Radio, Background and Development

RADIO – A BREAKTHROUGH IN MASS COMMUNICATION  
People around the world were benefiting from the newspapers as one fine mean of mass communication since the middle of 15th century that in the last decade of the 19th century scientists came close to opening gates for an entirely different means of communication which would require no paper and printing press and transportation of the publication. It was a mean to carry your voice to million others in a flash of an eye. It was the invention of radio.  
It was a miracle in the field of mass communication that a person could address a very number of audiences and that too, to a distance of thousands of kilometers away.  
What is radio? Radio is a technology that allows the transmission of signals by modulation of electromagnetic waves with frequencies below those of light.   
Science of Radio waves Radio waves are a form of electromagnetic radiation, and are created whenever a charged object accelerates with a frequency that lies in the radio frequency (RF) portion of the electromagnetic spectrum. This is the range from a few tens of hertz to a few giga hertz. Electromagnetic radiation travels by means of oscillating electric and magnetic fields that pass through the air and the vacuum of space equally well, and does not require a medium of transport.   
By contrast, other types of electromagnetic radiation, with frequencies above the RF range are gamma rays, X-rays, and infrared, ultraviolet and visible light.   
How the miracle came about? The theoretical basis of the propagation of electromagnetic waves was first described in 1873 by James Clerk Maxwell in his paper to the Royal Society A dynamical theory of the electromagnetic field, which followed his work between 1861 and 1865.   
In 1878 David E. Hughes was the first to transmit and receive radio waves when he noticed that his induction balance caused noise in the receiver of his homemade telephone. He demonstrated his discovery to the Royal Society in 1880 but was told it was merely induction.   
It was Heinrich Rudolf Hertz who, between 1886 and 1888, first validated Maxwell's theory through experiment, demonstrating that radio radiation had all the properties of waves. A great achievement indeed it proved to be.   
Marconi recognized as radio inventor In 1896 Guglielmo Marconi was awarded what is sometimes recognized as the world's first patent for radio with British Patent 12039, Improvements in transmitting electrical impulses and signals and in apparatus therefor. In 1897 he established the world's first Radio Station on the Isle of Wight, England. The same year in the USA, some key developments in radio's early history were created and patented by Nikola Tesla. The US Patent Office reversed its decision in 1904, awarding Guglielmo Marconi a patent for the invention of radio, possibly influenced by Marconi's financial backers in the States, who included Thomas Edison and Andrew Carnegie. Some believe this was done to allow the US Government to avoid having to pay the royalties that were being claimed by Nikola Tesla for use of his patents.   
In 1909 Marconi, with Karl Ferdinand Braun, was also awarded the Nobel Prize in Physics for "contributions to the development of wireless telegraphy". Marconi opened the world's first "wireless" factory in Hall Street, Chelmsford, England in 1898, employing around 50 people. Around 1900, Tesla opened the Wardenclyffe Tower facility and advertised services. By 1903, the tower structure neared completion. Various theories exist on how Tesla intended to achieve the goals of this wireless system (reportedly, a 200 kW system). Tesla claimed that Wardenclyffe, as part of a World System of transmitters,

would have allowed secure multichannel transceiving of information, universal navigation, time synchronization, and a global location system.   
Others work acknowledgement  In 1894 British physicist Sir Oliver Lodge demonstrated the possibility of signaling using radio waves using a detecting device called a coherer, a tube filled with iron filings which had been invented by Temistocle Calzecchi-Onesti at Fermo in Italy in 1884. Edouard Branly of France and Alexander Popov of Russia later produced improved versions of the coherer. Popov, who developed a practical communication system based on the coherer, is often considered by his own countrymen to have been the inventor of radio.   
On Christmas Eve, 1906, Reginald Fessenden (using his heterodyne principle) transmitted the first radio audio broadcast in history from Brant Rock, Massachusetts. Ships at sea heard a broadcast that included Fessenden playing the song O Holy Night on the violin and reading a passage from the Bible. The world's first radio news programme was broadcast August 31st 1920 by station 8MK in Detroit, Michigan. The world's first regular wireless broadcasts for entertainment commenced in 1922 from the Marconi Research Centre at Writtle near Chelmsford, England, which was also the location of the world's first "wireless" factory.   
Early radios ran the entire power of the transmitter through a carbon microphone. While some early radios used some type of amplification through electric current or battery, through the mid 1920s the most common type of receiver was the Crystal set. In the 1920s, amplifying vacuum tubes revolutionized both radio receivers and radio transmitters.   

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