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|ITU radio bands|
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The Ku band ( // ) is the portion of the electromagnetic spectrum in the microwave range of frequencies from 12 to 18 gigahertz (GHz). The symbol is short for "K-under" (originally German : Kurz-unten), because it is the lower part of the original NATO K band, which was split into three bands (Ku, K, and Ka) 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. In radar applications, it ranges from 12 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521-2002.
The electromagnetic spectrum is the range of frequencies of electromagnetic radiation and their respective wavelengths and photon energies.
Microwaves are a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter; with frequencies between 300 MHz (1 m) and 300 GHz (1 mm). Different sources define different frequency ranges as microwaves; the above broad definition includes both UHF and EHF bands. A more common definition in radio engineering is the range between 1 and 100 GHz. In all cases, microwaves include the entire SHF band at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations.
German is a West Germanic language that is mainly spoken in Central Europe. It is the most widely spoken and official or co-official language in Germany, Austria, Switzerland, South Tyrol in Italy, the German-speaking Community of Belgium, and Liechtenstein. It is also one of the three official languages of Luxembourg and a co-official language in the Opole Voivodeship in Poland. The languages which are most similar to German are the other members of the West Germanic language branch: Afrikaans, Dutch, English, the Frisian languages, Low German/Low Saxon, Luxembourgish, and Yiddish. There are also strong similarities in vocabulary with Danish, Norwegian and Swedish, although those belong to the North Germanic group. German is the second most widely spoken Germanic language, after English.
Ku band is primarily used for satellite communications, most notably the downlink used by direct broadcast satellites to broadcast satellite television, and for specific applications such as NASA's Tracking Data Relay Satellite used for both space shuttle and International Space Station (ISS) communications. Ku band satellites are also used for backhauls and particularly for satellite from remote locations back to a television network's studio for editing and broadcasting. The band is split by the International Telecommunication Union (ITU) into multiple segments that vary by geographical region. NBC was the first television network to uplink a majority of its affiliate feeds via Ku band in 1983.
Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commonly referred to as a satellite dish and a low-noise block downconverter.
The National Aeronautics and Space Administration is an independent agency of the United States Federal Government responsible for the civilian space program, as well as aeronautics and aerospace research.
The International Space Station (ISS) is a space station in low Earth orbit. The ISS programme is a joint project between five participating space agencies: NASA, Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada). The ownership and use of the space station is established by intergovernmental treaties and agreements.
Some frequencies in this radio band are employed in radar guns used by law enforcement to detect vehicles speeding, especially in Europe.
A radar speed gun is a device used to measure the speed of moving objects. It is used in law-enforcement to measure the speed of moving vehicles and is often used in professional spectator sport, for things such as the measurement of bowling speeds in cricket, speed of pitched baseballs, athletes and tennis serves.
Segments in most of North and South America are represented by ITU Region 2 from 11.7 to 12.2 GHz (Local Oscillator Frequency (LOF) 10.75 to 11.25 GHz), allocated to the FSS (fixed satellite service), uplink from 14.0 to 14.5 GHz. There are more than 22 FSS Ku band satellites orbiting over North America, each carrying 12 to 48 transponders, 20 to 120 watts per transponder, and requiring a 0.8-m to 1.5-m antenna for clear reception.
The International Telecommunication Union (ITU), in its International Radio Regulations, divides the world into three ITU regions for the purposes of managing the global radio spectrum. Each region has its own set of frequency allocations, the main reason for defining the regions.
The watt is a unit of power. In the International System of Units (SI) it is defined as a derived unit of 1 joule per second, and is used to quantify the rate of energy transfer. In dimensional analysis, power is described by .
The 12.2 to 12.7 GHz (LOF 11.25 to 11.75 GHz) segment is allocated to the BSS (broadcasting satellite service). BSS (DBS direct broadcast satellites) normally carry 16 to 32 transponders of 27 MHz bandwidth running at 100 to 240 watts of power, allowing the use of receiver antennas as small as 18 inches (450 mm).
Segments in those regions are represented by ITU Region 1 and they are, the 11.45 to 11.7 and 12.5 to 12.75 GHz bands are allocated to the FSS (fixed satellite service, uplink 14.0 to 14.5 GHz). In Europe Ku band is used from 10.7 to 12.75 GHz (LOF Low 9.750 GHz, LOF High 10.750 GHz) for direct broadcast satellite services such as those carried by the Astra satellites. The 11.7 to 12.5 GHz segment is allocated to the BSS (broadcasting satellite service).
SES Astra SA was a corporate subsidiary of SES, based in Betzdorf, in eastern Luxembourg, that maintained and operated the Astra series of geostationary communication satellites between 2001 and 2011.
Australia is part of ITU Region 3 and the Australian regulatory environment provides a class license that covers downlinking from 11.70 GHz to 12.75 GHz and uplinking from 14.0 GHz to 14.5 GHz.
The ITU has categorized Indonesia as Region P, countries with very high rain precipitation. This statement has made many people unsure about using Ku-band (11 – 18 GHz) in Indonesia. If frequencies higher than 10 GHz are used in a heavy rain area, a decrease in communication availability results. This problem can be solved by using an appropriate link budget when designing the wireless communication link. Higher power can overcome the loss to rain fade.
Measurements of rain attenuation in Indonesia have been done for satellite communication links in Padang, Cibinong, Surabaya and Bandung. The DAH Model for rain attenuation prediction is valid for Indonesia, in addition to the ITU model. The DAH model has become an ITU recommendation since 2001 (Recommendation No. ITU-R P.618-7). This model can create a 99.7% available link so that Ku-band can be applied in Indonesia.
The use of the Ku-band for satellite communications in tropical regions like Indonesia is becoming more frequent. Several satellites above Indonesia have Ku-band transponders, and even Ka band transponders. Newskies (NSS 6), launched in December 2002 and positioned at 95° East, contains only Ku-band transponders with a footprint on Indonesia (Sumatra, Java, Borneo, Celebes, Bali, Nusa Tenggara, Moluccas). NSS 6 is intended to be replaced by SES-12 at the same location, which launched in June 2018 and carries 54 Ku-band transponders. The iPSTAR satellite, launched in 2004 also uses Ku band footprints. Other satellites that provides Ku band covers Indonesia are Palapa D, MEASAT 3/3A, JCSAT-4B, AsiaSat 5, ST 2, Chinasat 11, Korea Telecom Koreasat 8/ABS 2 (2nd half 2013), and SES-8.
Other ITU allocations have been made within the Ku band to the fixed service (microwave towers), radio astronomy service, space research service, mobile service, mobile satellite service, radiolocation service (radar), amateur radio service, and radionavigation. However, not all of these services are actually operating in this band and others are only minor users.
Compared with C-band, Ku band is not similarly restricted in power to avoid interference with terrestrial microwave systems, and the power of its uplinks and downlinks can be increased. This higher power also translates into smaller receiving dishes and points out a generalization between a satellite's transmission and a dish's size. As the power increases, the size of an antenna's dish will decrease. [ page needed ] This is because the purpose of the dish element of the antenna is to collect the incident waves over an area and focus them all onto the antenna's actual receiving element, mounted in front of the dish (and pointed back towards its face); if the waves are more intense, fewer of them need to be collected to achieve the same intensity at the receiving element.
A major attraction of the band over lower frequency microwave bands is that the shorter wavelengths allow sufficient angular resolution to separate the signals of different communication satellites to be achieved with smaller terrestrial parabolic antennas. From the Rayleigh criterion, the diameter of a parabolic dish required to create a radiation pattern with a given angular beamwidth (gain) is proportional to the wavelength, and thus inversely proportional to the frequency. At 12 GHz a 1-meter dish is capable of focusing on one satellite while sufficiently rejecting the signal from another satellite only 2 degrees away. This is important because satellites in FSS (Fixed Satellite Service) service (11.7-12.2 GHz in the U.S.) are only 2 degrees apart. At 4 GHz (C-band) a 3-meter dish is required to achieve this narrow angular resolution. Note the inverse linear correlation between dish size and frequency. For Ku satellites in DBS (Direct Broadcast Satellite) service (12.2-12.7 GHz in the U.S.) dishes much smaller than 1-meter can be used because those satellites are spaced 9 degrees apart. As power levels on both C and Ku band satellites have increased over the years, dish beam-width has become much more critical than gain.
The Ku band also offers a user more flexibility. A smaller dish size and a Ku band system's freedom from terrestrial operations simplifies finding a suitable dish site. For the end users Ku band is generally cheaper and enables smaller antennas (both because of the higher frequency and a more focused beam).Ku band is also less vulnerable to rain fade than the Ka band frequency spectrum.
There are, however, some disadvantages of Ku band system. Around 10 GHz is the absorption peak due to orientation relaxation of molecules in liquid water. Above 10 GHz, Mie scattering takes over. The effect is a noticeable degradation, commonly known as rain fade, at heavy rain (100 mm/h). This problem can be mitigated, however, by deploying an appropriate link-budget strategy when designing the satellite network, and allocating a higher power consumption to compensate rain fade loss. Therefore, the Ku band satellites typically require considerably more power to transmit than the C-band satellites.
A similar phenomenon, called "snow fade", is not specific for the Ku band. It is due to snow or ice accumulation on a dish significantly altering its focal point.
The satellite operator's Earth Station antenna does require more accurate position control when operating at Ku band due to its much narrower focus beam compared to C band for a dish of a given size. Position feedback accuracies are higher and the antenna may require a closed loop control system to maintain position under wind loading of the dish surface.
A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Communications satellites are used for television, telephone, radio, internet, and military applications. There are 2,134 communications satellites in Earth's orbit, used by both private and government organizations. Many are in geostationary orbit 22,236 miles (35,785 km) above the equator, so that the satellite appears stationary at the same point in the sky, so the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track it.
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter. Radio waves with frequencies above the UHF band fall into the super-high frequency (SHF) or microwave frequency range. Lower frequency signals fall into the VHF or lower bands. UHF radio waves propagate mainly by line of sight; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for television broadcasting, cell phones, satellite communication including GPS, personal radio services including Wi-Fi and Bluetooth, walkie-talkies, cordless phones, and numerous other applications.
A satellite dish is a dish-shaped type of parabolic antenna designed to receive or transmit information by radio waves to or from a communication satellite. The term most commonly means a dish used by consumers to receive direct-broadcast satellite television from a direct broadcast satellite in geostationary orbit.
A very small aperture terminal (VSAT) is a two-way satellite ground station with a dish antenna that is smaller than 3.8 meters. The majority of VSAT antennas range from 75 cm to 1.2 m. Data rates, in most cases, range from 4 kbit/s up to 16 Mbit/s. VSATs access satellites in geosynchronous orbit or geostationary orbit to relay data from small remote Earth stations (terminals) to other terminals or master Earth station "hubs".
The 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 S band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a part of the microwave band of the electromagnetic spectrum covering frequencies from 2 to 4 gigahertz (GHz). Thus it crosses the conventional boundary between the UHF and SHF bands at 3.0 GHz. The S band is used by airport surveillance radar for air traffic control, weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station. The 10 cm radar short-band ranges roughly from 1.55 to 5.2 GHz. The S band also contains the 2.4–2.483 GHz ISM band, widely used for low power unlicensed microwave devices such as cordless phones, wireless headphones (Bluetooth), wireless networking (WiFi), garage door openers, keyless vehicle locks, baby monitors as well as for medical diathermy machines and microwave ovens. India’s regional satellite navigation network (IRNSS) broadcasts on 2.483778 to 2.500278 GHz.
The X band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of the X band is rather indefinitely set at approximately 7.0–11.2 GHz. In radar engineering, the frequency range is specified by the IEEE at 8.0–12.0 GHz. The X band is used for radar, satellite communication, and wireless computer networks.
Rain fade refers primarily to the absorption of a microwave radio frequency (RF) signal by atmospheric rain, snow, or ice, and losses which are especially prevalent at frequencies above 11 GHz. It also refers to the degradation of a signal caused by the electromagnetic interference of the leading edge of a storm front. Rain fade can be caused by precipitation at the uplink or downlink location. It does not need to be raining at a location for it to be affected by rain fade, as the signal may pass through precipitation many miles away, especially if the satellite dish has a low look angle. From 5% to 20% of rain fade or satellite signal attenuation may also be caused by rain, snow, or ice on the uplink or downlink antenna reflector, radome or feed horn. Rain fade is not limited to satellite uplinks or downlinks, as it can also affect terrestrial point-to-point microwave links.
Satellite Internet access is Internet access provided through communications satellites. Modern consumer grade satellite Internet service is typically provided to individual users through geostationary satellites that can offer relatively high data speeds, with newer satellites using Ku band to achieve downstream data speeds up to 506 Mbit/s.
Thuraya is a United Arab Emirates-based regional mobile-satellite service (MSS) provider. The company operates two geosynchronous satellites and provides telecommunications coverage in more than 161 countries in Europe, the Middle East, North, Central and East Africa, Asia and Australia. Thuraya’s L-band network delivers voice and data services
NSS-6 is a communications satellite owned by SES WORLD SKIES.
Microwave transmission is the transmission of information by microwave radio waves. Although an experimental 40-mile (64 km) microwave telecommunication link across the English Channel was demonstrated in 1931, the development of radar in World War II provided the technology for practical exploitation of microwave communication. In the 1950s, large transcontinental microwave relay networks, consisting of chains of repeater stations linked by line-of-sight beams of microwaves were built in Europe and America to relay long distance telephone traffic and television programs between cities. Communication satellites which transferred data between ground stations by microwaves took over much long distance traffic in the 1960s. In recent years, there has been an explosive increase in use of the microwave spectrum by new telecommunication technologies such as wireless networks, and direct-broadcast satellites which broadcast television and radio directly into consumers' homes.
Badr-4 is an EADS Astrium-built communications satellite operated by Arabsat, launched 8 November 2006 on a Proton-M/Briz-M rocket. It provides fixed satellite communications services in C- and Ku-bands from the 26° East orbital position.
Radio is the technology of signaling or communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by a radio receiver connected to another antenna. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking and satellite communication among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal in the transmitter. In radar, used to locate and track objects like aircraft, ships, spacecraft and missiles, a beam of radio waves emitted by a radar transmitter reflects off the target object, and the reflected waves reveal the object's location. In radio navigation systems such as GPS and VOR, a mobile receiver receives radio signals from navigational radio beacons whose position is known, and by precisely measuring the arrival time of the radio waves the receiver can calculate its position on Earth. In wireless radio remote control devices like drones, garage door openers, and keyless entry systems, radio signals transmitted from a controller device control the actions of a remote device.
Intelsat 901 (IS-901) was the first of 9 new Intelsat satellites launched in June 2001 at 342°E, providing Ku-band spot beam coverage for Europe, as well as C-band coverage for the Atlantic Ocean region, and provides features such as selectable split uplink for SNG, tailored for increased communications demands such as DTH and Internet.
X band or SHF Satellite Communication is widely used by military forces for beyond line of sight communications. X band is used because it provides a compromise between the characteristics of different frequency bands which is particularly suited to the needs of military users. The characteristics include interference and rain resilience, terminal size, data rates, remote coverage and whether it is reserved for governmental use.
Es'hail 2 is a Qatari satellite, launched aboard a SpaceX Falcon 9 rocket on November 15, 2018. Es'hail 2 was built by Japan's Mitsubishi Electric company, and will operate at 26° East longitude along a geostationary orbit to provide direct-to-home television services in the Middle East and North Africa region. The satellite will feature 24 Ku-band and 11 Ka-band transponders to provide direct broadcasting services for television, government and commercial content distribution. In addition to commercial services, the payload of Es'hail 2 includes a linear transponder with a bandwidth of 250 kHz and 8MHz for the amateur radio satellite service, with uplink on 2.4 GHz and downlink on 10.45 GHz.
The C band is a designation by the Institute of Electrical and Electronics Engineers (IEEE) for a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 4.0 to 8.0 gigahertz (GHz); however, this definition is the one used by radar manufacturers and users, not necessarily by microwave radio telecommunications users. The C band is used for many satellite communications transmissions, some Wi-Fi devices, some cordless telephones as well as some surveillance and weather radar systems.