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Shortwave can also refer to a shortwave trough in meteorology. A shortwave or shortwave trough is an embedded kink in the Trough / Ridge pattern
A solid-state, analog shortwave receiver
A solid-state, analog shortwave receiver

Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than the long wave lengths widely in use at that time. Radio is the transmission of signals by Modulation of electromagnetic waves with frequencies below those of visible Light. Frequency is a measure of the number of occurrences of a repeating event per unit Time. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. In Physics wavelength is the distance between repeating units of a propagating Wave of a given Frequency. The longwave Radio band is a range of frequencies used for AM broadcasting, which extends from 148 An alternate name is HF or high frequency radio. High frequency (HF radio frequencies are between 3 and 30 MHz. High frequency (HF radio frequencies are between 3 and 30 MHz. Short wavelengths are associated with high frequencies because there is an inverse relationship between frequency and wavelength. An inverse or negative relationship is a Mathematical relationship in which one Variable decreases as another increases

Contents

Overview

Radio amateurs discover long distance shortwave propagation

Amateur radio operators are usually credited with the discovery of long distance communication in the shortwave bands. Amateur radio, often called ham radio, is both a Hobby and a service in which participants called "hams" use various types of Radio communications Shortwave bands are frequency allocations for use within the High frequency radio spectrum The first successful transatlantic tests were conducted by radio amateurs in December 1921 operating in the 200 meter mediumwave band, the shortest wavelength then available to amateurs. Medium Wave (MW is a part of the Medium frequency (MF radio band used mainly for AM broadcasting. In 1922 hundreds of North American amateurs were heard in Europe at 200 meters and at least 20 North American amateurs heard amateur signals from Europe. The first two way communications between North American and Hawaiian amateurs began in 1922 at 200 meters. Although operation on wavelengths shorter than 200 meters was technically illegal (but tolerated as the authorities mistakenly believed at first that such frequencies were useless for commercial or military use), amateurs began to experiment with those wavelengths using newly available vacuum tubes shortly after World War I.

Extreme interference at the upper edge of the 150-200 meter band--the official wavelengths allocated to amateurs by the Second National Radio Conference in 1923--forced amateurs to shift to shorter and shorter wavelengths; however, amateurs were limited by regulation to wavelengths longer than 150 meters. See also Amateur radio An amateur radio operator is an individual who typically uses equipment at an Amateur radio station to engage in two-way A few fortunate amateurs who obtained special permission for experimental communications below 150 meters completed hundreds of long distance two way contacts on 100 meters in 1923 including the first transatlantic two way contacts in November 1923, on 110 meters.

By 1924 many additional specially licensed amateurs were routinely making transoceanic contacts at distances of 6000 miles and more. On September 21, several amateurs in California completed two way contacts with an amateur in New Zealand. On October 19th, amateurs in New Zealand and England completed a 90 minute two way contact nearly half way around the world. On October 10th, three shortwave bands were officially made available to amateurs by the Third National Radio Conference, at 80, 40 and 20 meters. Shortwave bands are frequency allocations for use within the High frequency radio spectrum The 10 meter band was created by the Washington International Radiotelegraph Conference on November 25, 1927. The 15 meter band was opened to amateurs in the United States on May 1, 1952.

Marconi takes the world by surprise

In June and July 1923, Guglielmo Marconi quietly completed successful night time transmissions on 97 meters from Poldhu Wireless Station, Cornwall to his yacht Elettra in the Cape Verde Islands. Marchese Guglielmo Marconi mar'koni (25 April 1874 – 20 July 1937 was an Italian inventor best known for his development of a Radiotelegraph system Poldhu is a small area in south Cornwall, England, UK, situated on the Lizard Peninsula it comprises Poldhu Point and Poldhu Cove Cornwall ( Kernow ˈkɛɹnɔʊ is the most southwesterly county of England, on the Peninsula that lies to the west of the River Tamar The Republic of Cape Verde ( Portuguese: Cabo Verde, 'kabu 'veɾdɨ is a Republic located on an Archipelago in the Macaronesia In September 1924, Marconi completed successful daytime and nighttime transmissions on 32 meters from Poldhu to his yacht in Beirut. Marconi took the world by surprise in July 1924 when he 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. The UK-to-Canada shortwave "Beam Wireless Service" went into commercial operation on 25 October, 1926. Beam Wireless Services from the UK to Australia, South Africa and India went into service in 1927.

Shortwave soon became an extremely disruptive technology. Far more spectrum is available for long distance communication in the shortwave bands than in the longwave bands; and shortwave transmitters, receivers and antennas were orders of magnitude less expensive than the multi-hundred kilowatt transmitters and monstrous antennas needed for longwave.

Shortwave communications began to grow exponentially in 1927, similar to the internet in the late 20th century. By 1928, more than half of long distance communications had transitioned from transoceanic cables and longwave wireless services to shortwave and the overall volume of transoceanic shortwave communications had vastly increased. Shortwave also ended the need for multi-million dollar investments in new transoceanic telegraph cables and massive longwave wireless stations, although some existing transoceanic telegraph cables and commercial longwave communications stations remained in use until the 1960s.

The cable companies began to lose large sums of money in 1927, and a serious financial crisis threatened the viability of cable companies that were vital to strategic British interests. The British government convened the Imperial Wireless and Cable Conference [2] 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 and Wireless Ltd. in 1934. Cable & Wireless ( is a British Telecommunications company In the mid-1980s it became the first company in the UK to offer an alternative Telephone

Shortwave propagation

Shortwave frequencies are capable of reaching any location on the Earth because they can be refracted by the ionosphere (a phenomenon known as Skywave propagation). The ionosphere is the uppermost part of the atmosphere, distinguished because it is Ionized by solar radiation Skywave is the propagation of electromagnetic waves bent (refracted back to the Earth's surface by the Ionosphere. The selection of a frequency to use to reach a target area depends on several factors:

Types of Modulation

Further information: Modulation

Independent from frequency, the receiver must also be capable of receiving the modulation type being transmitted. In Telecommunications, modulation is the process of varying a periodic Waveform, i AM, Singlesideband and CW are common modulations. Types of modulation frequently used in the shortwave frequency range are:

Users

Some major users of the shortwave radio band include:

The term DXing, in the context of listening to radio signals of any user of the shortwave band, is the activity of monitoring distant stations. DXing is the hobby of tuning in and identifying distant Radio or Television signals or making two way radio contact with distant stations in Amateur radio In the context of amateur radio operators, the term 'DXing' refers to the two-way communications with a distant station, using shortwave radio frequencies.

The Asia-Pacific Telecommunity estimates that there are approximately 600,000,000 shortwave broadcast radio receivers in use in 2002. See also 2002 (disambiguation Year 2002 ( MMII) was a Common year starting on Tuesday of the Gregorian calendar. WWCR claims that there are 1. WWCR is a Shortwave Radio station located in Nashville Tennessee in the United States. 5 billion shortwave receivers worldwide. [3]

Shortwave broadcasting frequency allocations

The World Radiocommunication Conference (WRC), organized under the auspices of the International Telecommunication Union, allocates bands for various services in conferences every few years. World Radiocommunication Conference (WRC is organized by ITU to review and if necessary revise the Radio Regulations, the international treaty governing the use The next WRC is scheduled to take place in 2007. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century.

At WRC-97 in 1997, the following bands were allocated for international broadcasting. International broadcasting is Broadcasting that is deliberately aimed at a foreign rather than a domestic audience (listed in the table):

Meter Band Frequency Range Remarks
120 m 2,300 - 2,495 kHz tropic band
90 m 3,200 - 3,400 kHz tropic band
75 m 3,900 - 4,000 kHz shared with the amateur radio 75/80 meter band
60 m 4,750 - 5,060 kHz tropic band
49 m 5,900 - 6,200 kHz  
40 m/41m 7,100 - 7,350 kHz shared with the amateur radio 40 meter band
31 m 9,400 - 9,900 kHz Currently most heavily used band
25 m 11,600 - 12,100 kHz  
22 m 13,570 - 13,870 kHz substantially used only in Eurasia
19 m 15,100 - 15,800 kHz  
16 m 17,480 - 17,900 kHz  
15 m 18,900 - 19,020 kHz almost unused, could become a DRM band
13 m 21,450 - 21,850 kHz  
11 m 25,600 - 26,100 kHz may be used for local DRM broadcasting


AM shortwave broadcasting channels are allocated with a 5 kHz separation for traditional analog audio broadcasting. Amateur radio, often called ham radio, is both a Hobby and a service in which participants called "hams" use various types of Radio communications Amateur radio, often called ham radio, is both a Hobby and a service in which participants called "hams" use various types of Radio communications

International broadcasters for practical reasons sometimes operate outside the normal WRC-allocated bands or use off-channel frequencies to attract attention in crowded bands (60m, 49m, 40m, 41m, 31m, 25m).

The new digital audio broadcasting format for shortwave DRM operates 10 kHz or 20 kHz channels. Digital Audio Broadcasting ( DAB) also known as Eureka 147, is a Digital radio technology for Broadcasting Radio stations used in Digital Radio Mondiale ( DRM) is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcasting, particularly

There are some ongoing discussions with respect to specific band allocation for DRM, as it mainly transmitted in 10 kHz format.

The power used by shortwave transmitters ranges from less than one watt for some experimental and amateur radio transmissions to 500 kilowatts and higher for intercontinental broadcasters and over-the-horizon radar. Over-the-horizon radar, or OTH (sometimes also beyond the horizon, or BTH) is a design concept for Radar systems to allow them to detect targets

Shortwave transmitting centers often use specialized antenna designs (like the ALLISS antenna technology) to concentrate radio energy at the target area. An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into Disambiguation Financial Instruments The Alliss Grant a US Financial Aid instrument see &.

Shortwave broadcasting

There are two aspects of shortwave broadcasting

Shortwave does possess a number of advantages over newer technologies, including the following:

These benefits are widely regarded as being outweighed by the drawbacks such as these:

Amateur radio

In the U. S. and Canada, no license is required to own or operate a shortwave receiver. The privilege of operating a shortwave radio transmitter for non-commercial two way communications known as amateur radio is granted through a licensing process by authorized government agencies. Amateur radio, often called ham radio, is both a Hobby and a service in which participants called "hams" use various types of Radio communications

In the USA, the licensing agency is the Federal Communications Commission (FCC). In Canada, the licensing agency is Industry Canada. Industry Canada is the department of the Government of Canada with responsibility for regional economic development investment and innovation/ Research and development As of February 2007, the FCC eliminated the Morse code requirement for all Amateur Radio operator classes, thereby allowing more operators to transmit in the HF bands. Morse code is a Character encoding for transmitting telegraphic information using standardized sequences of short and long elements to represent the letters numerals

Amateur radio operators have made many technical advancements in the field of radio and make themselves available to transmit emergency communications when normal communications channels fail. Some amateurs practice operating off the power grid so as to be prepared for power loss. It should be noted that many amateur radio operators started out as Shortwave Listeners (SWLs) and actively encourage SWLs to become amateur radio operators.

The 2003 World Radiocommunication Conference (WRC) removed the global requirement for Morse code proficiency needed to access most shortwave frequencies for the amateur radio service, but left the decision to each administrative body (e. World Radiocommunication Conference (WRC is organized by ITU to review and if necessary revise the Radio Regulations, the international treaty governing the use g. Federal Communications Commission in the United States; Industry Canada in Canada). Many countries have phased out this requirement from their licenses and give access to the shortwave frequencies to all licencees. A few countries however have decided to keep the Morse Code requirement for the foreseeable future. In July 2005, the Federal Communications Commission recommended the removal of the Morse code requirement for amateur radio licenses the United States, as part of a Notice of Proposed Rulemaking in WT Docket 05-235. A notice of proposed rulemaking or NPRM is issued by law when a regulatory agency of the United States Federal Government wishes to add remove [4] This docket was released after 18 proposals, including one from the ARRL for widespread changes in the Amateur Radio Service rules were received and considered by the FCC. The American Radio Relay League (ARRL is the largest membership association of Amateur radio enthusiasts in the USA. These proposals had attracted 6200 comments from the Amateur Radio Service community. The FCC released a Report and Order on December 19, 2006, eliminating the Morse code requirement for amateur radio licensing in the United States.

Shortwave listening

Further information: Shortwave listening

Many hobbyists listen to shortwave broadcasters without operating transmitters. Shortwave listening (abbreviated as SWLing) is the Hobby of tuning for Shortwave Radio broadcasts located on shortwave frequencies In some cases, the goal is to hear as many stations from as many countries as possible (DXing); others listen to specialized shortwave utility, or "ute", transmissions such as maritime, naval, aviation, or military signals. DXing is the hobby of tuning in and identifying distant Radio or Television signals or making two way radio contact with distant stations in Amateur radio Others focus on intelligence signals from numbers stations, or the two way communications by amateur radio operators. Numbers stations are Shortwave radio stations of uncertain origin

Many listeners tune the shortwave bands for the programmes of stations broadcasting to a general audience (such as Radio Canada International, Voice of America, BBC World Service, Radio Australia,Radio Netherlands, etc. Radio Canada International ( RCI) is the International broadcasting service of the Canadian Broadcasting Corporation (CBC Voice of America ( VOA) is the official external radio and Television broadcasting service of the United States federal government. ABC Radio Australia is the international broadcasting and online service operated by the Australian Broadcasting Corporation, Australia 's public broadcaster Radio Netherlands Worldwide ( RNW, short for Radio Nederland Wereldomroep in Dutch) is a public Radio and Television network based ). Today, through the evolution of the Internet, the hobbyist can listen to shortwave signals via remotely controlled shortwave receivers around the world, even without owning a shortwave radio. Many international broadcasters (such as Radio Canada International [2], the BBC and Radio Australia) offer live streaming audio on their websites.

Shortwave listeners, or SWLs, can obtain QSL cards from broadcasters, utility stations or amateur radio operators as trophies of the hobby. In Radiocommunication and radio Broadcasting, QSL is one of the Q codes used in radiocommunication Some stations even give out special certificates, pennants, stickers and other tokens and promotional materials to shortwave listeners.

Utility stations

Utility stations are stations that do not broadcast to the general public. There are shortwave bands allocated to the use of merchant shipping, marine weather, and ship-to-shore stations; for aviation weather and air-to-ground communications; for military communications; for long-distance governmental purposes, and for other non-broadcast communications. Many radio hobbyists specialize in listening to "ute" broadcasts, which often come from places without shortwave broadcasters.

Unusual signals

Numbers stations are shortwave radio stations of uncertain origin that broadcast streams of numbers, words, or phonetic sounds. Numbers stations are Shortwave radio stations of uncertain origin Although officially there is no indication of their origin, radio hobbyists have determined that many of them are used by intelligence services as one-way communication to agents in other countries. For other examples, see The Conet Project. The Conet Project Recordings of Shortwave Numbers Stations is a four- CD set of recordings of Numbers stations mysterious Shortwave radio stations

Shortwave's future

Further information: The future of shortwave listening

The development of direct broadcasts from satellites has reduced the demand for shortwave receivers, but there are still a great number of shortwave broadcasters. Shortwave listening (abbreviated as SWLing) is the Hobby of tuning for Shortwave Radio broadcasts located on shortwave frequencies A new digital radio technology, Digital Radio Mondiale, is expected to improve the quality of shortwave audio from very poor to standards comparable to the FM broadcast band. Digital radio describes Radio technologies which carry Information as a Digital signal, by means of a Digital modulation method Digital Radio Mondiale ( DRM) is a set of digital audio broadcasting technologies designed to work over the bands currently used for AM broadcasting, particularly The future of shortwave radio is threatened by the rise of power line communication (PLC), also known as Broadband over Power Lines (BPL), where a data stream is transmitted over unshielded power lines. Power line communication ( PLC) also known as power line carrier, mains communication, power line telecom ( PLT) or power line Power line communication ( PLC) also known as power line carrier, mains communication, power line telecom ( PLT) or power line As the frequencies used overlap with shortwave bands, severe distortions make listening to shortwave radio near power lines difficult or impossible. However, because it is a cheap and effective way to receive communications in countries with poor infrastructure, shortwave will be around for years to come.

Shortwave broadcasts and music

Some musicians have been attracted to the unique aural qualities of shortwave radio, employing shortwave radios as live instruments in a number of pieces, and or using sampled broadcasts, used tape loops of broadcasts, or drawn inspiration from the unusual sounds on some frequencies. A sampler is an electronic musical instrument closely related to a Synthesizer. Tape loops are loops of prerecorded Magnetic tape used to create repetitive rhythmic musical patterns or dense layers of sound

John Cage used radios live on several occasions, while Karlheinz Stockhausen used shortwave radio in works including Hymnen (1966–67), Kurzwellen (1968), Spiral (1968), and Michaelion (1997). WikipediaWikiProject Composers#Lead section --> John Milton Cage Jr Hymnen is a work by Karlheinz Stockhausen, composed in 1966–67 and elaborated in 1969 Licht (Light subtitled "The Seven Days of the Week" is a cycle of seven Operas composed by Karlheinz Stockhausen which in total lasts over Holger Czukay, a student of Stockhausen, was one of the first to use shortwave in a rock music context. Holger Czukay (born 24 March 1938) is a German musician probably best known as a co-founder of the Krautrock group Can. Rock music is a genre of Popular music often though not necessarily employing Electric guitar, Bass guitar, and Drums. In 1975, German electronic music band Kraftwerk recorded a full length concept album around simulated radiowave and shortwave sounds, entitled Radio-Activity. Electronic music is music that employs Electronic musical instruments and Electronic Music technology in its production Kraftwerk (ˈkʁaftvɛɐk German for " power plant " or " Power station " is an influential Electronic music band from In Popular music, a concept album is an Album which is "unified by a theme which can be instrumental compositional narrative or lyrical" For other uses of "Radio activity" and "radioactivity" see Radioactive (disambiguation.

Among others, Tom Robinson, Peter Gabriel, Pukka Orchestra, AMM, John Duncan, Orchestral Manoeuvres in the Dark (on their Dazzle Ships album), Pat Metheny, Aphex Twin, Boards of Canada, Rush, Able Tasmans, Team Sleep, Meat Beat Manifesto, Tim Hecker, Jonny Greenwood of Radiohead, and Wilco have also used or been inspired by shortwave broadcasts. Tom Robinson (born June 1, 1950, in Cambridge) is an English singer/ Songwriter and broadcaster probably best-known Peter Brian Gabriel (born 13 February 1950 in Chobham, Surrey, England) is an English Musician and Songwriter. The Pukka Orchestra was a Canadian New Wave band in the 1980s AMM are an important British Free improvisation group founded in London, England in 1965 John Duncan may refer to John Duncan aka John Dongan (fl c 1410 Manx religious leader John Duncan (theologian (1796-1870 Orchestral Manoeuvres in the Dark (often abbreviated to OMD) are a Synthpop group whose founding members are originally from the Wirral Peninsula Dazzle Ships is the fourth Album by Orchestral Manoeuvres in the Dark, released in 1983 Patrick Bruce Metheny (born August 12, 1954 in Lee's Summit Missouri) is an American Jazz Guitarist and Composer Boards of Canada (BoC are a Scottish Electronic music duo consisting of brothers Michael Sandison (born June 1, 1970) and Marcus Eoin Sandison Rush is a Canadian rock band originally formed in August 1968 in the Willowdale neighbourhood of Toronto, Ontario, currently comprised of The Able Tasmans were an indie band from Auckland, New Zealand. Team Sleep is an American experimental Alternative rock group led by singer/guitarist Chino Moreno, better known for fronting the Sacramento-based Meat Beat Manifesto, often shortened to Meat Beat or MBM, is an Electronic music outfit originally consisting of Jack Dangers and Jonny Tim Hecker is an electronic musician and sound artist based in Montreal, Canada. Jonathan Richard Guy Greenwood (born 5 November 1971) is a BAFTA and Grammy -nominated musician and composer-in-residence for the BBC best Radiohead Wilco is an American rock band based in Chicago, Illinois. The band was formed in 1994 by the remaining members of Alternative country group

See also

Related topics

Related organizations or broacasters

References

  1. ^ Tomislav Stimac, "Definition of frequency bands (VLF, ELF... etc.)". Disambiguation Financial Instruments The Alliss Grant a US Financial Aid instrument see &. Amateur radio, often called ham radio, is both a Hobby and a service in which participants called "hams" use various types of Radio communications HRS type antennas are more or less the standard antenna used for long distance high power Shortwave broadcasting (> 1000 km International broadcasting is Broadcasting that is deliberately aimed at a foreign rather than a domestic audience Shortwave bands are frequency allocations for use within the High frequency radio spectrum A shortwave relay station typically consists of a transmitter building (or transmitter hall and one or more HRS type antennas. A phase-locked loop or phase lock loop (PLL is a Control system that generates a signal that has a fixed relation to the phase of a "reference" In Telecommunications, modulation is the process of varying a periodic Waveform, i Among the nations of the world the USA is unique in that it has allowed private ownership of commercial and non-commercial Shortwave stations that are not is Japan 's domestic Shortwave commercial Radio broadcasting station headquartered in 9-15 Akasaka 1-chōme Minato Tokyo. Superrock KYOI was a Short-wave Radio station located at Saipan island in the Pacific region from 1982 to 1989 IK1QFK Home Page (vlf. it).
  2. ^ Cable and Wireless — A history
  3. ^ Arlyn T. Anderson. Changes at the BBC World Service: Documenting the World Service's Move From Shortwave to Web Radio in North America, Australia, and New Zealand, Journal of Radio Studies 2005, Vol. 12, No. 2, Pages 286-304 (doi:10. 1207/s15506843jrs1202_8) mentioned in [1] WWCR FAQ
  4. ^ "FCC Proposes to Drop Morse Code Requirement for All License Classes", American Radio Relay League, Inc. , July 20, 2005. Retrieved on 2006-08-03. Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Events 8 - Roman Empire General Tiberius defeats Dalmatians on the river Bathinus. (English) 

External links

The following external link is designed for use by cell phones and mobile devices that can display content using Wireless Markup Language and the Wireless Application Protocol:

Dictionary

shortwave

-adjective

  1. (of radio waves) Having a wavelength of approximately 10 to 200 meters
  2. (of radio equipment) Capable of transmitting or receiving signals at such a wavelength.

-noun

  1. Any shortwave frequency, having a wavelengh between approximately 10 and 200 meters
  2. Any wave in the shortwave frequency band
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