Survivable Low Frequency Communications System

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

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

Transmitters

Silver Creek, Nebraska (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.^[2]^[3]

Receive Only

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

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 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
- 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

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

References

^ 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 Machine

External links

Mojave Roads: "Hawes Journal"

v t e United States Air Force system numbers
100–199	100 101 P 102 103 104 105 106¹ 107 A-1 A-2 108¹ 109¹ 110 111¹ 112 113¹ 114¹ 115¹ 116¹ 117 L M 118 A L P 119 C/F E L T Y 120 121 122 123 124 125 126 127¹ 128 129 130 131 132 A B 133 134¹ 135 136¹ 137¹ 138 139 140 141¹ 142 143–197¹ 198 199 B C D Y
200–299	200 201 A/L B/W E 202 203¹ 204 205 206 207¹ 208 209¹ 210 211¹ 212 213 214 215¹ 216 217 218 219¹ 220 221 222 A G 223¹ 224 225¹ 226 227–238¹ 239 240–278¹ 279 280–298¹ 299
300–399	300 301¹ 302 303 304¹ 305¹ 306 A/L B 307 308 309 310¹ 311¹ 312¹ 313¹ 314 315 A-1 A-2 316 317 318¹ 319 320¹ 321 322¹ 323 324 L M/N 325 326 327 E 328 E 329 F 330¹ 331¹ 332¹ 333¹ 334¹ 335 336 337 338–379¹ 380 A/B/E/F/N P 381–397¹ 398 399 A B
400–499	400 B/C/N E G/H M 401 402 403¹ 404 405 B C D 406¹ 407 408¹ 409¹ 410 E L 411 E L 412 413 414 L M 415 416 L M (I) M (II) P Q 417 418 L M 419¹ 420 L/W 421¹ 422 423 424 425 426 L M 427 L M 428 A L 429 430 431 G (I) G (II) 432 433 434 435 A L 436 437 438 439 440 441 A D L 442 443 444¹ 445 L M 446 447 448¹ 449¹ 450 451 D L 452 453 454¹ 455 456 457¹ 458 459 460 L 461 462 463 464 465 466 467 468 469 470 471 L (I) L (II) 472 473 474 L N 475¹ 476 E 477 478 A T 479¹ 480 481 L 482 E L M/Z 483 484 L M N 485 L Z 486 487 488 489 490 L M 491¹ 492 493 494 495 L (I) L (II) 496 497 A L (I) L 498 A C D E L 499 A C D
500–599	500 501–519¹ 520 521–529¹ 530 531–541¹ 542 543–549¹ 550 A E 551–559¹ 560 A F 561–569¹ 570 571–579¹ 580 A E 581–589¹ 590 591 592 593–599¹
600–699	600 601 A L 602 A L 603 A L 604 605 606 607 608¹ 609 610¹ 611¹ 612¹ 613¹ 614 615¹ 616 617¹ 618 619¹ 620 621 A/B (I) B (II) 622 623 624 625 626¹ 627 628¹ 629¹ 630¹ 631¹ 632 633 634 A B 635 636¹ 637¹ 638 639 640 641 642 643 644¹ 645¹ 646¹ 647¹ 648 A D P 649 A B C D E F L P 650 651 652 653¹ 654¹ 655 A (I) A (II) P 656 657¹ 658¹ 659¹ 660 661 662¹ 663¹ 664 665 A (I) A (II) 666 A C/P 667 668 669¹ 670 671¹ 672 A M/P 673¹ 674 675 676¹ 677¹ 678¹ 679 680 681 D E 682¹ 683 A J V 684¹ 685 686 687 J P 688¹ 689¹ 690 691 C X Z 692¹ 693 694¹ 695 A B C L N P Q R S (I) S (II) 696¹ 697¹ 698¹ 699¹
700–799	700–735¹ 736 737¹ 738¹ 739¹ 740¹ 741 742 743 744¹ 745 746–753¹ 754 755–799¹
800–899	800¹ 801¹ 802 L (I) L (II) 803¹ 804¹ 805¹ 806 807 808–816¹ 817 818¹ 819¹ 820¹ 821¹ 822¹ 823 824–831¹ 832 833¹ 834 835–845¹ 846 847–899¹
900–999	900–951¹ 952 853¹ 854¹ 855¹ 956 957–967¹ 968
¹ Unknown or not assigned

This page was last edited on 6 March 2024, at 07:09

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