Ku band

The Ku band (/ˌkeɪˈjuː/) 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 atmospeheric 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 12-18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521-2002.[1][2]

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.

Some frequencies in this radio band are employed in radar guns used by law enforcement to detect vehicles speeding, especially in Europe.[3]

IEEE Ku band
Frequency range
12–18 GHz
Wavelength range
2.5–1.67 cm
Related bands

Segments and regions

SuperDISH121
One use of the band is direct-broadcast satellite television. A satellite dish on a residence, which receives satellite television channels over a Ku band microwave beam from a broadcast communications satellite in a geostationary orbit 35,700 kilometres (22,000 miles) above the Earth.

The Americas

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 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).

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). 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).

Australia

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.[4]

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.

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.

Others

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.

Advantages

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.[5] 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).[6] Ku band is also less vulnerable to rain fade than the Ka band frequency spectrum.

Disadvantages

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.[7] Above 10 GHz, Mie scattering takes over. The effect is a noticeable degradation, commonly known as rain fade, at heavy rain (100 mm/h).[8] 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.

See also

References

  1. ^ IEEE Std 521 - 2002 URL only available to IEEE members
  2. ^ Note that in the band 11.2–12 GHz the working definitions of Ku band and X band overlap; satellite communications engineers would generally regard frequencies above 11.2 GHz as being part of the Ku band.
  3. ^ Radar Detectors Glossary
  4. ^ "Radiocommunications (Communication with Space Object) Class Licence 1998". Federal Register of Legislation. Australian Government. 2012-03-21. Retrieved 2016-07-06.
  5. ^ Mirabito, M; Morgenstern, B (2004). Satellites: Operations and Applications. The New Communication Technologies (5 ed.). Burlington: Focal Press. ISBN 978-0240805863.
  6. ^ Satellite Communications: Advantage and Disadvantages Archived 2007-10-23 at the Wayback Machine
  7. ^ Martin Chaplin: Water and Microwaves.
  8. ^ TECH-FAQ: Ku band.

External links

4DTV

4DTV is a proprietary broadcasting standard and technology for digital cable broadcasting and C-band/Ku-band satellite dishes from Motorola, using General Instrument's DigiCipher II for encryption. It can tune in both analog VideoCipher 2 and digital DCII satellite channels.

AMC-4

AMC-4 or AMERICOM-4, formerly GE-4, is a Dutch, previously American, commercial communications satellite.

AMC-4 was launched in 1999 as GE-4, GE Americom's fourth A2100 hybrid C-band and Ku-band satellite. The C-band payload was home to national television networks broadcasting to thousands of cable television headends. AMC-4's Ku-band transponders served the direct-to-home, VSAT, business television and broadband Internet market segments. These Ku-band transponders are designed to be switchable between North and South American coverages. It was renamed AMC-4 after GE Americom was bought by SES and re-branded SES Americom. In 2009, SES Americom merged with SES New Skies to form SES World Skies. AMC-4 has been replaced by SES-1 in 2010. AMC-4 has been moved to 134.9° W, and currently has no FTA signals.

AMC-6

AMC-6, formerly GE-6, is a commercial broadcast communications satellite owned by SES World Skies. Launched on October 21, 2000, from Baikonur Cosmodrome in Kazakhstan, AMC-6 became the fifth hybrid C band/Ku band satellite in the GE Americom fleet. The satellite provides coverage to the continental United States, Canada, the Caribbean islands, southern Greenland, and Central and South America. Located in a geostationary orbit parallel to the eastern United States coastline, AMC-6 provides service to commercial and government customers, and is used as an Internet platform due to its wide coverage, scale and redundancy. Some of its capabilities include VSAT networking, satellite news gathering and Ku band transceiver service. Launched as GE-6, it was renamed AMC-6 when SES took over GE Americom in 2001, forming SES Americom. This merged with SES New Skies in 2009 to form SES World Skies.

GSAT-10

GSAT-10 is an Indian communication satellite which was launched by Ariane-5ECA carrier rocket in September 2012. It has 12 KU Band, 12 C Band and 6 lower extended c band transponders, and included a navigation payload to augment GAGAN capacity. Following its launch and on-orbit testing, it was placed in Geosynchronous orbit at 83.0° East, from where it will provide communication services in India.

GSAT-11

GSAT-11 is an Indian geostationary communications satellite. The 5854 kg satellite is based on the new I-6K Bus and carry 40 transponders in the Ku-band and Ka-band frequencies (32 Ka × Ku-Band Forward Link Transponders and 8 Ku × Ka band Return Link Transponders), which are capable of providing up to 16 Gbit/s throughput. GSAT-11 is India's heaviest satellite.

Galaxy 19

Galaxy 19 is a communications satellite owned by Intelsat located at 97° West longitude, serving the North American market. Galaxy 19 replaced Galaxy 25 which is nearing the end of its design life and has been moved to 93.1°W longitude. It was built by Space Systems/Loral, as part of its FS-1300 line. Galaxy 19 was formerly known as Intelsat Americas 9 and was successfully launched September 24, 2008. It provides services in the C band and Ku band.

The clients for Galaxy 19 include the previous clients for Galaxy 25. Expanded services include higher-powered C-band and Ku band transponders as well as new, high-power Ka band service. As of August 2017, Galaxy 19 broadcast 172 Free-To-Air channels for North American televisions, from a diverse list of national and international sources. Galaxy 19 was launched using Sea Launch.

Galaxy 25

Galaxy 25 (G-25) launched in 1997 (formerly known as Intelsat Americas 5 (IA-5) until February 15, 2007 when it was renamed as result of the merger between owner Intelsat and PanAmSat or Telstar 5) is a medium-powered communications satellite formerly in a geostationary orbit at 0°N 97°W / 0; -97, above a point in the Pacific Ocean several hundred miles west of the Galapagos Islands. It was manufactured by Space Systems/Loral, part of its FS-1300 line, and is currently owned and operated by Intelsat. The satellite's main C-band transponder cluster covers the United States, southern Canada, and Mexico; its main Ku band transponder cluster covers the U.S., Mexico, and the northern Caribbean Sea. An additional C-band and a Ku band transponder pair targets the Hawaiian Islands.

Galaxy 25 has a projected life of 12 years. It was replaced by Galaxy 19 (formerly IA-9) in late 2008. When it was last in service at 97 degrees west, Galaxy 25 transmitted both free-to-air (FTA) direct-to-home (DTH) broadcasting and encrypted subscription channels / services. The replacement satellite, Galaxy 19 was successfully launched on September 24, 2008. Galaxy 25 has been moved to a different orbital position at 0°N 93.1°W / 0; -93.1 where it is currently broadcasting several services on its Ku band transponders.

Intelsat 20

Intelsat 20 is a geostationary communications satellite which is operated by Intelsat. It was constructed by Space Systems Loral, and is based on the LS-1300 satellite bus. It was launched on 2 August 2012, and replaces the Intelsat 7 and Intelsat 10 spacecraft at 68.5º East longitude. It is fully operational since September 2012.Intelsat 20 carries 24 IEEE C-band (NATO G/H-band), 54 IEEE Ku band (NATO J-band) transponders and 1 Ka band transponder. The C-band covers the Asia-Pacific region, while the Ku band transponders is used for Direct to Home broadcasting to Asia, Africa,Americas and the Middle East. The Ka band payload provides coverage to the Middle East and Central Asia

Intelsat 22

Intelsat 22, with the International Designator of the Committee on Space Research (COSPAR ID) 2012-011A is a satellite constructed by Boeing Space Systems for the Intelsat Corp.

The satellite was planned to be located at 72 degrees East Longitude over the Indian Ocean.

The Australian Defence Force (ADF) signed a $167 Million contract with Intelsat for the UHF payload on the Intelsat 22 satellite for 15 years of service.

Intelsat 35e

Intelsat 35e, also known as IS-35e is an Intelsat high-throughput geostationary communications satellite designed and manufactured by Boeing on the Boeing-702MP platform. It was launched on 5 July 2017.It is the fourth satellite of the EpicNG service and covers the Americas, Europe and Sub-Sahara Africa from the 34.5° west longitude. It has a mixed C band and Ku band, with the C band featuring EpicNG spot beams.

Intelsat 901

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.

JSAT (satellite constellation)

The JSAT constellation is a communication and broadcasting satellite constellation formerly operated by JSAT Corporation and currently by SKY Perfect JSAT Group. It has become the most important commercial constellation in Japan, and fifth in the world. It has practically amalgamated all private satellite operators in Japan, with only B-SAT left as a local competitor.It began in 1985 with the opening of the communication markets in Japan and the founding of Japan Communications Satellite Company, Satellite Japan Corporation, Space Communications Corporation. It grew by own investment, mergers and acquisitions of the parent companies. As of August 2016, in includes the fleets of three previously mentioned companies, Horizons Satellite and NTT DoCoMo and the DSN military network.

JUCE TV

JUCE TV is a youth-oriented Christian television network owned and operated by the Trinity Broadcasting Network. The network is aimed at teenagers and young adults between the ages of 13 and 30 years, and features a format similar to MTV and MTVU, airing Christian music videos, and original content such as Christian-themed entertainment and lifestyle programming, along with some church services.

JUCE TV is carried over-the-air on digital subchannels of TBN owned-and-operated and affiliated stations nationwide, usually on the third subchannel (for example, if the local TBN station broadcasts on channel 17, then JUCE TV would be carried on digital subchannel 17.3). Since June 1, 2015, the network has shared subchannel space with sister network Smile of a Child TV over-the-air; however, JUCE TV continues to operate as a separate 24-hour channel on pay television providers as well as on select digital streaming platforms that offer TBN's six U.S. networks.The network is also currently available through various cable providers nationwide as well as across North and Central America on Glorystar through the Ku band Galaxy 19 satellite and on C-Band Galaxy 14 satellite. The network is also live-streamed on its and TBN's official website as well as on the TBN Mobile App for the iPad, iPhone and iPod Touch. JUCE TV and other TBN-owned networks are broadcast internationally free-to-air via satellites such as ABS1 to India and Middle East on Ku band, Intelsat 701 and DTH to Australia and New Zealand on Optus B3 and also to Europe, North Africa and the Middle East via Eutelsat (Hotbird 13°E) and Agila 2 satellite (both C-band and Ku band signal) in Asia and the Philippines. Some JCTV programming can also be seen on Grace TV in Canada and on Trinity Broadcasting Network Europe.

List of SES satellites

This is a list of satellites operated by SES S.A.

List of satellites in geosynchronous orbit

This is a list of satellites in geosynchronous orbit. These satellites are commonly used for communication purposes, such as radio and television networks, back-haul, and direct broadcast. Traditional global navigation systems do not use geosynchronous satellites, but some SBAS navigation satellites do. A number of weather satellites are also present in geosynchronous orbits. Not included in the list below are several more classified military geosynchronous satellites, such as PAN.

Listings are from west to east (decreasing longitude in the Western Hemisphere and increasing longitude in the Eastern Hemisphere) by orbital position, starting and ending with the International Date Line.

A special case of geosynchronous orbit is the geostationary orbit, which is a circular geosynchronous orbit at zero inclination (that is, directly above the equator). A satellite in a geostationary orbit appears stationary, always at the same point in the sky, to ground observers. Popularly or loosely, the term "geosynchronous" may be used to mean geostationary. Specifically, geosynchronous Earth orbit (GEO) may be a synonym for geosynchronous equatorial orbit, or geostationary Earth orbit. Communications satellites are often given geostationary orbits, or close to geostationary, so that the satellite antennas that communicate with them do not have to move, but can be pointed permanently at the fixed location in the sky where the satellite appears.

Some of these satellites are separated from each other by as little as one tenth of a degree longitude. This corresponds to an inter-satellite spacing of approximately 73 km. The major consideration for spacing of geostationary satellites is the beamwidth at-orbit of uplink transmitters, which is primarily a factor of the size and stability of the uplink dish, as well as what frequencies the satellite's transponders receive; satellites with discontiguous frequency allocations can be much closer together.

As of April 2018, the website UCS Satellite Database lists 1,886 known satellites. This includes all orbits and everything down to the little CubeSats, not just satellites in GEO. Of these, 548 are listed in the database as being at GEO. The website provides a spreadsheet containing details of all the satellites, which can be downloaded.

Satellites in inclined geosynchronous orbit are so indicated by a note in the "remarks" columns. Data below is from 2015 and is out of date.

NSS-6

NSS-6 is a communications satellite owned by SES WORLD SKIES.

NSS-6 covers the whole of Asia with six high-performance Ku band beams, which can deliver broadband media to small businesses, ISPs or domestic rooftop antennas in those markets. The satellite delivers Direct-To-Home power and performance, as well as significant inter-regional connectivity. High-gain uplink performance (i.e. high receiver G/T figures) allows the use of small uplink antennas and/or amplifiers.

Manufacturer: Lockheed-Martin

Orbital Location: 95° East

Launch date: December 17, 2002

Launch Vehicle: Ariane 4

Number of Transponders (physical): Ku band: 50

Number of Transponders (36 MHz Equivalent): 60

Saturated EIRP Range: Ku band: 44 to 55 dBW

Frequency Band: Ku band uplink: 13.75 to 14.50 GHz

Frequency Band: Ka band uplink: 29.5 to 30.0 GHz

Frequency Band: Ku band downlink: 10.95 to 11.20 GHz, 11.45 to 11.70 GHz, 12.50 to 12.75 GHz

PBS Satellite Service

PBS Satellite Service (Also known as PBS National or simply PBS Satellite. Formerly known as PBS Schedule X in Eastern Time, with the west coast delay signal designated PBS-XD) are feeds relayed from PBS by satellite. The service provides a mixed variety of programming selected from PBS's regular network services. In the X/XD years a satellite feed was multicast by some PBS member stations on an over-the-air DTV subchannel along with their regular programming, or during overnight hours on their main channel to provide a second opportunity for viewers to watch or record primetime programming.

As of 2018, the PBS satellite feeds can be received unscrambled using a free-to-air satellite receiver set to these coordinates:

PBS at 125°W (on the AMC-21 satellite, Ku-band, unencrypted.

LPB at 87°W (on the SES-2 satellite), Ku-band, unencrypted.

PBS at 103°W (on the SES-3 satellite), C-band, unencrypted.Currently, select stations broadcast the feed, usually overnight, like KGTF (PBS Guam, broadcasts most of the channel as a localised feed). The channel is also available over satellite providers like DirecTV (Channel: 389). This channel is available to viewers of DirecTV (and other providers). PBS stations provide all of their channels free to TV providers who do not receive local channels.

SES-6

SES-6 is a commercial geostationary communication satellite owned and operated by SES.

Constructed by EADS Astrium, it was launched on June 3, 2013 and carries 48 Ku-band and 43 C-band transponders.

Satellite television

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.

A satellite receiver then decodes the desired television programme for viewing on a television set. Receivers can be external set-top boxes, or a built-in television tuner. Satellite television provides a wide range of channels and services. It is usually the only television available in many remote geographic areas without terrestrial television or cable television service.

Modern systems signals are relayed from a communications satellite on the Ku band frequencies (12–18 GHz) requiring only a small dish less than a meter in diameter. The first satellite TV systems were an obsolete type now known as television receive-only. These systems received weaker analog signals transmitted in the C-band (4–8 GHz) from FSS type satellites, requiring the use of large 2–3-meter dishes. Consequently, these systems were nicknamed "big dish" systems, and were more expensive and less popular.Early systems used analog signals, but modern ones use digital signals which allow transmission of the modern television standard high-definition television, due to the significantly improved spectral efficiency of digital broadcasting. As of 2018, Star One C2 from Brazil is the only remaining satellite broadcasting in analog signals, as well as one channel (C-SPAN) on AMC-11 from the United States.Different receivers are required for the two types. Some transmissions and channels are unencrypted and therefore free-to-air or free-to-view, while many other channels are transmitted with encryption (pay television), requiring the viewer to subscribe and pay a monthly fee to receive the programming.

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