History of the 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

Who invented the radio?

The credit of inventing the radio goes to a number of researchers. The names of Guglielmo Marconi, Nikola Tesla, Alexander Popov, Sir Oliver Lodge, Reginald Fessenden, Heinrich Hertz, Amos Dolbear, Mahlon Loomis, Nathan Stubblefield and James Clerk Maxwell can be included. But in general Guglielmo Marconi is known as “Father of Radio”


History of the radio in India

In British India broadcasting started in June 1923 with programmes by the Radio Club of Bombay, followed by other radio clubs. Then, by an agreement of 1926 the private Indian Broadcasting Company (IBC) was granted permission to operate two radio stations; the Bombay station was inaugurated on July 23, 1927, the Calcutta station followed on August 26, 1927. But already on March 1, 1930 the Company went into liquidation. Thus the Government took over the broadcasting facilities, starting the Indian State Broadcasting Service (ISBS) on April 1, 1930 (on experimental basis for two years, but continued in May 1932). On June 8, 1936 the ISBS was renamed All India Radio (AIR; also known as Akashvani since 1956). On October 1, 1939 the External Service started (with a broadcast in Pushtu); it was designated to counter radio propaganda from Germany, directed to Afghanistan, Iran and Arab countries. When India became independent in 1947, the AIR network had only six stations: Delhi, Bombay, Calcutta, Madras, Lucknow, and Tiruchi; the total number of radio sets at that time was about 275,000. On October 3, 1957 the Vividh Bharati Service was launched to comptete with Radio Ceylon. Television broadcasting began in Delhi in 1959 as part of AIR, but was separated from radio as Doordarshan on April 1, 1976. FM broadcasting commenced on July 23, 1977 in Madras and was expanded in the 1990s.

In radio transmission, what does FM stands for ?

Freequency Modulator

In radio transmission, what does AM stands for ?

Amplitude Modulation

What is the FM and AM radio frequency range?

The FM range is 88 - 108 MHz (with broadcast frequencies, or stations, assigned between 88.1 and 107.9 MHz every 0.2 MHz). The AM range is 535 - 1605 KHz (stations are assigned between 540 and 1600 KHz every 10 KHz).