Radio is indebted to two other discoveries for its birth- telephone and telegraph. These three technologies are very closely related. Radio started as wireless telegraphy. And it all began with invention of radio waves, which have capacity to send out speech, music, picture and all other data through air. A range of devices like radio, cordless phones, microwave TV broadcasts work with the help of electromagnetic waves.
During 1860s, James Maxwell, a Scottish physicist forecasted presence of radio waves. And in year 1886, Heinrich Hertz showcased projection of swift variation of the electric current into space in form of radio waves.
Twenty years after invention of telephone, music was set down on telephone line and Guglielmo Marconi was responsible for the radio signals. This Italian discoverer demonstrated radio communication’s feasibility. Fascinated by Hertz’s discovery of the radio waves, he 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 in 1896. Marconi then recognized its high potential and offered the discovery to Italian Government that had turned it down. He then realized a patent and experimented further after moving to England. In 1898, he flashed the results of Kingstown Regatta to Dublin Newspaper’s office, making first ever public broadcast of sports event. 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. And Marconi shared Nobel Prize in Physics for wireless telegraph in year 1909.
But his wireless telegraph only transmitted signals. Voice in radio came in the 1921. Soon after, in 1922, he introduced short wave transmissions. Marconi however was not the first one to invent radio. Nikola Tesla who moved to US in 1884, launched radio’s theoretical model prior to Marconi. In 1915, Tesla tried to acquire court’s injunction against Marconi. And in year 1943, Supreme Court US reviewed decision. And due to this Tesla was acknowledged as inventor of radio even when he did ever build working radio.
J.C. Bose was another claimant to throne of radio inventors. He showcased radio transmission to British Governor General in 1896 at Calcutta. The transmission was for a distance of around 3 miles. His instruments, Mercury Coherer attached to telephone detector, are still showcased Calcutta University’s Science College.
Bose had taken care of Hertz’s problem of not being able to penetrate through water, mountains or walls. Marconi’s Coherer is known to be exact copy of Bose’s Coherer. Initially, Bose was reluctant in applying for patent because he believed in free flow of inventions in the field of science. But eventually due to persuasion by his American friends he had applied for patent in 1901. US patent was awarded to him in year 1904.
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. Range of ocean liners installed the wireless equipments and in 1899, US Army established the wireless communication. Just after two years, Navy adopted wireless system and it was relief as Navy had been using homing pigeons and visual signaling for communication.
Radiotelegraph services were instituted in Hawaiian Islands in 1901. Marconi station situated in Massachusetts carried greetings between King Edward VII and Theodore Roosevelt. 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. Overseas radiotelegraph services were slowly developed, basically because early transmitter discharged the electricity between electrodes and within circuit causing high interference. DeForest and Alexanderson alternator took care of many such technical issues.
Lee Deforest was inventor of space telegraphy, Audion and triode amplifier. 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.
Since that time, there has been no looking back. Radio has now become a popular medium of portable entertainment. 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. Radio lovers have a reason to rejoice as there is a lot in store for them.