Wireless telegraphy

“ Just the same, only in radio telephony we are confronted by a problem not met with in wireless telegraphy. We have not only to transmit sound, such as isolated dots and dashes, but to send through the air every rise and fall and inflection of the human voice just as it is recorded in the minute lines of a phonographic record. ”

“ No such trouble can occur with wireless telegraphy, and if it becomes necessary to move a wireless station with great rapidity, as for instance on an unexpected advance of the enemy, it is an advantage to have no wire to bother about. ”

“ One of the greatest disadvantages of most systems of wireless telegraphy lies in the fact that no arrangement is provided for simultaneously transmitting and receiving wireless signals. It is usually necessary for one operator listening to another to have to wait until the finish signal is given before he can reply or interrupt in case he cannot understand part of the message, because the receiving apparatus of the transmitting station is necessarily disconnected from the aerial and the ground during the period a message is being sent. ”

“ The practical success of wireless telegraphy depends on the use of an adequate medium for the transmission of electricity. The most meagre training suffices to prevent the declaration that if wireless messages cannot be sent without apparatus they cannot be sent at all. ”

“ We still have our neighbors' call bells, and we could listen to their messages if we were gossips. The telephone service has been extended to great distances—for instance, from Boston to Omaha—not by relays, but by strengthening the blows upon the medium between the transmitting circuit and the receiving one, just as we desire to do in what is called wireless telegraphy, the apparatus of which is almost identical in principle to that employed in telephony. The individual call in telephony is not a success for nearly the same reasons that exist in the case of wireless telegraphy. ”

“ Telegraphy plays a very important part in warfare. The commander of even a small unit cannot see all that his men are doing or suffering, but is kept posted by telegraph or telephone, while communication between units depends very largely indeed upon such means. Wireless telegraphy, in land warfare, is largely devoted to communication between aircraft and the artillery batteries with which they are working, and to avoid interference with that important work telegraphy by wire is employed for most other purposes. ”

“ At present wireless telegraphy has not superseded the ordinary methods of communicating over land, but there can be no doubt that wireless telegraphy, if free from Government restrictions, would in certain circumstances very quickly supersede land-line telegraphy, while it has proved a formidable commercial competitor to the cable as a means of connecting this country with America. ”

“ The aerial wire is precisely the same for either wireless telegraphy or wireless telephony. The transmitter of a wireless telegraph set generally uses a spark gap for setting up the electric oscillations, while usually for wireless telephony a vacuum tube is employed for this purpose. The receptor for wireless telegraphy and telephony is the same and may include either a crystal detector or a vacuum tube detector, as will be explained presently. ”

“ Wireless telephones will not only transmit the speech more clearly and distinctly, but have the further advantages that the initial cost is very much lower than that of wire lines, the maintenance is almost nil in comparison, the depreciation is smaller, the number of employees required is less, and a break-down is limited to the inside of the station, where it could be quickly remedied by the substitution of a duplicate spare piece of apparatus. ”

“ This is a question which does not admit of an answer, for to no one man alone do we owe wireless telegraphy, though Hertz was the first to discover the waves which make it possible. However, it is to the men whose indefatigable labors and genius made the electric telegraph a reality, that we also owe wireless telegraphy as we have it at present, for the latter may be considered in many respects the resultant of the former, though both are different in medium.
Radio or wireless telegraphy in principle is as old as mankind. ”

“ Many of those who had followed wireless telegraphy from its beginnings and knew somewhat of the theory of how it worked, set up a hue and a cry that the signals he had received were sent by ships at sea, or else they were due to static, as we call it now, that is, little charges of atmospheric electricity which accumulates on the aerial wire and finally discharges through the detector into the ground and this makes a click in the head-phones that sounds like a dot. ”

“ While in the ordinary wireless instruments the discharge surges back and forth between the antenna and the earth, in the flying-machine wireless the discharge surges back and forth between the two antennæ. In the Wright machine, when equipped for wireless telegraphy, the two antennæ are placed one under the upper plane, the other under the lower plane of the flying-machine. [221]
More power is required for the wireless than for the wire telegraph. In the wire telegraph about one-hundredth horse-power is required to send a message one hundred and twenty miles. ”

“ Truly the science of radio-telegraphy has made rapid strides since the days of the “coherer,” until now, after the war, it is the most advanced in our human civilisation, and at the same time full of romance. Not a month passes but something new is discovered in that high-built, well-knit laboratory, where daily the keenest brains of wireless experimenters are at work devising, testing, and too often scrapping new instruments, new circuits, and new devices in order to improve and render less complicated both the ordinary wireless by Morse, and that modern marvel, the wireless telephone. ”

“ CHAPTER THREE THE RADIO AMATEUR MOVEMENT From the turn of the century enthusiastic young men who built their own items of electrical and wireless apparatus were known as "Wireless Experimenters". Many of them were later granted licences for the use of "Wireless Telegraphy for experimental purposes" (in the United Kingdom) by the Postmaster General under the terms of the 1904 Wireless Telegraphy Act. ”

“ As the waves shoot out and reach the distant station, the filings in the tube cohere and the current passing through them draws up the armature of the relay magnet. This closes the circuit of the recording instrument. It is broken constantly [156] by the tapper and instantly re-established by receiving waves.
The towers employed in 1920 for the transmission of wireless messages were very high. The manifest advantages of the system were apparent and long before 1930 wireless telegraphy came into general use. The new system proved the death-knell of telegraph poles, as well as ocean cables. ”

“ FIG. 153.—The aerial system of a transatlantic station.
The wireless telephone enables a passenger on board ship to communicate direct with his home by relaying the message over the line wires. By the same means the captain of a ship can call his home office and communicate with the owner of the vessel.
Telegraphs and telephones are the nerves of the world, carrying swift messages from its brain centers to its hands, annihilating distance in thought. All differences between men as individuals and people as nations can be traced to the lack of close contact. ”

“ Fire stations in New York City have been equipped with wireless telegraph sets, and they have proved so useful in spreading alarms and transmitting news of fires that they seem destined to come into universal use.
The outbreak of the world war gave a tremendous impetus to the development of wireless telegraphy. The German cable to the United States was cut in the early days of the conflict. The sending power of wireless stations had been sufficiently increased, however, so that the great German stations could communicate with those in the United States. ”

“ The history of wireless telegraphy and telephony is a striking example of how it is possible for scientists laboring in the field of pure research and stimulated by accumulated knowledge and imagination to arrive at discoveries of the most vital importance. ”

“ In days when wireless telegraphy is occupying such a great deal of the world’s attention, it is not likely to cause much astonishment in the reader to learn that wireless transmission of speech over considerable distances is an accomplished fact. ”

“ In a subsequent letter to the Editor Marconi wrote:
"In my opinion it would be a mistaken policy to introduce legislation to prevent amateurs experimenting with wireless telegraphy (which the authorities were contemplating) . Had it not been for amateurs, wireless telegraphy as a great world-fact might not have existed at all. A great deal of the development and progress of wireless telegraphy is due to the efforts of amateurs." ”

“ Wonderful as all this is, it is now eclipsed by wireless telegraphy—now passed beyond its experimental stages, and rapidly coming into the practical commerce of the nations. Man is no longer dependent upon a network of wires and cables for means of communication. The atmosphere enveloping the world affords sufficient means for conducting vibrations made intelligible by the instrument of man's invention; and today, even across the surface of the broad Atlantic, messages are transmitted by this means as easily as by means of the cable lines. ”

“ It is a matter of common knowledge that a large part of the important inventions in connection with wireless telegraphy have been the work of amateurs and private research and not the outcome of official brains or the handiwork of military or naval organisations. In fact we may say that wireless telegraphy itself in its inception was an amateur product. Numerous important inventions such as the crystal detector, the oscillating valve, the triode valve—have been due to private or amateur work. ”

“ Some scientific authorities claim that it was originated by Professor Dolbear, of Massachusetts. In 1899, messages were sent from England to France, and recently an intelligible message was flashed across the Atlantic Ocean. Unscientifically speaking, wireless telegraphy consists of discharging powerful electrical currents into the atmosphere, their vibrations being taken up by the natural electricity in the air, and received by wires placed at an elevation. Practically all sea-going steamers are equipped with wireless telegraphy. ”

“ This confession of weakness, this serious drawback of the nineteenth century, which added to the terrors of those “who go down into the great deep,” was fortunately not shared by the advanced sciences and arts of the twentieth century. Wireless telegraphy contributed almost as much to the comfort of ocean and ærial navigation as electricity. Telegraph poles that rendered hideous some of our most beautiful avenues and the antiquated ocean cables were entirely relegated into oblivion. ”

“ Wireless telegraphy, as it is practiced to-day, is based upon the fact that a system of wires or circuits, through which high frequency oscillations are surging, becomes a source of electromagnetic waves. Various methods have been devised for making the system more efficient and capable of giving better results with a given amount of power. ”

“ If full opportunities for such non-official research work are not restored, the progress of the art of radio telegraphy and radio telephony will be greatly hindered."
Professor W.H. Eccles wrote:
"Improvements and invention must be stimulated to the utmost. It is not impossible to devise laws to impose restrictions upon the emission of wireless waves as will preclude interference with the public radio service of the future (R.F.I. & T.V.I.?!!) and yet allow liberal opportunities for the experimental study of wireless telegraphy." ”

“ During some of the winter storms and blizzards, when miles of wires were down in all directions, wireless has been the sole means of communication in certain instances.
The process of sending a wireless message is very simple. The aerial switch is usually kept in such a position that the receiving instruments are connected to the ground and aerial so that the operator is always able to hear any one calling him. We will suppose for illustration that the land station at 42 Broadway, New York City, wishes to transmit a message to the steamer "Horatio Hall." ”

“ Wireless telegraphy already has reached remarkable perfection, but it is still a young science, and we may confidently expect developments which will enable us to send messages with all speed across vast gulfs of distance at present unconquered. ”

“ If the electricity with which any conducting body is charged be suddenly disturbed, electrical waves are generated which travel outwards in all directions with the velocity of light. The problem of wireless telegraphy is the problem of producing these waves by means of an instrument called a transmitter, and of recording their impact at a distance by means of an instrument called a receiver. ”

“ The wireless transmission of photographs has, no doubt, a great commercial value, but for any system to be commercially practicable, it must be simple, rapid, and reliable, besides being able to work {2}in conjunction with the apparatus already installed for the purpose of ordinary wireless telegraphy. ”

“ Marconi quickly found that the receiver was the least effective part of the existing apparatus. The waves spread in all directions from the sending station and become feebler and feebler as the distance increases. To make wireless telegraphy effective over any considerable distance a highly efficient and extremely sensitive receiving device is necessary. ”