Italian inventor and electrical engineer Guglielmo Marconi was born on 25 April, 1874, in Bologna and became a pioneer in the field of long-distance radio transmission and a key developer of radio telegraphy.
Marconi initially began experimenting with radio waves when he was 20 years old, with the hope of creating a form of wireless telegraphy.
By 1895 he had succeeded in transmitting a signal just over a mile ‒ but the Italian Ministry of Posts & Telegraphs was not interested in funding further research.
It later transpired that the letter he sent explaining his wireless telegraph machine had been dismissed as madness – the head of the ministry apparently scrawled "to the Longara" on the document, referring to an asylum in Rome.
Undaunted by lack of interest in his native Italy, Marconi travelled to London and, via family connections, was introduced to William Preece, engineer-in-chief to the General Post Office – a forerunner of today's BT. Preece and the Post Office supported Marconi in his early career in the UK.
On 27 July 1896, Marconi successfully demonstrated his wireless telegraphy system by sending a signal between two Post Office buildings.
The transmitter was placed on the roof of the Central Telegraph Office – at the junction of Newgate Street and St Martin’s Le Grand, where the BT Centre now stands – and a receiver on the roof of GPO South building on Carter Lane. A plaque on BT Centre commemorates this first public transmission of wireless signals.
Though the distance covered by the signal between the two London buildings was only 300 metres, the demonstration persuaded the GPO to fund further tests by Marconi on Salisbury Plain.
But despite recognising the system’s potential, the GPO failed to sign a formal agreement with Marconi – leaving him free to establish a private company (The Wireless Telegraph & Signal Company Ltd) in London in 1897.
The company enjoyed rapid success – first successfully transmitting across the English Channel in 1899, then across the Atlantic in 1901. Marconi’s company became well-known as a provider of wireless equipment and operators for shipping – most famously to the Titanic, whose wireless transmissions as the ship sank in April 1912 helped save many lives.
Herbert Samuel, postmaster general at the time, said of the Titanic disaster: “Those who have been saved, have been saved through one man, Mr Marconi... and his marvellous invention.” Marconi and his family had been invited to sail on the ship’s doomed maiden voyage but had been unable to make the journey.
Marconi shared the 1909 Nobel prize in physics with Karl Ferdinand Braun “in recognition of their contributions to the development of wireless telegraphy’’.
Braun's major contributions included introducing closed tuned circuits in the generating part of the transmitter, and its separation from the radiating part (the antenna) by means of inductive coupling – and, later, the use of crystals for receiving purposes. Braun also developed the first cathode ray tube in 1897 – a key element in the creation of television.
0 komentar:
Posting Komentar