Ku band
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| IEEE Radio bands |
- The correct title of this article is Ku band. It features superscript or subscript characters that are substituted or omitted because of technical limitations.
The Ku band (pronounced "kay-yoo"; Kurtz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 12 to 18 GHz.
Ku band is primarily used for satellite communications, particularly for satellite backhauls 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 Ku band in 1983.
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[edit] Segments and regions
[edit] The Americas
Segments in most of the Americas are represented by (ITU Region 2) and they are, the 11.7 to 12.2 GHz (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 Ku-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 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).
[edit] 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 10.600 GHz) for Direct Broadcast Satellite services like SES Astra.
The 11.7 to 12.5 GHz segment is allocated to the BSS (broadcasting satellite service).
[edit] 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.
[edit] Indonesia
The International Telecommunication Union, 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 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). 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.
[edit] Limits
Ku band signals can be affected by rain attenuation (rain fade). In case of TV reception, only heavy rainfalls (>100 mm/hr) will have noticeable effect for the user.
[edit] See also
[edit] External links
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| (Sorted by wavelength, short to long) Gamma ray • X-ray • Ultraviolet • Visible spectrum • Infrared • Terahertz radiation • Microwave • Radio waves |
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| Visible (optical) spectrum | Violet • Blue • Green • Yellow • Orange • Red |
| Microwave spectrum | W band • V band • K band: Ka band, Ku band • X band • C band • S band • L band |
| Radio spectrum | EHF • SHF • UHF • VHF • HF • MF • LF • VLF • ULF • SLF • ELF |
| Wavelength designations | Microwave • Shortwave • Mediumwave • Longwave |
