Guglielmo Marconi

From Citizendium
Revision as of 21:10, 26 September 2007 by Subpagination Bot (Talk | contribs) (Add {{subpages}} and remove any categories (details))

Jump to: navigation, search
This article has a Citable Version.
Main Article
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
This editable Main Article has an approved citable version (see its Citable Version subpage). While we have done conscientious work, we cannot guarantee that this Main Article, or its citable version, is wholly free of mistakes. By helping to improve this editable Main Article, you will help the process of generating a new, improved citable version.

Guglielmo Marconi (April 25, 1874 - July 20, 1937) was an Italian inventor, who is widely credited with the invention of radio communication, or more precisely, the first practical radiotelegraph system. Among his many honors, he was awarded the 1909 Nobel Prize in Physics jointly with Karl Ferdinand Braun, "in recognition of their contributions to the development of wireless telegraphy". Marconi helped found a number of communications companies, located throughout the world, which were a major force in establishing the radio industry.

Guglielmo Marconi, 1902

Birth and early years

Guglielmo Marconi's parents were Giuseppe Marconi, an Italian silk merchant, and his young Scots-Irish wife, Annie Jameson, whose grandfather founded the Jameson Whiskey distillery. Guglielmo was born near Bologna, Italy, and his education — much of it provided by private tutors — took place as the family moved between Bologna, Florence and Livorno. Although baptized in the Catholic church, his mother brought him up as a Protestant, and he became a member of the Anglican church, however, following his second marriage, he converted to Catholicism. Marconi spoke fluent English in addition to his native Italian — some English-language accounts even anglicized his first name to "William".

Early years

While growing up, Marconi was fascinated by science, and was especially interested in the ongoing discoveries in electricity. During his formative years, one of most important scientific developments of the day was Heinrich Hertz's proof of the existence of electromagnetic radiation, which became known as "Hertzian waves", and later "radio". Hertz published the results of his discoveries beginning in 1888, and his death in 1894 resulted in reviews of his earlier work, which in turn sparked Marconi's interest in the subject. In order to further his studies, Marconi was briefly permitted to attend the classes of a University of Bologna physicist, Augusto Righi, who had been conducting research into high-frequency radio signals.

The experimental transmissions made by Hertz, Righi and others had been detectable for only short distances, but Marconi became convinced that it should be possible for radio waves to be used for longrange "wireless telegraph" signaling. Previously, numerous other inventors had tried to develop wireless telegraph systems, in order to eliminate the connecting wires needed by the electric telegraph. A variety of technologies had been investigated, but so far no one had been able to develop a commercially successful solution. In the autumn of 1894, Marconi began the single-minded pursuit of his goal, conducting extensive experiments in the attic of his home, the Villa Griffone in Pontecchio, Italy. He constructed much of his own equipment — always methodical, he often worked more by trial-and-error than with a full understanding of the physics involved. His initial experiments involved replicating the work done by earlier investigators, while beginning to add his own refinements. His original experimental equipment consisted of the following main components:

  1. A simple spark-gap transmitter, closely modeled after Righi's, which was itself very similar to the transmitter which Hertz had employed in his experiments.
  2. A standard telegraph key to control the transmitter, and produce short and long pulses, creating the dots-and-dashes needed for Morse code signaling.
  3. A filings-coherer receiver, which was activated by the transmission of the radio signals. This was a modified version of Edouard Branly's original "radio-conductor", with refinements to make it smaller, more sensitive, and more reliable. (Marconi later estimated that he spent over 1,000 hours perfecting his coherer).
  4. A recording device, controlled by a relay action triggered by the coherer. Initially this was a ringing bell, but in keeping with Marconi's ultimate objective, the final design called for the substitution of a telegraph register, to record the received Morse code on a roll of paper tape.

Other experimenters had employed similar spark-gap transmitters and coherer-receivers, however, none had been able to achieve transmission ranges greater than a few hundred meters. In the summer of 1895, Marconi moved his equipment outdoors, and at first was only able to match the distances achieved by the others. However, at this point he made two critical improvements. First, he increased the length of the transmitter and receiver antennas, which had the side-effect of increasing the transmission frequencies to ones with better propagation characteristics. Next, he changed the orientation of the dipole antennas from horizontal to vertical, and let the lower end of each antenna touch the ground. This had the side-effect of significantly increasing the transmission distance, although at the time Marconi did not fully understand why this had occurred. (The reason was eventually determined to be due to the fact that adding antenna "ground connections" allowed the radio signals to use the Earth as a "waveguide", creating "surface waves" which followed the terrain, instead of merely traveling in straight lines through the air.) With these improvements, Marconi was now able to transmit to a distance of around 1.5 kilometers (1 mile). More importantly, the use of surface waves meant he could send radio signals over the crest of a hill, and thus was no longer limited to "line of sight" communication. Marconi had now also convinced his father, who had financed the initial experimentation, of the potential of his ideas, and received the support needed to continue his work.

Demonstrations and tests

In early 1896, Marconi, only 21 years old, traveled with his mother to London, England in order to promote his radio inventions for both commercial and military applications. However, upon his arrival, British customs agents smashed the equipment, fearing it might be a disguised bomb. The inventor was able to quickly rebuild his devices, then used his extensive family connections to obtain a letter of introduction from A. A. Campbell Swinton, which provided access to William Preece, the Chief Electrical Engineer of the British Post Office. Preece was a recognized expert in wireless telegraphy, due to his experiments with a system of his own invention, that however employed electromagnetic induction instead of radio signals, and which, despite some successes, had proven to be of only limited practicality. Preece was impressed by the young inventor and his accomplishments, and sponsored a series of demonstrations conducted by the British government. In March, 1897, Morse code transmissions were sent across the Salisbury Plain for a distance of about 6 kilometers (4 miles), and, on May 13, 1897, replicating work Preece had done earlier using his induction method, the Bristol Channel was spanned from Lavernock Point, South Wales to Brean Down, a distance of 14 kilometers (8.7 miles). Preece was so impressed by these demonstrations that he prepared two lectures in London to introduce Marconi's work to the public: "Telegraphy without Wires," delivered at the Toynbee Hall on December 11, 1896, followed by "Signalling through Space without Wires", given at the Royal Institute on June 4, 1897.

Additional successful demonstrations followed, covering progressively longer distances, and Marconi was beginning to receive international attention and acclaim. In July, 1897, he returned to the country of his birth for a series of tests conducted at La Spezia, which were sponsored by the Italian government. The commercial firm Lloyds was interested in setting up radio stations to communicate with approaching ocean vessels, which resulted in test transmissions that took place between Ballycastle and Rathlin Island, Ireland in May, 1898. A well publicized test on March 27, 1899 resulted in the successful demonstration of two-way communication across the English Channel, between Wimereux, France and the English Cliffs of Dover. Next, in the fall of 1899, Marconi was invited to make his first demonstrations in the United States, reporting bulletins "live" for the New York Herald about the progress of the America's Cup yacht races held at New York. Afterward, he made private tests for the United States Navy.

Developing a new industry

Initial commercial development

Marconi with radio equipment, around 1903
On June 2, 1896, Marconi filed a Provisional Specification with the British Patent Office, describing in general his radio devices. This was followed by a more comprehensive Complete Specification, filed on March 2, 1897. Marconi was issued British Patent 12,039 on July 2, 1897, for Improvements in transmitting electrical impulses and signals, and in apparatus therefor. This patent is generally considered to be the first one ever issued specifically for radio communication.

The British Post Office tried to interest the British government in purchasing the rights to Marconi's work. However, on July 20, 1897, a commercial firm, the Wireless Telegraph and Signal Company, Ltd., based in London, was incorporated, financed largely by members of Marconi's family on his mother's side. (This firm was renamed Marconi's Wireless Telegraph Company, Ltd. in March of 1900.) Marconi became the new company's Chief Engineer and one of its directors. Over the next few years a series of additional companies were established worldwide, two of the most prominent being the Marconi Wireless Telegraph Company of America, Inc. (also known as American Marconi) on November 8, 1899, and The Marconi International Marine Communication Company, Ltd., on April 25, 1900. The latter company leased Marconi equipment to shipping lines and provided operators who worked for the wireless company, not the ship lines. Passengers were soon sending telegrams by radio called "Marconigrams".

In November, 1897, the first permanent radio station in the world was constructed, located on south coast of England at The Needles, Isle of Wight. In 1898, Marconi also built the world's first "wireless telegraph" factory, located at Hall Street in Chelmsford, England, which initially had around fifty employees. After the formation of an organized company, Marconi began hiring important associates, who brought technical skills needed by the growing firm which the self-trained inventor did not have. Important employees would include Oliver Lodge, John Ambrose Fleming and R. N. Vyvyan. Marconi himself took on more of a leadership role and was less technically involved, although in 1902 he received a patent for a magnetic receiver — known affectionately as "maggie" — that was the company's standard through World War One.

In spite of the Marconi's initial technical success, most of the Marconi companies did not earn a profit for a number of years after their founding. A majority of company income came from shipboard leases, and the publicity about the value of radio that followed the sinking of the RMS Titanic in 1912, combined with regulations that began requiring radio transmitters on ocean liners, served to edge the companies into profitability. While Marconi-affiliated companies quickly established dominance in the United Kingdom and its colonies, other firms, especially German-based Telefunken, provided significant competition. In the United States, Marconi faced extensive resistance from the United States Navy, which was unhappy with the company's policy of leasing instead of selling equipment, and was also fearful of British domination and control of radio communication, much as that county had dominated ocean cables. Starting in 1906, the United Wireless Telegraph Company was the largest American radio firm, but United's business was geared more toward wild stock promotion than setting up a viable radio company. When United Wireless went bankrupt in 1912, its assets were absorbed by Marconi, giving American Marconi a near-monopoly position in the United States. However, this was only temporary, and after the end of World War One, pressure by the U.S. government, led by the Navy, forced Marconi out of the U.S. market, by engineering the sale of American Marconi's assets to the General Electric Company, which, on November 20, 1919, used them to form the Radio Corporation of America.

Transatlantic experimentation

The most valuable feature of the new "wireless telegraphy" was its ability to provide communication where regular telegraph lines could not be run, and the revolutionary possibilities for ship communication by radio were seen as a major financial opportunity for the Marconi companies, which soon began construction of high-powered shore stations, initially located along the Atlantic coasts. In addition to general land-to-sea communication, in 1904 a commercial service was set up, to transmit news summaries overnight to subscribing ocean-going ships, which used these reports to supplement their daily passenger newspapers.

Marconi looks on as associates raise a kite antenna, Saint John's, Newfoundland, December, 1901
Although the high-power shore stations were said at the time of their construction to be intended only for communicating with ships in mid-ocean, Marconi's additional, albeit unpublicized, goal was to establish transoceanic signaling. Success in this endeavor would be both a publicity coup, and increase potential revenues, by allowing radio to compete with the transoceanic telegraph cables. Quietly testing the possibilities, Marconi soon made the stunning announcement that, on December 12, 1901, he had personally received, at Signal Hill in Saint John's, Newfoundland, a test transmission of the Morse code letter "S" transmitted across the Atlantic from the new high-power station located at Poldhu, Cornwall, England — a distance of approximately 3,500 kilometers (2,100 miles). Not surprisingly, this was acclaimed as a great scientific triumph. However, there was also some skepticism about this claim that continues to the present day. The reported signals had been heard only faintly and sporadically, moreover, the simple transmissions consisted only of the three dots of the Morse code letter S sent repeatedly, produced by a transmitter whose signals were low-frequency cracklings that were difficult to differentiate from the stray noise of atmospheric static. Finally, there had been no independent confirmation of the reported reception. (Marconi had been blocked from doing further tests in Newfoundland after objections were raised by the local ocean cable company, which held a legal monopoly on the colony's transatlantic telegraphic communication.)

In view of the lingering doubts, Marconi prepared a better organized test, conducted aboard the S.S. Philadelphia. In February, 1902, this ship steamed westward from Great Britain, with Marconi recording signals that were sent daily at regular intervals from the Poldhu station. The carefully documented results showed that signals strong enough for coherer-tape reception were received up to a distance of 2,496 kilometers (1,551 miles). In addition, audio reception, which didn't require as strong a signal, but also did not provide a permanent record, was maintained for 3,378 kilometers (2,099 miles).

However, there turned out to be an interesting footnote. The test signals had actually been heard much farther during the night than during the day, thus, these tests were the first to show that mediumwave and longwave radio signals travel greater distances during nighttime hours. (Although at this time Marconi was completely mystified why this was so, it was later determined this phenomenon was the result of the nighttime signals being refracted back to the Earth by the ionosphere.) During daytime hours, which was when the Newfoundland tests had taken place, the transmissions had been heard only about 1,125 kilometers (700 miles) out, or less than half the distance that had been claimed for the Newfoundland transmissions, so Marconi's Newfoundland claims remained somewhat in doubt. Still, these tests did prove that radio signals could successfully span hundreds of kilometers, in spite of the fact that some scientists had thought that radio signals were limited to only line-of-sight distances.

Marconi continued to develop the transatlantic links, initially optimistic that his company could soon provide a commercial radiotelegraph service. A Marconi station located at Glace Bay, Nova Scotia, Canada, sent the first radio message to cross the Atlantic in an eastward direction, on December 17, 1902. Then, on January 18, 1903, the first transatlantic radio transmission originating from the United States was sent from a second Marconi station, located near Wellfleet, Massachusetts — this transmission consisted of greetings from Theodore Roosevelt, the President of the United States, to King Edward VII. However, despite these experimental successes, establishing reliable transatlantic communication, especially during the summer and daylight hours, turned out to be much more difficult than expected. It was not until the fall of 1907 that a transatlantic radiotelegraph service was finally inaugurated, and for many years after this the company was unable to provide a fully reliable service.

Effects from the Titanic

On April 15, 1912, the Titanic disaster occurred, which, in the midst of the tragedy, also brought increased prominence to the value of radio in general, and Marconi's fame in particular. The Titanic's radio room was staffed by two Marconi radio operators, who through their efforts were able to attract the help needed to save over 700 lives. The survivors were brought aboard the Carpathia, which was also staffed by Marconi radio operators. When the Carpathia docked in New York City, Marconi went aboard ship, accompanied by New York Times reporter, who received an exclusive interview with the Titanic's surviving radio operator. Marconi later gave evidence about seagoing radio practices at the Court of Inquiry which was convened to investigate the loss of the famous ship.

Patent issues

Marconi was careful to note that his work built upon the discoveries of numerous other scientists and experimenters, however, he also insisted that it was his improvements and hard work which first made radio practical for long-distance communication. His original design, which consisted of a simple spark-gap transmitter and coherer-receiver, was very similar to what many other experimenters had used, and the transmitter was clearly based on one used by Augusto Righi, which Marconi had personally seen. Marconi's major claims were that his improvements in coherer design, combined with the grounded antennas, meant he was able send radio signals over much greater distances than anyone else had previously. However, there was controversy, especially in Britain, whether his overall design qualified for patent protection, or if his system derived too much from the earlier work by Hertz, Branley, Lodge and Righi to be considered novel enough to be patentable. The British press in particular complained that Marconi's system was too much like that used in 1894 for widely publicized demonstrations by Oliver Lodge to qualify for a patent.

Marconi's original equipment was a simple, untuned, "two-circuit" design, which, while groundbreaking at the time, also had the limitation that trying to operate multiple transmitters from the same locality resulted in mutually disruptive interference. (This was amply demonstrated in 1901, when Marconi returned to New York to again report results on the America's Cup race. This time there were two upstart American firms that decided to also provide the same service — with all three transmitters operating simultaneously, the result was chaos, as all of the signals were blotted out). Marconi addressed the need for better tuning by developing a more refined "four-circuit" design, which included two tuned circuits at both the transmitting and receiving antennas. On April 26, 1900, he was issued British patent number 7,777 to cover this four-circuit design. However, various degrees of electrical tuning research had been done by, among others, Nikola Tesla, Oliver Lodge, Karl Braun, and John Stone Stone, so what became known as the "four-sevens" patent, along with its equivalents issued in other countries, faced numerous legal challenges. In 1911, Mr. Justice Parker of the British High Court of Justice ruled in favor of Marconi's tuning patent, however, shortly after this ruling, the Marconi Company purchased the Lodge-Muirhead Syndicate, in order to gain control of a tuning patent issued to Oliver Lodge in 1897 that Marconi was concerned might be ruled to have priority. In the United States, Judge Van Vechten Veeder in 1914 upheld all the Marconi patents, ruling that "I find that the evidence establishes Marconi's claim that he was the first to discover and use any practical means for effective telegraphic transmission and intelligible reception of signals produced by artificially formed Hertz oscillations". (A 1915 U.S. case involving a suit against Telefunken was suspended with the outbreak of World War One.) These favorable rulings eventually led American Marconi to sue the United States for compensation for using some of its patents during World War One. This case dragged on until 1943, when the United States Supreme Court overturned Marconi's U.S. version of the four-sevens patent, ruling that it had been fully anticipated by John Stone Stone, and also contained elements of earlier work done by Karl Braun and Nikola Tesla.

Later work

Although their operations providing radiotelegraph services soon spread over much of the world, the Marconi companies tended to be technically conservative. John Ambrose Fleming in particular stressed the supposed superiority of "whipcrack" spark transmitters, which had the practical effect of limiting the company to only telegraphic signaling, as spark transmitters could not be used for audio transmissions. This left other experimenters free to develop continuous-wave transmitters, which would prove to be more efficient, and which were also capable of audio transmissions. The company did eventually catch up, and in 1920, experimenting with a vacuum-tube (valve) transmitter, the Marconi station located at the Chelmsford factory broadcast the first entertainment programs to take place in the United Kingdom. In 1922, the Marconi Research Centre at Writtle, near Chelmsford, commenced a regular schedule of entertainment broadcasts. When the British Broadcasting Company was created later that year, the Marconi company was a major participant. On a personal level, in the 1920s Marconi became interested in shortwave transmissions, and, echoing his voyage on the Philadelphia twenty years earlier, conducted reception research, this time aboard his personal yacht Elettra.

Personal information

Marconi had both a older stepbrother, Luigi, and an older brother, Alfonso. On March 16, 1905, Marconi married for the first time, to Beatrice O'Brien, who was the daughter of Edward Donough O'Brien, 14th Baron Inchiquin, Ireland. They would have three daughters together (one of whom lived only a few weeks), plus one son. The couple divorced in 1924, and the marriage was formally annulled by the Catholic Church in 1927. This left Marconi free to remarry, which he did on June 15, 1927, to Maria Cristina Bezzi-Scali. This marriage produced a daughter.

Marconi's honors included becoming a Senatore in the Italian Senate in 1914, and, ten years later, being made a marchese by King Victor Emmanuel III. In 1914, he was appointed an Honorary Knight Grand Cross of the Royal Victorian Order in the United Kingdom. During World War I, Marconi was in charge of the radio service for Italian military.

Although he had often said he was not political, in 1923 Marconi joined the Italian Fascist party. In 1930, he was appointed President of the Accademia d'Italia by the Italian dictator Benito Mussolini — this position in turn meant that Marconi was now a member of the Fascist Grand Council. In 1935, after Italian forces invaded Ethiopia, Marconi made numerous controversial speeches supporting the action. Because of this, the BBC later banned him from talking about the topic on its airwaves.

Following his death from a heart attack at age 63, Italy held a state funeral for Marconi. Radio stations worldwide held tributes for his accomplishments.

Further reading

  • Aitken, Hugh G. J., Syntony and Spark: The Origins of Radio, New York: John Wiley & Sons, 1976. ISBN 0-471-01816-3
  • Aitken, Hugh G. J., The Continuous Wave: Technology and American Radio, 1900-1932, Princeton, New Jersey: Princeton University Press, 1985. ISBN 0-691-08376-2.
  • Baker, W. J., A History of the Marconi Company, 1970.
  • Bussey, Gordon, Marconi's Atlantic Leap, Coventry, England: Marconi Communications, 2000. ISBN 0-95389-676-6
  • Coe, Douglas and Kreigh Collins (ills), Marconi, Pioneer of Radio, New York, J. Messner, Inc., 1943. LCCN 43010048
  • Garratt, G. R. M., The early history of radio: from Faraday to Marconi, London, Institution of Electrical Engineers in association with the Science Museum, History of technology series, 1994. ISBN 0-85296-845-0 LCCN gb 94011611
  • Geddes, Keith, Guglielmo Marconi, 1874-1937, London : H.M.S.O., A Science Museum booklet, 1974. ISBN 0-11-290198-0 LCCN 75329825 (ed. Obtainable in the U.S.A. from Pendragon House Inc., Palo Alto, California.)
  • Hancock, Harry Edgar, Wireless at sea; the first fifty years: A history of the progress and development of marine wireless communications written to commemorate the jubilee of the Marconi International Marine Communication Company, Limited, Chelmsford, Eng., Marconi International Marine Communication Co., 1950. LCCN 51040529 /L
  • Jolly, W. P., Marconi, 1972.
  • Marconi, Degna, My Father, Marconi, James Lorimer & Co, 1982. ISBN 0-919511-14-7
  • Marconi's Wireless Telegraph Company, Year book of wireless telegraphy and telephony, London : Published annually, beginning in 1913, for the Marconi Press Agency Ltd., by the St. Catherine Press / Wireless Press. LCCN 14017875 sn 86035439.
  • Masini, Giancarlo, Guglielmo Marconi, Turin: Turinese typographical-publishing union, 1975. LCCN 77472455 (ed. Contains 32 tables outside of the text)
  • Weightman, Gavin, Signor Marconi's magic box: the most remarkable invention of the 19th century & the amateur inventor whose genius sparked a revolution, 1st Da Capo Press ed., Cambridge, MA : Da Capo Press, 2003. ISBN 0-306-81275-4

External links