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. 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. 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 (1st Aerospace Communications Group) Hawes Air Force Station, California (Det 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, Oklahoma Barksdale AFB, Louisiana (8th Air Force Command Post) Beale AFB, California (9 SRW Command Post) Blytheville AFB, Arkansas (97 BW Command Post) Carswell AFB, Texas (7 BW Command Post) Castle AFB, California (93 BW Command Post) 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,