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Short-wave
Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (approximately 100 to 10 metres in wavelength). It lies between the medium frequency band (MF) and the bottom of the VHF band. Radio waves in the shortwave band can be reflected or refracted from a layer of electrically charged atoms in the atmosphere called the ionosphere. Therefore, short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon. This is called skywave or "skip" propagation. Thus shortwave radio can be used for communication over very long distances, in contrast to radio waves of higher frequency, which travel in straight lines (line-of-sight propagation) and are generally limited by the visual horizon, about 64 km (40 miles). Shortwave broadcasts of radio pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Broadcasting
International broadcasting consists of radio and television transmissions that purposefully cross international boundaries, often with then intent of allowing expatriates to remain in touch with their countries of origin as well as educate, inform, and influence residents of foreign countries. Content can range from overt propaganda and counterpropaganda to cultural content to news reports that reflect the point of view and concerns of the originating country or that seek to provide alternative information to that otherwise available as well as promote tourism and trade. In the first half of the twentieth century, international broadcasting was used by colonial empires as a means of connecting colonies with the metropole (for example the BBC Empire Service as well as France's Poste Colonial and the Dutch overseas radio services, PCJJ and PHOHI). When operated by governments or entities close to a government, international broadcasting can be a form of soft power. Less frequentl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionosphere
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, 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 Earth. Travel through this layer also impacts GPS signals, resulting in effects such as deflection in their path and delay in the arrival of the signal. History of discovery As early as 1839, the German mathematician and physicist Carl Friedrich Gauss postulated that an electrically conducting region of the atmosphere could account for observed variations of Earth's magnetic field. Sixty years later, Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada) usin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortwave Bands
Shortwave bands are frequency allocations for use within the shortwave radio spectrum (the upper medium frequency Fband and all of the high frequency Fband). Radio waves in these frequency ranges can be used for very long distance (transcontinental) communication because they can reflect off layers of charged particles in the ionosphere and return to Earth beyond the horizon, a mechanism called skywave or “skip” propagation. They are allocated by the ITU for radio services such as maritime communications, international shortwave broadcasting and worldwide amateur radio. The bands are conventionally named by their wavelength in metres, for example the ‘20 meter band’. Radio propagation and possible communication distances vary depending on the time of day, the season and the level of solar activity. International broadcast bands These bands are used by powerful long range AM radio stations, many operated by governments, which broadcast to multiple countries. Most inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Wave
In radio, longwave (also spelled long wave or long-wave and commonly abbreviated LW) is the part of the radio spectrum with wavelengths longer than what was originally called the medium-wave (MW) broadcasting band. The term is historic, dating from the early 20th century, when the radio spectrum was considered to consist of LW, MW, and short wave radio, short-wave (SW) radio bands. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short' (i.e. very high frequency, VHF, ultra high frequency, UHF, and microwave). In contemporary usage, the term ''longwave'' is not defined precisely, and its intended meaning varies. It may be used for radio wavelengths longer than 1,000 m i.e. Frequency, frequencies smaller than 300 kilohertz (kHz), including the International Telecommunication Union (ITU) low frequency (LF, 30–300 kHz) and very low frequency (VLF, 3–30 kHz) bands. Sometimes the upper limit is taken to be hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Radio
The early history of radio is the history of technology that produces and uses radio instruments that use radio waves. Within the timeline of radio, many people contributed theory and inventions in what became radio. Radio development began as "wireless telegraphy". Later radio history increasingly involves matters of broadcasting. Discovery In an 1864 presentation, published in 1865, James Clerk Maxwell proposed theories of electromagnetism and mathematical proofs demonstrating that light, radio and x-rays were all types of electromagnetic waves propagating through free space. Between 1886 and 1888 Heinrich Rudolf Hertz published the results of experiments wherein he was able to transmit electromagnetic waves (radio waves) through the air, proving Maxwell's electromagnetic theory. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medium Wave
Medium wave (MW) is a part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. The spectrum provides about 120 channels with more limited sound quality than FM stations on the FM broadcast band. During the daytime, reception is usually limited to more local stations, though this is dependent on the signal conditions and quality of radio receiver used. Improved signal propagation at night allows the reception of much longer distance signals (within a range of about 2,000 km or 1,200 miles). This can cause increased interference because on most channels multiple transmitters operate simultaneously worldwide. In addition, amplitude modulation (AM) is often more prone to interference by various electronic devices, especially power supplies and computers. Strong transmitters cover larger areas than on the FM broadcast band but require more energy and longer antennas. Digital modes are possible but had not yet reached momentum. MW was the main radio b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Russo-Ukrainian War
The Russo-Ukrainian War began in February 2014 and is ongoing. Following Ukraine's Revolution of Dignity, Russia Russian occupation of Crimea, occupied and Annexation of Crimea by the Russian Federation, annexed Crimea from Ukraine. It then supported Russian separatist forces in Ukraine, Russian paramilitaries who began a War in Donbas, war in the eastern Donbas region against Ukraine's military. In 2018, Ukraine declared the region to be Russian-occupied territories of Ukraine, occupied by Russia. These first eight years of conflict also included List of Black Sea incidents involving Russia and Ukraine, naval incidents and Russo-Ukrainian cyberwarfare, cyberwarfare. In February 2022, Russia launched a Russian invasion of Ukraine, full-scale invasion of Ukraine and began occupying more of the country, starting the biggest conflict in Europe since World War II. The war has resulted in a Ukrainian refugee crisis, refugee crisis and hundreds of thousands of deaths. In early 201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guglielmo Marconi 1901 Wireless Signal
Guglielmo () is the Italian form of the masculine name William. It may refer to: People with the given name Guglielmo: * Guglielmo I Gonzaga (1538–1587), Duke of Mantua and Montferrat * Guglielmo Agnelli (c. 1238 – 1313), Italian sculptor and architect * Guglielmo Arena (born 1973), Swiss football manager * Guglielmo Bergamasco (c. 1485 – 1550), Italian architect * Guglielmo Borremans (1670–1744), Baroque painter * Guglielmo Bosca (born 1993), Italian alpine skier * Guglielmo Caccia (1568–1625), Italian painter * Guglielmo Achille Cavellini (1914–1990), influential Italian art collector and mail artist * Guglielmo da Leoni (c. 1664 – 1740), Italian painter and engraver * Guglielmo da Marsiglia (1475–1537), Italian painter of stained glass * Guglielmo della Porta (c. 1500 – 1577), Italian architect and sculptor * Guglielmo della Scala (died 1404), Lord of Verona * Guglielmo Ebreo da Pesaro (c. 1420 – c. 1484), Italian dancing-master * Guglielmo Emb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Spectrum
The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particularly in telecommunication. To prevent interference between different users, the generation and transmission of radio waves is strictly regulated by national laws, coordinated by an international body, the International Telecommunication Union (ITU). Different parts of the radio spectrum are allocated by the ITU for different radio transmission technologies and applications; some 40 radiocommunication services are defined in the ITU's Radio Regulations (RR). In some cases, parts of the radio spectrum are sold or licensed to operators of private radio transmission services (for example, cellular telephone operators or broadcast television stations). Ranges of allocated frequencies are often referred to by their provisioned use (for exampl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grundig Satellit Professional 400
Grundig ( , , ) is a Turkey, Turkish home appliances and consumer electronics brand. It is owned by Arçelik, Arçelik A.Ş., the Major appliance, white goods (major appliance) manufacturer of Turkish conglomerate Koç Holding. Originally a Germany, German consumer electronics company, Grundig Gesellschaft mit beschränkter Haftung, GmbH was founded in 1945 by Max Grundig and was headquartered for the most part in Nuremberg until its insolvency in 2003. The Grundig company helped fuel the Wirtschaftswunder, post-war economic miracle of West Germany and it grew to become one of the leading manufacturers in the world of radio, TV, recording and other electronic equipment in the following decades. In the 1970s, Philips began acquiring Grundig's shares, leading to complete control in 1993, but Philips divested Grundig by 1998. Grundig filed for bankruptcy in April 2003 after years of losses and strong competition from cheaper Asian competitors. Most of the former Grundig business ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medium Frequency
Medium frequency (MF) is the International Telecommunication Union, ITU designation for Radio frequency, radio frequencies (RF) in the range of 300 kilohertz (kHz) to 3 megahertz (MHz). Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hectometer band as the wavelengths range from ten to one hectometers (1000 to 100 m). Frequencies immediately below MF are denoted as low frequency (LF), while the first band of higher frequencies is known as high frequency (HF). MF is mostly used for AM broadcasting, AM radio broadcasting, Radio beacon, navigational radio beacons, maritime ship-to-shore communication, and transoceanic air traffic control. Propagation Radio waves at MF wavelengths propagate via ground waves and reflection from the ionosphere (called skywaves). Ground waves travel just above the earth's surface, following the terrain. At these wavelengths, they can bend (diffraction, diffract) over hills, and travel be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Radio
Internet radio, also known as online radio, web radio, net radio, streaming radio, e-radio and IP radio, is a digital audio service transmitted via the Internet. Broadcasting on the Internet is usually referred to as webcasting since it is not transmitted broadly through wireless means. It can either be used as a stand-alone device running through the Internet, or as a software running through a single computer. Internet radio is generally used to communicate and easily spread messages through the form of talk. It is distributed through a wireless communication network connected to a switch packet network (the internet) via a disclosed source. Internet radio involves streaming media, presenting listeners with a continuous stream of audio that typically cannot be paused or replayed, much like traditional broadcast media; in this respect, it is distinct from on-demand file serving. Internet radio is also distinct from podcasting, which involves downloading rather than streaming. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
