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802.11/WLAN/Wi-Fi/WiGig
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Wireless LANS utilize various channels in the 2.4, 5, and 6 GHz bands (multiple countries), and (in theory) the 3.6 GHz band (U.S. only). For a list of which channels are available in which regions, refer to the Wikipedia article.
Wi-Fi is a trademark permitted for devices that are based upon a published standard of the IEEE 802.11 committee and that have been certified by the Wi-Fi Alliance. Wi-Fi is presently incorporated in about three billion devices. Wireless cash registers were one of the earliest applications of what is now Wi-Fi.
Wi-Fi devices operate on an unlicensed basis, generally meaning they cannot cause interference to licensed services, and must accept any interference caused to them. Wi-Fi shares bands with other unlicensed or ISM devices, such as cordless phones at 2.4 and 5.8 GHz and microwave ovens at 2.4 GHz.
Some of the key patents related to Wi-Fi are credited (in the courts at least) to the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia, which has collected over $400 million in royalties and legal settlements over patent rights.
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Frequency Bands |
Band | Use | Service | Table |
2400 - 2495 MHz | Wireless LANs | - | - |
3655 - 3700 MHz | Wireless LANS (U.S. only; standardized but not used) | - | - |
4910 - 4990 MHz | Wireless LANs (Japan) (U.S. public safety 4940-4990) | - | - |
5030 - 5090 MHz | WLANs (Japan, 2002-2017) | - | - |
5150 - 5350 MHz | Wireless LANs (U-NII-1 and U-NII-2A) | - | - |
5470 - 5895 MHz | Wireless LANs (U-NII-2C, U-NII-3, U-NII-4) | - | - |
5925 - 7125 MHz | Wireless LANs (U-NII-5, U-NII-6, U-NII-7, U-NII-8) | - | - |
42.39 - 46.71 GHz | Wireless LANs (WiGig) | - | - |
57.24 - 74.52 GHz | Wireless LANs (WiGig) | - | - |
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RADARSAT
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According to the Canadian Space Agency,
RADARSAT-1 is a sophisticated Earth observation satellite developed by Canada to monitor environmental changes and the planet's natural resources.
Launched in November 1995, RADARSAT-1 provides Canada and the world with an operational radar satellite system capable of timely delivery of large amounts of data. Equipped with a powerful synthetic aperture radar (SAR) instrument, it acquires images of the Earth day or night, in all weather and through cloud cover, smoke and haze.
Canada also operates RADARSAT-2:
Launched in December 2007, Canada's next-generation commercial radar satellite offers powerful technical advancements that will enhance marine surveillance, ice monitoring, disaster management, environmental monitoring, resource management and mapping in Canada and around the world.
This project represents a unique collaboration between government and industry. MacDonald, Dettwiler and Associates Ltd. (MDA) will own and operate the satellite and ground segment. The Canadian Space Agency helps fund the construction and launch of the satellite and will recover this investment through the supply of RADARSAT-2 data to the Government of Canada during the lifetime of the mission.
Both satellites operate in non-GSO orbits with altitudes randing from 792-813 km, and an orbital inclination of 98.6 deg. The peak radiated power for RADARSAT-1 is 4350 W, and for RADARSAT-2 it is 2400 or 3700 W.
Additional satellites in the RADARSAT series are planned, including RADARSAT-3 and RADARSAT-Next Generation (RNG).
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Frequencies |
Frequency | Bandwidth | Use | Service | Table |
5300 MHz | 30 MHz | RADARSAT-1 | Earth Exploration-satellite | - |
5405 MHz | 100 MHz | RADARSAT-2 | Earth Exploration-satellite | - |
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