The Ground Wave Emergency Network (GWEN) was a US Air Force command and control communications system, deployed briefly between 1992 and 1994, intended for use by the United States government to facilitate military communications before, during and after a nuclear war. Specifically, the GWEN network was intended to survive the effects of an electromagnetic pulse from a high-altitude nuclear explosion and ensure that the United States President or their survivors could issue a launch order to Strategic Air Command bombers by radio.

Low frequency (LF) is the ITU designation for radio frequencies (RF) in the range of 30–300 kHz. Since its wavelengths range from 10–1 km, respectively, it is also known as the kilometre band or kilometre waves.