Glossary - U

Ultra High Frequency (UHF)
radio band with frequencies in the range 300 MHz to 3 GHz
(physics)

Ultraviolet (UV)
a form of electromagnetic radiation between X-rays and visible light in the electromagnetic spectrum; ultraviolet radiation has a wavelength between about 10 and 400 nm
(physics)

Uplink
signal path from the transmitting earth station to the satellite; also the earth station transmitting the signal
(communications)