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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) | - | - |
External Links:
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Radio Astronomy Formaldehyde (H2CO) Observations
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Radio astronomers observe molecular lines of formaldehyde at both 14.49 GHz and 4830 MHz. According to the European Science Foundation's Committee on Radio Astronomy Frequencies (CRAF):
At 14.4885 GHz an important formaldehyde (H2CO) line exists, which has been observed in the direction of many galactic sources. Since these lines originate from the upper levels of ortho-formaldehyde their study gives valuable information on the physical conditions of the interstellar medium, because the excitation energies required to produce such lines are different from the energies required to produce the H2CO lines observed at 4829.66 MHz.
There is no formal allocation to the radio astronomy service in these bands, but the international footnote 5.149 and the U.S. footnote US203 note that consideration should be taken to the use of 14.47-14.5 GHz and 4825-4835 MHz band segments for radio astronomy.
In the U.S., there is an increasing use of the entire 14-14.5 GHz band by vehicle-, ship-, and airplane-based Internet terminals that communicate through geostationary satellites (14-14.5 GHz is used as the uplink band). Such activities are required by the FCC to be coordinated with the radio astronomy service.
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Frequency Bands |
Band | Use | Service | Table |
4825 - 4835 MHz | Radio astronomy observations of formaldehyde (4829.66 MHz) | Radio Astronomy | - |
14.47 - 14.5 GHz | Radio astronomy observations of formaldehyde (14.4885 GHz) | Radio Astronomy | - |
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