The AN/FRC-117 Survivable Low Frequency Communications System (SLFCS) was a communications system designed to be able to operate, albeit at low data transfer rates, during and after a

nuclear attack Nuclear warfare, also known as atomic warfare, is a military conflict or prepared political strategy that deploys nuclear weaponry. Nuclear weapons are weapons of mass destruction; in contrast to conventional warfare, nuclear warfare can prod ...

. The system used both

very low frequency Very low frequency or VLF is the ITU designation for radio frequencies (RF) in the range of 3–30 kHz, corresponding to wavelengths from 100 to 10 km, respectively. The band is also known as the myriameter band or myriameter wave ...

(VLF), and

low frequency 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. LF radio waves ...

(LF) radio bands.

Mission

SLFCS was used for

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

nuclear forces' command and control communications for

Emergency Action Message In the United States military's strategic nuclear weapon nuclear command and control (NC2) system, an Emergency Action Message (EAM) is a preformatted message that directs nuclear-capable forces to execute specific Major Attack Options (MAOs) ...

dissemination and force direction. Single channel, receive only capability was provided at

ICBM An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...

launch control centers. The single channel operated between 14 kHz and 60 kHz to receive commands from remotely located Combat Operations Center – Transmit/Receive (T/R) sites; this low frequency range is only slightly affected by nuclear blasts. For example, the Silver Creek site typically transmitted at 34.5 kHz. The transmitter could be tuned to any designated frequency in the above mentioned range. Receivers could receive down to 14.0 kHz. SLFCS' primary advantage was that it would experience minimal radio signal degradation as a result of nuclear detonations. It would be an alternate means of communication during and after detonations, providing a survivable command and control communications network for the

Strategic Air Command Strategic Air Command (SAC) was a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible for command and control of the strategic bomber and intercontinental ballistic missile compon ...

( SAC), the

Joint Chiefs of Staff The Joint Chiefs of Staff (JCS) is the body of the most senior uniformed leaders within the United States Department of Defense, which advises the president of the United States, the secretary of defense, the Homeland Security Council and ...

( JCS), and

North American Aerospace Defense Command North American Aerospace Defense Command (NORAD ; , CDAAN), known until March 1981 as the North American Air Defense Command, is a Combined operations, combined organization of the United States and Canada that provides aerospace warning, air ...

(

NORAD North American Aerospace Defense Command (NORAD ; , CDAAN), known until March 1981 as the North American Air Defense Command, is a combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and pr ...

). SLFCS would also relay signals from the

Navy A navy, naval force, military maritime fleet, war navy, or maritime force is the military branch, branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral z ...

's LF/

VLF Very low frequency or VLF is the ITU designation for radio frequencies (RF) in the range of 3–30 kHz, corresponding to wavelengths from 100 to 10 km, respectively. The band is also known as the myriameter band or myriameter wave ...

systems.

Locations

Transmitters

Silver Creek, Nebraska Silver Creek is a village in Merrick County, Nebraska, United States. The population was 320 at the 2020 census. It is part of the Grand Island metropolitan area. History Silver Creek was platted in 1866 when the Union Pacific Railroad was ext ...

(Detachment 1, 1st Aerospace Communications Group) * Hawes Air Force Station, California (Detachment 2, 33rd Communications Squadron) * PACCS aircraft * NAOC (formerly known as NEACP)

GREEN PINE Stations

The GREEN PINE communication system took messages broadcast over SLFCS and 'upconverted' them to UHF messages for bombers headed north. There were a handful of GREEN PINE stations in the northern portions of Alaska and Canada.

Receive Only

Altus AFB Altus Air Force Base (Altus AFB, AAFB) is a United States Air Force base located approximately east-northeast of Altus, Oklahoma. The host unit at Altus AFB is the 97th Air Mobility Wing (97 AMW), assigned to the Nineteenth Air Force (19 ...

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

Barksdale AFB Barksdale Air Force Base (Barksdale AFB) is a United States Air Force (USAF) base in Bossier Parish, Louisiana, in northwest Louisiana. Much of the base is within the city limits of Bossier City, Louisiana, along the base's western and northwest ...

Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...

(

8th Air Force The Eighth Air Force (Air Forces Strategic) is a numbered air force (NAF) of the United States Air Force's Air Force Global Strike Command (AFGSC). It is headquartered at Barksdale Air Force Base, Louisiana. The command serves as Air Forces S ...

Command Post) *

Beale AFB Beale Air Force Base (AFB) is a United States Air Force base in Yuba County, California. It is outside Linda, about east of the towns of Marysville and Yuba City, and about north of Sacramento. The host unit at Beale is the 9th Rec ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

( 9 SRW Command Post) * Blytheville AFB,

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

( 97 BW Command Post) CLOSED *

Carswell AFB Naval Air Station Joint Reserve Base Fort Worth (abbreviated NAS JRB Fort Worth) includes Carswell Field, a military airbase located west of the central business district of Fort Worth, in Tarrant County, Texas, United States. This military ...

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

( 7 BW Command Post) CLOSED *

Castle AFB Castle Air Force Base (Castle AFB, 1941–1995) is a former United States Air Force Strategic Air Command base in California, northeast of Atwater, California, Atwater, northwest of Merced, and about south of Sacramento, California, Sacrament ...

( 93 BW Command Post) CLOSED * Davis-Monthan AFB,

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

- 390th SMW (18 LCCs) CLOSED * Dyess AFB,

( 96 BW Command Post) *

Eielson AFB Eielson Air Force Base is a United States Air Force (USAF) base located approximately southeast of Fairbanks, Alaska, and just southeast of Moose Creek, Alaska. It was established in 1943 as Mile 26 Satellite Field and redesignated Eielson A ...

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

( 6 SW Command Post) *

Ellsworth AFB Ellsworth Air Force Base (AFB) is a United States Air Force (USAF) base located about northeast of Rapid City, South Dakota, just north of the town of Box Elder. The host unit at Ellsworth is the 28th Bomb Wing (28 BW). Assigned to the Glob ...

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota people, Dakota Sioux ...

- 44th SMW (16 terminals - 15 LCCs and Wing Command Post) CLOSED *

Fairchild AFB Fairchild Air Force Base (AFB) is a United States Air Force base, located in the northwest United States in eastern Washington, approximately southwest of Spokane. The host unit at Fairchild is the 92nd Air Refueling Wing (92 ARW) assigne ...

Washington Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A ...

* F.E. Warren AFB,

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

- 90th Missile Wing, 20th Air Force (21 terminals- 20 LCCs, 1 at 20th AF Missile Operations Center) *

Grand Forks AFB Grand Forks Air Force Base (AFB) is a United States Air Force installation in northeastern North Dakota, located north of Emerado and west of Grand Forks. The host unit is the 319th Reconnaissance Wing (319 RW) assigned to the Air Combat ...

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

- 321st SMW (16 terminals - 15 LCCs and Wing Command Post) CLOSED *

Griffiss AFB Griffiss International Airport is a public airport in the northeastern United States, located east of the central business district of Rome, a city in Oneida County, New York. Publicly-owned by the county, the airport is located on the form ...

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

CLOSED * Grissom AFB,

Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...

* K.I. Sawyer AFB,

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

CLOSED *

Little Rock AFB Little Rock Air Force Base is a United States Air Force base located approximately northeast of Little Rock, Arkansas. The facility covers 6,217 acres (2,516 ha) with a resident population of over 3,300 and working population of approximate ...

- 308th SMW (18 LCCs) CLOSED *

Loring AFB Loring Air Force Base was a United States Air Force installation in northeastern Maine, near Limestone and Caribou in Aroostook County. It was one of the largest bases of the U.S. Air Force's Strategic Air Command during its existence, and was ...

Maine Maine ( ) is a U.S. state, state in the New England region of the United States, and the northeasternmost state in the Contiguous United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Provinces and ...

( 42 BW Command Post) CLOSED *

Rickenbacker AFB Rickenbacker Air National Guard Base is an Ohio Air National Guard installation at Rickenbacker International Airport near Lockbourne in southern Franklin County. The base was named for the famous early aviator and Columbus native Eddie R ...

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

Malmstrom AFB Malmstrom Air Force Base is a United States Air Force base in Cascade County, Montana, United States, adjacent to the city of Great Falls. It was named in honor of World War II POW Colonel Einar Axel Malmstrom. It is the home of the 341st Mi ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

341st SMW (20 terminals - 20 LCCs) *

Mather AFB Mather Air Force Base (Mather AFB) was a United States Air Force Base, which was closed in 1993 pursuant to a post-Cold War BRAC decision. It was located east of Sacramento, on the south side of U.S. Route 50 in Sacramento County, Californ ...

CLOSED *

McConnell AFB McConnell Air Force Base is a United States Air Force base located four miles (6 km) southeast of the central business district of Wichita, a city in Sedgwick County, Kansas, United States., effective 2007-12-20 The airbase was named in ...

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

22 BW (Command Post), 381st SMW (18 LCCs) CLOSED *

Minot AFB Minot Air Force Base ( ; ) is a United States Air Force (USAF) installation in Ward County, North Dakota, north of the city of Minot via U.S. Route 83. In the 2020 census, the base was counted as a CDP with a total population of 5 ...

( 5 BW/ 91 SMW 15 LCCs) * Pease AFB,

New Hampshire New Hampshire ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec t ...

( 509 BW Command Post) CLOSED *

Plattsburgh AFB Plattsburgh Air Force Base is a former United States Air Force (USAF) Strategic Air Command (SAC) base covering 3,447 acres (13.7 km) in the extreme northeast corner of New York, located on the western shore of Lake Champlain opposite Burl ...

( 380 BW Command Post) CLOSED *

Robins AFB Robins Air Force Base is a major United States Air Force installation located in Houston County, Georgia, United States. The base is located just east of the city of Warner Robins, south-southeast of Macon and approximately south-southeast ...

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

( 19 BW Command Post) *

Seymour Johnson AFB Seymour Johnson Air Force Base is a United States Air Force (USAF) base located in Goldsboro, North Carolina. The base is named for U.S. Navy Lt. Seymour A. Johnson, a test pilot from Goldsboro who died in an F4F Wildcat crash near Norbeck, Mary ...

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

( 68 BW Command Post) *

Travis AFB Travis Air Force Base is a United States Air Force base under the operational control of Air Mobility Command (AMC), located three miles (5 Kilometre, km) east of the central business district of the city of Fairfield, California, Fairfield, i ...

Vandenberg AFB Vandenberg Space Force Base , previously Vandenberg Air Force Base, is a United States Space Force Base in Santa Barbara County, California. Established in 1941, Vandenberg Space Force Base is a space launch base, launching spacecraft from the ...

( 1 STRAD Command Post)1 LCC O1A *

Whiteman AFB Whiteman Air Force Base is a United States Air Force base located just south of Knob Noster, Missouri, United States. The base is the current home of the B-2 Spirit bomber. It is named for 2nd Lt George Whiteman, who was killed during the atta ...

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

- 351st SMW (16 terminals - 15 LCCs and Wing Command Post) CLOSED *

Wurtsmith AFB Wurtsmith Air Force Base is a decommissioned United States Air Force base in Iosco County, Michigan. Near Lake Huron, it operated for seventy years, from 1923 until decommissioned in 1993. On January 18, 1994, Wurtsmith was listed as a Superfun ...

CLOSED *

March AFB March Air Reserve Base (March ARB), previously known as March Air Force Base (March AFB), is located in Riverside County, California, between the cities of Riverside, Moreno Valley, and Perris. It is the home to the Air Force Reserve Comm ...

(15th AF COC)

History

The first program (487L) took six years from the time of the initial requirement to full operation. The second part (616A), which was basically a modification of an already operational system, took 10 years.

Chronology

*1961 **29 Sep – Headquarters USAF issues Specific Operating Requirement 193, for the Survivable Low Frequency Communications System; system is envisioned to link Alternate Joint Command Center with command centers of SAC, NORAD, SAC numbered air forces with LF radio networks; a total of 18 transmit/receive (T/R) sites and 375 LF-receive only (R/O) in all SAC launch facilities, mobile Minuteman trains, SAC air base control rooms, and SAC UHF positive control stations in the northern tier *1962 **12 Mar – Amendment to SOR 193 changes number of transmit T/R sites to 19 (three each at AJCC, SAC, NORAD, two each at 2d Air Force,

15th Air Force The Fifteenth Air Force (15 AF) is a numbered air force of the United States Air Force's Air Combat Command (ACC). It is headquartered at Shaw Air Force Base. It was reactivated on 20 August 2020, merging the previous units of the Ninth Air Fo ...

and

, one each at

Larson AFB Larson Air Force Base is a former United States Air Force base located five miles (8 km) northwest of the central business district (CBD) of Moses Lake, in Grant County, Washington. After its closure in 1966, the airport facility became ...

, Southern

, Sondrestrom AB, and the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

; Full Operating Capability was extended from July 1964 to May 1965. **27 Apr – A revised program directive delineated the network; T/R equipment would be installed at HQ SAC, the SAC numbered air force headquarters, and in the ABNCP, Alternate Joint Command Center (AJCC) and NORAD command center. 14 Green Pine stations, missile launch control centers, all SAC bomber wing command posts would have R/O terminals, as would the NORAD regional control centers. Initial Operating Capability (IOC) was placed at 1 Oct 1966. *1968 **29 Jul 1968 – Silver Creek site accepted by SACAir Force Historical Research Agency: "History of 3902d Air Base Wing, July – September 1968" **19 Aug 1968 – Silver Creek site turned on for continuous operation **5 Sep 1968 – Silver Creek begins operational testing *1971 **16 Jun – SLFCS IOC obtained by SAC units *1974 **26 Jul – HQ USAF approves Program 616A (Improved SLFCS); system would improve SLFCS by providing anti-jam protection, improved

modems The Democratic Movement (, ; MoDem ) is a centre to centre-right political party in France, whose main ideological trends are liberalism and Christian democracy, and that is characterised by a strong pro-Europeanist stance. MoDem was establish ...

, increased range and make it compatible with the

LF/VLF system *1978 **SAC conducts Initial Operational Test and Evaluation (IOT&E) at

for Program 616A; test is successful *1986 **30 Sep – deactivation of Hawes Radio Relay Site, Hinkley, California **20 Oct – destruction of Hawes Radio Relay Site by the Army Corps of Engineers *1996 ** Rapid Execution and Combat Targeting (REACT) upgrade to

Minuteman Minutemen were members of the organized New England colonial militia companies trained in weaponry, tactics, and military strategies during the American Revolutionary War. They were known for being ready at a minute's notice, hence the name. Min ...

launch control center The Rocco A. Petrone Launch Control Center (commonly known as just the Launch Control Center or LCC) is a four-story building at NASA's Kennedy Space Center on Merritt Island, Florida, used to manage rocket launch, launches of launch vehicles from ...

s complete; advances allow SLFCS messages to be handled automatically by Higher Authority Communications/Rapid Message Processing Element (HAC/RMPE) *2005 **11 Nov – last

Launch Control Center The Rocco A. Petrone Launch Control Center (commonly known as just the Launch Control Center or LCC) is a four-story building at NASA's Kennedy Space Center on Merritt Island, Florida, used to manage rocket launch, launches of launch vehicles from ...

receives

Minimum Essential Emergency Communications Network The Minimum Essential Emergency Communications Network (MEECN) is a network of systems providing uninterrupted communications throughout the pre-, trans-, and post-nuclear warfare environment. At minimum, MEECN is designed to provide a one-way flow ...

( MEECN) upgrade, rendering SLFCS obsolete.Air Force Space Command: "Minot completes final MEECN modifications", 17 Nov 2005
*2010 MMP – Minuteman Minimum Essential Emergency Communications Network Program now in the upgrade portion. Work In Progress. Advanced EHF will be available once upgrade is complete.

Photo gallery

File:33d Communications Squadron.PNG, 33d Comm Squadron, Hawes AFS, California File:1st Aerospace Communications Group.PNG, 1st Aerospace Comm Group, Offutt AFB, Nebraska

References

External links

* {{USAF system codes Military radio systems of the United States Nuclear warfare United States Department of Defense Military communications of the United States United States nuclear command and control

Mission

Locations

Transmitters

GREEN PINE Stations

Receive Only

History

Chronology

Photo gallery

See also

References

External links