Editing Shortwave radio (section)

===Development===
[[File:Guglielmo Marconi 1901 wireless signal.jpg|thumb|right|Radio amateurs carried out the first shortwave transmissions over a long distance before those of [[Guglielmo Marconi]].]]
The name "shortwave" originated during the beginning of radio in the early 20th century, when the [[radio spectrum]] was divided into [[long wave]] (LW), [[medium wave]] (MW), and short wave (SW) bands based on the length of the wave. Shortwave radio received its name because the wavelengths in this band are shorter than 200&nbsp;m (1,500&nbsp;kHz) which marked the original upper limit of the [[medium frequency]] band [[History of radio|first used]] for radio communications. The broadcast medium wave band now extends above the 200&nbsp;m / 1,500&nbsp;kHz limit.

Early long-distance [[radio telegraphy]] used long waves, below 300&nbsp;[[kilohertz]] (kHz) / above 1000 m. The drawbacks to this system included a very limited spectrum available for long-distance communication, and the very expensive [[transmitter]]s, receivers and gigantic antennas. Long waves are also difficult to beam directionally, resulting in a major loss of power over long distances. Prior to the 1920s, the shortwave frequencies above 1.5&nbsp;MHz were regarded as useless for long-distance communication and were designated in many countries for amateur use.<ref name=Nebeker2009/>

[[Guglielmo Marconi]], pioneer of radio, commissioned his assistant [[Charles Samuel Franklin]] to carry out a large-scale study into the transmission characteristics of short-wavelength waves and to determine their suitability for long-distance transmissions. Franklin rigged up a large antenna at [[Poldhu|Poldhu Wireless Station]], [[Cornwall]], running on 25&nbsp;kW of power. In June and July&nbsp;1923, wireless transmissions were completed during nights on 97&nbsp;meters (about 3&nbsp;MHz) from Poldhu to Marconi's yacht ''Elettra'' in the [[Cape Verde|Cape Verde Islands]].<ref name=Bray2002/>

In September 1924, Marconi arranged for transmissions to be made day and night on 32 meters (about 9.4 MHz) from Poldhu to his yacht in the harbour at [[Beirut]], to which he had sailed, and was "astonished" to find he could receive signals "throughout the day".<ref>{{cite book |last=Marconi |first=Degna |title=My Father, Marconi |url=https://books.google.com/books?id=vtYy9TLrbA0C&pg=PA207 |publisher=Edizione Frassinelli |location=Toronto / New York |date=1996 |orig-year=1962 |page=207 |isbn=1-55071-044-3}}</ref> Franklin went on to refine the directional transmission by inventing the [[curtain array]] aerial system.<ref name=Beauchamp2001/><ref name=Franklin_1986/> In July 1924, Marconi entered into contracts with the British [[General Post Office]] (GPO) to install high-speed shortwave telegraphy circuits from London to Australia, India, South Africa and Canada as the main element of the [[Imperial Wireless Chain]]. The UK-to-Canada shortwave "Beam Wireless Service" went into commercial operation on 25&nbsp;October 1926. Beam Wireless Services from the UK to Australia, South Africa and India went into service in 1927.<ref name=Bray2002/>

Shortwave communications began to grow rapidly in the 1920s.<ref name=BeyondIonosph/> By 1928, more than half of long-distance communications had moved from [[Submarine communications cable|transoceanic cables]] and longwave wireless services to shortwave, and the overall volume of transoceanic shortwave communications had vastly increased. Shortwave stations had cost and efficiency advantages over massive longwave wireless installations.<ref name=Hugill_1999/> However, some commercial longwave communications stations remained in use until the 1960s. Long-distance radio circuits also reduced the need for new cables, although the cables maintained their advantages of high security and a much more reliable and better-quality signal than shortwave.

The cable companies began to lose large sums of money in 1927. A serious financial crisis threatened viability of cable companies that were vital to strategic British interests. The British government convened the Imperial Wireless and Cable Conference<ref name=PorthCurnoPLC/> in 1928 "to examine the situation that had arisen as a result of the competition of Beam Wireless with the Cable Services". It recommended and received government approval for all overseas cable and wireless resources of the Empire to be merged into one system controlled by a newly formed company in 1929, Imperial and International Communications Ltd. The name of the company was changed to [[Cable & Wireless plc|Cable and Wireless Ltd.]] in 1934.

A resurgence of long-distance cables began in 1956 with the laying of [[TAT-1]] across the Atlantic Ocean, the first voice frequency cable on this route. This provided 36 high-quality telephone channels and was soon followed by even higher-capacity cables all around the world. Competition from these cables soon ended the economic viability of shortwave radio for commercial communication.