attain the greater stature. It grows toward the day when wires, now vital nerves of civilization, will be left to moulder in forgotten conduits; when your telephone, your stove, your heating plant, your light —all will inhale power through an antenna on your roof. Automobiles, airplanes, trains, ships, will ride the pulsing power in the air like surf-boarders on the crest of a wave—the wave of the future, which will emanate from a couple of copper doughnuts called a Klystron.

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Beating the Celestial Strip-Tease

by Bill Williams

THE Eskimos call them “the dancing souls of the dead.” The ancient Norsemen said they were Valkyries carrying warriors to Valhalla. Modem scientists call them a “celestial strip-tease.” But communication engineers call the Northern Lights a plain pain in the neck.

The Northern Lights—the Aurora Borealis —have been the subject of superstition and folk-lore for ages. There have been tales as fabulous as the eerie lights themselves—of immense radium mines in the Arctic that glow at night, of frigid goddesses of the glacial ice, of vast fires that bum beyond the rim of the earth.

So long as the ghostly Gay White Way of the Heavens did nothing more to disturb us than frighten a few superstitious people, scientists paid no particular attention to them.

But since the advent of radio and long-range telegraphic and cable circuits, it has been noted that the Northern Lights are always associated with tremendous magnetic storms which play havoc with communications systems. And this discovery has spurred our scientists to a closer study of the stratospheric fireworks, until, now, we are beginning to learn something other than myth about them..

A few years ago, a magnetic storm accompanied by an unusual display of Northern Lights usually meant a complete breakdown of radio and telegraphic communication for several hours. Today, due to new facts which study of the phenomena have yielded and new methods of “dodging” electronic pyrotechnics developed by engineers, an outburst of the Aurora is not nearly so serious a threat to the vital flow of intelligence among humans.

The terrific display of Northern Lights and its accompanying magnetic storm on September 18 of this year—the most intense ever recorded in the United States—found communications engineers prepared. For the first time during such a storm, as a result, they were able to maintain radio communications, even with Europe. The tricks they used in keeping information channels open were almost as interesting as the latest explanations of the phenomenon of Aurora.

In the first place, it should be made plain that the Aurora and the magnetic storms on the earth’s surface are merely related phenomena, and not the same thing. Both, however, are due to gigantic exploding “spots” which show up on the face of the sun.

Only this year have scientists been able to make the definite assertion that both the Northern Lights and the terrestial magnetic storms are certainly due to sunspots. In the past, they have noted the relationship between these phenomena, but have not been sure that this relationship was not merely coincidental. This year, however, H. W. Wells of the Department of Terrestial Magnetism of the Carnegie Institute, was able to predict accurately the September 18 display several days ahead of time.

Before the September 18 Aurora, also, motion pictures were made of one of the sun’s spots for the first time, according to the report of Dr. Edison Pettit of the Mount Wilson Ob- servatory, using a new type of instrument known as an interference polarizing monochromator. The sunspot was shown to be a solar tornado of fiery gas, whirling on the surface of the sun at a speed of 120,000 miles per hour.

When first seen, the tornado was 8,000 miles wide at its base and 38,000 miles high! A smoke-like column projecting from its top reached an elevation of 68,000 miles, and during the course of observation a knot of gas broke away from the top and was hurled upward at a speed of 130,000 miles per hour!

But this “movie actor sunspot” was a baby compared to many sun-spots!

In the unimaginable heat of these fiery cyclones of the sun, hydrogen and helium atoms are being constantly broken up and reformed, and in the process great waves of solar radiation are shot out into space.

It has now been definitely determined that ordinary solar radiation—sunlight, as we know it, from the infra-reds through the ultra-violets— increases measurably during periods of sunspot activity. But also, observations by Dr. Harlan T. Stetson of the Massachusetts Institute of Technology have definitely shown that sunspots produce another radiation, different from sunlight, in the form of relatively slow-moving electrically charged particles, somewhat akin to electrons and protons.

Whereas light travels at a speed of 186,324 miles per second, these electrically charged particles travel at a speed of only 1,200 miles per second, approximately. These mysterious electrical “shots” are about 150 times slower than light.

Light, at its terrific speed shoots down upon the earth without being appreciably affected by the earth’s magnetic field.

But the sunspot’s slower electrically charged particles, traveling only about 1,200 miles a second, are seized upon by the earth’s magnetic field as they enter the outer atmosphere, and are drawn toward the magnetic poles.

Now, these slow-moving streams of electrical particles are what cause the Aurora, as we shall explain in a moment. Their attraction to the magnetic poles, due to their slowness, is the reason why the Aurora is seen principally in far northern latitudes. At times of great sunspot activity, more of these electrical particles are produced and they tend to “pile up” and back down into the lower latitudes. The September 18 Aurora was seen as far south as Georgia and Southern California.

Now for the manner in which these mysterious energy-bombardments from the sun cause the Northern Lights to light: The Norwegian geophysicist, Vegard, has recently explained that, in the simplest terms, the Northern Lights are lit in very much the same manner that one of our modern neon advertising signs is made to glow!

A neon sign is a sealed tube containing neon gas at low pressure, with an electric filament introduced. When the electricity is turned on, the filament shoots off electrons and the electrons bombard the gas. Outer electrons are stripped from the gas atoms by this bombardment, trans- forming the gas into an unbalanced energy-state which causes it to glow. Neon produces a red color. But scientists can reproduce all the eerie colors of the Northern Lights in the laboratory by bombarding various types of gases. Nitrogen glows green; mercury vapor, a blue-green; argon, a pink shade, and so on.

Scientists have now proven to their own satisfaction that this is exactly what happens in the upper areas of the atmosphere when the gases of the atmosphere, at low pressure, are bombarded by the electrified particles shot off from sun-spots. The Aurora is a celestial “strip-tease,” in which energy-particles from the sun strip electrons from the gas atoms of the super-stratosphere and cause them to luminesce.

They have even reproduced exactly the mysterious yellowish-green which is characteristic of the Aurora. This color, due to a single wave-length no where else duplicated in nature, puzzled researchers for a generation, until Sir John McLennan of the University of Toronto demonstrated in the laboratory that it is given off by atomic oxygen in a peculiar state of excitation, and then only when mixed with some of the other gases normally found in the atmosphere—argon, neon, helium and nitrogen.

The significance of this green line light is due not alone to its presence in the Aurora. It is also the most conspicuous light-line found in the luminescence of the night sky which is present all over the earth every night. On a clear, moonless night, sky-light is equivalent to that of a 25-candlepower lamp about 300 meters away. It has been found that the stars contribute approximately one-fourth of this light, and the balance is due to luminescence.

Experiments done by Stormer almost complete man’s knowledge of the Aurora. Stormer, in recent tests, determined that the Aurora occurs not at great distances above the earth, as was originally believed, but in that section of the atmosphere ranging from 50 to 80 miles from the earth’s surface. He measured the Aurora by photographing the phenomenon against a background of stars and then calculated by triangulation.

Dr. Stetson, of M. I. T., explained recently that there is a regular sequence of magnetic phenomena. First, sunspots are observed. There is a lag of about a day, and then the Aurora appears in the night sky. At about the same time, short- wave radio transmission is affected—in some cases completely blanketed out. Then, about a day later, standard-broadcast waves are affected.

In some instances, telegraphic communications are blanketed out, and the news teletypes in newspaper offices, and tickers in brokerage offices cease to function or bring in nothing but garbled messages.

During the September 18 storm, radio and telegraphic engineers whipped the sunspots for the first time in history.

By experimentation, they had learned that only east-west messages, or those running counter to the south-north magnetic field, are affected by these magnetic outbursts. They had also learned, as outlined above, that shortwave and standard broadcast frequencies are affected at different times during a magnetic storm.

RCA beat the magnetic waves on their foreign broadcasts by sending their messages “around the elbow.” They fired their radio messages south from New York to Buenos Aires, where it was automatically made to “turn the elbow” and was relayed to London, thereby dodging the storm by a 12,000-mile north-south detour. The messages made no stop in the Argentine and were flashed directly across the South and North Atlantic to out-trick nature’s bombardment.

Success was also achieved for transoceanic messages by alternating between long wave and short wave broadcast senders. The storm lasted for 25 hours, according to RCA engineers, but at no time was service cut off.

From the first observations recorded by literate men, the sublime display of the Northern Lights has stirred practical observers to lyrical ecstasies, and the scientific explanation detracts little from the enthusiasm.

One of the best descriptions is quoted from a Norse manuscript of the year 1250: “It appears like a flame of strong fire seen from afar. Pointed shafts of unequal and very variable size dart upwards into the air, so that now the one and now the other is the higher, and the light is floating in a shining blaze. So long as these rays are highest and brightest, this sparkling fire gives so much light that, out of doors, one can find one’s way about and even hunt. In houses with windows it is light enough for men to see each other’s faces.

“But this light is so variable that it sometimes seems to grow obscure, as if a dark smoke or thick fog is breathed on it, and soon the light seems to be stifled in this smoke. As night ends and dawn approaches the light begins to pale, and disappears when day breaks. Some people maintain that this light is a reflection of the fire which surrounds the seas of the north and south. Others say it is the reflection of the sun when it is below the horizon. For my part I think it is produced by the ice which radiates at night the light which it has absorbed from tlie day’s sunshine.”

Dr. Irving Krick, noted meteorologist, recently announced that he had determined a definite cycle of weather behavior which corresponds to the known 11-year cycle of sun-spot activity, which may make possible long distance weather forecasting hitherto undreamed of. The Harvard School of Business has released a report showing a direct relationship between solar radiation and the ups and downs of the stock markets. Scientists have found a relationship between sunspot radiation and crimes of violence. It has even been pointed out as significant that both World War I and World War II broke out at periods of maximum sunspot activity.

Science has explained the mystery of what makes the Northern Lights light. Perhaps even greater mysteries of the Northern Lights and their effect upon mankind’s behavior are only now opening up.

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Wounded Veterans Discover New Joys in Wireless Music

Radio Outfit Now Becomes Hospital “Nurse”

By Armstrong Perry

DO you know what “ether” means to thousands of weary hospital patients these days?

It no longer suggests shock and the painful after effects of an operation. Rather, the word brings thoughts of pleasure, recreation, and amusement. For the radiophone has at last entered the hospital— where, above all places, it belongs—and musical entertainments, broadcasted daily through the ether from dozens of transmitting stations, are now being borne into hospital wards and orphan asylums, bringing comfort and delight to the lonely inmates.

Radio amateurs, in regions where broadcasts are thick, have long since found wireless a blessing in hours of illness. It is, indeed, a common practice now, around New York City, for the owner of a receiving set to liven up a sickroom—his own or a relative’s—by hooking up his apparatus to the bed springs, which work wonderfully as an aerial. The patient, donning the head phones, can lie at ease by the hour, hearing the gossip and news of the great outside world, and catching in endless variety the lectures, sermons, songs, and instrumental music with which the great transmitting stations are now filling the ether.

From this use of radio in the sickroom at home to the installation of receiving sets in hospitals, has been an inevitable step. Equipped with a loud speaker, one reasonably priced receiving set can now entertain an entire ward, wiping out forever the gloom and hopelessness of hospital life.

Ask the boys in Ward 37, at Fox Hills Hospital, Staten Island, N. Y., for instance. They know! For the “godmothers” of the twenty-five wounded soldiers in this ward of the great government institution on Staten Island gave their “boys” a radio set last Christmas. Since that time, there are few dull moments in the ward.

The boys began by receiving an elaborate Christmas program from the Newark, N. J., station. At that time the loud speaker had not been delivered, but the inmates of the ward and their visitors passed the receiver from ear to ear, and improvised a paper horn that made the songs and messages audible to an attentive group. This new interest in life, and the keen pleasure that the radiophone has brought the wounded veterans, is doing as much for their health as careful nursing.

In fact, in numerous instances radio is making it possible for the hospital staffs to give their patients something more than medical care. In one of the greatest army hospitals located in Washington, D. C., several hundred patients at a time have been entertained by one pleasant-voiced nurse, who reads magazines into the transmitter, tells stories, and sings or says the little cheering things that only a woman can say.

At other times during this second experiment, a phonograph was started in the central station. It was connected with a radiophone transmitter that changed the sound waves into radio waves. The radio waves swept over and through the hundred or more buildings that constitute the hospital. Wherever they encountered metal, they sent electric currents through it.

In a white iron bed a soldier snapped a little clip onto his bed spring, picked up an instrument that resembled a telephone receiver, and heard the music of the distant phonograph as distinctly as though the machine were playing beside his bed. The electric currents were changed back, by the radio receiver, into sounds he could enjoy.

Hospital authorities who see in this an example worthy of imitation — and experience proves that it is—may be interested in a technical fact. The inventor of the system discovered that he could transmit voice and music within the area covered by the hospital without using high frequency currents such as are required in ordinary radio work. The radio waves from his apparatus travel through space at the rate of less than 10,000 waves a second. Passing through the magnets of the receiver, they cause vibrations of the diaphragm slowly enough to be heard as sound by the human ear. The bed spring is the “aerial.” The body of the patient, quite unknown to him, serves as a “counterpoise,” and makes it unnecessary to have a ground connection.

The particular system to be used is not important. One large hospital may broadcast its own entertainment throughout all the buildings. Another, like Fox Hills, may have an ordinary receiving set equipped with a loud speaker that permits a roomful of patients to “listen-in” on the regular broadcasts now blanketing the nation.

The latter is the simplest and most promising plan. And everybody who knows the ordinary gloominess of life in great institutions will realize how completely it will cheer the dreary life of the patients.

A Radio Letter from One Reader and a Broadcast Message to All
Editor of popular Science monthly: When I lost my eyesight,. some months ago, I suddenly found myself deprived of the majority of pleasures that others enjoy. I realized then how dreary and lonely must be the lives of thousands of inmates of homes for the blind—and, indeed, of all institutions.

But to-day, despite my misfortune, I have a brilliant vision for the happiness of these people. A wireless telephone, installed a few weeks ago, has brought me again all the joys that mean most to mankind. I hear daily of the doings of the outside world. I get the news—national, international, political, every kind—even before people who are able to read it in their newspapers. I hear lectures, sermons, and concerts.

Hours of suffering are turned to ceaseless pleasure wherever a radiophone receiving set is at hand. Let me urge you to advocate the installation of receiving sets for the benefit of those confined to homes and charitable institutions.

Roswell Prescott.
Newark, N. J.

“popular science monthly requires no urging in this cause. Founded fifty years ago by a famous blind scientist, E. L. Youmans, who contributed greatly to the development of science in America, the magazine feels a special sympathy for the blind. Moreover, POPULAR science MONTHLY believes that few marvels of applied science in all the magazine’s 50-year history have brought blessings to mankind exceeding the present promise of the wireless telephone.

We therefore raise the banner now for the extension of radiophone communication by popular demand to its maximum of utility.

And we ask public spirited readers in every city to start a local campaign for the installation of wireless receiving sets with loud speakers, in deserving institutions.

Think what this will mean to the shut-ins in orphanages, in homes for the aged or the blind, and in hospitals. It means that the walls of the institutions are extended to the limits of the earth, as the listeners hear concerts from New York, opera from Chicago, press messages from all over the world, church services from Pittsburgh, news from the local paper, music from many broadcasting stations—more entertainment, more points of interest, one is tempted to say, than the average healthy person enjoys.

Many newspapers, like the Newark, N. J., Call, the Detroit News, the Seattle Post-Intelligencer, are already sending out wireless broadcasts. In every town a newspaper might go a step further and take up this campaign for radio in hospitals and asylums. Three hundred subscriptions of a dollar each would completely equip one hospital.

Which town will be first?

Popular science Monthly stands behind the enterprise, ready to give all possible cooperation and information.

No Static on Micro-Waves

LIVELY interest has been aroused, among television and short-wave enthusiasts, in New York City, by the present activities of the National Broadcasting Company, in regard to experiments on ultra-short waves. Apparatus is being set up in the tower of the lofty Empire State Building, and short antennas erected about its mooring mast. While official information has not been forthcoming as to wavelengths and schedules, it is evident from the dimensions of the antenna that the work is on ultrashort waves, such as are now being similarly tested in Holland and Germany.

The ultra-short wave is readily reflected, so that it does not pass beyond the horizon of the antenna; and obstacles such as hills cast shadows in its path. It is therefore adapted only to local broadcasts of this nature, so far as present knowledge goes.

The “micro-wave,” however, is in still another order of wavelength—less than a meter (39.37 inches). It is even more markedly “quasi-optical”—that is, subject to the laws governing the transmission of light; but with extremely low power it is capable of transmitting distinct signals between any two points between which there is a clear space. Recent experiments were very successful across the English Channel.

The Marquis Marconi, who has always taken especial interest in short-wave work, states in a recent interview that he is now working on 10- to 20-inch waves (25 to 50 centimeters) on distances between ten and twenty miles, with perfect speech transmission. These waves penetrate brick and wooden walls readily, though steel-frame buildings reflect them. Since their frequency is above that of interference from “static” and electrical appliances, reception is unmarred by noise.

The particular value of the micro-waves for television is shown by the fact that they may be modulated with wavebands a hundred times wider than those used for ordinary broadcasting; and therefore they are adapted to the transmission of the most detailed images; while, for local programs, perfect reception, free from “atmospherics” and “man-made static,” may be relied upon. At the present time, the entire spectrum of micro-waves, with its numerous channels, is open for experiment by all licensed stations. Developments in the next year will be rapid.

“The great advantage in the use of ultra-short waves which has been yet discovered is that there is a complete absence of the static and fading, so troublesome on somewhat longer waves. Operation, also, is extremely economical.”

—Marconi

MOBILE STATIONS Broadcast Major EVENTS

HISTORY in the making is now brought into the homes of millions of American people through the use of mobile radio stations capable of broadcasting from the actual scene of any major event or catastrophe. Carrying broadcasting and receiving equipment, announcers and engineers, the mobile stations can rush to fires, flood areas, political and other events at a moment’s notice.

While one crew of engineers rushes to the scene another group hurriedly sets up high frequency receiving apparatus atop nearby buildings for picking up the signals from the portable or mobile station. Special telephone lines then carry the announcer’s voice to the key station where the broadcast is sent out to network stations throughout the country.

That was actually a pretty good guess.

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COMSAT: Communication in the Space Age

Not experimental, but commercial, instant worldwide information transmission by satellite
By RAY D. THROWER

In the 17th century, it took about 4 months for news of the New World to reach Europe. Now, with satellite communication, news whips around the globe in seconds. In less than 3 years, instant global communication will be a reality. Advanced communications equipment and the space-age vehicle, the Communications Satellite Corp. and its international partner, Intelsat, are all together responsible for that.

“Just what is COMSAT?” is a question one frequently hears. Many have the idea that COMSAT is a government agency, staffed by Federal civil-service personnel. This mistaken idea probably comes from the fact that COMSAT was authorized by the Communications Satellite Act passed by Congress in 1962. The basic Communications Act of 1934 made no specific provisions for satellite communication. In fact, in 1934, satellite communication was placed in the category of Buck Rogers space adventure stories, popular in the late 1930′s. COMSAT’s relationship to the Federal Government is about the same as the relationship of other communication companies such as General Telephone & Electronics, American Telephone & Telegraph, and International Telephone & Telegraph. They are all Government-regulated, profit-making stockholder-owned organizations.

Radio-Electronics visited the new earth-station facilities at Brewster Flat, Wash., and Paumalu, Oahu, Hawaii, and obtained an interview with Wallace M. Lauterbach. Western area manager for the Communications Satellite Corp. Lauterbach has been in communications for about 25 years.

He was graduated in 1941 from the US Military Academy with a BS in electrical engineering. He obtained his MS from the University of Illinois. During World War II. he commanded signal troops in the Pacific Theater. Since then, he has been executive officer to the Chief Signal Officer, Department of the Army; a member of the US delegation to the International Telecommunications Union in Geneva; military assistant to the telecommunications adviser to the President; and first Commanding Officer, US Army Strategic Communications Command.

When Colonel Lauterbach retired from active duty in June, 1965, he was an obvious choice for Western area manager, Communications Satellite Corp.

After we toured the COMSAT site at Brewster Flat, Wash., Lauterbach invited us into his office for some discussion about COMSAT and the future of space-age communications.

RADIO-ELECTRONICS: What is COMSAT’s purpose?

COLONEL LAUTERBACH: It’s to be a world-wide commercial communications satellite network to provide communications services to business, government, and individuals. Understand one thing: When we speak in terms of “communications” here at COMSAT, we mean not just telephone conversations, though they will be an important part of COMSAT’s activity. But I think the important contributions will be data transmission and. to a lesser degree, video communication.

R-E: Well, will the communications satellites be flexible enough to handle the different kinds of communications circuits you’re talking about? For example, can one single satellite take care of voice, data and video traffic, too?

LAUTERBACH: I’ll give you a qualified yes to that question. Qualified only because of the way it was worded. Yes, the present satellites can handle voice, data and video. But not all at the same time. They can handle a mixture of voice and data. The exact number of circuits depends on the speed, and therefore the bandwidth, of the data circuit. The real limiting factor is the terminal equipment used at the earth stations. The receivers and transmitters are the same for all modes, but the demodulating and modulating equipment is different for voice, data and video.

R-E: How many of each type circuit can satellites handle?

LAUTERBACH: Early Bird, which was our first program, can handle 240 two-way telephone conversations, or 6,200 full duplex, simultaneous teletype circuits, or one television video circuit. It can handle a few computer circuits or hundreds. As I mentioned before, the exact number of computer circuits will depend on the speed of transmission of the data.

R-E: I see. I’d guess that the communications satellites launched early this year can handle more than the 240 voice circuits of Early Bird, true? Do you have a name for the current program?

LAUTERBACH: Let’s take those in reverse. Early Bird was one name for what we call Intelsat I. That’s a single satellite located over the Atlantic off the east coast of South America. The current program, the one that affects us here at Brewster Flat and at Paumalu. is called the Intelsat II series. We have several satellites for this second phase. One did not achieve a usable orbit and is idle. The second is stationed above the Pacific Ocean about halfway between here and Australia. A third will be put on the opposite side of the globe over the Atlantic off the west coast of Africa.

As to channel capacity, Intelsat II spacecraft have the same capacity as Early Bird but more than twice the area of coverage. However, we’re constructing what we call Intelsat III. That will be what we call a “multiple-access” type communications satellite. These so-called global satellites, for use starting in 1968, will have a capacity in excess of 1,200 voice circuits each.

R-E: You’ve mentioned Intelsat several times. What is that?

LAUTERBACH: Intelsat stands for International Telecommunications Satellite Consortium. It’s an organization made up of a group of the member nations of the ITU. the International Telecommunications Union, which is an arm of the United Nations. Right now we have more than 55 member nations in Intelsat. Intelsat owns the satellites. COMSAT holds a majority interest, and acts as manager of Intelsat. Each member nation, or its commercial representative, will own its own earth station. We expect to have as many as 30 earth stations operational by 1968.

R-E: You also mentioned ”multiple-access” satellites. What do you mean by that?

LAUTERBACH: Well, by using a single broadband input receiver, a large number of earth stations, say, 10 or more, can communicate through the same satellite simultaneously, even though each earth station transmits on a different frequency. In fact, for the system to work, each earth station must transmit on a different frequency. Each station is assigned a band in the satellite receiver’s spectrum so one earth station’s transmissions won’t interfere with those of another.

Actually, you know, the communications satellite is a glorified translator, comparable to the vhf/uhf translators used to serve a lot of communities with TV. Our translation frequency is 2.225 GHz.

R-E: What bands do you operate in? I read that it was in the 6-GHz and 4-GHz bands, but there are already so many microwave systems operating in those bands, it would seem you’d have quite an interference problem.

LAUTERBACH: Exactly. Actually, you have no idea of the number of common-carrier microwave systems in operation.

R-E: What are common carriers?

LAUTERBACH: A common carrier is an organization, like a telephone company, that sells communications services. There are so many in operation in the bands we operate in that we’ve had to get sort of a special dispensation from the FCC that any future systems in our vicinity will be installed and operated on a noninterference basis. General Telephone Co. of the Northwest brings in the microwave relay channels that carry the COMSAT circuits out of Brewster Flat. They had to do some special engineering to get their microwave in here in the 1 1-GHz band, so as not to interfere with our 4- and 6-GHz operation.

R-E: What about the case where there was already a system in operation in your band? What do you do then? I’d think this might be pretty important when it comes to site selection.

LAUTERBACH: You’ve just hit on one of the most difficult things about setting up an earth station: site selection. Yes, we have to have an “electronically quiet” environment. Our receivers, which are cryogenic systems by the way, have a sensitivity of —159 dBm*, so, not just any place will do. We looked for quite a while before finding the Brewster Flat site. We’re in the bottom of a saucer-shaped depression between several mountain ranges. The mountains shield us from other microwave systems. Of course, we have a certain maximum angular elevation limit on our surroundings. Anything above 4° might obstruct the path to the “bird.”

R-E: You mentioned your receivers are cryogenic devices. This means they’re supercooled to reduce the natural electron noise, doesn’t it?

LAUTERBACH: Yes. They’re cooled to 4° Kelvin. And that’s close to absolute zero.

R-E: That should keep anything quiet!

LAUTERBACH: It does a good job of it. Actually, we’re not the first to use cryogenics. Radioastronomy systems have been using them for years and many of the telemetry systems for space work use cryogenics.

R-E: Besides the use of cryogenics, are there any other specific technical details in the COMSAT system that aren’t used in the usual communications system?

LAUTERBACH: Oh, yes. One thing that seems to surprise quite a few technicians and even some of the younger engineers is the fact that we transmit and receive simultaneously on the same antenna.

R-E: Could you explain how that works?

LAUTERBACH: The technique has been used for years in microwave and vhf and uhf communications. We use what we call a duplexer. It’s a resonant-cavity device, actually two cavities, one tuned to the transmit frequency and one to the receive frequency. At the resonant frequency, the cavity represents a low impedance to any energy it sees. At any other frequency it looks like an extremely high impedance, so the transmitter output is effectively isolated from the receiver input, but the receiver can still “see” any signal that’s on its frequency.

R-E: Sounds like something very useful. It lets you get away from having to build two of these “monster” antennas for each direction of transmission, doesn’t it?

LAUTERBACH: It sure does. And that cuts down on the overhead. There are some microwave systems that connect as many as eight transmitters and eight receivers to the same antenna, all operating simultaneously.

R-E: Whew! Let’s see. COMSAT was organized in 1962, and you launched your first satellite, Early Bird, in 1965, if memory serves me right . . . ?

LAUTERBACH: That’s correct.

R-E: Then, how did you manage to get all the engineering talent together to design your systems on such short notice?

LAUTERBACH: Our initial ground systems were designed and built by private contractors such as Page Communication Engineers, Sylvania, ITT Federal Labs and others. This may change with COMSAT engineers designing at least portions of the systems. Also, we already find ourselves having to provide engineering and technician advisory services to many national governments. Our transportable earth stations can be taken to remote locations and made fully operational in about 30 days and for a fraction of the cost of the large fixed station. [Since this interview, the 42-foot transportable antenna at Brewster Flat has been dismantled and shipped to the Philippines, where it has been leased for a year.—Editor] We realize that many of the countries that install these systems won’t have personnel trained. So, there is the definite possibility that COMSAT, through Intelsat, may provide the technicians and engineers to train some of the technicians and engineers of newer Intelsat members.

R-E: It seems like COMSAT will be a very interesting job opportunity. I imagine a few engineers and technicians would like to work for a prestige organization like yours.

LAUTERBACH: Definitely. And, with our expansion programs, we’re always looking for people with skills we can use. At a typical earth station, we need about 40 to 50 technical people. About 20% are engineers, the rest technicians. Multiply that by those 30 earth stations I mentioned a moment ago and you have a sizable work force around the world involved in commercial satellite communications.

R-E: What kind of background do you look for in an engineer or technician?

LAUTERBACH: Experienced communications people. We need technicians with vhf and microwave experience and backgrounds in multiplex carrier communications. Solid-state and cryogenic experience is highly desirable.

R-E: Mr. Lauterbach, is a satellite communications system really necessary? Aren’t the undersea cables reliable enough?

LAUTERBACH: The undersea cables? Yes, they certainly are reliable. They’ve served us well for many years and they’ll continue. But their capacity and flexibility are limited. In 1960, there were only about 600 communication circuits out of the United States to the rest of the world overseas. Most of these were by cable, a few by radio. With the growth of the world’s population and the increasing business and government communication needs, we’ll need 12,000 circuits by 1980. We added 240 circuits with Early Bird. This amounted to an increase of about 30%, but the most impressive improvement is the instantaneous availability of these circuits over an area of tens of thousands of square miles.

R-E: What kinds of customers will COMSAT serve?

LAUTERBACH: The most often mentioned example is NASA. We’re providing just about every conceivable type communications circuit to NASA for the Apollo program. Probably one of the most interesting services we propose is to provide voice and data communication to aircraft in flight on trans-oceanic runs.

R-E: Oh, I think I understand. On long over-water flights, vhf communication won’t work, and the hf radio bands are pretty crowded—and not always reliable.

LAUTERBACH: Exactly. Direct communication will play an important role in air traffic control in the future, especially when the 2,000-mile-per-hour passenger liners go into service. Recent estimates show that at any given moment there are over 280 aircraft over the Atlantic alone. And don’t forget the ships at sea. We can provide them with telephone and data service to the home office. That way, if there’s a change in the price of say, oil, in a certain port, the home office can direct the tanker to go to another port where the price is better.

R-E: What about the possibilities of satellite communications systems being used for worldwide educational television? Does COMSAT or anyone else have anything along these lines?

LAUTERBACH: Yes. ABC, CBS and NBC have already expressed interest in this area. Certainly it would be technically feasible. Actually, when we consider the ETV aspect of satellite communications, the only thing that keeps us from doing it is “doing it.” The technology exists. The only thing still necessary is the political and economic backing. COMSAT has already outlined a program for a domestic US satellite system that would serve the major TV networks as well as handle ETV.

R-E: How about computers? Couldn’t they be tied together by communications satellites? This would help in making data available on a world-wide scale. Hugo Gernsback, editor-in-chief of Radio-Electronics, in editorials for December 1959 and May 1964, urged the establishment of a “national facts center.” Using your facilities, a facts center could be international, couldn’t it?

LAUTERBACH: Someone’s been reading our mail! Seriously, though, the establishment of information grids, connected by relay satellite, has already been proposed. Some authorities think that in less than 10 years a student will be able to dial a local computer on his home telephone and program problems into it. This is already being done on a limited scale, but not with relay satellites for computer interconnect. But it could be done.

R-E: I’ll bet engineering firms and other businesses would benefit from being able to tie into such a system.

LAUTERBACH: They certainly would. And they’d find the cost not much more than a monthly telephone bill and a lot less than owning and maintaining their own computer.

R-E: Seems like you’re going to have a lot of people relying on your satellite. What happens if it goes bad after just a few days of operation? Or what if it doesn’t work to begin with? You can’t send a man up to fix it—not yet, anyway. What do you do?

LAUTERBACH: To begin with, our systems are designed to minimize failure. Each component and each unit is designed and tested to meet extreme requirements. The chance of failure is pretty remote. If a failure should occur in a critical component after the bird is up, we still wouldn’t have a failure because the equipment has built-in redundancy. That means there is a parallel unit that will take over the function of the defective unit. And, if, just if, the bird should be a total failure, we do have a couple of spares we can send up. But that’s expensive.

R-E: I guess you’re pleased with Early Bird’s performance. It went up in, let’s see, April of 1965, wasn’t it? And it’s still operating.

LAUTERBACH: Yes, Early Bird had a life expectancy of 18 months. It’s exceeded that by quite a margin. And looks like it will keep going for a while yet. The satellites orbited this year are designed to operate for 3 years and the ones planned for Intelsat III are being designed for a life of 5 years. R-E: What is the power of the transmitter in the satellite?

LAUTERBACH: Six Watts.

R-E: Six watts? But the one at the earth station is 12,000 watts!

LAUTERBACH: It does seem strange, but remember that right now our techniques don’t permit a very high power-to-weight ratio. We’re limited to low-powered transmitters on the satellites. We make up for this by using the large antennas and cryogenic receivers at the earth station. Going the other way, we can transmit from earth with high power and large antennas, with their high gain, and come up with a respectable signal level for the satellite receiver. This way, we can use fairly conventional circuits for the receivers in the birds and get away from having to put huge antennas and cryogenic receiver systems in orbit.

R-E: Then, actually, the complicated circuits are at the earth stations, more so than in the satellites?

LAUTERBACH: In a manner of speaking, that’s true. But that isn’t to say that the circuits in the satellites aren’t up to the state of the art. Some of our equipment is far advanced from the equipment of the more conventional, earthbound systems.

It has to be, because of size and weight limits.

There’s a great future for satellite communications and its engineers and technicians—a future where not even the sky is the limit.

In late January, Intelsat II’s Pacific satellite Lani Bird began to serve in two major functions. AT&T started using the satellite for commercial telephone service—with 6 circuits to Hawaii and 30 to Japan. And ITT initiated commercial TV use of Intelsat II with transmission of an NBC newscast to Nippon Television Corp. Fulltime commercial service is now underway between North America, Hawaii and Japan. The Atlantic satellite Canary Bird was lofted March 22. —Editor

Dolls Dance to Radio Music

FROM Germany comes the latest radio novelty. It is a platform upon which a group of dolls dance to the tune of music issuing from your radio receiver.

The device is a mystery until you understand the dance platform is caused to vibrate by means of a small needle which connects with a headphone, as illustrated in the accompanying drawing.

This headphone is connected up with your radio receiver, so that the same current sounds the music and excites the dancers. The effect of the contrivance is extremely fascinating.

Radio Speaker Like Chandelier

LOUD speakers which are placed in or on top of your receiving set cabinet are now being supplanted by a new amplifier that hangs from the ceiling like a beautiful metal chandelier.

The new amplifier is made up of a number of tone tubes which not only amplify the sounds but also give musical notes a rich tone. Each tube tones one note. Any electrical connection may be used between receiving set and chandelier.

down to the last component SONY CB-901 spells quality

SONY
RESEARCH MAKES THE DIFFERENCE

Unlike ordinary Citizens Band transceivers, there are certain distinct advantages in owning the SONY CB-901 fully transistorized unit. One of the most important is the separate speaker and microphone, rather than the combined speaker-microphone found in other sets. This means greater ease in operating and superior clarity in transmission and reception. Components in the SONY are designed and manufactured by SONY itself, rather than bought on the open market. This includes—most importantly—the 9 transistors. From raw materials to finished product. SONY quality control watches its components, to make certain only the finest pos- sible parts are used. But undoubtedly the most significant advantage is the SONY reputation for quality, gained in years of pioneering leadership in the field of transistorized electronics. Powered by 8 penlite cells, with push-to-talk control, telescoping whip antenna, range of up to 6 miles, and earphone for private listening, the SONY CB-901 operates where others fail. Including batteries, leather case. $149.95 per pair.

SONY CORPORATION OF AMERICA 514 Broadway, New York 12, N.Y.

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What the Sputniks Said

Russian scientists disclose how radio waves travel from their satellites to earth

By A. J. Steiger

Radio LISTENERS who tracked the earth-circling travels of Sputnik I have reported new discoveries in short-wave propagation, including a round-the-world echo, according to preliminary findings published in a recent issue of Radio, a Russian popular electronics journal.

What the Sputniks discovered about prospects for using solar power to operate space vehicle instruments is also discussed in the Moscow journal. These reports on Russia’s pioneer space vehicles’ discoveries, the first to be published, are translated here.

Propagation Conditions. “Preliminary results of reception of Sputnik I radio signals,” writes Prof. A. Kazantsev, Doctor of Technical Sciences, in Radio, “show that in the 15-meter wave band these signals were received at very great distances, far surpassing the distance of direct visibility and in a number of cases reaching 10, 000 kilometers. Very valuable material on possible ways of short-wave propagation can be derived from study of the data on long-distance reception of these signals.

“It will be recalled that the satellite orbit’s perigee (its lowest point) was in the northern hemisphere and its apogee (highest point) was in the southern hemisphere. The apogee’s altitude reached about 1000 kilometers above the earth’s surface. In the southern hemisphere, therefore, the satellite traveled above the principal layer of the ionosphere, layer F2, which conditions short-wave reflection.

“Concerning the northern hemisphere, especially interesting short-wave propagating conditions were created. At certain intervals Sputnik I was above the F2 layer of maximum ionization, at others below it, and at certain times close to the maximum.

“When Sputnik I was above layer F2, then passing from above through the mass of the ionosphere, the radio waves were reflected from the earth’s surface and propagated further by single or multiple reflection from layer F2 in those areas where its critical frequency had sufficiently high values (Fig. 1).

“It is also possible that radio waves coming into the ionosphere from above at a sloping angle are considerably refracted and therefore penetrate into an area outside the bounds of direct geometric visibility (Fig. 2).

“When Sputnik I was below layer F2 (Fig. 3), and approached an observation point from a global area lighted by the sun, the radio signals on the 15-meter wave band could come from the satellite to a point of reception, after going through consecutive reflections from layer F2 and the earth’s surface, and then through direct visibility.”

Limited Reception. “If the satellite, after passing over the observation point, moved away into an unlighted area of the globe, signal reception ceased in a relatively short distance, depending on limits of visibility.

“Non-symmetrical reception conditions were also observed. When the satellite was close to layer F2 of maximum ionization, then especially favorable conditions might develop for the formation of radio-wave conducting channels able to propagate radio waves over very long distances (Fig. 4).

“There is evidence, in fact, that along with satellite signals which reached the observation point by the shortest route, signals were sometimes received that had traveled around the globe (round-the-world radio echo). One of the USSR’s most skillful radio amateurs, Yu. N. Prozorskiy of Moscow, on October 8 at 0007-0008 hours recorded the reception of such a round-the-world radio echo in the 15-meter wave band.

“Concerning signals in the 7.5-meter wave band, as far as can be judged at present, they were as a rule received in the limits of direct visibility, although in certain cases owing to high values of daytime critical frequencies of the F2 layer, this wave could be propagated also outside direct visibility.

“A conclusion can be drawn as to precisely what way radio-wave propagation occurred after correlation has been established between the altitudes of Sputnik I and the real altitudes of the F2 layer at one and the same moment, and analysis of the propagation conditions.”

Sun’s Radiation. Discussing preliminary findings of Sputnik II with respect to solar radiation in outer space, Russian Academician A. I. Berg, leading Russian authority on space-flight electronics, wrote in Radio: “Of special interest for radio specialists was the data picked up by the second Soviet satellite on solar radiation in the short-wave band which has a direct effect on conditions in the upper layers of the atmosphere.

“During the course of more than a hundred years, scientists have been exploring the intensity and spectral composition of the radiant energy which falls on the earth from the sun, and have on this basis indirectly been attempting to determine what these magnitudes are for conditions outside the earth’s atmosphere.

“The most reliable data at present permit assuming that the density of the stream of the sun’s radiant energy, beyond the limits of the atmosphere, is equal to 1.4 kilowatt per square meter. In actinometry and meteorology, this magnitude is called the ‘solar constant.’ About 9% of this stream falls on the ultraviolet part of the solar spectrum, about 40% on the visible part, and 51% on the far red and infrared parts of the sun’s spectrum.

“At the earth’s surface, with the sun standing at an altitude of 30° above the horizon, the density of the stream of solar energy is considerably less owing to the dispersion and absorption of solar energy by the atmosphere. It amounts to not more than 30 to 35% of the stream density beyond atmospheric limits and is differently distributed. Only 2 to 3% of it falls in the spectrum’s ultraviolet part, 44% in the visible spectrum, and 54% in spectral heat rays.

“Making these data more precise, particularly the direct measurement of stream density of the sun’s radiant energy, i.e., the solar constant beyond atmospheric limits, will make it possible to determine accurately the sun’s effective temperature and density of the radiant energy stream emitted by a unit of solar surface. Precise measurement here is of interest to astrophysics first of all, but it is of more than [theoretical] importance.”

Battery Requirements. “If a transistor solar battery of 1 square meter in area be constructed and faced toward the sun even with the accuracy of a 30° angle, then as might be expected this surface will be exposed to solar power of the order of 1 kilowatt. With 10% battery efficiency in conversion of solar energy to electricity, the output of such a solar battery surface might be expected to reach 100 watts of electric power.

“But if it be assumed that a satellite flying at a great height is exposed to the sun’s rays approximately two-thirds of its orbit circuit time around the earth, then the solar battery can be expected to produce 100 watt-hours of energy. However, to secure such conditions, the spectral characteristics of the transistor battery must be close to the above-indicated frequency distribution of solar energy, especially in the visible and infrared parts of the spectrum, and, moreover, such a battery must operate on an optimum load.

“Unfortunately, the materials presently known that will permit creating batteries that possess high internal resistance are complex and cumbersome. A much lower-magnitude of electric energy should therefore be expected. But even this would nevertheless have great importance as a possible alternate way of powering space vehicle measuring instruments—a solar battery, for example, used in combination with an ordinary or storage battery.” —

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Take Your Radio on Your Motor Camping Trip

Edited by CHARLES MAGEE ADAMS

WITH the advent of summer, the thoughts of many are turning eagerly vacation-ward. For a goodly proportion of car owners this means anticipation of a long interesting motor trip, with the added pleasure of camping en route. To the radio contingent the attractive prospect of such an expedition may be tinged with regret at leaving behind the trusty receiver and the programs it brings nightly. But that need not be the case.

It is comparatively simple to take along a radio on an automobile camping trip and extract from it as much pleasure as at home. Not an a. c. receiver, to be sure. Current for its proper operation is not available in every shady nook so delightful for a camp site. However, the automobile makes a battery set quite convenient and practical. Its starting battery supplies an ample source of A power. The weight of dry Bs is no obstacle, and installation of the whole outfit is a problem against which fans will delight to pit their ingenuity.

This article is intended to offer some general suggestions regarding such an installation. They must needs be general since the conditions encountered vary so widely that no two cases are alike. But the suggestions to be offered should prove helpful in meeting individual problems.

At the risk of smothering a rosy hope, let it be said at the outset that the operation of a receiver while the car is in motion is usually not practicable. Interference caused by the ignition system is prohibitive without elaborate shielding. Added to this, there is the annoyance of microphonic tubes and vibration of condenser plates. Accordingly, the fan will have to be content with reception only during stops, which is what most wish anyhow.

First—regarding the receiver. Any good battery set will do. Preferably it should have two or three stages of r.f. amplification, because of the aerial and ground limitations. Also, it should be as compact as possible. If one is being purchased, a five- or six-tube job of the type turned out in the last two or three years will be just the thing, and a used specimen can be picked up at a very modest price.

Second—the ground and aerial. For the former, the car frame is convenient and surprisingly satisfactory. But care should be taken to see that a clean tight contact with bare metal is made. If good DX is desired, a pipe can be carried and driven into moist earth, or a length of wire or a zinc plate immersed in running water.

The type of aerial used will depend entirely on conditions and the fan’s choice. The simplest form consists of five or six turns of insulated wire (No. 14 r. c. preferred) wrapped around the car’s top, with a half inch or inch between turns. If the top is of metal, the wire should be outside, while if it is of wood and fabric the wire may be inside.

A better aerial, though one not so convenient, can be made by stringing up the usual length of wire between two trees (provided, they grow where needed). Failing this, 50 or 100 feet of insulated wire can simply be laid out in a straight line on the ground and used as the aerial. Good results can be obtained, too, by driving a nail into a tree and connecting the aerial lead to this.

Mounting the receiver presents a nice little problem. If possible, it is desirable to have it installed within the car permanently. A shelf at the rear of the front seat is excellent provided that can be managed.

The loudspeaker deserves more than passing attention. It is not recommended that an open cone be used. This type is quite vulnerable to the damage inevitable in motor travel. An enclosed cone is preferable, provided it is small enough. A horn is still less likely to be damaged but has the disadvantage of being awkwardly large, when space is an important matter. A solution of the difficulty lies in rigging up a speaker from a standard unit, with a home-made horn of proper size and shape. This can be made of cardboard and to fit into the available space.

If the receiver is carried packed and set up at night, a simple and effective means of battery connection is the cable and plug arrangement. The cable is connected to the receiver posts, and the various battery leads brought to the terminal plate, which can be mounted at any convenient point. AH connections can then be made merely by slipping the plug attached to the cable over the pins on this terminal plate.

The logical place to carry B batteries is the tool box or compartment under the rear deck. Care must be taken, however, to wedge them tightly in place to prevent jolting about and breaking connections. Also, they must not be short-circuited by tools or the metal compartment walls. A good safeguard against this is covering the tops of the batteries with heavy paper or a burlap bag.

The fan need have no fear that the use of a receiver at night will drain the starting battery dangerously. The amount of current consumed by a five- or six-tube set is small in comparison with that drawn by a starter, and with the long steady charge of the day’s driving the battery should be kept in tip top condition notwithstanding several hours’ radio use each night.

Altogether, the fan can expect real fun from devising a radio installation for his automobile camp along the lines suggested.

RADIO LINKS SINGER AND ORCHESTRA
Convalescing from injuries received in an automobile accident, a radio performer recently sang to her audience from a room in a Philadelphia hospital, while she listened through headphones to an accompaniment played by a dance orchestra in a plane flying 5,000 feet overhead. A dual hook-up enabled listeners-in to hear the voice of the star perfectly blended with the music.

Now “Flying Stenographers” span the sea!

You are familiar with teleprinter service which delivers a typed message, by wire, at high speed. Now this useful service takes to the air on a person-to-person basis, and is spanning the Atlantic Ocean by radio!

This new achievement, called TEX, was developed by RCA engineers and European experts. Its heart is an amazing machine that thinks in code, detects errors which may have come from fading or static —and automatically insists on a correction!

If, when RCA’s “TEX” is at work, a letter becomes distorted, the receiving instrument rejects the character and sends back a “Repeat, please” signal in fractions of a second — until a correct signal is received. Like other RCA advances in radio, television, and electronics, RCA’s TEX system helps make radio waves more useful to all of us — and in more ways!

See the newest in radio, television, and electronics at RCA Exhibition Hall, 36 West 49th St., N. Y. Radio Corporation of America, Radio City, New York 20.
RCA – Radio Corporation of America

World Leader in Radio – First in Television

HERE IT IS
THE AMAZING NEW Man-From-Mars RADIO HAT

COMPLETE 2-TUBE RADIO BUILT INTO A HAT

Here’s the famous two-tube topper you’ve read about in LIFE. TIME, POPULAR SCIENCE, BUSINESS WEEK, and many other magazines and newspapers, coast-to-coast. Now, you too can own this wonderful “dream-come-true” radio hat. A perfect gift idea! Study these amazing features….
• Covers entire broadcast band within 20 mile radius • Set weighs 5 ozs., hat 7 ozs. • Conceals in lining 1/4 thick • Absolutely mobile…no extra aerial needed
• Volume and tone equal to many portables • Regulation waterproof sun helmet… adjustable size, comes in many colors

“Works fine” – Life Mag

At your local dealer, or fill out and mail coupon below:

AMERICAN MERRILEI – 918 Halsey St., B’klyn 33, N.Y.

Radio Store Provides Free Clubroom for Wireless Amateurs

IN the back of a retail electrical store located in the skyscraper section of New York City, there is a unique club-room for radio amateurs. A full set of radio receiving equipment has been installed with an aerial on the roof. Apparatus can be tested out in actual practice, and the visiting amateur is given the privilege of taking any piece of apparatus from stock to connect up and use as he sees fit. The employees of the store make no attempt whatever to sell goods to the amateurs using the club-room. Even if the visitor asks for information, it is given without any intimation that he is expected to buy.

Amateurs who live many miles apart and who know each other only via wireless, form a habit of dropping into the club and talking over their installations. If one has a new idea in hook-ups, there is a chance to test it out. If a newcomer wishes to learn the standard connections, there are blueprints on the walls. If a “club member” has a theory of radio to demonstrate, he can step to the blackboard and sketch it out with the other amateurs present giving criticism and argument. Sometimes, if one is lucky, one may meet some of the experts from the big wireless companies, and get the latest “dope” direct.

By promoting interest in radio, the clubroom has proved a moneymaker for the store. The goods sell themselves, for by listening to the conversations in the clubroom the beginner in wireless finds out what he needs for a first class station, and goes out into the store and buys it. He has learned the right name, too, and does not waste the clerks’ time nor compel the salesman to give a curtain lecture on electricity and magnetism every time a receiver is sold. Best of all, the clubroom gives the amateurs a chance to exchange ideas and stimulates their interest in radio.

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What’s What in Radio Today

by Jay Earle Miller

What is the screen grid tube? What does it do? What are the advantages of the condenser speaker? These are a few of the questions that occur to folk trying to keep abreast of developments. Mr. Miller, who attended the Chicago radio shows, here gives the answers.

I WENT to a furniture show the other day and saw some clever new adaptations of radio to home decorating.

And then I went to a radio show and saw the finest furniture exhibit in Chicago.

That, in brief, is the status of the radio business in this winter season of 1929-1930. Radio has gone Grand Rapids with a vengeance. There’s no comfort in that for the dyed-in-the-wool fan who helped raise this radio business from its crystal detector days, but the lady who wants a decorative piece of furniture for the home, and the man who wants the chain programs, with the best possible reproduction, and beyond that doesn’t care how the thing works, are at last getting their innings.

In the technical field the most interesting developments of the year have been the screen grid tube and the condenser speaker, the latter having its first public showing at the shows.

The truth about the screen grid tube lies somewhere between the statement of one show salesman that the manufacturers took it up to give them something new to talk about, and the equally emphatic declaration of another salesman that it is the greatest discovery since Dr. Lee De Forest pumped the air out of the first three – element radio valve. Both salesmen, by the way, represented tube manufacturers. The truth seems to be that the screen grid tube is an excellent improvement when properly used, and not so good unless a set has been specifically redesigned to take advantage of its characteristics. The tube, for the benefit of those who have not seen one, consists of four elements instead of three. There is the familiar cathode, or filament in the center, the usual grid to act as a valve in intercepting the streams of filament electrons, and the plate, which the electrons bombard, but outside of the plate is a fourth element, the screen grid, looking something like a tube formed of fine netting. Screen grid tubes are not exactly new, for Europe has had them for four or five years, but the usual European design placed the screening grid between the old grid and the plate, instead of outside the latter.

In theory the screen grid tube, as used in the radio frequency stages, develops a possible amplification of forty times the input, as compared to an average amplification of eight in the old 201-A of more or less blessed memory. That means that with 201-A’s the first tube in the r. f. stage amplified the signal eight times, or 64 times the original input, and so on.

In actual practice a couple of manufacturers, through careful design, are getting amplification of thirty-five times out of the new screen grids, which is close enough to the theoretical perfect to make the tube well worth while. Careful design, in those cases, includes shielding the lube, shielding the coils separately, and also shielding the condensers.

The condenser speaker invented by Colin B. Kyle, a California school teacher, was the one new thing in reproducers this year, and, though fifteen manufacturers of sets have been licensed to use it next year, it so far appears only in sets made by a sub- sidiary of the company that financed Kyle’s invention. The condenser speaker, however, got a good boost at the Chicago show when all of the exhibition rooms were completely equipped with a broadcast system employing them, with excellent results.

The chief advantage of the speaker is that it lends itself to such varied use, though this is backed by excellent reproduction, as good as any dynamic, magnetic or cone type in general use, and better than many of them. The speaker is made in standard sections, about 8 by 12 inches in size, and any number of these sections can be combined to build a speaker of any size or shape. The sections are hardly an inch thick, and a half dozen of them assembled behind a framed tapestry can hang on the wall like a picture.

Unlike all previous speakers it has no moving parts, in the accepted sense, and no magnets or coils. A plate of aluminum is punched full of little slots, about 1/2 by 1 inch, coated with a thin non-conductor, and over that is glued a sheet of foil. The metal plate is given a negative bias of some 400 volts, and one side of the radio output is attached to the plate and the other to the foil.

One interesting thing about the show was the number of makers who are getting away from revolving dials and producing a straight line tuning device, with a knob moving from side to side. An interesting improvement, shown on two makers’ sets, was a semi-automatic tuner, in which the favorite stations are marked on a horizontal strip of cardboard, the knob is shifted until a pointer points to the one desired, and the knob is then pulled outward, when the connecting mechanism revolves the condensers to the exact point needed to tune in that station.

Another interesting tuning device has come out of Thomas A. Edison’s laboratory, a red light behind a transparent revolving strip, which lights only when the station is exactly tuned. A station is tuned to maximum volume, and its call letters then written on the transparent strip. Next a screw driver or the edge of a dime is inserted in a screw head beside tin tuning dial, the screw given a half turn, and a cam arrangement operates a punch which marks an impression in a thin copper disc, revolving beside a contact point. Next time you want that station the warning light will come on when the impression of the disc touches the contact point.

Comparing this year’s New York and Chicago exhibitions with the shows of three years ago some of the notable changes were: Bakelite panels have absolutely disappeared, in favor of wood in practically all of the console models and wood or metal in the other sets.

There was not a single kit or parts maker displaying at the Chicago show, with the exception of one manufacturer of short wave transmitters and receivers. Not a sin- gle storage battery was on exhibition —everybody having gone “all-electric.” The only dry cell exhibit was confined to small flashlight and electric lantern batteries. A number of cabinet makers exhibited, but confined their attention to the trade, and none offered cabinets for heme built sets.

The all-electric extent of the shows this year is surprising, for apparently nothing is being offered for the family that hasn’t had its house wired, or lives beyond the reach of the electric lighting lines. Of course, there are still large stocks of battery sets on the markets, unloaded at sacrifice prices, but none of them get into the shows. A typical newspaper advertisement during the Chicago show offered $285 seven-tube console models at $49.50.

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Eight Ring Radio Circus

TO AM and FM a new kind of broadcasting has been added—PTM, pulse time modulation. By transmitting eight or more different programs at one time on one frequency, it may help solve the traffic problem in the radio spectrum.

PTM was developed to meet the need for crowding more broadcasts into the ultra-high-frequency range between 300 and 3,000 megacycles. These microwaves are relatively immune to fading and static, but travel only along a line of sight, limiting reception to the horizon of the transmitter. A high building or hill blocks off the region behind it. Hence, microwaves should be broadcast from the highest point in the area. Since only one antenna can go there, UHF broadcasting is sharply restricted.

Developed by International Telephone and Telegraph Corp. engineers to solve this problem, PTM is a completely different method of broadcasting. Instead of using continuous waves of varying amplitude, like AM, or of varying frequency, like FM, it chops a constant-amplitude, constant-frequency wave into pulses. Variation in the spacing of these pulses modulates the signal.

To transmit several programs on one PTM wave (multiplexing), the individual pulses are simply mixed together. Thus, for an eight-broadcast system, succeeding pulses are unrelated, but every eighth one belongs to the same program. The receiver unscrambles the pulses by time-delay circuits, and the push of a button selects a program. The sound from the loudspeaker is intermittent, but it comes and goes so quickly— 24,000 times a second—that it sounds continuous, just as interrupted images on a movie screen look continuous.

An experimental PTM station in New York City broadcasts on 930 megacycles, using a stacked, square-loop antenna. This radiates horizontal, pancakelike beams that lose little power to the sky. As many as 16 high-fidelity broadcasts are possible, and several hundred radiotelegraph messages can be handled at once.

Since PTM uses its own unique modulation system, listeners need special receivers. PTM sets have two main advantages: fixed frequency, needing no complicated tuning devices, and a directional, high-gain antenna permanently aimed at the single sending station. Tonal quality and cost of the sets are about the same as those of a high-quality AM or FM receiver.

Eventually, if crowding of the air waves continues to increase, eight entertainment programs may be broadcast by one PTM station. For the present, however, the difficulty of replacing millions of home radios makes such a use of PTM unlikely. Many other applications are likely to come sooner. The Signal Corps, for which PTM was originally developed, uses it in field communications (PSM, January, ’46, p. 188). Cities could make all municipal broadcasts from one PTM station. Firms that telephone recorded music to restaurants could use a single PTM station to offer eight choices. Business and market news might go out over PTM, and press associations could use it for teletype and radiophoto services. All these varied types of transmission have been successfully demonstrated.

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Home Newspapers by Radio

Your Home a Silent “Press Room” . . . Automatic Facsimile Reproduction . . . Latest News by Breakfast Time . . . Bulletins Are Now Being Broadcast

A PRIVATE newspaper with any spot in your home as the press room, the world’s best editors and reporters on your staff, is available today to anyone in the United States possessing an ordinary radio receiving set. No thundering press will deafen you while your newspaper is being printed; instead, equipment contained in a small attractive box will silently print your “latest edition” while you sleep, completing it in time for reading at breakfast.

The name of this service now available is facsimile, first cousin of television since it shares with it some of the same basic principles. Unlike its more glamorous and well publicized relation, facsimile steps into broadcasting from other communication fields in which it already has proved its capabilities in a quiet but exceedingly effective manner. Facsimile has been in daily commercial use for several years, speeding news-photographs back and forth across the country via the telephone circuits and across the Atlantic by short waves.

In spite of the rapid development and use of every-day wire and radio facsimile service, many are unaware of its greater capabilities as a mass communications medium in the broadcasting field. This is largely because facsimile transmissions have been employed almost entirely to handle press photos for subsequent newspaper reproduction; in the average layman’s mind this is the limitation of the method. Many also confuse television with facsimile and ask why television ultimately will not perform the same duty.

FACSIMILE, in its electrical communications sense, involves the conversion of illustrations or other copy, such as printed matter, photographs, line drawings, sketches, and so on, into electrical signals which can be sent over radio or telephone circuits. At the receiver, the signal is automatically converted back into visible form, appearing as a recorded replica of the original copy. The received copy is permanent and, like a printed page, can be handled, observed, or read whenever desired.

Television also involves the conversion of visible aspects of subjects into electrical signals which can be sent to distant points. However, the frequencies required for this conversion are such that ordinary telephone circuits or conventional sound broadcasting equipment cannot handle the signal. Costly coaxial cables with associated high frequency signalling apparatus or ultrahigh frequency radio transmitters and receivers are therefore required.

In addition, there is as much difference in the technique of the two mediums of communication as there is between making a newspaper and a motion picture. Where facsimile is concerned with the transmission and subsequent recording of copies of still subjects such as pictures and printed pages, television deals with moving objects or persons. The image on the screen of a television receiver has the basic qualities of a motion picture. The image moves, it is transitional, and when the show is over the screen is blank. Since nothing has been recorded, the images will not be seen unless someone watches the screen when they are to be received.

Facsimile and television thus perform widely different functions. Each will fit into the communications picture as separate services, having fundamental distinctions as widely divergent as those of the public press and the motion picture.

The Finch facsimile transmitter now employed by many broadcasters (see listing on page 335) in their experimental service, uses a scanning machine in which the copy to be sent over the air is inserted in what is termed the “copy head.” This holds and advances the copy in front of the “scanning head,” consisting of a small electric bulb, lens system, and photo-cell. Light from the bulb is focused as a small spot on the surface of the paper carrying the copy; the reflected light is picked up by the photo-cell. The scanning head is moved from side to side by an electric motor so that the spot of light traces a series of parallel paths across the copy which is moved upward through a distance equal to the diameter of the light spot at the end of each scanning stroke. In this manner, the entire surface of the paper is scanned, line by line; the black, halftone, and white areas reflect to the photo-cell varying amounts of light ranging from minimum to maximum. These variations in reflected light effect a change in the amount of current flowing through the photo-cell. This current is fed to the radio transmitter in the same manner as sound broadcast signals are handled. Any conventional receiver tuned to the frequency of the transmitter will then pick up the signals which may be rendered audible by a loudspeaker, or used to operate a “home” facsimile recorder.

The recorders now in use are self-synchronizing. This is an important advantage; the recorder may be located in one state and the transmitter in another—the system does not depend upon local power lines for synchronization. Recorders are available for a.c. or d.c. operation, or for battery supply for farm use.

THE recording machine is similar in many ways to the scanning instrument. What is termed a “receiving copy head” holds the dry processed recording paper, which is fed as a continuous strip two newspaper columns wide from a roll carried in the lower part of the machine. A recording stylus is moved by a small electric motor from side to side across the surface of the paper, forming marks on the paper corresponding in position and shade to the elements of the copy at the transmitter. When the incoming signal is strongest the line traced by the passage of current is darkest; when it is weakest no mark is made. At the end of each of these recording strokes the paper is moved up by an amount equal to the width of each line element. By means of extremely short low-tone signal impulses sent out by the transmitter just before the start of each recording stroke, and by the use of a small motor turning over at a predetermined speed, the recording stylus moves across the paper in step with the scanning head of the transmitter, recording copy in its proper position. In this manner the recorded copy is built up line by line to appear as a duplicate of the original. One hundred lines will build an inch of reproduced copy; at the operating speed of the present machine, a two column newspaper will be “printed” at the rate of five feet per hour. It is not impractical to hope for a newspaper of five columns in the near future—tabloid size.

The actual home recording machine, which, it is claimed, can be made to sell for less than $50 in mass production, is small enough to be housed as a complete unit in a cabinet approximately a foot square. It may be connected without auxiliary amplifying equipment to the output circuit of any broadcast receiver having a power rating of three watts or more. In operation the broadcasting station from which facsimile signals are sent is tuned in with a receiver as would be the case if regular sound programs were to be received. The loudspeaker is switched off and the facsimile recorder is switched on; the volume control of the receiver is turned to the point where copy has the desired contrast. The resulting recording operation is wholly automatic and requires no attention. Paper costs will be about 15 cents per week.

Until the development of an automatic machine and inexpensive dry recording paper of wide latitude which requires no liquids for moistening or smudgy carbon transfers for printing, the adaptation of facsimile recording methods to home service seemed rather remote. Concentration on the automatic recording problem has resulted in the present-day home facsimile machine which safely operates without attention throughout long facsimile broadcasting periods.

During the present experimental period—and probably thereafter—facsimile broadcasts take place between midnight and 6 a.m. when sound broadcasting facilities are ordinarily idle. Time clocks will turn the radio receiver and recording motor on and off at specified hours. “Printing” of illustrated world events, bulletins with latest news flashes, photographs, market reports, weather maps, cartoons, recipes, and illustrated advertisements of all sorts, will thus be effected in homes while their occupants sleep, the machine being practically silent and entirely automatic in its operation.

THIS, to some who are not familiar with facsimile developments, may sound like one of H. G. Wells’ prophecies. That it is not, is attested by the fact that at the present many of the leading major broadcasting stations in the country already have been granted FCC permits and have inaugurated such a service using regular broadcasting frequencies and full power in experimental transmissions to determine public reaction and to obtain basic engineering data for home facsimile services. In addition, other important stations have applied to the FCC and are considering the possibilities of facsimile service.

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What the New Domestic COMMUNICATIONS SATELLITES Will Do for You

Canada’s pioneering Aniks, and U.S. successors, are introducing the revolutionary innovation of overland telephone-and-TV relays in the sky. They promise bargain rates for long-distance phone calls, picture phones that everyone can afford—and better television programs, by way of novel kinds of TV networks

By WERNHER von BRAUN
PS Consulting Editor, Space

On Jan. 11, 1973, Rudy Pudluk, community manager of Resolute on a Canadian island above the Arctic Circle, made a long-distance phone call to Ottawa. The English-speaking Eskimo chatted with Gerard Pelletier, Minister of Communications, and with David Golden, president of Telesat Canada, whose system carried his voice across the frozen North.

His call began commercial operations of Anik 1, North America’s first domestic communications satellite—and the world’s first domestic one in a synchronous orbit, like that of our transocean Intelsat satellites.

Anik 1 was launched from Cape Kennedy on Nov. 9, 1972. It hangs stationary with respect to Earth, 22,300 miles high, over the equator and the eastern Pacific at 109° west longitude (which puts it due south of Gallup, N.M., and mid western Canada). From its lofty height it views Canada coast to coast.

By the time you read this it will have been joined nearby in orbit by an identical twin, Anik 2, if all has gone well. One communications satellite has ample relaying range to span the continent; Anik 2 will simply add more message-carrying capacity, and be a backup in orbit. Anik 3, completing the litter, will be kept on the ground as a spare.

Within a year the United States will follow Canada’s example and launch domestic communications satellites of its own. They’ll transmit phone calls, television programs, telegrams, Telex, U.S. Postal Service Mailgrams, facsimiles of documents, computer data. A hotel-reservation service may find you accommodations via satellite.

A new kind of message net. For years we’ve enjoyed the advantages of transocean phone-and-TV satellites—but the Western world has waited until now for domestic ones, satellites linking points within a country’s own borders.

Understandably they came first in the Soviet Union—a nation with interior distances so vast that people in Vladivostok are awakening to a new day, when their countrymen in Kiev are going to bed the night before. Since 1965, the USSR has been spanned by Molniya (“lightning”) domestic communications satellites in elliptical orbits at steep angles to the equator.

Communications have to be switched from one Molniya to another as they pass successively over the country. Currently, however, the Russians are reported to have developed a synchronous version (awaiting launching at this writing) that will stay put in the sky as the Aniks do.

Anik means “brother” in Eskimo —and Telesat Canada, established by the Canadian Parliament in 1969, has set up a network extending all the way from Canada’s densely populated south to the remote northern settlements of its Eskimos and Indians.

The 37 satellite-linked earth stations of its initial net include two “heavy-route” ones at the Toronto and Victoria transcontinental-route terminals, with 98-foot dish antennas resembling those for global satellites; other stations’ dishes are smaller. Six “network television” stations transmit and receive TV; 25 “remote TV” stations receive it only.

“Northern telecommunication” stations at Resolute and Frobisher Bay establish a moderate-traffic phone link to lines in the south. “Thin-route” stations on Baffin Island and at Igloolik provide limited phone service to small Arctic communities. High-frequency radiotelephone links, available only two hours a day and subject to interference and fading, served Arctic outposts before.

What Aniks are like. Skillful design makes Anik an “economy” satellite. At bargain cost it offers phone-and-TV capacity in the same class with the big Intelsat IVs from the same maker, Hughes Aircraft.

Smaller than an Intelsat IV (11% feet high instead of 17%) and much lighter in weight (about 1200 pounds at liftoff, vs. 3100), an Anik is less expensive to buy, and to launch into orbit, a service for which the owner reimburses NASA. A Thor-Delta vehicle suffices, rather than the huskier Atlas-Centaur it takes to loft the Intelsat. All told, an Anik in orbit costs about $16% million, compared to about $29% million for an orbited Intelsat IV. It likewise is designed for a seven-year lifetime.

Chunky little Anik receives signals from Earth, and retransmits them back to other points, with a five-foot parabolic antenna of fine gold mesh rather than a solid dish. For electric power, some 20,000 solar cells surround Anik’s drum-shaped body. According to Telesat Canada, an Anik satellite’s 12 transponders (radio repeaters) give it a total capacity of up to nearly 12,000 oneway voice circuits—enough for 6000 two-way phone conversations—or 12 color television programs, at once.

Up to within a few months of Anik 1′s launching, the United States had done little about domestic communications satellites of its own.

It had been a pioneer with communications satellites. It played a leading part in establishing the Comsat/Intelsat net of global satellite links; and the Aniks themselves were built by a U.S. firm. But U.S. domestic ones long went neglected, for a simple reason: The U.S. already had a splendid network of coaxial cables and microwave towers, which seemed entirely capable of providing good long-distance communications and of expanding fast enough to meet ever-growing needs.

Domestic communications satellites, however, can do things far beyond the reach of any earthbound system. Realizing this, the Federal Communications Commission cleared the way for them on June 16, 1972. It laid down the basic rules in a memorable “open skies” decision, which assured lively competition in the field: A go-ahead for U.S. systems. The FCC announced it was ready to license a limited number of technically and financially qualified U.S. companies to set up their own commercial systems of domestic communications satellites. Each system was to consist of the necessary space elements and ground stations, and would be expected to offer its channels to an emerging market of interested customers.

The scramble was on!

Some U.S. companies couldn’t wait to get their own satellites into orbit, and began setting up arrangements with Telesat Canada to lease Anik channels—which could serve U.S. cities just as well. Canadian users’ needs already claimed most of Anik 1′s capacity, but Anik 2 would have plenty to spare. The American Satellite Corp. and RCA were among prospective U.S. Anik customers.

Efforts to get systems of U.S. domestic communications satellites into early operation looked much like a race, with at least seven contenders. These were examples: Even before Hughes had completed Canada’s three Aniks, it had Western Union’s order for three more of the same. Western Union planned to orbit the first of them before mid-1974. Its “Westar” domestic-satellite system, besides carrying its own messages, would have channels to lease to all comers.

American Satellite Corp. (jointly owned by Fairchild Industries and Western Union International) contracted with Hughes for three 12-transponder domestic satellites, and made a down payment to NASA for a first launch in the third quarter of 1974. By then it planned to have a network of eight ground stations, near New York, Dallas, Chicago, Washington, Atlanta or Miami, Los Angeles, San Francisco, and Seattle.

It has also initiated, with Fair-child, design and development of an advanced 24-transponder domestic communications satellite for future use in its system.

Big ones by 1975. For lease to AT&T, Communications Satellite Corp. will establish a U.S. domestic-satellite system with four big satellites, three in orbit and one on the ground. The first is to be launched in 1975. Announced details show them to be as large as Comsat’s global Intelsat IVs and of even greater message capacity: They’ll be about 18 feet high and weigh about 3100 pounds at liftoff by Atlas-Centaur vehicles. Each 24-transponder satellite will provide some 14,400 two-way voice-grade circuits. It will have two dish antennas of five-foot diameter, one vertically polarized and the other horizontally polarized (see box on technology below).

The three orbiting satellites will provide domestic-satellite service to all 50 states and Puerto Rico, and will be incorporated into AT&T’s nationwide network “to expand and diversify its services to customers.”

A satellite in synchronous orbit (as all these coming ones will be) is like a 22,300-mile-high microwave tower. It is in line-of-sight contact with every point in the U.S. Radio energy can therefore be beamed up to it (“uplink”) and down from it (“downlink”) in straight lines. Relatively short stretches of land lines, of course, connect users with the nearest Earth terminals.

Innovations we’ll see. Changes we can expect domestic satellites to bring about have been compared to those from paperback books. Books weren’t new; the real novelty of the paperbacks was their availability in so many places and at such low cost.

Even the most conservative planners expect the FCC’s “open skies” ruling to revolutionize the entire pattern of telecommunications in the United States. Here is why domestic communications satellites (“dom-sats” as they’re already being called (or short) are so exciting:

• They can provide many more channels, for the same investment, than conventional long-distance cables or microwave lines.

• A domestic communications satellite can carry a telephone call from Washington to Los Angeles as cheaply as from Washington to Baltimore.
Beyond a certain distance—say, 1000 miles for the present—the satellite route is the more economical one. First rates proposed for leasing U.S. domestic-satellite voice circuits give a striking example. The cost is only one-third as much as for coast-to-coast voice-grade circuits by land routes.

Presuming that the ultimate user will eventually share the benefit of the saving, agreeably lower rates for long-distance telephone calls could be your introduction to the practical advantages of domestic satellites.

• Communications satellites can connect one point with a multitude of other points—unlike a coaxial cable or a string of microwave towers on the ground, which always go from one point to another point.

In a TV hookup, for example, a domestic satellite can relay a program originating in New York to 50 or more TV stations throughout the nation, for local transmission—either via broadcast or cable TV.

Better TV on the way. Joining cable-TV systems into regional and national networks by satellite may be foreshadowed as early as this month. Subject to FCC clearance, an East (‘oast program was to be transmitted to Anaheim, Calif., by way of Anik in a June trial planned by TelePrompTer Corp., the largest cable-TV operator. This would test the feasibility of its “spacecast” plan to connect its cable-TV systems in 33 states and two Canadian provinces with a U.S. domestic satellite in 1974.

The predictable hook-up of local cable TV to satellites will drastically change our entire mode of distributing television programs.

A vast number of available uplink channels can simultaneously bring an advanced satellite dozens of different programs, originating in different cities. Each receiving station can draw upon a rich variety of fare for its viewers’ delectation. Moreover, the number of receiving stations can far exceed the present number of television stations, because they quietly feed the received signal into the local TV cable, rather than tying up a precious frequency “on the air.”

You’ll have a wider choice of what you want to watch through a recent FCC ruling: Franchises for new cable-TV installations, henceforth, will be granted only if they provide two-way communication.

If you prefer a free program sponsored by a commercial advertiser, fine. If you don’t want to miss a particular noncommercial pay-TV program—one of 50 programs the satellite may offer at the time—you just punch a two-digit number into a “touch-tone” communicator on your television set. The cable relay station will release the requested program to your set, and bill you at the end of the month.

In this way TV at last will break free of “lowest common denominator” programs (which often capture the highest Nielsen ratings), and be able to meet the infinite diversity of individual tastes.

TV will also be enabled to make a much greater contribution in the field of education. Congestion at campuses could be relieved if students went to their universities only for seminars, discussions, and laboratory work, while boning up on their chosen subjects via TV.

TV direct from the sky. A high-powered synchronous satellite can broadcast TV programs, beamed up to it from a central ground transmitter, direct to specially equipped individual receiving sets on Earth. (Due to the shorter frequencies used, the familiar rake-shaped TV antenna will be replaced by a wire-mesh dish about the size of a beach umbrella.) While this may be a long way off for home entertainment, it has immediate interest for educational programs in remote areas.

As soon as next year, the huge Fairchild-built ATS-F television-broadcast satellite, first of its kind, will give the idea a trial. (ATS is for Applications Technology Satellite, a many-purpose NASA series; F designates the sixth.) Weighing 2800 pounds at launch by a Titan III-C into synchronous orbit, ATS-F will unfold in space great solar-panel booms of total 52-foot span and an umbrella-shaped antenna of 30-foot diameter. First, in U.S. experiments, it will broadcast educational programs to Indian reservations in the Rockies, and to Eskimo settlements in Alaska.

In 1975, ATS-F’s thrusters will nudge it around the equator from the Pacific to the Indian Ocean for a momentous trial of a plan to beam educational TV all over northern In- dia LPS, May ’70], Experimental broadcasts will go to community TV receivers set up for the purpose in hundreds of remote villages.

Success of this ATS-F experiment would open the way to a projected operational system of India’s own, which could well make it the first country with direct sky-to-receiver television on a national scale. The full-fledged system would reach as many as thousands of villages via satellite, with educational programs broadcast in local tongues and suited especially to local needs.

More things are ahead. Steerable needle beams (see “technology” box) will open up a new era in communication with moving vehicles. Telephone service enroute can be provided quite readily for passengers in aircraft, ships, buses, and autos. In the eighties, automobiles will come with a circular receive-and-transmit antenna buried in the roof, flush and invisible. It will permit you to call anyone else on the globe from your moving car.

Picture phones for everyone. The almost unlimited channel capacity of communications satellites will finally transform video telephone service from an expensive luxury into a popular-priced amenity of everyday living.

This will not only be good news for young lovers—it will also help to keep fathers and husbands at home. Future monthly meetings of a national corporation’s general managers will no longer require their physical presence at corporate headquarters in a distant city.

Instead, each participant will sit before a 3-D color camera in a booth at his home office. Relayed by satellite, the images of all the others are projected upon the curved wall of the booth, and their voices are heard. All have the feeling of being seated together in the same room, around the same table.

Letting the electrons and microwaves do the traveling will become the fashion of the eighties. In the long run it will help to reduce traffic congestion and air pollution; it could even contribute to abating the energy crisis and countering the troublesome trend toward ever more urbanization.

I have heard it said that if Alexander Graham Bell had waited until the advent of satellites and microwaves to invent the telephone, instead of stringing the globe with millions of tons of copper wire, he would have opted for switchboards in the sky.

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What’s ahead in domestic satellites’ technology Reducing ground stations’ cost will help them grow in number to make the most of domestic communications satellites. This can be done by boosting power (and cost) of the satellite. The trend is that way in the Intelsat community—so a trans-ocean message to a developing country’s $3-million ground station won’t incongruously have to reach a town 50 miles away by the local tom-tom system. (It had been only logical to put the burden of weight and expense on the ground when the satellites and launch techniques were in their infancy.) As important as higher power is “spectrum conservation.” Frequencies are limited; separate use of the same frequency in “vertical” and “horizontal” polarization makes them go twice as far. The electromagnetic waves swing up-and-down, left-and-right, respectively. Careful antenna and circuit design can keep them from interfering with each other. An alternative is to aim two beams of identical frequency at different spots on Earth—as can be done with large enough antenna dishes, far enough apart.

Higher frequencies will reduce the size of large, cumbersome-to-launch antenna arrays and ultimately permit steerable needle-sharp beams to be pointed down at small-area ground targets. That will open the way to high-speed channel switching, another way to get more mileage from limited frequencies. When the satellite relays a TV program to a ground station or a number of them, of course it ties up that frequency for the program’s duration. But the frequency used to relay a rare telephone call to a remote town can be reassigned to another call in much less time.
Beam-steering and frequency-reassignment require sophisticated equipment. To route a dial-phone call, you dial digits that activate a string of switching relays. A similar coded instruction will be sent to future satellites from the call-originating ground station. Solid-state switching equipment will select an available downlink frequency and aim it by needle-sharp beam at the destination. A great number of beams can emanate simultaneously from a satellite.

Advanced technology will enable one satellite to handle 100,000 circuits or more with ease.

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How Ingenious Sound Producing Devices Fool Radio Microphone

You can’t always believe what you hear over the radio—the picture above proves it. Sound producing machinery of a large chain broadcasting company is shown. Thirty-three separate sound effects arc produced by the cabinet before which the operator is sitting, but in addition to this a large number of individual devices are employed, including numerous bells of various tones, a cigar box with a pulley and piece of string to simulate the sound of a curtain being drawn in a theater, oar locks used in acts calling for a rowboat, and a pillow to be struck with slats to produce the thudding effect of a prize fight blow against human flesh. Drawing a taut rubber band over a length of broomstick produces sound of a watch being wound.

The complete effect of a locomotive pulling out of a station is produced for radio audiences with these devices. Roller skates mounted on a revolving drum simulate click of train wheels over the rail joints. At right, a corrugated surface produces the puffing effect of a locomotive when wire brush is rasped across it.

Sea and water effects are produced with drums, two types of which are shown in the above drawing. Both are loaded with small peas and stones which rattle over corrugated surfaces, the main difference being that one drum contains a heavier “charge” of stones than the other. Thus, when used in unison, both the roar of beating sea waves and the soft swish of water against a sandy beach can be reproduced.

Here are two of the most novel radio sound-makers. At the left, a piece of string, suspended through the bottom of a tin pail, produces the roar of a lion when a bit of leather rubbed with rosin is pulled along it. Above, the sound of an airplane motor is reproduced by lengths of soft rubber hose beaten against a drum head by an electric motor. Apparent speed and distance of the airplane is controlled by regulating the small motor to speed up or slow down the revolving hose.

PLANES’ RADIO MESSAGES “CANNED” FOR DISASTER RECORD

RADIO communications between plane pilots and airport dispatchers are now permanently recorded on wax cylinders by an electrical machine recently installed by the U. S. Bureau of Air Commerce at a California landing field. Reports made by pilots and orders given by dispatchers, kept on file in record form, are thus available to examiners investigating the causes of any accident to a plane.

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WORLD RADIO BATTLE LOOMS

Priceless radio frequencies will be doled out at international conference to be held in Cairo early in 1938.

by Roland C. Davies

AS THE smoke of foreign conflict rises above the horizon, students of world affairs realize that international broadcasting is perhaps the most potent arm of propaganda to dump nations into the inferno of war or to maintain peace.

Almost daily the press tells how foreign nations are using that marvel of modern science to tell the world via short-wave radio of their nationalistic aims, armed strength and economic prestige.

Within the next few months, the doling out of the coveted radio frequencies on a worldwide scale will be taken up by two international parleys, with the allocations of ether channels to international broadcasting as the outstanding and most controversial problem.

First is the biennial meeting of the International Radio Consulting Committee, commonly termed the CCIR, at Bucharest, Rumania, in the Spring of 1937. Then will come the Third International Radio Conference, which meets every five years, to be held in February, 1938, at Cairo, Egypt.

The Cairo conference will capture the eyes of the entire radio world, because it has treaty-making powers in drawing up the rules that govern frequency allocations, interference and use of radio. The findings of the CCIR at Bucharest, however, are purely advisory and are confined to technical problems. They carry the weight of a world consensus for the guidance of the treaty-making assembly at the Egyptian capital in 1938.

During the last six months a score of American government radio experts, aided by the leading technical brains of the nation’s broadcasting and communications companies, have been busy drafting the United States proposals to be presented at the Cairo conference. The American program is to be forwarded by this coming November to the other nations, which in turn send their proposals to the United States so that all may study in advance the plans that will come before the international conference.

There is a saying in world capitals that the United States has not only never been defeated in a war but also has never lost an international radio conference, although this nation may have been the victim of shrewd diplomats in recent arms and economic parleys. Back in 1927, when the nations first assembled in Washington for a world radio agreement, the United States took the leading role. At that time the use of radio by ships was the principal international problem, with broadcasting limited chiefly to national boundaries. At Madrid in 1932, broadcasting became the critical problem, but the squabbles were confined in a large degree to European nations.

However, the Cairo Radio Conference is expected to become the scene of a bitter fight. The larger European powers—England, France, Germany, Italy and Soviet Russia—together with Japan, are to be pitted against the smaller countries, while the United States will hold the balance of power. The short waves for international broadcasting will be the issue at stake. In the past the larger nations, due to greater technical progress, have grabbed the better allocations for broadcasting and communications, but now the smaller countries have developed their radio facilities and are demanding their place in the sun on the ground that each sovereign entity is entitled to its share of the valuable channels in the ether.

THIS is everyone’s War… if you are not able to serve in the Army or Navy, you can serve on the production front. Elmer is doing his duty by leaving his non-essential position and taking a job in the war plant.

THE HAMMARLUND MFG. CO., Inc., 460 WEST 34th St., NEW YORK, N. Y.

New FM Auto Radio

OUR recent survey “FM Radios for Your Car” (December 1959) contained several reports from leading auto radio makers which stated flatly they had no plans for marketing an FM auto radio. Motorola was one of them. In spite of their former stand—or perhaps because of our article—Motorola is now mass producing the FM-900, a mobile radio that tunes 88-108 mc. This under-the-dash-installation unit can operate independently of the car’s AM set. Three transistors power the hybrid circuit, which contains seven additional tubes. FM-900 shares the AM set’s antenna and can be used with any 12-volt, negatively grounded ignition system. No need to sell the FM set when you sell your car. It may be moved from auto to auto, or auto to boat. Other features are AGC, AFC and $125 price.

KENNEDY ANTENNAS… Probe the secrets of inter-stellar space

Somewhere in the nearly empty reaches of outer space, two hydrogen atoms collide. After a 100-million year journey at the speed of light, the signal generated by that accidental collision reaches a super-sensitive radio telescope antenna in Massachusetts and is recorded — and so one grain more is added to man’s knowledge of the universe.

Modern miracles like this happen every day at Harvard University’s Agassiz Station Observatory, where a giant new radio telescope, with its 60′ Kennedy antenna, is taking man further back in time . . . and further out into space . . . than he has ever been before.

ANTENNA EQUIPMENT
D. S. KENNEDY & CO.
COHASSET, MASS. – TEL.: C04-1200

Down-To-Earth SOLUTIONS to Out-Of-This- World PROBLEMS

Tracking Antennas
Radio Telescopes
Radar Antennas
Tropospheric Scatter
Ionospheric Scatter

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Could You Become a Radio Star?

By Alfred Albelli

If you have ability as an entertainer, along with a good radio personality, fame and fortune may await you if you can pass the radio audition test, as described here.

NO DOUBT everyone would get a great thrill hearing his name announced over a network of powerful broadcasting stations as the artist who will next entertain the vast multitudes of listeners-in with a song, a string of jokes, or a speech treating subjects of interest to the nation. And no doubt, also, everyone would get even a greater thrill out of receiving each month a salary and royalty check of the generous four-figure proportions that most radio entertainers pull down.

To achieve fame and fortune as a radio star, however, you must first go through a trial by fire, an audition in which your “radio personality” is given a severe test before the microphone to determine whether you can click with the great unseen audience of critical listeners-in.

With the phenomenal advance of radio as a source of popular entertainment, radio broadcasting studios have become swamped with artists who are ambitious to make a name for themselves. With Amos and Andy’s salary reaching into the dizzy thousands for their radio act, with the unprecedented popularity of acts like Rudy Vallee’s crooning, and with a thousand other temptations to incite the ambitious, everybody from 17 to 70, from Maine to California, wants to get on the air and achieve fame as a radio star.

The result of all this has been the establishment of a special artist bureau at each large broadcasting station. The purpose of this bureau is to give auditions to these thousands of ambitious singers or speakers.

Governing the artist bureau of the famous Columbia broadcasting station in New York are Henry Burr, famous concert tenor, and Leroy Mountcastle, who came into the radio field from the phonograph business, where he learned what music audiences prefer.

“Requests by ambitious artists to be heard at our bi-weekly auditions pour in steadily day in and day out,” said Mr. Mountcastle, at an interview recently at his studio in New York. “They appear here in person, they write, telephone and telegraph. They must be heard, and it is up to us to give them a fair hearing. Since last January 1 we have had 2000 auditions, with about 100 applicants at each hearing.”

Mr. Mountcastle then led the way to the audition quarters, the trial chamber where the applicant for a place on the air and a handsome salary goes through with his or her act. This chamber is a large, specially constructed room, with acoustic qualities as near perfect as possible. In one corner there is a piano on which reposes a vase of flow-firs. This gives a psychological touch, Mr. Mountcastle explained. An attempt is made to make the grim chamber appear cozy and benevolent, and not bare of all humanness.

Close to the piano is the microphone. It Stands there so menacingly that one is reminded of the sword of Damocles hanging over one’s head. There is no other instrument or furniture in this hall.

From here one passes into the control-room. It is here that the judges sit in solemn conclave and pass on the talents, or lack of them, of the person before the microphone.

A window has been installed in the wall separating these two rooms in order that the judges may glance through every now and then and behold the artist’s stance before the microphone, while he listens to the voice over the loud speaker installed on his desk.

“How do we know the microphone voice? Reasonably enough,” explained Mr. Mountcastle, “we have to get it over the microphone. We look first for smoothness and clearness of sound. There has to be a fine tone quality and clear diction. We have to watch and see if the voice has an edge, which breaks and causes the most uncomfortable feeling to the listener. In other words we must beware of the cracked voice.

“Our worst enemy in these radio trials is the fear complex. Sometimes during the tryout I notice that the artist is nervous and actually frightened. He seems to think the mike is going to attack him on the slightest provocation. Over the supersensitive microphone this nervousness of tone is registered in all its imperfections.

“One cannot detect a good radio voice in ordinary conversation; one can only judge it by hearing it over the air. The moment a prospect opens his or her mouth before a microphone we know whether they have a radio voice. A flop voice on the air is just as noticeable over the loud speaker in our audition room as is a bicycle pump voice on the talking screen. Often we press the buzzer after we have heard a single line. It’s no use wasting anyone’s time.

“But everyone gets a fair hearing at the radio audition. Every broadcasting company is on the look-out for first-rate talent. Radio artists of the first water are rare. Out of 200,000 applicants we got only 12 persons. But they were the best to be had, and their financial returns have been commensurate with their ability. Take Maurice Chevalier, for instance. We paid him $15,000 for four songs once.

“Lastly we have to seek out radio announcers. Geniuses like Graham MacNamee are rare. Radio broadcasting companies are in the market for them all the time. He must be able to carry out such a speech as the following without a hitch: “‘. . . Among other prominent musical directors you will hear our Gustave Haenschen and his orchestra, the Detroit Symphony, under the direction of Ossip Gabrilo-witsch, featuring Jascha Heifetz and Fritz Kreisler as guest soloists. Ignace Jan Paderewski will accompany a concert featuring the phenomenal youngster, Jehudi Menuhin, while Ernestine Schumann-Heink will sing the “Erl King” of Franz Schubert. The fiery Russian, Peter Illitch Tschaikovsky, with selections from the “Oiseau de Feu” and the “Symphony Pathetique”.’ “If a person with announcer ambitions can weather his way through that storm, we figure he can navigate his course in any crisis, except, of course, at prize-fights. We can’t keep him from getting excited and stuttering and sputtering out the ring action.

“Yeah. Everybody wants to get on the air. There’s good money in it, Amos and Andy will tell you. But passing the radio test is no cinch, not by a long shot.”

AIR-TO-GROUND TV SYSTEM Transmits Combat Pictures on FM

Airborne military television crams a self-contained transmitting station into a small reconnaissance plane, then flies this ever-moving station over unpredictable terrain. Taking these adverse conditions into account, Admiral developed an extremely compact television system which uses FM transmission for the picture. It is now in production for the U.S. Army Signal Corps. Even under difficult conditions, this equipment provides excellent definition.

The transmitting plane, flying at approximately 1,000 feet, would have a line-of-sight range of 25 or 30 miles. This would enable a battle commander aided by a panel of TV screens, each screen showing a different sector, to coordinate military operations over a wide area.

In addition, a mobile ground-to-ground TV system is under development. Inquire about Admiral’s exceptional capabilities in the field of military electronics. Address inquiries to:

Admiral
CORPORATION
Government Laboratories Division, Chicago 47.

Look to Admiral for
RESEARCH • DEVELOPMENT • PRODUCTION
In the fields of:
COMMUNICATIONS UHF AND VHF • MILITARY TELEVISION RADAR • RADAR BEACONS AND IFF • RADIAL TELEMETERING • DISTANCE MEASURING MISSILE GUIDANCE • CODERS AND DECODERS CONSTANT DELAY LINES • TEST EQUIPMENT

Facilities Brochure describing Admiral plants, equipment and experience sent on request.

Engineers: The wide scope of work in progress at Admiral creates challenging opportunities in the field of your choice. Write Director of Engineering and Research, Admiral Corporation, Chicago 47, Illinois.