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K Band (NATO)
The NATO K band is the obsolete designation given to the radio frequencies from 20 to 40 GHz (equivalent to wavelengths between 1.5 and 0.75 cm) during the cold war period. Since 1992 frequency allocations, allotment and assignments are in line to NATO Joint Civil/Military Frequency Agreement (NJFA). However, in order to identify military radio spectrum requirements, e.g. for crises management planning, training, electronic warfare Electronic warfare (EW) is any action involving the use of the electromagnetic spectrum (EM spectrum) or directed energy to control the spectrum, attack an enemy, or impede enemy assaults. The purpose of electronic warfare is to deny the opponen ... activities, or in military operations, this system is still in use. References {{EMSpectrum Microwave bands Satellite broadcasting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one hertz is the reciprocal of one second. It is named after Heinrich Rudolf Hertz (1857–1894), the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz). Some of the unit's most common uses are in the description of periodic waveforms and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the clock speeds at which computers and other electronics are driven. The units are sometimes also used as a representation of the energy of a photon, via the Planck relation ''E'' = ''hν'', where ''E'' is the photon's energy, ''ν'' is its freq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centimetre
330px, Different lengths as in respect to the Electromagnetic spectrum, measured by the Metre and its deriveds scales. The Microwave are in-between 1 meter to 1 millimeter. A centimetre (international spelling) or centimeter (American spelling) (SI symbol cm) is a Units of measurement, unit of length in the International System of Units (SI), equal to one hundredth of a metre, ''centi'' being the SI prefix for a factor of . The centimetre was the base unit of length in the now deprecated centimetre–gram–second (CGS) system of units. Though for many physical quantities, SI prefixes for factors of 103—like ''milli-'' and ''kilo-''—are often preferred by technicians, the centimetre remains a practical unit of length for many everyday measurements. A centimetre is approximately the width of the fingernail of an average adult person. Equivalence to other units of length : One millilitre is defined as one cubic centimetre, under the SI system of units. Other uses In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Millimetre
330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter. The millimetre (American and British English spelling differences#-re, -er, international spelling; International System of Units, SI unit symbol mm) or millimeter (American and British English spelling differences#-re, -er, American spelling) is a Units of measurement, unit of length in the International System of Units (SI), equal to one thousandth of a metre, which is the SI base unit of length. Therefore, there are one thousand millimetres in a metre. There are ten millimetres in a centimetre. One millimetre is equal to micrometres or nanometres. Since an inch is officially defined as exactly 25.4 millimetres, a millimetre is equal to exactly (≈ 0.03937) of an inch. Definition Since 1983, the metre has been defined as "the length of the path travelled by light in vacuum during a time interval of of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K Band (IEEE)
The IEEE K-band is a portion of the radio spectrum in the microwave range of frequencies from 18 to 27-Gigahertz (GHz). The range of frequencies in the center of the K-band between 18- and 26.5-GHz is absorbed by water vapor in the atmosphere due to its resonance peak at 22.24-GHz, . Therefore these frequencies experience high atmospheric attenuation and cannot be used for long distance applications. For this reason the original K-band has been split into three bands, Ka-band, K-band, and Ku-band as detailed below. The K stands for Kurz which stems from the German word for short. Subdivisions Because of the water vapor absorption peak in the center of the band, the IEEE K-band is conventionally divided into three sub-bands: * Ku-band: K-under band, 12–18-GHz, mainly used for satellite communications, direct-broadcast satellite television, terrestrial microwave communications, and radar, especially police traffic-speed detectors. * K-band 18–27-GHz: Due to the 22-GHz wate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ka Band
The Ka band (pronounced as either "kay-ay band" or "ka band") is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz), i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters. The band is called Ka, short for "K-above" because it is the upper part of the original NATO K band, which was split into three bands because of the presence of the atmospheric water vapor resonance peak at 22.24 GHz (1.35 cm), which made the center unusable for long range transmission. The 30/20 GHz band is used in communications satellite uplinks in either the 27.5 GHz and 31 GHz bands, and high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement. The Kepler Mission used this frequency range to downlink the scientific data collected by the space telescope. The designation "Ka ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super High Frequency
Super high frequency (SHF) is the ITU designation for radio frequencies (RF) in the range between 3 and 30 gigahertz (GHz). This band of frequencies is also known as the centimetre band or centimetre wave as the wavelengths range from one to ten centimetres. These frequencies fall within the microwave band, so radio waves with these frequencies are called microwaves. The small wavelength of microwaves allows them to be directed in narrow beams by aperture antennas such as parabolic dishes and horn antennas, so they are used for point-to-point communication and data links This article from the beginning of the microwave era predicted the future value of microwaves for point-to-point communication. and for radar. This frequency range is used for most radar transmitters, wireless LANs, satellite communication, microwave radio relay links, satellite phones (S band), and numerous short range terrestrial data links. They are also used for heating in industrial microwave heatin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extremely High Frequency
Extremely high frequency (EHF) is the International Telecommunication Union (ITU) designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band and the far infrared band, the lower part of which is the terahertz band. Radio waves in this band have wavelengths from ten to one millimetre, so it is also called the millimetre band and radiation in this band is called millimetre waves, sometimes abbreviated MMW or mmWave. Millimetre-length electromagnetic waves were first investigated by Indian physicist Jagadish Chandra Bose, who generated waves of frequency up to 60GHz during experiments in 18941896. Compared to lower bands, radio waves in this band have high atmospheric attenuation: they are absorbed by the gases in the atmosphere. Absorption increases with frequency until at the top end of the band the waves are attenuated to zero within a few meters. Absorption by humidity in the atmosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Atlantic Treaty Organization
The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two North American. Established in the aftermath of World War II, the organization implemented the North Atlantic Treaty, signed in Washington, D.C., on 4 April 1949. NATO is a collective security system: its independent member states agree to defend each other against attacks by third parties. During the Cold War, NATO operated as a check on the perceived threat posed by the Soviet Union. The alliance remained in place after the dissolution of the Soviet Union and has been involved in military operations in the Balkans, the Middle East, South Asia, and Africa. The organization's motto is ''animus in consulendo liber'' (Latin for "a mind unfettered in deliberation"). NATO's main headquarters are located in Brussels, Belgium, while NATO's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the upper limit of audio frequencies and the lower limit of infrared frequencies; these are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range. Electric current Electric currents that oscillate at radio frequencies (RF currents) have special properties not shared by direct current or lower audio frequency alternating current, such as the 50 or 60 Hz current used in electrical power distribution. * Energy from RF currents in conductors can radiate into space as electromagnetic waves ( radio waves). This is the basis of radio technology. * RF current does not penetrate deeply into electrical c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter ''lambda'' (λ). The term ''wavelength'' is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids. Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. Wavelength depends on the medium (for example, vacuum, air, or water) that a wav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NJFA
__NOTOC__ NATO Joint Civil/Military Frequency Agreement (NJFA) and is the universal NATO common civil/military treaty to regulate the military access to the radio frequency spectrum in the range of 14 kHz to 100 GHz in peacetime, during exercises, in times of crisis, and in military operations. This document has been the basis for the frequency utilisation in NATO-Europe since 1982. Nations and organisations, e.g. partnership for peace countries, are invited to participate as deemed to be necessary. The national representatives of the frequency sovereignty agree unanimous to changes of the NJFA, in line to decisions of World Radiocommunication Conferences, operational requirement of the armed forces, and technical developments. However, the provision of "Article 38 of the International Telecommunication Convention, Nairobi 1982" remains untouched.International Telecommunication Convention, Nairobi 1982; § 163, 1. The member countries contain full sovereignty pertaining m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Warfare
Electronic warfare (EW) is any action involving the use of the electromagnetic spectrum (EM spectrum) or directed energy to control the spectrum, attack an enemy, or impede enemy assaults. The purpose of electronic warfare is to deny the opponent the advantage of—and ensure friendly unimpeded access to—the EM spectrum. EW can be applied from air, sea, land, and/or space by crewed and uncrewed systems, and can target communication, radar, or other military and civilian assets. The electromagnetic environment Military operations are executed in an information environment increasingly complicated by the electromagnetic spectrum. The electromagnetic spectrum portion of the information environment is referred to as the electromagnetic environment (EME). The recognized need for military forces to have unimpeded access to and use of the electromagnetic environment creates vulnerabilities and opportunities for electronic warfare in support of military operations. Within the informat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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