Shortwave may refer to:
The ionosphere is the ionized part of Earth's upper atmosphere, from about 48 km (30 mi) to 965 km (600 mi) altitude, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an important role in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth.
The BBC World Service is an international broadcaster owned and operated by the BBC. It is the world's largest of any kind. It broadcasts radio news, speech and discussions in more than 40 languages to many parts of the world on analogue and digital shortwave platforms, internet streaming, podcasting, satellite, DAB, FM and MW relays. In 2015, the World Service reached an average of 210 million people a week. In November 2016, the BBC announced that it would start broadcasting in additional languages including Amharic and Igbo, in its biggest expansion since the 1940s.
Shortwave radio is radio transmission using shortwave (SW) radio frequencies. There is no official definition of the band, but the range always includes all of the high frequency band (HF), which extends from 3–30 MHz ; above the medium frequency band (MF), to the bottom of the VHF band.
In radio, longwave, long wave or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band. The term is historic, dating from the early 20th century, when the radio spectrum was considered to consist of longwave (LW), medium-wave (MW), and short-wave (SW) radio bands. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters. Frequencies immediately below HF are denoted medium frequency (MF), while the next band of higher frequencies is known as the very high frequency (VHF) band. The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or "skywave" propagation – these frequencies are suitable for long-distance communication across intercontinental distances and for mountainous terrains which prevent line-of-sight communications. The band is used by international shortwave broadcasting stations (3.95–25.82 MHz), aviation communication, government time stations, weather stations, amateur radio and citizens band services, among other uses.
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. Understanding the effects of varying conditions on radio propagation has many practical applications, from choosing frequencies for international shortwave broadcasters, to designing reliable mobile telephone systems, to radio navigation, to operation of radar systems.
In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. Since it is not limited by the curvature of the Earth, skywave propagation can be used to communicate beyond the horizon, at intercontinental distances. It is mostly used in the shortwave frequency bands.
Radio Havana Cuba is the official government-run international broadcasting station of Cuba. It can be heard in many parts of the world including the United States on shortwave frequencies. Radio Havana, along with Radio Rebelde, Cubavision Television and other Cuban radio and television broadcasts to North, Central and South America via free-to-air programming from the Hispanisat satellite over the Atlantic Ocean and via Internet streaming.
The Voice of Greece, also known as ERA 5, is the international service of Greek state radio on shortwave and via satellite and the internet. On 11 June 2013, the Greek government announced the closure of the state broadcaster ERT from 12 June 2013 as an austerity measure.
Shortwave listening, or SWLing, is the hobby of listening to shortwave radio broadcasts located on frequencies between 1700 kHz and 30 MHz. Listeners range from casual users seeking international news and entertainment programming, to hobbyists immersed in the technical aspects of radio reception and collecting official confirmations that document their reception of distant broadcasts (DXing). In some developing countries, shortwave listening enables remote communities to obtain regional programming traditionally provided by local medium wave AM broadcasters. In 2002, the number of households that were capable of shortwave listening was estimated to be in the hundreds of millions.
Vatican Radio is the official broadcasting service of Vatican City.
Glenn Hauser is an internationally known American DXer and radio host from Enid, Oklahoma. He produces and presents a weekly 30-minute program, World Of Radio, heard on a number of non-commercial AM and FM stations throughout the U.S. and worldwide on shortwave.
DXing is the hobby of receiving and identifying distant radio or television signals, or making two-way radio contact with distant stations in amateur radio, citizens' band radio or other two-way radio communications. Many DXers also attempt to obtain written verifications of reception or contact, sometimes referred to as "QSLs" or "veries". The name of the hobby comes from DX, telegraphic shorthand for "distance" or "distant".
ABC Radio Australia, also known as Radio Australia, is the international broadcasting and online service operated by the Australian Broadcasting Corporation (ABC), Australia's public broadcaster. Most programming is in English, with some in Tok Pisin.
A communications receiver is a type of radio receiver used as a component of a radio communication link. This is in contrast to a broadcast receiver which is used to receive radio broadcasts. A communication receiver receives parts of the radio spectrum not used for broadcasting, that includes amateur, military, aircraft, marine, and other bands. They are often used with a radio transmitter as part of a two-way radio link for shortwave radio or amateur radio communication, although they are also used for shortwave listening.
The Woofferton transmitting station is owned and operated by Encompass Digital Media, as one of the BBC's assets which were handed over as part of the privatization of World Service distribution and transmission in 1997. It is the last remaining UK shortwave broadcasting site, located at Woofferton, south of Ludlow, Shropshire, England. The large site spreads across into neighbouring Herefordshire.
The Grigoriopol transmitter is a very large broadcasting facility situated near Maiac, an urban settlement 11 km northeast of Grigoriopol, Transnistria (Moldova).
World War II Radio Heroes: Letters of Compassion is a book by psychologist Lisa Spahr, co-authored with Austin Camacho, that recounts her personal investigation of the activities of shortwave radio listeners who notified families of captured U.S. military personnel of their status as prisoners of war during World War II. It documents Spahr's search to locate and thank the listeners who wrote letters to her great-grandmother reporting details of her grandfather's capture and internment in a German prison camp in 1943.
Curtain arrays are a class of large multielement directional wire radio transmitting antennas, used in the shortwave radio bands. They are a type of reflective array antenna, consisting of multiple wire dipole antennas, suspended in a vertical plane, often in front of a "curtain" reflector made of a flat vertical screen of many long parallel wires. These are suspended by support wires strung between pairs of tall steel towers, up to 300 ft (90 m) high. They are used for long-distance skywave transmission; they transmit a beam of radio waves at a shallow angle into the sky just above the horizon, which is reflected by the ionosphere back to Earth beyond the horizon. Curtain antennas are mostly used by international short wave radio stations to broadcast to large areas at transcontinental distances.
A shortwave radio receiver is a radio receiver that can receive one or more shortwave bands, between 1.6 and 30 MHz. A shortwave radio receiver often receives other broadcast bands, such as FM radio, Longwave and Mediumwave. Shortwave radio receivers are often used by dedicated hobbyists called shortwave listeners.