"GWEN is a radio communications system designed to relay emergency messages between strategic military areas in the continental United States. The system is immune to the effects of high-altitude electromagnetic pulse (HEMP) energy surges caused by nuclear detonations in the ionosphere that would disrupt conventional communications equipment. A failure of such equipment would prevent timely communications among top military and civilian leaders and strategic Air Force locations and prevent U.S. assessment and retaliation during an attack. GWEN is an essential part of a defense modernization program to upgrade and improve our nation's communications system, thereby strengthening deterrence..."
The plan was that GWEN should be able to survive the effects of a, EMP (El;ectro-Magnetic Pulse) so that surviving leadership could retain control and direct military response via emergency messages. Early research showed that low frequency signals between 150-200 kHZ were less effected EMP. Based on that somewhat dubious idea, they pressed on. In 1978 they began testing groundwave transmissions at Kirtland Air Force Base. Eventually they would deploy a system on a sub-set of frequencies between 150-175 kHz. The network was conceived as a network of more than a hundred radio towsers based around major US cities. The final number was just 58. The network had three types of stations: Receive-only, Relay-only, and input/output stations, which presumably are send/receive.
Initially called PGCS, (Proliferated Groundwave Communications System,) The USAF put out some Program management documents around 1981, and in 1982 they changed the name to GWEN. In 1987, the Air Force Electronic Systems Division published an environmental impact study for GWEN more-or-less determining that it was harmless. Very little happened until 1992 when the USAF began actual deployment. They described sites in the following dull language:
"The facility will consist of a 299-foot-tall, low-frequency (LF) transmitter tower, three equipment shelters, an access road, and associated fences. The tower will be supported by 24 guy wires, including 12 top-loading elements. An equipment shelter at the tower base will contain an antenna tuning unit. An 8-foot-high chain link fence topped with barbed wire will surround the tower base and associated equipment shelter. A radial ground plane, composed of 60 to 100, 0.128-inch- diameter copper wires buried about 12 inches underground, will extend out about 330 feet from the tower base. A 4-foot-high fence will be installed around the perimeter of the copper radials. A second equipment area located at the site perimeter will contain two shelters housing a back-up power group (BUPG) with two internal fuel storage tanks and radio processing equipment. The BUPG will operate during power outages and for testing purposes. An LF receive antenna, consisting of a pair of 4-foot-diameter rings mounted on a 10-foot pole, and an ultrahigh-frequency (UHF) antenna, used for communicating with airborne input/output terminals and consisting of a 9-foot-high whip-like antenna mounted on a 30-foot-high pole, will also be located in this area. An 8-foot-high chain link fence topped with barbed wire will enclose the entire equipment area. A 10- foot-wide gravel road will connect this area to the tower base. A 12-foot-wide gravel road will provide access to the site from a public road."Not very exciting right? During deployment of the network it was found that GWEN had some interference issues. Those selected low frequencies were not vacant. GWEN ultimately did not survive.Citizens groups felt that a GWEN tower made their small town a Soviet nuclear target, then there were the cranks who believe that the government was using GWEN for mind control. As satellite systems became more viable the military lost interest. Today the network is shut down, but the USAF still operates many of these sites just leasing tower spare to offset the huge cost of the network.