Invention of radio

[4] In April 1872 William Henry Ward received U.S. patent 126,356 for a wireless telegraphy system where he theorized that convection currents in the atmosphere could carry signals like a telegraph wire.

[8] In the United Kingdom, William Preece was able to develop an electromagnetic induction telegraph system that, with antenna wires many kilometers long, could transmit across gaps of about 5 kilometres (3.1 miles).

To few men in the world has such an experience been vouchsafed... it took physicists some decades to grasp the full significance of Maxwell's discovery, so bold was the leap that his genius forced upon the conceptions of his fellow-workers.

"Berend Wilhelm Feddersen,[37] a German physicist, in 1859, as a private scholar in Leipzig, succeeded in experiments with the Leyden jar to prove that electric sparks were composed of damped oscillations.

In 1870 the German physicist Wilhelm von Bezold discovered and demonstrated the fact that the advancing and reflected oscillations produced in conductors by a capacitor discharge gave rise to interference phenomena.

[31] When German physicist Heinrich Rudolf Hertz was looking for a subject for his doctoral dissertation in 1879, instructor Hermann von Helmholtz suggested he try to prove Maxwell's theory of electromagnetism.

[56][57] In different experiments, he noticed contractions in frogs' legs caused by lightning and a luminous discharge from a charged Leyden jar that disappeared over time and was renewed whenever a spark occurred nearby.

[66][54] Early experimenters In 1890, Édouard Branly[67][68][69] demonstrated what he later called the "radio-conductor,"[70] which Lodge in 1893 named the coherer, the first sensitive device for detecting radio waves.

[citation needed] On 1 June 1894, at a meeting of the British Association for the Advancement of Science at Oxford University, Lodge gave a memorial lecture on the work of Hertz (recently deceased) and the German physicist's proof of the existence of electromagnetic waves 6 years earlier.

When the small electrical charge from waves from an antenna were applied to the electrodes, the metal particles would cling together or "cohere" causing the device to become conductive allowing the current from a battery to pass through it.

[79] Lodge's lectures were widely publicized and his techniques influenced and were expanded on by other radio pioneers including Augusto Righi and his student Guglielmo Marconi, Alexander Popov, Lee de Forest, and Jagadish Chandra Bose.

[86] The form of 'Coherer' devised by Professor Bose, and described by him at the end of his paper 'On a new Electro Polariscope' allowed for the sensibility and range to appear to leave little to be desired at the time.

[86] In 1896, the British, Daily Chronicle reported on his UHF experiments: "The inventor (J. C. Bose) has transmitted signals to a distance of nearly a mile and herein lies the first and obvious and exceedingly valuable application of this new theoretical marvel."

After Bose's Friday Evening Discourses at the Royal Institution, The Electric Engineer expressed 'surprise that no secret was at any time made as to its construction, so that it has been open to all the world to adopt it for practical and possibly money-making purposes.'

[88] In 1894–95 the Russian physicist Alexander Stepanovich Popov conducted experiments developing a radio receiver, an improved version of coherer-based design by Oliver Lodge.

Other experimental stations were established at Lavernock Point, near Penarth; on the Flat Holmes, an island in mid-channel, and at Brean Down, a promontory on the Somerset side.

The aerial conductor on shore was a strip of wire netting attached to a mast 40 feet (12 m) high, and several hundred messages were sent and correctly received during the progress of the races.

[citation needed] At this time the Prince of Wales, later King Edward VII, had the misfortune to injure his knee, and was confined on board the royal yacht Osborne, based in Cowes Bay.

Marconi fitted up his apparatus on board the royal yacht by request, and also at Ladywood Cottage, in the grounds of Osborne House, Isle of Wight, where his Mother Queen Victoria was staying.

[112] The distances covered were small; but as the yacht moved about, on some occasions high hills were interposed so that the aerial wires were overtopped by hundreds of feet, yet this was no obstacle to communication.

Immediately afterward the apparatus was placed by request at the service of the United States Navy Board, and some highly interesting experiments followed under Marconi's personal supervision.

[128][129] In 1902, a Marconi station was established in the village of Crookhaven, County Cork, Ireland to provide marine radio communications to ships arriving from the Americas.

The Cunard Daily Bulletin, a 32-page illustrated paper published on board these ships, recorded news received by wireless telegraphy, and was the first ocean newspaper.

[citation needed] In June and July 1923, Marconi's shortwave transmissions took place at night on 97 meters from Poldhu Wireless Station, Cornwall, to his yacht Elettra in the Cape Verde Islands.

In July 1924, Marconi entered into contracts with the British General Post Office (GPO) to install telegraphy circuits from London to Australia, India, South Africa and Canada as the main element of the Imperial Wireless Chain.

[152] The report noted that the system was well adapted for use in squadron signalling, under conditions of rain, fog, darkness and motion of speed although dampness affected the performance.

[citation needed] In late 1886, Reginald Fessenden began working directly for Thomas Edison at the inventor's new laboratory in West Orange, New Jersey.

Fessenden, experimenting with a high-frequency spark transmitter, successfully transmitted speech on 23 December 1900, over a distance of about 1.6 kilometres (0.99 mi), the first audio radio transmission.

The credit for the development of this machine is due to Charles Proteus Steinmetz, Caryl D. Haskins, Ernst Alexanderson, John T. H. Dempster, Henry Geisenhoner, Adam Stein, Jr., and F. P.

In an interview with a New York Journal correspondent, Fessenden stated that in his early apparatus he did not use an air transformer at the sending end, nor a concentric cylinder for emitters and antennae,[154][155] and had used capacity, but arranged in a manner entirely different from that in other systems, and that he did not employ a coherer or any form of imperfect contact.