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Magic Band
The 6-meter band is the lowest portion of the very high frequency (VHF) radio spectrum (50.000-54.000 MHz) internationally allocated to amateur radio use. The term refers to the average signal wavelength of 6 meters. Although located in the lower portion of the VHF band, it nonetheless occasionally displays propagation mechanisms characteristic of the high frequency (HF) bands. This normally occurs close to sunspot maximum, when solar activity increases ionization levels in the upper atmosphere. Worldwide 6-meter propagation occurred during the sunspot maximum of 2005, making 6 meter communications as good as or, in some cases and locations, better than HF frequencies. The prevalence of HF characteristics on this VHF band has inspired amateur operators to dub it the "magic band". In the northern hemisphere, activity peaks from May through early August, when regular sporadic E propagation enables long-distance contacts spanning up to for single-hop propagation. Multiple-h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
50125 KHz FT-857D
5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. Humans, and many other animals, have 5 digits on their limbs. Mathematics 5 is a Fermat prime, a Mersenne prime exponent, as well as a Fibonacci number. 5 is the first congruent number, as well as the length of the hypotenuse of the smallest integer-sided right triangle, making part of the smallest Pythagorean triple ( 3, 4, 5). 5 is the first safe prime and the first good prime. 11 forms the first pair of sexy primes with 5. 5 is the second Fermat prime, of a total of five known Fermat primes. 5 is also the first of three known Wilson primes (5, 13, 563). Geometry A shape with five sides is called a pentagon. The pentagon is the first regular polygon that does not tile the plane with copies of itself. It is the largest face any of the five regular three-dimensional regular Platonic solid can have. A conic is determine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel 1 (North American TV)
In North American broadcast television frequencies, channel 1 was a former broadcast ( over-the-air) television channel which was removed from service in 1948. During the experimental era of TV operation, Channel 1 was moved around the lower VHF spectrum repeatedly, with the entire band displaced upward at one point due to an early 40 MHz allocation for the FM broadcast band. After FM was moved to its current frequencies in 1946, TV Channel 1's last assigned band was 44 to 50 MHz. This allocation was short-lived. Until 1948, Land Mobile Radio and television broadcasters shared the same frequencies, which caused interference. This shared allocation was eventually found to be unworkable, so the FCC reallocated the Channel 1 frequencies for public safety and land mobile use and assigned TV channels 2–13 exclusively to broadcasters. Aside from the shared frequency issue, this part of the VHF band was (and to some extent still is) prone to higher levels of radio-fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Amateur Radio Union
The International Amateur Radio Union (IARU) is an international confederation of national organisations that allows a forum for common matters of concern to amateur radio operators worldwide, and collectively represents matters to the International Telecommunication Union (ITU). The International Amateur Radio Union was founded in 1925 and, as of July 2021, it is composed of 172 national member societies. History Following an informal meeting in 1924 of representatives from France, Great Britain, Belgium, Switzerland, Italy, Spain, Luxembourg, Canada, and the United States, a plan was formulated to hold an International Amateur Congress in Paris, France, in April 1925. This Congress was held for the purpose of founding an international amateur radio organization. The Congress was attended by representatives of 23 countries in Europe, Americas, and Asia. A constitution for the IARU was adopted on April 17, and the formation of the International Amateur Radio Union was ratified on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Society Of Great Britain
The Radio Society of Great Britain (RSGB) is the United Kingdom's recognised national society for amateur radio operators. The society was founded in 1913 as the London Wireless Club, making it one of the oldest organisations of its kind in the world. Through its work, it represents the interests of the UK's 80,000 licensed radio amateurs in the United Kingdom and certain dependent territory, dependent territories of the United Kingdom at the International Amateur Radio Union, acting as a medium for communication between the licensed operators and the UK government. Role The RSGB has traditionally acted as the organisation through which its members interact with the telecommunications regulatory authority of the United Kingdom, Ofcom. Although Ofcom has used its web site to solicit opinions directly from all amateur radio enthusiasts and other interested parties, the RSGB continues to advise and to seek to influence Ofcom on the likely impact of proposed changes in many areas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel 1 (NTSC-M)
In North American broadcast television frequencies, channel 1 was a former broadcast ( over-the-air) television channel which was removed from service in 1948. During the experimental era of TV operation, Channel 1 was moved around the lower VHF spectrum repeatedly, with the entire band displaced upward at one point due to an early 40 MHz allocation for the FM broadcast band. After FM was moved to its current frequencies in 1946, TV Channel 1's last assigned band was 44 to 50 MHz. This allocation was short-lived. Until 1948, Land Mobile Radio and television broadcasters shared the same frequencies, which caused interference. This shared allocation was eventually found to be unworkable, so the FCC reallocated the Channel 1 frequencies for public safety and land mobile use and assigned TV channels 2–13 exclusively to broadcasters. Aside from the shared frequency issue, this part of the VHF band was (and to some extent still is) prone to higher levels of radio-frequ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Military Communications
Military communications or military signals involve all aspects of communications, or conveyance of information, by armed forces. Examples from '' Jane's Military Communications'' include text, audio, facsimile, tactical ground-based communications, naval signalling, terrestrial microwave, tropospheric scatter, satellite communications systems and equipment, surveillance and signal analysis, security, direction finding and jamming. IHS Jane'sbr>Military Communications Retrieved 2012-01-23. The most urgent purposes are to communicate information to commanders and orders from them. Military communications span from pre-history to the present. The earliest military communications were delivered by runners. Later, communications progressed to visual signals. For example, Naval ships would use flag signaling to communicate from ship to ship. These flags are a uniform set of easily identifiable nautical codes that would convey visual messages and codes between ships and fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio Frequency Allocations
Amateur radio frequency allocation is done by national telecommunication authorities. Globally, the International Telecommunication Union (ITU) oversees how much radio spectrum is set aside for amateur radio transmissions. Individual amateur stations are free to use any frequency within authorized frequency ranges; authorized bands may vary by the class of the station license. Radio amateurs use a variety of transmission modes, including Morse code, radioteletype, data, and voice. Specific frequency allocations vary from country to country and between ITU regions as specified in the current ITU HF frequency allocations for amateur radio. The list of frequency ranges is called a ''band allocation'', which may be set by international agreements, and national regulations. The modes and types of allocations within each frequency band is called a bandplan; it may be determined by regulation, but most typically is set by agreements between amateur radio operators. National authoriti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-meter Band
The 4-metre (70 MHz) band is an amateur radio band within the lower part of the very high frequency (VHF) band. As only a few countries within and outside of Europe have allocated the band for amateur radio access, the availability of dedicated commercially manufactured equipment is limited. Most radio amateurs active on the band are interested in home construction or the modification of private mobile radio (PMR) equipment. As a result, communication on the 4-metre band tends to focus on technical topics, with long 'rag chews' being the norm as long as there is some local activity. History Historical Overview The 4-meter band, occupying the 70 MHz frequency range, has been historically significant for various regional radio services. Post-World War II, the United Kingdom allocated a segment of the band, specifically 56-68 MHz, to British community radio stations, a provision that lasted until 1949. This allocation was subsequently reassigned for television broadcast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analogue Terrestrial Television In The United Kingdom
Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog signals **** Analog computer, a computer that uses analog signals ** Analog recording, information recorded using an analog signal * Functional analog (electronic), a system that fulfills the same function as another * Structural analog (electronic), a system that has the same structure as another Entertainment Albums and songs * ''Analog'' (album), an album by Eureka Farm * "Analog" (song), a song by Tyler, The Creator, featuring Hodgy Beats, from ''Goblin'' * ''Analogue'' (album), a 2005 album by A-ha ** "Analogue" (All I Want), the title track of the 2005 album by A-ha Books and magazines * ''Analog Science Fiction and Fact'', a science-fiction magazine * '' ANALOG Computing'', a 1981–1989 magazine about Atari computers * ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The UK includes the island of Great Britain, the north-eastern part of the island of Ireland, and most of List of islands of the United Kingdom, the smaller islands within the British Isles, covering . Northern Ireland shares Republic of Ireland–United Kingdom border, a land border with the Republic of Ireland; otherwise, the UK is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. It maintains sovereignty over the British Overseas Territories, which are located across various oceans and seas globally. The UK had an estimated population of over 68.2 million people in 2023. The capital and largest city of both England and the UK is London. The cities o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
