Invention of Radio - Development of Radio - Later Radio Development - Marconi

Marconi

Guglielmo Marconi studied at the Leghorn Technical School, and acquainted himself with the published writings of Professor Augusto Righi of the University of Bologna. In 1894, Sir William Preece delivered a paper to the Royal Institution in London on electric signalling without wires. In 1894 at the Royal Institution lectures, Lodge delivers "The Work of Hertz and Some of His Successors". Marconi is said to have read, while on vacation in 1894, about the experiments that Hertz did in the 1880s. Marconi also read about Tesla's work. It was at this time that Marconi began to understand that radio waves could be used for wireless communications. Marconi's early apparatus was a development of Hertz’s laboratory apparatus into a system designed for communications purposes. At first Marconi used a transmitter to ring a bell in a receiver in his attic laboratory. He then moved his experiments out-of-doors on the family estate near Bologna, Italy, to communicate further. He replaced Hertz’s vertical dipole with a vertical wire topped by a metal sheet, with an opposing terminal connected to the ground. On the receiver side, Marconi replaced the spark gap with a metal powder coherer, a detector developed by Edouard Branly and other experimenters. Marconi transmitted radio signals for about 1.5 miles (2.4 km) at the end of 1895.

By 1896, Marconi introduced to the public a device in London, asserting it was his invention. Despite Marconi's statements to the contrary, though, the apparatus resembles Tesla's descriptions in his research, demonstrations and patents. Marconi's later practical four-tuned system was pre-dated by N. Tesla, Oliver Lodge, and J. S. Stone. He filed a patent on his earliest system with the British Patent Office on June 2, 1896.

Marconi was awarded a patent for radio with British patent No. 12,039, Improvements in Transmitting Electrical Impulses and Signals and in Apparatus There-for. The complete specification was filed March 2, 1897. This was Marconi's initial patent for the radio, though it used various earlier techniques of various other experimenters (primarily Tesla) and resembled the instrument demonstrated by others (including Popov). During this time spark-gap wireless telegraphy was widely researched. In July, 1896, Marconi got his invention and new method of telegraphy to the attention of Preece, then engineer-in-chief to the British Government Telegraph Service, who had for the previous twelve years interested himself in the development of wireless telegraphy by the inductive-conductive method. On June 4, 1897, he delivered "Signalling through Space without Wires". Preece devoted considerable time to exhibiting and explaining the Marconi apparatus at the Royal Institution in London, stating that Marconi invented a new relay which had high sensitiveness and delicacy.

In 1896, Bose went to London on a lecture tour and met Marconi, who was conducting wireless experiments for the British post office. The Marconi Company Ltd. was founded by Marconi in 1897, known as the Wireless Telegraph Trading Signal Company. Also in 1897, Marconi established the radio station at Niton, Isle of Wight, England. Marconi's wireless telegraphy was inspected by the Post Office Telegraph authorities; they made a series of experiments with Marconi's system of telegraphy without connecting wires, in the Bristol Channel. The October wireless signals of 1897 were sent from Salisbury Plain to Bath, a distance of 34 miles (55 km). Marconi's reputation is largely based on the making of his law (1897), and other accomplishments in radio communications and commercializing a practical system.

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. Signals were obtained between the first and last-named points, a distance of, approximately, 8 miles (13 km). The receiving instrument used was a Morse inkwriter of the Post Office pattern. In 1898, Marconi opened a radio factory in Hall Street, Chelmsford, England, employing around 50 people. In 1899, Marconi announced his invention of the "iron-mercury-iron coherer with telephone detector" in a paper presented at Royal Society, London.

In May, 1898, communication was established for the Corporation of Lloyds between Ballycastle and the Lighthouse on Rathlin Island in the North of Ireland. In July, 1898, the Marconi telegraphy was employed to report the results of yacht races at the Kingston Regatta for the Dublin Express newspaper. A set of instruments were fitted up in a room at Kingstown, and another on board a steamer, the Flying Huntress. 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.

At this time His Majesty King Edward VII, then Prince of Wales, had the misfortune to injure his knee, and was confined on board the royal yacht Osltorm in Cowes Bay. Marconi fitted up his apparatus on board the royal yacht by request, and also at Osborne House, Isle of Wight, and kept up wireless communication for three weeks between these stations. 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. These demonstrations led the Corporation of Trinity House to afford an opportunity for testing the system in practice between the South Foreland Lighthouse, near Dover, and the East Goodwin Lightship, on the Goodwin Sands. This installation was set in operation on December 24, 1898, and proved to be of value. It was shown that when once the apparatus was set up it could be worked by ordinary seamen with very little training.

At the end of 1898 electric wave telegraphy established by Marconi had demonstrated its utility, especially for communication between ship and ship and ship and shore. Electric wave telegraphy had the advantages as follows:

• Transmission worked as well by night as by day, and in bad weather, fogs, or storms, as well as in fair weather; provided that the proper insulation of the aerial wire or elevated conductor was maintained.
• In certain electrical conditions of the atmosphere, and during thunderstorms, some difficulty was usually found in working, owing to the atmospheric discharges affecting the sensitive tube, and therefore making stray marks on the Morse tape of the printer, but seldom sufficient to interrupt communication altogether.
• The interposition of high hills, trees, or the curvature of the earth did not prevent communication, though slightly affecting the power required. It worked particularly well over sea surface, and between ships and shore stations.
• The apparatus could be set up and handled by any ordinary telegraphist, and the record was made on paper strip in the usual Morse code.
• Transmission easily covered distances far beyond those feasible or attained by other systems of wireless telegraphy.
• Lastly, the apparatus required was by no means costly, and, with the exception of the mast required for upholding the aerial wire, it occupied but little space, and was particularly adapted for use on board ship.

The Haven Hotel station and Wireless Telegraph Mast was where much of Marconi's research work on wireless telegraphy was carried out after 1898. In 1899, he transmitted messages across the English Channel. Also in 1899, Marconi delivered "Wireless Telegraphy" to the Institution of Electrical Engineers. In addition, in 1899, W. H. Preece delivers "Aetheric Telegraphy", stating that the experimental stage in wireless telegraphy had been passed in 1894 and inventors were then entering the commercial stage. Preece, continuing in the lecture, details the work of Marconi and other British inventors. In October, 1899, the progress of the yachts in the international race between the Columbia and Shamrock was successfully reported by aerial telegraphy, as many as 4,000 words having been (as is said) despatched from the two ship stations to the shore stations. 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. The Marconi Company was renamed Marconi's Wireless Telegraph Company in 1900.

In 1901, Marconi claimed to have received daytime transatlantic radio frequency signals at a wavelength of 366 metres (820 kHz). Marconi established a wireless transmitting station at Marconi House, Rosslare Strand, Co. Wexford in 1901 to act as a link between Poldhu in Cornwall and Clifden in Co. Galway. His announcement on 12 December 1901, using a 152.4-metre (500 ft) kite-supported antenna for reception, stated that the message was received at Signal Hill in St John's, Newfoundland (now part of Canada) via signals transmitted by the company's new high-power station at Poldhu, Cornwall. The message received had been prearranged and was known to Marconi, consisting of the Morse letter 'S' - three dots. Bradford has recently contested the reported success, however, based on theoretical work as well as a reenactment of the experiment. It is now well-known that long-distance transmission at a wavelength of 366 meters is not possible during the daytime, because the skywave is heavily absorbed by the ionosphere. It is possible that what was heard was only random atmospheric noise, which was mistaken for a signal, or that Marconi may have heard a shortwave harmonic of the signal. The distance between the two points was about 3,500 kilometres (2,200 mi).

The Poldhu to Newfoundland transmission claim has been criticized. There are various science historians, such as Belrose and Bradford, who have cast doubt that the Atlantic was bridged in 1901, but other science historians have taken the position that this was the first transatlantic radio transmission. Critics have claimed that it is more likely that Marconi received stray atmospheric noise from atmospheric electricity in this experiment. The transmitting station in Poldhu, Cornwall used a spark-gap transmitter that could produce a signal in the medium frequency range and with high power levels.

Marconi transmitted from England to Canada and the United States. In this period, a particular electromagnetic receiver, called the Marconi magnetic detector or hysteresis magnetic detector, was developed further by Marconi and was successfully used in his early transatlantic work (1902) and in many of the smaller stations for a number of years. 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. A ship's master could contact shipping line agents ashore to enquire which port was to receive their cargo without the need to come ashore at what was the first port of landfall. Ireland was also, due to its western location, to play a key role in early efforts to send trans-Atlantic messages. Marconi transmitted from his station in Glace Bay, Nova Scotia, Canada across the Atlantic, and on 18 January 1903 a Marconi station sent a message of greetings from Theodore Roosevelt, the President of the United States, to the King of the United Kingdom, marking the first transatlantic radio transmission originating in the United States

In 1904, Marconi opened the ocean daily newspaper, the Cunard Daily Bulletin, on the R.M.S. "Campania." At the start, the passing events were printed in a little pamphlet of four pages called the Cunard Bulletin. The title would read Cunard Daily Bulletin, with subheads for "Marconigrams Direct to the Ship." All the passenger ships of the Cunard Company are fitted with Marconi's system of wireless telegraphy, by means of which constant communication was kept up, either with other ships or with land stations on the eastern or western hemisphere. The RMS Lucania, Oct., 1903, with Marconi on board, was the first vessel to hold communication with both sides of the Atlantic. The Cunard Daily Bulletin, a thirty-two page illustrated paper published on board these boats, recorded news received by wireless telegraphy, and is first ocean newspaper. In August, 1903, in agreement was made with the British Government by which the Cunard Co. were to build two steamers, to be, with all other Cunard ships, at the disposal of the British Admiralty for hire or purchase whenever they may be required, the Government lending the company £2,600,000 to build the ships and granting them a subsidy £150,000 a year. One was the RMS Lusitania and the RMS Mauritania.

In June and July 1923, Marconi's shortwave transmissions were completed during nights on 97 meters from Poldhu Wireless Station, Cornwall, to his yacht Elettra in the Cape Verde Islands. In September 1924, Marconi transmitted during daytime and nighttime on 32 meters from Poldhu to his yacht in Beirut. Marconi, in July 1924, 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. The UK-to-Canada shortwave "Beam Wireless Service" went into commercial operation on 25 October 1926. Beam Wireless Services from the UK to Australia, South Africa and India went into service in 1927. Electronic components for the system were built at Marconi's New Street wireless factory in Chelmsford.

Marconi would jointly receive the 1909 Nobel Prize in Physics with Karl Ferdinand Braun for contributions to the existing radio sciences. Marconi's demonstrations of the use of radio for wireless communications, equipping ships with life saving wireless communications, establishing the first transatlantic radio service, and building the first stations for the British short wave service, have marked his place in history. Shortly after the turn of the 20th century, the US Patent Office re-awarded Marconi a patent for radio. The U.S. Patent RE11,913 was granted on June 4, 1901. Marconi's U.S. Patent 676,332 was awarded on June 11, 1901, also. This system was more advanced than his previous works. The United States Supreme Court, decision of MARCONI WIRELESS T. CO. OF AMERICA v. U.S., 320 U.S. 1 (1943) stated that “Marconi's reputation as the man who first achieved successful radio transmission … is not here in question” this statement is followed by “Marconi's patent involved no invention over Lodge, Tesla, and Stone”. The 1943 decision didn't overturn Marconi's original patents, or his reputation as the first person to develop practical radiotelegraphic communication. It just said that the adoption of adjustable transformers in the transmitting and receiving circuits, which was an improvement of the initial invention, was anticipated by patents issued to Oliver Lodge and John Stone. (This decision wasn't unanimous).