Technical Origins of Radio

Early in that year the author was fortunate enough to succeed in constructing a practical receiver of electric waves, based on a principle different from that of the coherer.

Continuing Radios’ First Triumph,
with a selection from his address to the Royal Institution of Great Britain by Gugllelmo Marconi. This selection is presented in 2 easy 5 minute installments. For works benefiting from the latest research see the “More information” section at the bottom of these pages.

Gugllelmo Marconi (1874-1937) is generally considered to be the father of radio.

Previously in Radios’ First Triumph.

Time: 1909
Place: Mid Atlantic

The following account is printed by special permission of Signor Marconi. It is part of an address delivered by him before the Royal Institution of Great Britain, and traces the progress of his great invention in the days before its value had received world-wide recognition.

The phenomena of electromagnetic induction, revealed chiefly by the memorable researches and discoveries of Faraday, carried out in the Royal Institution, have long since shown how it is possible for the transmission of electrical energy to take place across a small air space between a conductor traversed by a variable current and another conductor placed near it, and how such transmission may be detected and observed at distances greater or less, according to the more or less rapid variation of the current in one of the wires, and also according to the greater or less quantity of electricity brought into play.

Maxwell, inspired by Faraday’s work, gave to the world in 1873 wonderful mathematical theory of electricity and magnetism, demonstrating on theoretical grounds the existence of electromagnetic waves, fundamentally similar to but enormously longer than waves of light. Following up Max well, Hertz in 1887 furnished his great practical proof of the existence of these true electromagnetic waves.

Building on the foundations prepared by these great men, the author carried out in 1895 and 1896 his first tests, with apparatus which embodied the principle on which long-distance wireless telegraphy is successfully worked at the present day.

The main feature of the system is the utilization of the earth effect by connecting both the transmitting and receiving instruments between earth and a raised capacity.

The later improvements introduced in the author’s system of wireless telegraphy have been directed toward the following ends:

1. To obtain independence of communication or the prevention of interference between several neighboring stations.
2. To increase the distance of communication.
3. To increase the efficiency of the apparatus, its accuracy, and working speed.

One of the chief objections which are raised against wireless telegraphy is that it is possible to work only two or a very limited number of stations in the immediate vicinity of each other without causing mutual interference or producing a jumble by the confusion of the different messages. This objection appears to be much more serious to that section of the public which knows little or nothing of telegraphy in general than to telegraph engineers, who know that without organization and discipline the same interference would occur in the great majority of ordinary land telegrams. For example, there is an “omnibus” line between Cork and Crookhaven. On this line there are a dozen or more telegraph offices, all with their instruments joined up to the same wire running from the terminal stations. Now, if any of these offices should proceed to send a message, say to Cork, while this office is receiving another message from Crookhaven, it would cause an interference which would result in the confusion of the two messages, thus rendering them unintelligible. Any message sent on the line will affect all the instruments and can be read by all the other telegraph offices on the line; but certain rules and regulations are laid down and adhered to by the operators in the employ of the General Post Office which make it impossible for one station to interfere with the rest. It is obvious that these same rules are applicable to every case in which a group of equally tuned wireless telegraph stations happen to be in proximity to each other.

Although in many instances untuned wireless telegraphy may prove of great utility, it is, however, clear that so long as some method of rendering stations completely independent of one another was not devised, a very important and effectual limit to the practical utilization of wireless telegraphy would be imposed. The new method adopted by the author in 1898 was a step in the right direction. This improvement was described by the author in a discourse which he had the honor to deliver in the Royal Institution in February, 1900.

Up to the commencement of 1902 the only receivers that could be practically employed for the purpose of wireless telegraphy were based on what may be called the coherer principle — that is, the detector, the principle of which is based on the discoveries and observations made by S. A. Varley, Professor Hughes, Calsecchi Onesti, and Professor Branly.

Early in that year the author was fortunate enough to succeed in constructing a practical receiver of electric waves, based on a principle different from that of the coherer. Speaking from the experience of its application for over two years to commercial purposes, the author is able to say that, in so far as concerns speed of working, facility of adjustment, reliability, and efficiency when used on tuned circuits, this receiver has left all coherers or anticoherers far behind.

This detector is and has been successfully employed for both long and short distance work. It is used on the ships of the Royal Navy and on all transatlantic liners which are carrying on a long-distance news service. It has also been used to a large extent in the tests across the Atlantic Ocean.

As already stated, the adoption of this magnetic receiver was the means of bringing about a great improvement in the practical working conditions of wireless telegraphy by making it possible to do away with the troublesome adjustments necessary when using coherers, and also by considerably increasing the speed at which it is possible to receive, the speed depending solely on the ability of the individual operators.

A very considerable amount of public interest has been centered during the last few years on the tests and experiments in which the author has been engaged in investigating the possibilities of wireless telegraphy over very great distances, and especially on the tests which are being carried out across the Atlantic Ocean.

Edward J. Wheeler begins here. Gugllelmo Marconi begins here. Arthur D. H. Smith begins here.

More information here and here, and below.

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