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Survivable Low Frequency Communications System

January 12, 2024

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.[1] The system used both very low frequency (VLF), and low frequency (LF) radio bands.

Mission edit

SLFCS was used for United States nuclear forces' command and control communications for Emergency Action Message dissemination and force direction. Single channel, receive only capability was provided at ICBM 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 (SAC), the Joint Chiefs of Staff (JCS), and North American Aerospace Defense Command (NORAD). SLFCS would also relay signals from the Navy's LF/VLF systems.

Locations edit

Transmitters edit

GREEN PINE Stations edit

See also: Green Pine (communications)

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.[2][3]

Receive Only edit

History edit

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 edit

  • 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 and 8th Air Force, one each at Larson AFB, Southern Alaska, Sondrestrom AB, and the United Kingdom; 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 SAC[4]
    • 19 Aug 1968 – Silver Creek site turned on for continuous operation[4]
    • 5 Sep 1968 – Silver Creek begins operational testing[4]
  • 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, increased range and make it compatible with the Navy LF/VLF system
  • 1978
    • SAC conducts Initial Operational Test and Evaluation (IOT&E) at Ellsworth AFB, South Dakota for Program 616A; test is successful
  • 1986
  • 1996
  • 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 edit

  •  
    33d Comm Squadron, Hawes AFS, California
  •  
    1st Aerospace Comm Group, Offutt AFB, Nebraska

See also edit

 
Wikimedia Commons has media related to Survivable Low Frequency Communications System.

References edit

  1. ^ GlobalSecurity.org (2005-04-28). "Survivable Low Frequency Communications System (SLFCS) – United States Nuclear Forces". Retrieved 2007-10-04.
  2. ^ Strategic Air Command Regulation 100-24 Vol III: SAC Communications System Operations/EWO Support Requirements, 6 Jul 1979
  3. ^ Santa Barbara Amateur Radio Club Key Klix: "Survivable LF Comm System", April 2008, Vol 55, No. 4
  4. ^ a b c Air Force Historical Research Agency: "History of 3902d Air Base Wing, July – September 1968"
  5. ^ Selnick, D., "Higher Authority Communications/Rapid Message Processing Element (HAC/RMPE)", 2002
  6. ^ Air Force Space Command: "Minot completes final MEECN modifications", 17 Nov 2005 24 March 2010 at the Wayback Machine

External links edit

  • Mojave Roads: "Hawes Journal"

January 12, 2024
survivable, frequency, communications, system, slfcs, communications, system, designed, able, operate, albeit, data, transfer, rates, during, after, nuclear, attack, system, used, both, very, frequency, frequency, radio, bands, contents, mission, locations, tr. 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 1 The system used both very low frequency VLF and low frequency LF radio bands Contents 1 Mission 2 Locations 2 1 Transmitters 2 2 GREEN PINE Stations 2 3 Receive Only 3 History 3 1 Chronology 4 Photo gallery 5 See also 6 References 7 External linksMission editSLFCS was used for United States nuclear forces command and control communications for Emergency Action Message dissemination and force direction Single channel receive only capability was provided at ICBM 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 SAC the Joint Chiefs of Staff JCS and North American Aerospace Defense Command NORAD SLFCS would also relay signals from the Navy s LF VLF systems Locations editTransmitters edit Silver Creek Nebraska Detachment 1 1st Aerospace Communications Group Hawes Air Force Station California Detachemnt 2 33rd Communications Squadron PACCS aircraft NAOC formerly known as NEACP GREEN PINE Stations edit See also Green Pine communications 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 2 3 Receive Only edit Altus AFB Oklahoma Barksdale AFB Louisiana 8th Air Force Command Post Beale AFB California 9 SRW Command Post Blytheville AFB Arkansas 97 BW Command Post CLOSED Carswell AFB Texas 7 BW Command Post CLOSED Castle AFB California 93 BW Command Post CLOSED Davis Monthan AFB Arizona 390th SMW 18 LCCs CLOSED Dyess AFB Texas 96 BW Command Post Eielson AFB Alaska 6 SW Command Post Ellsworth AFB South Dakota 44th SMW 16 terminals 15 LCCs and Wing Command Post CLOSED Fairchild AFB Washington F E Warren AFB Wyoming 90th Missile Wing 20th Air Force 21 terminals 20 LCCs 1 at 20th AF Missile Operations Center Grand Forks AFB North Dakota 321st SMW 16 terminals 15 LCCs and Wing Command Post CLOSED Griffiss AFB New York CLOSED Grissom AFB Indiana K I Sawyer AFB Michigan CLOSED Little Rock AFB Arkansas 308th SMW 18 LCCs CLOSED Loring AFB Maine 42 BW Command Post CLOSED Rickenbacker AFB Ohio Malmstrom AFB Montana 341st SMW 20 terminals 20 LCCs Mather AFB California CLOSED McConnell AFB Kansas 22 BW Command Post 381st SMW 18 LCCs CLOSED Minot AFB North Dakota 5 BW 91 SMW 15 LCCs Pease AFB New Hampshire 509 BW Command Post CLOSED Plattsburgh AFB New York 380 BW Command Post CLOSED Robins AFB Georgia 19 BW Command Post Seymour Johnson AFB North Carolina 68 BW Command Post Travis AFB California Vandenberg AFB California 1 STRAD Command Post 1 LCC O1A Whiteman AFB Missouri 351st SMW 16 terminals 15 LCCs and Wing Command Post CLOSED Wurtsmith AFB Michigan CLOSED March AFB California 15th AF COC History editThe 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 edit 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 and 8th Air Force one each at Larson AFB Southern Alaska Sondrestrom AB and the United Kingdom 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 SAC 4 19 Aug 1968 Silver Creek site turned on for continuous operation 4 5 Sep 1968 Silver Creek begins operational testing 4 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 increased range and make it compatible with the Navy LF VLF system 1978 SAC conducts Initial Operational Test and Evaluation IOT amp E at Ellsworth AFB South Dakota 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 launch control centers complete advances allow SLFCS messages to be handled automatically by Higher Authority Communications Rapid Message Processing Element HAC RMPE 5 2005 11 Nov last Minuteman Launch Control Center receives Minimum Essential Emergency Communications Network MEECN upgrade rendering SLFCS obsolete 6 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 edit nbsp 33d Comm Squadron Hawes AFS California nbsp 1st Aerospace Comm Group Offutt AFB NebraskaSee also edit nbsp Wikimedia Commons has media related to Survivable Low Frequency Communications System Post Attack Command and Control System PACCS Ground Wave Emergency Network GWEN Minimum Essential Emergency Communications Network MEECN Emergency Rocket Communications System ERCS Hawes Radio Tower Location of the West Coast SLFCS transmitter until the mid 1980s at Hawes field Silver Creek Communications Annex Location of the East Coast SLFCS transmitter until the mid 1990sReferences edit GlobalSecurity org 2005 04 28 Survivable Low Frequency Communications System SLFCS United States Nuclear Forces Retrieved 2007 10 04 Strategic Air Command Regulation 100 24 Vol III SAC Communications System Operations EWO Support Requirements 6 Jul 1979 Santa Barbara Amateur Radio Club Key Klix Survivable LF Comm System April 2008 Vol 55 No 4 a b c Air Force Historical Research Agency History of 3902d Air Base Wing July September 1968 Selnick D Higher Authority Communications Rapid Message Processing Element HAC RMPE 2002 Air Force Space Command Minot completes final MEECN modifications 17 Nov 2005 Archived 24 March 2010 at the Wayback MachineExternal links editMojave Roads Hawes Journal Retrieved from https en wikipedia org w index php title Survivable Low Frequency Communications System amp oldid 1163296545, wikipedia, wiki, book, books, library,

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