ام الياس عضو محترف
عدد الرسائل : 756 العمر : 39 نقاط : 5787 تاريخ التسجيل : 16/09/2008
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| موضوع: Radio history الجمعة فبراير 27, 2009 12:12 am | |
| Twenty years after the telephone was invented and music was first sent down a telephone line, Guglielmo Marconi sent radio signals. Marconi (1874-1937) was born in Italy and studied at the University of Bologna. He was fascinated by Heinrich Hertz's earlier discovery of radio waves and realised that it can be used for sending and receiving telegraph messages, referring to it as "wireless telegraphs." Marconi's first radio transmissions, in 1896, were coded signals that were transmitted only about 1,6 km (a mile) far. Marconi realised that it held huge potential. He offered the invention to the Italian government but they turned it down. He moved to England, took out a patent, and experimented further. In 1898 Marconi flashed the results of the Kingstown Regatta to the offices of a Dublin newspaper, thus making a sports event the first "public" broadcast. The next year Marconi opened the first radio factory in Chelmsford, Essex and established a radio link between Britain and France. A link with the USA was established in 1901. In 1909 Marconi shared the Nobel prize in physics for his wireless telegraph. Marconi became a wealthy man. Signals only But Marconi's wireless telegraph transmitted only signals. Voice over the air, as we know radio today, came only in 1921. Marconi went on to introduce short wave transmission in 1922. Marconi was not the first to invent the radio, however. Four years before Marconi started experimenting with wireless telegraph, Nikoli Tesla, a Croatian who moved to the USA in 1884, invented the theoretical model for radio. Tesla tried unsuccessful to obtain a court injunction against Marconi in 1915. In 1943 the US Supreme Court reviewed the decision. Tesla became acknowledged as the inventor of the radio - even though he did not build a working radio. Who then, tell me?! There are other claims to the throne of radio inventor. Indian scientist Sir J.C. Bose demonstrated the radio transmission in 1896 in Calcutta in front of the British Governor General. The transmission was over a distance of three miles from the Presidency College and Science College in Calcutta. The instruments ('Mercuri Coherer with a telephone detector') are still there in the science museum of the Calcutta University. Thus writes contributor Dipak Basu, referencing the Proceedings of the IEEE, January, 1998. Bose repeated his demonstration in the Royal Society in London in 1899 in the presence of Lord Rayleigh (Nobel prize winner in Physics, 1904), Fleming (Professor at London university and later an advisor to the Marconi company), and Lord Lister (President of the Royal Society). As a result he was offered Professorship in Cambridge, but declined. Bose had solved the problem of the Hertz not being able to penetrate walls, mountains or water. Marconi was present in the meeting of the Royal Society and it is thought that he stole the notetbook of Bose that included the drawing of the 'Mercuri Coherer with a telephone detector'. Marconi's Coherer, which he used in 1901, was the exact copy of that of Bose. Apparently Marcon was unable to explain how he got to the design. He said that an Italian Navy engineer called Solari had developed it, but Solari late denied it. Marconi then said that Italian Professor Timasina did, which later was exposed as a lie by another Italian professor, Banti. Bose did not apply for a patent on his design because he believed in the free flow of inventions in science. But under pressure from American friends, he applied for the patent in September 1901. He was awarded the US patent for the invention of the radio in 1904. By that time Marconi had received his patent and international recognition. "Hello Rainey!" It is reputed that Nathan B. Stubblefield, a farmer from Murray, Kentucky, made a voice transmission four years before Marconi transmitted radio signals. in 1892, Stubblefield handed his friend Rainey T. Wells a box and told him to walk away some distance. Wells said later: "I had hardly reached my post.. when I heard I heard HELLO RAINEY come booming out of the receiver." Stubblefield demonstrated his invention to the press in 1902 but, being afraid that his invention will be stolen, never marketed his wireless radio. When he was found dead in 1929, his radio equipment was gone. Nikoli Tesla remains to be acknowledged as the inventor of the radio. Radio everywhere Today, there are more than 33,000 radio stations around the world, with more than 12,000 in the US alone. Worldwide there are 2,24 billion radio sets, or one radio for every 2.5 persons; proof that video never killed the radio star. In 1894 the president of the Royal Society, Lord Kelvin, prophesied that radio had no future. The first radio factory was opened by Marconi 5 years later. Marconi invented the radio direction finder, a radio signal device used by planes and ships to fix their positions. He also invented the automatic alarm which picks up distress signals and sounds an alarm. He also introduced the use of ultrahigh-frequency (UHF) waves for radio communication. Marconi died in Rome in 1937 while in charge of scientific research for Mussolini's government. After the invention of the transistor by Bell Labs scientists in 1947, several US electronics companies rejected the idea of a portable radio. They apparently said: "Who would want to carry a radio around with them?" At the time, radio sets were rather large. When Bell Labs put the transistor on the market in 1952 they had few takers apart from a small Japanese start-up called Sony. Sony introduced the transistor radio in 1954. The phonograph was invented by Thomas Edison in 1877, the long-playing record by Paul Goldmark in 1948, and the CD by Philips in 1980. The LP is not dead yet: more than 20 million were sold in 1997. In the same period, more than 1,4 billion cassettes were sold, and about 2,2 billion CDs. Not counting pirated copies! One in three CDs sold globally is manufactured illegally, with the worst culprits residing in China, Russia and Mexico. | |
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