The Thermionic Valve—Broadcasting—The Beam System— New Uses of Wireless.
THERE is hardly any country more isolated than Labrador, and certainly none where conditions of life are harder. Inland lie rocks, bogs, forest, and for eight months of the year deep snow; seaward, fogs, ice floes, and storms of the most terrible description. The people who live along this coast are hardy fishermen, most of whom have never seen anything that could be called civilization. In the summer of 1923 a wireless set was installed in one of the fishing villages on this barren coast, and a grizzled old fisherman was asked to "listen in." Through the ‘phones there came to his ears the strains of an orchestra playing in a Canadian city many hundreds of miles to the south. The old fellow had never heard an orchestra in his life, and the others watching him hoped to see some signs of pleasure on his face. Instead, he removed the ‘phones and laid them down.
"‘Taint right," he said gruffly. "This here is witchcraft."
Witchcraft! Well, perhaps the old fellow was not very far wrong, for of all inventions made by man there is truly no other so uncanny as that of wireless telephony. To be able to broadcast a human voice across continents and seas over millions of square miles, in an instant of time, and as fully and clearly as the words were uttered, is, indeed, a tremendous achievement, and one so appealing to the imagination that it is probably for this reason that wireless telephony has progressed even more rapidly than its elder cousin, wireless telegraphy.
In point of fact, there is, however, less difference between the ages of the two inventions than is generally supposed. In 1899 Mr. A. Frederick Collins made the first successful experiment with wireless telephony at Narberth, Pennsylvania, when he succeeded in transmitting the human voice to a distance of three blocks of buildings. Later in the same year experiments were made in sending wireless signals across the Menai Strait, ordinary telephonic transmitters and receivers being used. A little later it was found desirable to install telephonic communication between the lighthouse on the Skerries and the coastguard station at Cemlyn, but the bottom of the Channel was so rough and the currents so fierce that a cable could not be laid.
A wire 750 yards in length was therefore erected along the Skerries, and on the mainland facing the rocks another stretch of wire a little over three miles in length. Each line terminated by an earth plate in the sea, and the distance between the two wires was two and four fifths miles. In this way telephonic communication was established and maintained in all weathers.
Modern "wireless" depends for its success upon the thermionic valve, which was invented by Dr. J. A. Fleming in 1904, and afterward much improved by Dr. Lee Deforest. In 1910 Dr. Deforest fitted up on the roof of the Metropolitan Opera House in New York a long-distance "radiophone", as he called it, by means of which the voices of the singers could be heard at distances up to about a hundred miles. Working with him was Mr. Kelly Turner, the inventor of the dictograph—a machine into which letters, etc., are dictated for typing at convenient times. A number of dictographs were installed on the stage of the theater, and wires ran from them to the radiophone on the roof. "It is now only a question of time," the inventor then stated, "for wireless music and theatre performances, lectures, and church services to be the common possession of stay-at-homes or travelers at sea."
The truth of this prophecy was demonstrated very soon, for within three years people were speaking to others by wireless over distances up to nearly four hundred miles—for example, between Berlin and Vienna. Words and music were transmitted and heard with great distinctness. In that same year, 1913, successful experiments were going on in England, where Mr. Grindell Matthews established communication between Northampton and Letchworth, a distance of forty miles, and the voices were heard as clearly as over the wire. At this time Mr. Marconi was experimenting with wireless telephony with vessels of the Italian Navy in the Mediterranean. In 1914 one of the best known of British wireless authorities, Mr. A. A. Campbell Swinton, said that the problem of wireless telephony from a commercial point of view was solved, and suggested that the new medium was specially adapted for the distribution of weather reports, time signals, and speeches. Yet even he could hardly have foreseen that within a few years as many private houses would be fitted with wireless sets as with the telephone.
In 1914 the thermionic valve was in use as a receiver, but as a transmitter it was still in the experimental stage. Then came the War, and with it a rapid, though secret, development of the wireless telephone. The Germans, the French, and the British all used the valve as a detector of wireless waves, with the result that messages sent by land lines to the trenches were open secrets, and new means had to be found for sending them.
Quite early in the War aircraft began to be fitted with small wireless sets, and in these the valve was used for sending as well as receiving. And so came into being the three-electrode thermionic valve, which consists of a vacuum bulb similar to an electric-light lamp, but having two other metal elements inside the bulb in addition to the filament. Toward the end of the War aeroplanes were communicating with their ground stations up to a distance of fifty miles and up to five miles with each other. By 1921 these distances had been doubled, and they have since been still further increased. Aeroplanes can now communicate with each other by telephony from fifty to one hundred miles and can speak to aerodromes as far as three or four hundred miles away.
One principal development of the valve was that of direction-finding. For this purpose the currents at a receiving station are so arranged that, on signals being heard, the direction of the sending station is at once known, and, if required, its exact position can be found by plotting its direction from two or more receiving stations.
The first occasion upon which audible speech crossed the Atlantic was during the War, when messages from Washington were heard in Paris, a distance of twenty-three hundred miles; to-day there is no ocean so broad that the human voice cannot be carried across it by wireless, and no place so remote but that its inhabitants can keep in touch with the rest of the world by wireless.
The British Broadcasting Company began a regular broadcasting service from London on November 14, 1922, and now also operates from many stations at different centers throughout Great Britain. Its concerts, etc., have reached the ears of listeners-in, amateur as well as professional, in the remotest parts of the world.
Similarly, American concerts can be heard all over England, as well as in Australia and elsewhere, and broadcasting on a large scale is being constantly extended in all parts of the world, including Australia and New Zealand and various states of South America, also Japan. It seems certain that the future has in store wonders of wireless far beyond anything already achieved. In 1924 Mr. Marconi’s experiments with the "beam" system were brought to a considerable pitch of perfection. By this newer system wireless waves can be concentrated in a beam somewhat like the way in which the rays of a lamp are concentrated by a reflector. This results in an immense saving of energy over the old system, whereby the rays are broadcast in all directions.
An interesting experiment was made during 1924. On several occasions mysterious signals had been received, which some believed had come from another planet— possibly Mars. In August, 1924, experiments were made with the object of endeavoring to receive any such signals. The set used contained twenty-four valves, and was the largest and most powerful ever constructed. No definite signals were obtained from Mars, but the experiment gave other interesting results.
Trade statistics prove the enormous popularity of wireless; in Britain and the United States alone innumerable firms are manufacturing wireless sets or accessories. Perhaps in the United States more than in any other country wireless is revolutionizing daily life. At the end of 1924 it was reckoned that there were nearly five million sets of receiving apparatus in use, or five times the number of licenses taken out at that date in England. The United States was first to fit out private cars with radio. In England police cars are fitted with wireless, which is a great help to the so-called "Flying Squad" in running down offenders; and in Austria transmitters are installed at headquarters of the Fire Brigade with receivers on the engines. In this way the fire chief can keep in constant touch with his subordinates.
The uses of wireless are endless and are constantly being extended. Wireless saves the lives of men at sea, tells the weather daily, helps to make flying safe, especially in fog, and gives the correct time to clocks all over the world. Experiments made in one of the deepest of Staffordshire coal mines showed that communication between the pithead and the men working thousands of feet below in the depths of the earth can be easily established and kept up with portable sets. Wireless may, therefore, save life in coal-pit disasters, for if men imprisoned by a fall of earth can wireless their position, delay in getting help may thus be avoided.
There is on record a case of the kind which is so strange as to be worth recording. During the War a party of British engineers burrowing in No Man’s Land were suddenly entombed by an explosion. One of their number had a small wireless set with which experiments were to be carried out below ground. The range of this set was small, but as a last resource it was decided to broadcast a message on it. The message was picked up by a British ‘plane traveling high in the air above the battlefield. Help came in time, and all the party were saved.
No one may safely prophesy as to the future of radio dynamics. If sound can be sent without wires, why not power also? So long ago as 1914 Mr. Marconi announced that he could light a lamp by wireless at a distance of no less than six miles. The famous American inventor, Mr. Nikola Tesla, has long been busy on the great problem of transmitting electric power through the ether without wires, and some of the results already reached are extremely startling.