The transmission of signals by modulation of electromagnetic waves with
frequencies below those of visible light. Electromagnetic radiation travels by
ectromagnetic fields that pass though the air and the vacuum of space.
Originally, radio or radiotelegraphy was called “wireless telegraphy”, which
was shortened to “ wireless” by the British. This word also appears in a 1907
article by Lee De Forest, was adopted by the united states navy in in 1912
and became common by the time of the first commercial broadcasts in the
United States in the 1920s.
In recent years the term "wireless" has gained renewed popularity through
the rapid growth of short-range computer networking. Radio systems used
for communications will have the following elements. With more than 100
years of development, each process is implemented by a wide range of
methods, specialized for different communications purposes.
This consists of a source of electrical energy, producing alternating current of
a desired frequency of oscillation. This consists of a source of electrical
energy, producing modulate some property of the energy produced to
impress a signal on it.
The radio was invent by Edouard Branly in 1897.
To pass message to other
https://en.wikipedia.org/wiki/Radio
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