The K_u band (pronounced "kay-yoo") is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to "K-under" — in other words, the band directly below the K-band. 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. ^[1][2] This article is about the term superscript as used in typography. ... A subscript is a number, figure, or indicator that appears below the normal line of type, typically used in a formula, mathematical expression, or description of a chemical compound. ... English phonology is the study of the phonology (ie the sound system) of the English language. ... Although some radiations are marked as N for no in the diagram, some waves do in fact penetrate the atmosphere, although extremely minimally compared to the other radiations The electromagnetic (EM) spectrum is the range of all possible electromagnetic radiation. ... This article is about the type of Electromagnetic radiation. ... K band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging between 12 to 63 GHz. ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ...

K_u band is primarily used for satellite communications, most notably NASA's Tracking Data Relay Satellite used for both space shuttles, and ISS communications. K_u 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 into multiple segments that vary by geographical region by the International Telecommunication Union (ITU). NBC was the first television network to uplink a majority of its affiliate feeds via K_u band in 1983. U.S. military MILSTAR communications satellite A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications using radio at microwave frequencies. ... For other uses, see NASA (disambiguation). ... The Tracking and Data Relay Satellite System (TDRSS) is a network of communications satellites (each called a Tracking and Data Relay Satellite or TDRS) used by NASA and other United States government agencies. ... This article is about the space vehicle. ... (Note - this refers to present TV usage, mainly in the USA. In the UK backhaul often means the optical fibre connection from the DSL equipment (DSLAM etc) in a telephone exchange back to the core network). ... Broadcasting is the distribution of audio and/or video signals which transmit programs to an audience. ... The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ... This article is about the television network. ... For the Jimi Hendrix song, see 1983. ...

Segments and regions

The Americas

Segments in most of the Americas are represented by (ITU Region 2) and they are, the 11.7 to 12.2 GHz (Local Oscillator Frequency (LOF) 10.750 GHz) band is allocated to the FSS (fixed service satellite, uplink 14.0 to 14.5 GHz). There are more than 22 FSS K_u-band satellites orbiting over North America, each carrying 12 to 24 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. ... Fixed Service Satellite (or FSS), is the official classification for geostationary communications satellites used chiefly for broadcast feeds for television and radio stations and networks, as well as for telephony, data communications, and also for direct-to-home (DTH) cable and satellite TV channels (although this role has been somewhat... Look up uplink in Wiktionary, the free dictionary. ... An Ontario Highway 407 toll transponder In telecommunication, the term transponder (short-for Transmitter-responder and sometimes abbreviated to XPDR, XPNDR or TPDR) has the following meanings: An automatic device that receives, amplifies, and retransmits a signal on a different frequency (see also broadcast translator). ... For other uses, see Watt (disambiguation). ...

The 12.2 to 12.7 GHz (LOF 11.250 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). Direct broadcast satellite (DBS) is a term used to refer to satellite television broadcasts intended for home reception, also referred to as direct-to-home signals. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ...

Europe and Africa

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). Fixed Service Satellite (or FSS), is the official classification (used chiefly in North America) for geostationary communications satellites used chiefly for broadcast feeds for television and radio stations and networks, as well as for telephony, data communications, and also for Direct-To-Home (DTH) cable and satellite TV channels (although... Look up uplink in Wiktionary, the free dictionary. ...

In Europe K_u band is used from 10.7 to 12.75 GHz (LOF Low 9.750 GHz, LOF High 10.600 GHz) for direct broadcast satellite services like SES Astra. Direct broadcast satellite (DBS) is a term used to refer to satellite television broadcasts intended for home reception, also referred to as direct-to-home signals. ... SES Astra SA, is a corporate subsidiary of SES, based in Betzdorf, in eastern Luxembourg, that owns and operates the Astra series of geostationary satellites, which transmit approximately 1100 analogue and digital television and radio channels via 176 transponders to 91 million households across Europe. ...

The 11.7 to 12.5 GHz segment is allocated to the BSS (broadcasting satellite service).

Australia

Australia is part of ITU Region 3 and the Australian regulatory environment provides a class license that covers downlinking from 12.25GHz to 12.75GHz and uplinking from 14.0GHz to 14.5GHz.

Others

Other ITU allocations have been made within the K_u 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. Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ...

Indonesia

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. The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ... A link budget is the accounting of all of the gains and losses from the transmitter, through the medium (free space, cable, waveguide, fiber, etc. ... In satellite communications, rain fade refers to the absorption of a microwave Radio Frequency (RF) signal by rain or snow, and is especially prevalent in frequencies above 11 GHz. ...

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). The iPSTAR satellite, launched in 2004 also uses Ku band footprints. Measat has named the Ku-band footprint directed towards Indonesia Ku-band for Indonesi. Measat 4 plans to cover the whole of Indonesia from West to East. This satellite will be launched by Malaysia in 2007. An Ontario Highway 407 toll transponder In telecommunication, the term transponder (short-for Transmitter-responder and sometimes abbreviated to XPDR, XPNDR or TPDR) has the following meanings: An automatic device that receives, amplifies, and retransmits a signal on a different frequency (see also broadcast translator). ... The Ka band (kurz-above band) is a portion of the K band of the microwave band of the electromagnetic spectrum. ... For other uses, see Sumatra (disambiguation). ... This article is about the Java island. ... Φ Borneo is the third largest island in the world and is located at the centre of Maritime Southeast Asia. ... Map of Sulawesi pictures by Julianto Halim Sulawesi (or Celebes) is a large Indonesian island. ... This article is about the Indonesian island. ... Categories: Islands of Indonesia | Southeast Asia geography stubs | Indonesia geography stubs ... This page is about the geography and history of the island group in Indonesia — for the political entities encompassing the islands, see Maluku (Indonesian province) and North Maluku. ... ...

Advantages

Compared with C-band, K_u 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 dish’s size can decrease.^[3] // The NATO C band is that portion of the electromagnetic spectrum between 500 MHz and 1000 MHz. ...

The K_u band also offers a user more flexibility. A dish smaller size and a K_u band system’s freedom from terrestrial operations simplifies finding a suitable dish site. K_u band is generally cheaper and enables smaller antennas (both because of the higher frequency and a more focused beam).^[4] K_uband is also less vulnerable to rain fade than the K_a-band frequency spectrum.

Disadvantages

There are, however, some disadvantages of K_u band system. Especially at frequencies higher than 10 GHz in heavy rain fall areas, a noticeable degradation occurs, due to the problems caused by and proportional to the amount of rainfall (commonly known as "rain fade").^[5] 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 reduce rain fade loss. The K_u band is not only used for television transmission, which some sources imply, but also very much for digital data transmission via satellites, and for voice/audio transmissions. In satellite communications, rain fade refers to the absorption of a microwave Radio Frequency (RF) signal by rain or snow, and is especially prevalent in frequencies above 11 GHz. ...

The higher frequency spectrum of the K_u band is particularly susceptible to signal degradation, considerably more so than C-band satellite frequency spectrum. A similar phenomenon, called "snow fade" (where snow or ice accumulation significantly alters the focal point of a dish) can also occur during winter precipitation. Also, the K_uband satellites typically require considerably more power to transmit than the C-band satellites. Under both "rain fade" and "snow fade" conditions, Ka and Ku band losses can be marginally (but significantly) reduced using super-hydrophobic Lotus effect coatings. In satellite communications, rain fade refers to the absorption of a microwave Radio Frequency (RF) signal by rain or snow, and is especially prevalent in frequencies above 11 GHz. ... Water on the surface of a lotus leaf The Lotus effect in material science is the observed self-cleaning property found with lotus plants. ...

References

The X band (3-cm radar spot-band) of the microwave band of the electromagnetic spectrum roughly ranges from 5. ...

External links

• Spectrum allocation chart