Shortwave,
as the name suggests, is operated in short wavelengths, usually in the range of
3-30 MHZ. These are typically short-range operated by the mechanism of
reflection and refraction. With the discovery of radio waves in the early 20th
century, three major bands were defined: longwave, mediumwave, and short wave.
The shortwaves have a wavelength lesser than 200 meters. Shortwave frequency
gained such importance because long-distance communication with Longwave
frequency could not be directly transmitted and needed vary large antennas, resulting
in expensive receiver equipment and high cost. This also resulted in high
maintenance costs for large wave radio frequency equipment.
The pioneers
to work on mass scale on short wave applications are the Marconi assisted by
Charles Franklin. In early 1920, they carried out large-scale transmission
study cases to see the effectiveness of shortwaves in radio communication. They
tested high-power transmission tests that involved a 97 meters distance
communication over a 3MHz channel over a radio station in Poldhu and Marconi’s
yatch, known as Elettra. With this successful experiment Marconi went into
contract with British GPO and developed many commercial shortwave telegraphy
circuits between British and other continents and countries like Australia,
United Kingdom, Canada, and India. Shortwave communication became so popular
that half of the longwave communications were taken over by shortwave
communication within the next 5 years.
Shortwave is
also used for international broadcasting by many governments. They mostly use
it to convey information to overseas people due to its wide-ranging flexibility
and ability to reach distant corners of the globe. It's often used to access
places where radio isn't accessible, particularly by smaller groups, including
alternative media.
Shortwave
broadcasts can produce sounds effects as they have bursts of distortion
sounding unclear at some aural frequencies, modifying natural sound harmonics
due to echoes and phase distortion. A Russian physicist Leon Theremin, also a
musician was the first person who used shortwave frequency in music equipment.
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