Ku band

The Ku band () 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 atmospheric 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 to 18 GHz according to the formal definition of radar frequency band nomenclature in IEEE Standard 521–2002. 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 International Space Station (ISS) communications and SpaceX Starlink satellites. 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.