Friday, November 28, 2014

RADIO

When we talk about mass communication, one of the device came in our mind is the Radio. Actually Radio was the first device which made mass communication possible. Information can be transferred miles of distance though Radio very easily. Here we will see how Radio was invented.
In 1885, Heinrich Hertz was the first to prove that electric waves could be transmitted and received wirelessly in the form of electromagnetic waves. Today it is recognized as the fundamental building block of radio and every frequency measurement is named after him(Hertz).

In 1891, the radios were used mainly for maintaining contact between ships out a sea. However, contact was not in the form of speech, but  Morse code messages were sent back and forth between ships and stations on the land. During time of distress, a sinking ship would use a radio messaged nearby vessels and stations on the land to ask for help. The radio proved to be very useful during the First World War. Both sides used the radio to relay messages to troops and top officials as well as to people not on the battle front.

In 1893, Nikolai Tesla made first public demonstration of radio by transmitting electromagnetic waves in St. Louis, Missouri.

In 1896, Guglielmo Marconi realized that it could be used for receiving and sending the telegraph messages, referring to it as wireless telegraphs. His earliest radio transmissions, the coded signals transmitted to only a mile far.  Then he filed for patent protection of his radio apparatus and moved to England for further experiments.


In 1899, the R.F. Matthews was the first ship to request emergency assistance using a wireless apparatus (Marconi’s system). The following year, he opened his radio factory in Essex, thus establishing link between France and Britain. He then established link with USA in year 1901.
In 1901, First trans-Atlantic signal sent-by Marconi from Ireland to Canada.

There has been tremendous growth of the radio over the years. Transmitters earlier were known as spark gap machines. It was established for ship-to-ship and ship-to-shore communication. The communication was just confined to two points then and was not public broadcasting as it is today. Wireless signals demonstrated effective communication for the purpose of rescue in case of sea disasters.


 In year 1905, Port Arthur’s naval battle was also reported over wireless and US weather department tried radiotelegraphy for speeding notice weather condition.Eventually radio transmitters were improved.

He shared Nobel Prize in Physics for wireless telegraph in year 1909.But his wireless telegraph only transmitted signals.

It was Reginald Fessenden who developed a way to combine sound and radio carrier waves. His first effort to transmit this mixed signal to a receiver removing  the carrier wave so that  the listener could hear the original sound got failed. However, in 1906, using Alexanderson’s Alternator, Fessenden made the first long range transmission of voice.
Lee DeForest is credited with the “father of American radio.” DeForest was a direct competitor to Marconi at the turn of the century (1899), when he was the chief scientist at the U.S.’s first radio firm ‘American Wireless Telephone
and Telegraph’.
 In 1906, Lee DeForest produces the “Audion,” a triode vacuum tube that allowed for amplification of radio signals.
Lee Deforest was inventor of space telegraphy. In early 1990s, delicate and effective detector of the electromagnetic radiation was needed for developing the radio further. And Lee Deforest discovered the detector. He was the first person to use term ‘radio’.


His work resulted in discovery of AM radio that capably broadcasted various radio stations which early gap transmitters did not allow.
Radio has now become a popular medium of portable entertainment.
Europe’s most famous broadcasting station, the British Broadcasting Company or BBC, began following in 1922. In fact, Marconi was one of the founding members along with other prominent leaders in the field of wireless manufacturers. Broadcasts began locally in London, but by 1925 it has spread to most of the United Kingdom. The station aired plays, classical music and variety programs. In 1927 the BBC became the British Broadcasting Corporation when it was granted it a Royal Charter. When the Second World War began all the television stations shut down and it fell on the shoulders of the radio to cover the war.


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Edwin Armstrong—this WWI Army officer, Columbia University engineering professor, and creator of FM radio
invented the regenerative circuit, the first amplifying receiver and reliable continuous-wave transmitter; and the
superheterodyne circuit, a means of receiving, converting and amplifying weak, high-frequency electromagnetic
waves.
In 21stcentury, technological advancements have given birth to internet radio. Satellite radio is also recent development in the field. One can listen to various international radio stations without any hassles. Besides all these latest editions, Ham radio would be next big thing. This technology is gearing up to hit the market soon.




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