Tuesday, June 16, 2009

The earliest radio



The earliest radio could not broadcast sound or verbal communication and was called the "wireless telegraph." The first display of wireless telegraphy took place in the lecture theater of the Oxford University Museum of Natural History on August 14, 1894, conceded out by Professor Oliver Lodge and Alexander Muirhead. During the display a radio signal was sent from the adjacent Clarendon laboratory building, and received by device in the lecture theater.

In 1895 Alexander Stepanovich Popov built his initial radio receiver, which enclosed a coherer. Further developed as a lightning detector, it was offered to the Russian Physical and Chemical Society on May 7, 1895. A representation of Popov's lightning detector was printed in the Journal of the Russian Physical and Chemical Society the same year. Popov's receiver was shaped on the improved basis of Lodge's receiver, and in the beginning proposed for reproduction of its experiments.

Sony Company was the first to introduce transistorized radio in the year 1960. It was small in size that can fit in a vest pocket, and able to be powered by a small battery. It was tough, for the reason that it had no vacuum tubes to burn out. Digital transmissions was started and to be applied to broadcasting only in the late 1990s.