I2MOV - Radioamatore

Guglielmo Marconi

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Guglielmo Marconi was born in Bologna on 25th April 1874, the son of an Italian country gentleman who married a young Irish girl, Annie Jameson.Guglielmo received no formal education, and showed little interest in his studies, except in physics, and the course at technical school was not finished, but he studied physics in Livorno at home of the Prof. Vincenzo Rosa.

At the age of twenty the young genius began, as an amateur, experiments which in about a year led to the invention of radiotelegraphy. These experiments took place in the attic room ofVilla Griffone”, in Pontecchio, the country house of his father, in the borough of SASSO.

Following the earlier mathematical work of Clerk Maxwell and the experiments of Heinrich Hertz, Marconi realized a practical system of communicating intelligence without the use of connecting wires. He first transmitted signals inside the attic room, which, had a range of only a few meters. Then the distances were increased, using a sensitive “coherer” in the receiver, in which Marconi had an original mixture of powders. Batteries a bell were inserted in series with the coherer. Guglielmo was persistent and experiments went on throughout the winter of 1894, regardless of food or sleep. With subsequent modifications Marconi progressively increased the range of communication. In the spring of 1895 his experiments were transferred to the garden, and it was here in the summer, that Marconi made his crucial discoveries. By increasing the “capacity” of his equipment with the use of sheet-iron slabs, the length of waves was brought from the original 40-80 cm to the band of high frequencies (about 50 m).

Thus Marconi had invented the antenna-earth system. Signals were successfully received at a distance of 2400 m, and finally , at the end of September, transmission was obtained beyond a hill; this historical experiment concluded with the famous rifle shot, celebrating the “birth of radio”.

Marconi’s invention was offered to the Ministry of Posts and Telegraphs in Roma; but they politely declined.

On the 12th February 1896 Guglielmo and his mother left for London, to be received by his cousin Henry Jameson Davis.

Marconi was introduced to William Preece, Engineer in Chief of the Post Office. The invention gave rise to great interest and Mr. Preece offered the young Italian full support, placing laboratories and engineers of the Post Office at Marconi’s disposal. A period of public demonstration began, each carefully prepared, with great publicity. Marconi was followed in his experiments by crowds of curious people and admirers.

Marconi delivered lectures and had meetings with scientists, politicians and journalists. He was received by Ministers, and later by Kings. He was soon to became very popular, a front page man, loved by people all over the world, and grateful, in view of the value of radio to human civilization and the safety of lives.

Marconi registered his inventions but always allowed Italy to take free advantage of his patents; he was a great patriot. In the sphere of application, each one of Marconi’s experiments represented a novelty, a stage in the progress of radio, and a new record. After the demonstration at the Post Office, in London, 1896 and Salisbury Plain 1896-1897, QRB 15 km; and the Bristol Channel 1897, QRB 13 km; came the experiments in Roma and the Gulf of La Spezia, July 1897, QRB 16 km.

In 1897 three stations were set up, at The Needles, Alum Bay, Isle of Wight; at Bournemouth; then at the nearby village of Poole. A receiver installed aboard a tug-boat could pick up signals at a distance of 30 km.

The 3rd June 1898 saw Marconi opening the first public commercial radiotelegraph service between The Needles and Bournemouth, QRB 30 km.

Then followed radiotelegraphy aboard ships and at a lighthouse; the commission of Lloyds 1898; the journalistic service at Kingstown Regatta 1898, QRB 36 km; the station at Osborne House and the Royal Yacht 1898. In the same year Marconi opened the world’s first radio factory at Chelmsford, Essex. In 1899 the transmissions over the Channel, Vimereux-Dover 51 km; Vimereux-Harwich and Chelmsford 130 km; and the Royal Navy exercises July 1899, QRB 140 km.

The first trip to U.S.A. and the service at America’s Cup, October 1899; experiments for the American Navy; the transmissions between The Needles and the Lizard 1900, QRB 300 km; the link France-Corsica, 1901.

It was in Poldhu, near HELSTON, Cornwall, that in 1901, Marconi constructed a big station of 25 kW which represented the last word in the radio communication field for a number of years: tuned circuits were employed and the antenna supported by towers of 69 m .

From Poldhu came the famous “S” over the Atlantic to St. John’s, Newfoundland, 12th December 1901, QRB 3400 km; at Poldhu the messages to His Majesty were received from Canada on 20th December 1902, QRB 4000 km; and from U.S.A. 18th January 1903, QRB 5000 km. The news of the great conquest - the first DX –was incredulous to many a renowned scientist, witness how much the inventions were ahead of other researchers in the field.

Marconi experimented with his apparatus aboard ships. From June to September 1902 tests were made on the Italian warship “Carlo Alberto” from Italy to the North Sea; then to Kronstadt, near St.Petersburg, and messages were exchanged with Poldhu. At night time the signals reached beyond high mountains and over the European Continent. Propagation was investigated by Marconi during numerous trips; in his life he crossed the Atlantic 65 times ! In 1903, during a trip to U.S.A. he received news from his stations in Europe and America, and for the first time a daily news paper was printed aboard ship.

At Poldhu many historical experiments were carried out, with the use of ever new and revolutionary devices invented by Marconi; beam antennas and the magnetic detector etc. until 1933, when the installation was completely pulled down.

In 1907 the Marconi Company set up a new station at Clifden, Ireland, with a power of 300 kW, using a new invention of the great man, the disc discharger, and a new kind of beam antenna. Clifden handled the traffic between the new and the old world, while Poldhu controlled marine communication. For a long time the Marconi Company led the coasts stations equipped with the Marconi system. In 1905 there were 110 war-ships and 70 merchant ships with 50 coast stations. By 1914, more than 1500 ships. Numerous radio-beacons were set up by Marconi, and he had invented a radio-compass.

In addition to the Marconi Wireless Telegraph Company of England, other companies were founded by Marconi in Argentina, U.S.A., France, Spain, Russia, Australia, Belgium and Italy. Also, the International Marine Company and the Wireless Press Company.

In 1912 the network of Marconi stations comprised Aden, Algeria, Australia, Azores, Belgium, Brazil, Burma, China, Curacao, France, French Guyana, Germany, India, Japan, Jamaica, Mexico, Morocco, Netherlands, Norway, Romania, Russia, Senegal, South Africa, Sweden, Tobago, Trinidad, Uruguay, Zanzibar, and 4 stations in the Pacific Ocean and 13 stations in Italy.

The contribution by Marconi and his assistants was great in the use of valves, continuous waves, and radiotelephony. An absolute record was the conquest of distance, that Marconi made in 1918, with transmissions from England to Australia.

Big stations with incredible powers were realized by the Marconi Company, at Rugby in England, 1400 kW, and waves of 18700 m; Buenos Aires, 800 kW, 12000 and 16000 m .

Then started the era of “broadcasting”. The first station in England was at Marconi’s factory at Chelmsford, with the call 2MT; regular programmes were transmitted in 1922. In the same year a broadcasting station was born in London, 2LO installed at Marconi House in the Strand.

Marconi showed great interest in HF from early times. In the period 1916-1926 he investigated the propagation of those frequencies and proved the possibility offered by HF to great distances and with low power. In 1919 he bought a yacht of 72m called “Elettra”, which became his laboratory ship. In 1922 the cruise of Elettra in the Atlantic marked a turning point of radio communication. Poldhu transmitted on the bands of 32, 47, 60 and 90 m, with a power of 12 kW or less. Marconi on the Elettra at the Cape Verde Islands had incredible results. But signals were received also in New York, Rio de Janeiro, Buenos Aires, Montreal and Australia !

Elettra arrived in New York and Marconi made his famous lecture to the American Institute of Electrical Engineers, illustrating the properties of HF and announcing a new system of short wave beam stations.

With intuition, Marconi, once again had revolutionized the field of radio; he signaled the end of the big stations of great power and low frequencies. All this just when other companies, which always interfered with the work of Marconi, were engaged in super-powered stations in LF. But the Italian genius was to carry out his biggest accomplishment; The Imperial Wireless Scheme in HF 1926-1927, London, Cairo, Pretoria, Aden, Bangalore, Singapore, Glace Bay, Buenos Aires, Cape Town, Calcutta, Sydney; The Portuguese Colonial Network, Lisbon, Azores, Madeira, Cape Verde, Mozambique. Goa, Macao, Timor; and the stations in Madrid and Argentina.

Well known is the event of 26th March 1930 when Marconi sent out, from his yacht in Genova, telegraphic impulses which switched on the lamps of the Town Hall in Sydney 17 000 km.

On 12th October from Roma, Marconi illuminates the statue of the Corcovado in Rio de Janeiro by the same method.

A triumphal journey of Marconi took place, around the world, in 1933-1934. On 2nd October 1933 the “Marconi Day” was celebrated in Chicago at which the great man was present, and signals were transmitted around the world, to rebound through his stations at New York, London, Roma, Bombay, Manila, Honolulu, San Francisco and Chicago, in 3 minutes and 25 seconds.

Marconi was decorated with the Nobel Prize for Physics in 1909 at the age of 35. He received 15 degrees from different Universities; Senator of Italy; a Marquis; President of the Italian Academy; President of C.N.R.; Professor of Electromagnetic Waves at Roma University; Knight Grand Cross of the Royal Victorian Order, by which he could be called Sir Guglielmo or Sir William.

Marconi spent his last years in Italy, interested in the advanced field of electromagnetic waves; microwaves, radiolocation, and medical applications (Marconiterapia).

He died in Roma on 20th July 1937.

At an agreed time on the day after he died, the radio transmitters all over the world closed down, simultaneously, for two minutes, in memory of the man whose institutions and inventions had nullified distances with the conquest of the aether.

 
     
 

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Ultimo aggiornamento: 09-01-16