“Wireless Telegraphy”
The
discovery of radio has been a great part almost to all of the development of
high-tech gadgets. It literally means wireless telegraphy, a wireless
transmission of data through radio waves or electromagnetic waves. With the
help of antenna, usually placed on a high place, which converts the electric
currents into radio waves or radio waves into electric current and transmitter
which creates the signal through changing its energy property, receiver, and all
the other parts of a radio, wireless communication was made possible.
After more than a hundred
years of existence, radio is still an important innovation, only that it is
further developed into more modern versions. The early uses of radio were
mainly for sending telegraphic messages using Morse code
between ships and land, and for passing on military orders. The Japanese Navy
was one of the early users of this technology. On 1909, broadcasting began in
San Jose, California and became practicable in the 1920s predominantly in the
western countries with the extensive introduction of radio. Before the
television was invented, commercial radio broadcasts included news, music as
well as dramas, variety shows and other forms of entertainment.
Today, radio has diverse versions
already including RADAR (Radio Detection And Raging), wireless networks and
mobile communications. It is useful to electronic devices such as computer and
its parts and mobile phones. It made the amplification of weak signals in
electronic communication achievable.
The
development of radio and radio wave-based systems are
attributed to many "inventors" from different parts of the globe. Before
the radio was invented, it requires the invention, discoveries, and principles
of many scientists. The concept of radio started with the concept of
propagation of electromagnetic waves or radio waves on 1873 by James Clerk
Maxwell. It was then followed by the discovery that sparks could be heard in a
telephone receiver when David Hughes was experimenting with his carbon microphone.
He further developed his carbon-based detector and eventually ended up
inventing a device that could detect signals over a few hundred yards. Though
when he demonstrated his discovery to the Royal Society in 1880, they concluded
that it was only induction and so he abandoned the study underdeveloped.
In 1884, Temistocle Calzecchi-Onesti conducted experiments with tubes
containing powder of nickel silver with traces of mercury metal fillings and
their reactions when conducting electricity which lead to the development of
iron fillings filled with coherer, a radio detective device invented by Edouard
Branly in 1890. In 1885, Thomas Edison did some experiments on electrostatic coupling
system between elevated terminals.
From 1886-1888 Heinrich Rudolf Hertz conducted his own experiment on
transmission of radio waves through space. He was able to transmit radio waves
through air confirming Maxwell’s electromagnetic theory and publish the results
of his experiment afterwards and soon the scientist referred to radio waves as ‘Hertzian
waves’. After the discovery of Heinrich Rudolf Hertz, physicists such as John Perry,
Frederick Thomas Trouton and William Crookes suggested that radio waves or Hertzian
waves can be use to communicate wirelessly between 1890-1892.
In 1893, Nikola Tesla proposed at St. Louis, Missouri and at the Franklin Institute in Philadelphia that radio transmission is a possible means of telecommunication. His
study is based on the researches of Hertz and Maxwell. In 1895, Alexander
Stephanovich Popov also conducted some experiments regarding Hertz’s research
and built his first radio receiver with its coherer in it, which is further
refined as a lightning detector.
In
1894, Guglielmo Marconi, an Italian inventor, began working on the concept of
commercial wireless telegraphy system based on Hertz’s research. He built a
radio wave system capable of transmitting signals at long distances (2.4 km) in
1985 and found out that transmission range is proportional to the square of
antenna height currently known as Marconi’s Law. He established a radio station
on the Isle of Wight, England in 1987. In 1898 Marconi opened his
"wireless" factory in the former silk-works at Hall Street, England
with around 60 employees. Marconi held
the patent rights for radio shortly after 1900s. Soon, Marconi became more
successful than any other inventor and his business turned into a global
business.
* radio receiver receives its input from an antenna, uses electronic filters to separate a wanted radio signal from all other signals picked up
by this antenna, amplifies it to a level suitable for
further processing, and finally converts through demodulation and decoding the signal
into a form usable for the consumer, such as sound, pictures, digital data,
measurement values, navigational positions, etc
Sources:
Mary Catherine Sy
2013-09736
No comments:
Post a Comment