GWEN was part of the Strategic Modernization Program designed to upgrade the nation's strategic communication system, thereby strengthening the value of nuclear deterrence. The GWEN communication system, established in the late 1980s, was designed to transmit critical Emergency Action Messages (EAM) to United States nuclear forces. EMP can produce a sudden power surge over a widespread area that could overload unprotected electronic equipment and render it inoperable. In addition, EMP could interfere with radio transmissions that use the ionosphere for propagation. It was thought that GWEN would use a ground-hugging wave for propagation and so be unaffected by the EMP. The network was conceived as an array of approximately 240 radio transceivers distributed across the continental USA which operated in the Low frequency (LF) radio band.