<\/p>\n
AN\/URC-117 Ground Wave Emergency Network<\/h1>\n\nFrom Wikipedia, the free encyclopedia<\/div>\n<\/div>\n<\/div>\n\n\n\n![\"\"](\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/4\/42\/Typical_GWEN_relay_node.PNG\/220px-Typical_GWEN_relay_node.PNG\")
<\/a><\/p>\n\n<\/div>\nTypical GWEN relay node<\/p>\n<\/div>\n<\/div>\n<\/div>\n
The\u00a0Ground Wave Emergency Network<\/b>\u00a0(GWEN<\/b>) was a\u00a0command and control<\/a>\u00a0communications system intended for use by the United States government to facilitate\u00a0military communications<\/a>\u00a0before, during and after a\u00a0nuclear war<\/a>. Specifically, the GWEN network was intended to survive the effects of an\u00a0electromagnetic pulse<\/a>\u00a0from a\u00a0high-altitude nuclear explosion<\/a>\u00a0and ensure that the United States President or his survivors could issue a launch order to\u00a0Strategic Air Command<\/a>\u00a0bombers by radio.[1]<\/a><\/sup>[2]<\/a><\/sup>[3]<\/a><\/sup><\/p>\nAN\/URC-117 was the system’s\u00a0Joint Electronics Type Designation System<\/a>\u00a0identifier, which signified various radio components installed in different locations.[4]<\/a><\/sup>\u00a0Each GWEN Relay Node site featured a\u00a0longwave<\/a>\u00a0transmitting tower, generally between 290 and 299 feet (88 and 91\u00a0m) tall, and emitting an\u00a0RF<\/a>\u00a0output of between 2,000 and 3,000\u00a0watts<\/a>. Of 240 planned GWEN towers, only 58 were built. In 1994, a defense appropriations bill banned the funding of new GWEN tower construction, and a few months later, the GWEN program was cancelled by the\u00a0US Air Force<\/a>.[5]<\/a><\/sup>\u00a0The\u00a0United States Coast Guard<\/a>\u00a0later outfitted a number of former GWEN sites to house the National\u00a0Differential GPS<\/a>\u00a0system.[6]<\/a><\/sup>[7]<\/a><\/sup><\/p>\n <\/p>\n
\n\nContents<\/h2>\n
[hide<\/a>]<\/p>\n<\/div>\n\n- 1History<\/a><\/li>\n
- 2Operations<\/a>\n
\n- 2.1Problems<\/a><\/li>\n<\/ul>\n<\/li>\n
- 3Site layout<\/a><\/li>\n
- 4GWEN site locations<\/a><\/li>\n
- 5Termination<\/a><\/li>\n
- 6Gallery<\/a><\/li>\n
- 7See also<\/a><\/li>\n
- 8References<\/a><\/li>\n
- 9External links<\/a><\/li>\n<\/ul>\n<\/div>\n
<\/p>\n
<\/h2>\n
GWEN was part of the Strategic Modernization Program designed to upgrade the nation’s strategic communication system, thereby strengthening the value of nuclear\u00a0deterrence<\/a>. The GWEN communication system, established in the late 1980s, was designed to transmit critical\u00a0Emergency Action Messages<\/a>\u00a0(EAM) to United States nuclear forces.\u00a0EMP<\/a>\u00a0can produce a sudden\u00a0power surge<\/a>\u00a0over 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\u00a0propagation<\/a>. It was thought that GWEN would use a ground-hugging wave for propagation and so be unaffected by the EMP.[1]<\/a><\/sup>\u00a0The network was conceived as an array of approximately 240\u00a0radio<\/a>\u00a0transceivers<\/a>\u00a0distributed across the\u00a0continental USA<\/a>\u00a0which operated in the\u00a0Low frequency<\/a>\u00a0(LF)\u00a0radio band<\/a>.<\/p>\nAnalysis showed that low-frequency (150-190 kilohertz) radio transmissions were largely unaffected by high-altitude EMP, and the Air Force Weapons Laboratory (Kirtland Air Force Base<\/a>) tested a small scale ‘groundwave’ transmission system in 1978-1982. Based on the groundwave concept’s promise, USAF Headquarters issued a draft Program Management Directive (PMD) for a “Proliferated Groundwave Communications System (PGCS)” on 25 August 1981. The name of this proposed network system was changed from PGCS to Groundwave Emergency Network in February 1982[8]<\/a><\/sup>\u00a0The Air Force placed a tentative initial operating capability for GWEN by January 1992.[2]<\/a><\/sup><\/p>\nWhen doubts arose regarding the threat of electromagnetic pulse to permanently shut down communications, only 58 of the originally planned 240 GWEN towers were built. In 1994 a defense appropriations bill banned new towers from being built, and shortly after, the GWEN program was cancelled by the Air Force.[5]<\/a><\/sup><\/p>\n<\/h2>\n
Command and control messages originating at various military installations were transmitted on the 225 to 400\u00a0MHz<\/a>\u00a0band and received by a network of unmanned relay stations, called “Relay Nodes”, dispersed throughout the contiguous 48 states. The Relay Nodes would re-transmit these command and control messages to each other, and to Strategic Air Command operating locations and launch control centers using\u00a0low frequencies<\/a>\u00a0in the 150-175\u00a0kHz<\/a>range in order to take advantage of ground-hugging\u00a0radio propagation<\/a>\u00a0similar to commercial\u00a0AM radio<\/a>\u00a0stations.[1]<\/a><\/sup><\/p>\nDistance between the Relay Nodes were approximately 150\u2013200 miles, determined by the ground wave transmission range.[1]<\/a><\/sup>\u00a0During initial operations, the Relay Nodes would receive and relay brief test messages every 20 minutes.[2]<\/a><\/sup>\u00a0The system had built-in redundancy, using\u00a0packet switching<\/a>\u00a0techniques for reconstruction of connectivity if system damage occurred.[9]<\/a><\/sup><\/p>\n<\/h3>\n
Early in its lifetime, electrical interference problems caused by GWEN system operation began to surface. Since the stations were using LF, the chosen frequency was within 1\u00a0kHz of the operating frequency of nearby electrical\u00a0carrier current<\/a>\u00a0systems. With GWEN handling constant voice, teletype and other data traffic, it caused interference to the power companies diagnostic two kilohertz side carrier tone. When the side carrier tone disappeared due to interference from GWEN, the power grid would interpret that as a system fault.[10]<\/a><\/sup><\/p>\n<\/h2>\n
The overall area of a GWEN Relay Node was approximately 11 acres (4.5\u00a0ha), approximately 700 feet (210\u00a0m) \u00d7 700 feet. It was surrounded on the perimeter by locked, 8-foot-high (2.4\u00a0m) chain-link fences topped with barbed wire. Typical site features included:[1]<\/a><\/sup><\/p>\n\n- A main\u00a0Longwave<\/a>\u00a0transmitting tower (generally between 290 and 299 feet (88 and 91\u00a0m) tall<\/li>\n
- A radial network of underground wires forming a large\u00a0ground plane<\/a>\u00a0to serve as a reflecting surface for\u00a0radio waves<\/a><\/li>\n
- Three electronic equipment shelters; two located near the perimeter of the site, and one at the base of the tower containing an\u00a0antenna-tuning unit<\/a>\u00a0(ATU)<\/li>\n
- UHF and LF receive antennas mounted on either a 10 ft. mast, 30 ft. light pole, or 60-150 ft. tower.<\/li>\n
- A diesel backup generator, with a two-chambered fuel tank having a capacity of 1,020 US gallons (3,900\u00a0l)<\/li>\n<\/ul>\n
The main GWEN antenna operated intermittently in the LF band at 150 to 175 kilohertz (kHz) (below the bottom of the\u00a0AM broadcast band<\/a>\u00a0at 530\u00a0kHz). The peak broadcasting power was from 2,000 to 3,000 watts. The UHF antenna operated at 20 watts, between 225 and 400 megahertz (MHz).[1]<\/a><\/sup><\/p>\n<\/h2>\n
A 1998\u00a0Department of Transportation<\/a>\u00a0environmental impact survey that proposed repurposing a number of existing GWEN sites for use by the\u00a0Nationwide Differential Global Positioning System<\/a>\u00a0listed the locations of 29 GWEN sites:[6]<\/a><\/sup><\/p>\n\n- Appleton, Washington<\/a><\/li>\n
- Austin, Nevada<\/a><\/li>\n
- Bakersfield, California<\/a><\/li>\n
- Billings, Montana<\/a><\/li>\n
- Bobo, Mississippi<\/a><\/li>\n
- Clark, South Dakota<\/a><\/li>\n
- Edinburg, North Dakota<\/a><\/li>\n
- Fenner, California<\/a><\/li>\n
- Flagstaff, Arizona<\/a><\/li>\n
- Gettysburg, Pennsylvania<\/a><\/li>\n
- Goodland, Kansas<\/a><\/li>\n
- Grady, Alabama<\/a><\/li>\n
- Great Falls, Montana<\/a><\/li>\n
- Hackleburg, Alabama<\/a><\/li>\n
- Hagerstown, Maryland<\/a><\/li>\n
- Hawk Run, Pennsylvania<\/a><\/li>\n
- Kirtland AFB, New Mexico<\/a><\/li>\n
- Klamath Falls, Oregon<\/a><\/li>\n
- Macon, Georgia<\/a><\/li>\n
- Medford, Wisconsin<\/a><\/li>\n
- Medora, North Dakota<\/a><\/li>\n
- Onondaga, Michigan<\/a><\/li>\n
- Penobscot, Maine<\/a><\/li>\n
- Pueblo, Colorado<\/a><\/li>\n
- Ronan, Montana<\/a><\/li>\n
- Savannah Beach, Georgia<\/a><\/li>\n
- Spokane, Washington<\/a><\/li>\n
- Summerfield, Texas<\/a><\/li>\n
- Whitney, Nebraska<\/a><\/li>\n<\/ul>\n
<\/h2>\n
Some of the initial towers had prompted groups of citizens in\u00a0Massachusetts<\/a>,\u00a0Oregon<\/a>,\u00a0Pennsylvania<\/a>, and\u00a0California<\/a>\u00a0to organize to fight construction of GWEN towers in their areas. The groups believed that the presence of a GWEN node would increase the community’s “strategic worth” in the eyes of the Soviet Union and thus invite attack. Responding to these groups, the Air Force repeatedly downplayed the importance of the towers, stating they were not worth that kind of attention by the Soviet Union.[2]<\/a><\/sup><\/p>\nAmid controversy and world geopolitical changes, GWEN’s value diminished greatly in the post-Cold War<\/a>\u00a0environment, in addition to its existence being rendered moot by the sustained effectiveness of predecessor and follow-on systems (Survivable Low Frequency Communication System<\/a>\u00a0and\u00a0Minimum Essential Emergency Communication Network<\/a>\u00a0respectively). As early as 1990, legislative measures were enacted to terminate the program.[11]<\/a><\/sup><\/p>\nIn 1994, new construction of GWEN towers were banned after a defense appropriations bill eliminated any funding for the towers for one year. A few months later, the\u00a0United States Air Force<\/a>\u00a0announced that they would terminate the construction contract to build the remaining 25 towers, except for monies used to dismantle the system.[12]<\/a><\/sup><\/p>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"from\u00a0https:\/\/en.wikipedia.org\/wiki\/AN\/URC-117_Ground_Wave_Emergency_Network AN\/URC-117 Ground Wave Emergency Network From Wikipedia, the free encyclopedia Typical GWEN relay node The\u00a0Ground Wave Emergency Network\u00a0(GWEN) was a\u00a0command and control\u00a0communications system intended for use by the United States government to facilitate\u00a0military communications\u00a0before, during and after a\u00a0nuclear war. Specifically, the GWEN network was intended to survive the effects of an\u00a0electromagnetic pulse\u00a0from a\u00a0high-altitude […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":178,"menu_order":99,"comment_status":"open","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-13656","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/13656","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/emrabc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13656"}],"version-history":[{"count":5,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/13656\/revisions"}],"predecessor-version":[{"id":13661,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/13656\/revisions\/13661"}],"up":[{"embeddable":true,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/178"}],"wp:attachment":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
<\/a><\/p>\nTypical GWEN relay node<\/p>\n<\/div>\n<\/div>\n<\/div>\n
The\u00a0Ground Wave Emergency Network<\/b>\u00a0(GWEN<\/b>) was a\u00a0command and control<\/a>\u00a0communications system intended for use by the United States government to facilitate\u00a0military communications<\/a>\u00a0before, during and after a\u00a0nuclear war<\/a>. Specifically, the GWEN network was intended to survive the effects of an\u00a0electromagnetic pulse<\/a>\u00a0from a\u00a0high-altitude nuclear explosion<\/a>\u00a0and ensure that the United States President or his survivors could issue a launch order to\u00a0Strategic Air Command<\/a>\u00a0bombers by radio.[1]<\/a><\/sup>[2]<\/a><\/sup>[3]<\/a><\/sup><\/p>\n AN\/URC-117 was the system’s\u00a0Joint Electronics Type Designation System<\/a>\u00a0identifier, which signified various radio components installed in different locations.[4]<\/a><\/sup>\u00a0Each GWEN Relay Node site featured a\u00a0longwave<\/a>\u00a0transmitting tower, generally between 290 and 299 feet (88 and 91\u00a0m) tall, and emitting an\u00a0RF<\/a>\u00a0output of between 2,000 and 3,000\u00a0watts<\/a>. Of 240 planned GWEN towers, only 58 were built. In 1994, a defense appropriations bill banned the funding of new GWEN tower construction, and a few months later, the GWEN program was cancelled by the\u00a0US Air Force<\/a>.[5]<\/a><\/sup>\u00a0The\u00a0United States Coast Guard<\/a>\u00a0later outfitted a number of former GWEN sites to house the National\u00a0Differential GPS<\/a>\u00a0system.[6]<\/a><\/sup>[7]<\/a><\/sup><\/p>\n <\/p>\n [hide<\/a>]<\/p>\n<\/div>\n <\/p>\n GWEN was part of the Strategic Modernization Program designed to upgrade the nation’s strategic communication system, thereby strengthening the value of nuclear\u00a0deterrence<\/a>. The GWEN communication system, established in the late 1980s, was designed to transmit critical\u00a0Emergency Action Messages<\/a>\u00a0(EAM) to United States nuclear forces.\u00a0EMP<\/a>\u00a0can produce a sudden\u00a0power surge<\/a>\u00a0over 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\u00a0propagation<\/a>. It was thought that GWEN would use a ground-hugging wave for propagation and so be unaffected by the EMP.[1]<\/a><\/sup>\u00a0The network was conceived as an array of approximately 240\u00a0radio<\/a>\u00a0transceivers<\/a>\u00a0distributed across the\u00a0continental USA<\/a>\u00a0which operated in the\u00a0Low frequency<\/a>\u00a0(LF)\u00a0radio band<\/a>.<\/p>\n Analysis showed that low-frequency (150-190 kilohertz) radio transmissions were largely unaffected by high-altitude EMP, and the Air Force Weapons Laboratory (Kirtland Air Force Base<\/a>) tested a small scale ‘groundwave’ transmission system in 1978-1982. Based on the groundwave concept’s promise, USAF Headquarters issued a draft Program Management Directive (PMD) for a “Proliferated Groundwave Communications System (PGCS)” on 25 August 1981. The name of this proposed network system was changed from PGCS to Groundwave Emergency Network in February 1982[8]<\/a><\/sup>\u00a0The Air Force placed a tentative initial operating capability for GWEN by January 1992.[2]<\/a><\/sup><\/p>\n When doubts arose regarding the threat of electromagnetic pulse to permanently shut down communications, only 58 of the originally planned 240 GWEN towers were built. In 1994 a defense appropriations bill banned new towers from being built, and shortly after, the GWEN program was cancelled by the Air Force.[5]<\/a><\/sup><\/p>\n Command and control messages originating at various military installations were transmitted on the 225 to 400\u00a0MHz<\/a>\u00a0band and received by a network of unmanned relay stations, called “Relay Nodes”, dispersed throughout the contiguous 48 states. The Relay Nodes would re-transmit these command and control messages to each other, and to Strategic Air Command operating locations and launch control centers using\u00a0low frequencies<\/a>\u00a0in the 150-175\u00a0kHz<\/a>range in order to take advantage of ground-hugging\u00a0radio propagation<\/a>\u00a0similar to commercial\u00a0AM radio<\/a>\u00a0stations.[1]<\/a><\/sup><\/p>\n Distance between the Relay Nodes were approximately 150\u2013200 miles, determined by the ground wave transmission range.[1]<\/a><\/sup>\u00a0During initial operations, the Relay Nodes would receive and relay brief test messages every 20 minutes.[2]<\/a><\/sup>\u00a0The system had built-in redundancy, using\u00a0packet switching<\/a>\u00a0techniques for reconstruction of connectivity if system damage occurred.[9]<\/a><\/sup><\/p>\n Early in its lifetime, electrical interference problems caused by GWEN system operation began to surface. Since the stations were using LF, the chosen frequency was within 1\u00a0kHz of the operating frequency of nearby electrical\u00a0carrier current<\/a>\u00a0systems. With GWEN handling constant voice, teletype and other data traffic, it caused interference to the power companies diagnostic two kilohertz side carrier tone. When the side carrier tone disappeared due to interference from GWEN, the power grid would interpret that as a system fault.[10]<\/a><\/sup><\/p>\n The overall area of a GWEN Relay Node was approximately 11 acres (4.5\u00a0ha), approximately 700 feet (210\u00a0m) \u00d7 700 feet. It was surrounded on the perimeter by locked, 8-foot-high (2.4\u00a0m) chain-link fences topped with barbed wire. Typical site features included:[1]<\/a><\/sup><\/p>\n The main GWEN antenna operated intermittently in the LF band at 150 to 175 kilohertz (kHz) (below the bottom of the\u00a0AM broadcast band<\/a>\u00a0at 530\u00a0kHz). The peak broadcasting power was from 2,000 to 3,000 watts. The UHF antenna operated at 20 watts, between 225 and 400 megahertz (MHz).[1]<\/a><\/sup><\/p>\n A 1998\u00a0Department of Transportation<\/a>\u00a0environmental impact survey that proposed repurposing a number of existing GWEN sites for use by the\u00a0Nationwide Differential Global Positioning System<\/a>\u00a0listed the locations of 29 GWEN sites:[6]<\/a><\/sup><\/p>\n Some of the initial towers had prompted groups of citizens in\u00a0Massachusetts<\/a>,\u00a0Oregon<\/a>,\u00a0Pennsylvania<\/a>, and\u00a0California<\/a>\u00a0to organize to fight construction of GWEN towers in their areas. The groups believed that the presence of a GWEN node would increase the community’s “strategic worth” in the eyes of the Soviet Union and thus invite attack. Responding to these groups, the Air Force repeatedly downplayed the importance of the towers, stating they were not worth that kind of attention by the Soviet Union.[2]<\/a><\/sup><\/p>\n Amid controversy and world geopolitical changes, GWEN’s value diminished greatly in the post-Cold War<\/a>\u00a0environment, in addition to its existence being rendered moot by the sustained effectiveness of predecessor and follow-on systems (Survivable Low Frequency Communication System<\/a>\u00a0and\u00a0Minimum Essential Emergency Communication Network<\/a>\u00a0respectively). As early as 1990, legislative measures were enacted to terminate the program.[11]<\/a><\/sup><\/p>\n In 1994, new construction of GWEN towers were banned after a defense appropriations bill eliminated any funding for the towers for one year. A few months later, the\u00a0United States Air Force<\/a>\u00a0announced that they would terminate the construction contract to build the remaining 25 towers, except for monies used to dismantle the system.[12]<\/a><\/sup><\/p>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":" from\u00a0https:\/\/en.wikipedia.org\/wiki\/AN\/URC-117_Ground_Wave_Emergency_Network AN\/URC-117 Ground Wave Emergency Network From Wikipedia, the free encyclopedia Typical GWEN relay node The\u00a0Ground Wave Emergency Network\u00a0(GWEN) was a\u00a0command and control\u00a0communications system intended for use by the United States government to facilitate\u00a0military communications\u00a0before, during and after a\u00a0nuclear war. Specifically, the GWEN network was intended to survive the effects of an\u00a0electromagnetic pulse\u00a0from a\u00a0high-altitude […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":178,"menu_order":99,"comment_status":"open","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-13656","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/13656","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/emrabc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=13656"}],"version-history":[{"count":5,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/13656\/revisions"}],"predecessor-version":[{"id":13661,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/13656\/revisions\/13661"}],"up":[{"embeddable":true,"href":"https:\/\/emrabc.ca\/index.php?rest_route=\/wp\/v2\/pages\/178"}],"wp:attachment":[{"href":"https:\/\/emrabc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Contents<\/h2>\n
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