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Monday, 19 June 2017

Radio broadcasting

The word 'broadcasting', referring to radio transmissions, was originally an agricultural term for the wide scattering of seeds.

In 1906 American inventor Lee de Forest invented the three-element "Audion" (triode) vacuum tube, the first practical amplification device. The tube represented the foundation of the field of electronics, making possible radio broadcasting.

The first public radio broadcast took place on January 13, 1910 when De Forest transmitted the voices of Metropolitan Opera stars to several receivers in New York City.

Six weeks later, on February 24, 1910, the Manhattan Opera Company's Mme. Mariette Mazarin sang "La Habanera" from Carmen over a transmitter located in De Forest's laboratory.

February 24, 1910 radio broadcast by Mme. Mariette Mazarin of the Manhattan Opera Company

De Forest's test broadcasts showed that the idea was not yet technically feasible, and the inventor would not make any additional entertainment broadcasts until late 1916, when more capable vacuum-tube equipment became available.

Following the development of vacuum-tube transmitters that made audio transmissions possible, the first spoken-word election night broadcast was made on November 7, 1916 by the DeForest Radio Telephone and Telegraph Company's station, 2XG, located in the Highbridge section of New York City. The broadcast announced the results of the presidential election between President Woodrow Wilson, the Democratic candidate, and Supreme Court Justice Charles Evans Hughes, the Republican candidate.

Lee DeForest broadcasting Columbia phonograph records

During the 1910s, the only listeners to voice radio were a few engineers and hobbyists called hams. The equipment was cumbersome and required a fair amount of technical knowledge. After World War I, technological advances brought more appliances into the home and radio companies formed to build and sell ready-made machines.

Montreal, Quebec radio station XWA, Canada's first and oldest broadcasting station, began test transmissions in 1919. Their first documented entertainment broadcast was made on the evening of May 20, 1920 when a concert was performed for a Royal Society of Canada audience listening 110 miles (175 kilometres) away at the Château Laurier in the city of Ottawa.

At the time these broadcasts received little publicity beyond a few local newspaper reports, in contrast to a similar broadcast made on June 15, 1920 by the Marconi station at Chelmsford in Essex, England featuring the famous soprano Dame Nellie Melba, which garnered broad international attention.

In 1920, Westinghouse Corporation, one of USA's leading radio manufacturers, had an idea for selling more of their products: It would offer programming. They built the first radio station, KDKA in Pittsburgh, which started broadcasting on the evening of November 2, 1920, with a transmission of the returns of the Harding-Cox presidential election.

On January 2, 1921 KDKA aired the first religious service in the history of radio. It was undertaken by Westinghouse to test its ability to do a remote broadcast far from a radio studio. Pittsburgh's Calvary Episcopal Church was chosen because one of the Westinghouse engineers was a member of the choir and was able to make the arrangements. KDKA soon offered a regular Sunday evening service from Calvary Episcopal Church.

KDKA was a huge success, inspiring other companies to take up broadcasting. Within four years there were 600 commercial stations around the US.

Circa 1921 photograph of the 9th floor KDKA transmission room.

While serving in the United States Army Signal Corps during World War I, electrical engineer Edwin H Armstrong invented the superheterodyne circuit. This is a highly selective means of receiving, converting, and greatly amplifying a wide spectrum of very weak, high-frequency electromagnetic waves. It laid the foundation for the success of radio broadcasting.

In 1933, Armstrong brought about an even more revolutionary change in the broadcasting business when he secured the circuit patents that were the basis of the frequency modulation (FM) system. He gave the first public demonstration of FM broadcasting in the United States at Alpine, New Jersey in 1935.

Commercial FM broadcasting began in 1941 in the U.S. when Nashville station W47NV started operations. W47NV was the first commercial FM radio station to receive a license, some 20 years after its AM radio counterpart, KDKA in Pittsburgh.

W47NV operated with 20,000 watts on a frequency of 44,700 kilocycles.

The world's first all-sports radio station, American radio station WFAN, was launched in New York City in 1987 as the world's first all-sports radio station.

Norway was the first country in the world to start phasing out the FM radio signal in favour of Digital Audio Broadcasting (DAB). It started turning off FM radio on January 11, 2017 in the northernmost city of Bodø.


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