Radio

The lightning-recording antenna was invented by Aleksandr Popov in 1895. The first experimental transmission of wireless signals were carried out by Guglielmo Marconi in the same year. A patent of wireless communication was filed by Marconi in 1896. In 1899, a 42 km link was laid between two cruisers containing Ducretet-Popov devices in France. In the same year, a wireless transmission was laid through the English Channel from Wimereux to Dover by Marconi. In 1901, Marconi demonstrated the first transatlantic wireless transmission between Poldhu and St. John's by using Morse code. In 1903, Valdemar Poulsen began arc transmission to create high-frequency alternators to send radio waves. The New York Times and the London Times knew about the Russo-Japanese war due to radio in 1903. In the next year, a commercial maritime radio network was established under the control of the Ministry of Posts and Telegraphs in France. Then, John Fleming invented the thermionic two-electrode valve so that sound transmission was feasible. In 1905, lead sulphide could be used to detect radio-electric signals. In 1906, Reginald Fessenden designed a high-frequency alternator and transmitted human voice over the radio. In 1906, Lee de Forest made the detection, transmission and amplification of sound possible. In 1910, a broadcast from the Metropolitan Opera House in New York city could be heard on a ship that was 20 km away. 1911 to 1930 was the period of the growth of the radio. The Radio Corporation of America was founded. This was done by combining General Electic, Western Electric, AT&T and Westinghouse. It was in this era that radio broadcasting began in Australia. Battery-powered receivers having headphones and valves were seen in France. A radio telephone concert was broadcast across the Atlantic Ocean to several receivers. In this era, radio broadcasting started in Shanghai and Cuba. The first regular broadcasts took place in Belgium, Norway, Germany, Finland and Switzerland. Soon radio became prevalent throughout the globe.