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The S band is defined by an IEEE standard for radio waves with frequencies that range from 2 to 4 GHz, crossing the conventional boundary between UHF and SHF at 3.0 GHz. It is part of the microwave band of the electromagnetic spectrum. The S band is used by weather radar, surface ship radar, and some communications satellites, especially those used by NASA to communicate with the Space Shuttle and the International Space Station. The 10-cm radar short-band ranges roughly from 1.55 to 5.2 GHz.
In the U.S., the FCC approved Digital Audio Radio Satellite (DARS) broadcasts in the S band from 2.31 to 2.36 GHz, currently used by Sirius XM Radio. More recently, it has approved for portions of the S band between 2.0 and 2.2 GHz the creation of Mobile Satellite Service (MSS) networks in connection with Ancillary Terrestrial Components (ATC). There are presently a number of companies attempting to deploy such networks, including ICO Satellite Management and TerreStar.
The 2.6 GHz range is used for China Multimedia Mobile Broadcasting, a satellite radio and mobile TV standard which, as with proprietary systems in the U.S., is incompatible with the open standards used in the rest of the world.
In May 2009, Inmarsat and Solaris Mobile (a joint venture between Eutelsat and Astra) were awarded each a 2×15 MHz portion of the S band by the European Commission.[1] The two companies are allowed two years to start providing pan-European MSS services for 18 years. Allocated frequencies are 1.98 to 2.01 GHz for Earth to space communications, and from 2.17 to 2.2 GHz for space to Earth communications.[2] Eutelsat W2A satellite launched in April, 2009 and located at 10° East is currently the unique satellite in Europe operating on S band frequencies.
In some countries, S band is used for Direct-to-Home satellite television (unlike similar services in most countries, which use Ku band). The frequency typically allocated for this service is 2.5 to 2.7 GHz (LOF 1.570 GHz).
Wireless network equipment compatible with IEEE 802.11b and 802.11g standards use the 2.4 GHz section of the S band. Digital cordless telephones operate in this band too. Microwave ovens operate at 2495 or 2450 MHz. IEEE 802.16a and 802.16e standards utilize a part of the frequency range of S band, under WiMAX standards most vendors are now manufacturing equipment in the range of 3.5 GHz. The exact frequency range allocated for this type of use varies between countries.
In North America, 2.4 - 2.483 GHz is an ISM band used for unlicensed spectrum devices such as cordless phones, wireless headphones, and video senders, among other consumer electronics uses, including Bluetooth which operates between 2.402 GHz and 2.480 GHz.
Amateur radio and amateur satellite operators have two S-band allocations, 13 cm (2.4 GHz) and 9 cm (3.4 GHz).
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S band is also used in optical communications to refer to the wavelength range 1460 nm to 1530 nm.
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