Project Sanguine
Project Sanguine was a US Navy project proposed in 1968 for communication with submerged submarines using extremely low frequency (ELF) radio waves. The initially proposed system, hardened to survive a nuclear attack, would have required a giant antenna covering two-fifths of the state of Wisconsin. The proposed approach was never implemented because of protests and potential environmental impact. A smaller, less hardened system called Project ELF consisting of two linked ELF transmitters located at Clam Lake, Wisconsin 46°05′05.6″N 90°55′03.7″W / 46.084889°N 90.917694°W and Republic, Michigan 46°20′10.1″N 87°53′04.6″W / 46.336139°N 87.884611°W was built beginning in 1982 and operated from 1989 until 2004. The system transmitted at a frequency of 76 Hz. At ELF frequencies, the bandwidth of the transmission was very small, so the system could only send short-coded text messages at a very low data rate. These signals were used to summon specific vessels to the surface to receive longer operational orders by ordinary radio or satellite communication.
Proposed system
The initially proposed system would have had a giant antenna consisting of 6,000 miles (9,700 km) of buried cables in a rectangular grid covering 22,500 square miles (58,000 km2), two-fifths of the state of Wisconsin,[1] powered by 100 underground power plants in concrete bunkers.[2][3] The cables were grounded at their ends, and loops of AC electric current flowed deep in the ground between the ends of the cable, generating ELF waves; this is called a ground dipole. The original design was projected to cost billions[4] and consume 800 megawatts of power.[1][5] The goal was a system that could transmit tactical orders one-way to US nuclear submarines anywhere in the world, and survive a direct nuclear attack.[2]
The project was controversial from the start and was attacked by politicians,
Project ELF
The scaled-down system the Navy constructed in 1969, called Project ELF, began official testing in 1982 and became officially operational in 1989.[9] It consisted of two transmitter facilities, one at Clam Lake, Wisconsin and one at Republic, Michigan.[9] with a total of 84 miles (135 km)[10] of above-ground transmission line antenna. The two transmitters normally operated synchronized as one antenna for greater range but could also operate independently. The scaled-down system was not designed to survive a nuclear attack.
The Clam Lake facility, which served as the test site and was originally called the Wisconsin Test Facility (WTF), consisted of two 14-mile (23 km) transmission line antennas (called ground dipoles) in the shape of a cross, with the transmitter station at their intersection.[1][11] The Republic facility consisted of three transmission lines, two 14-mile (23 km) and one 28-mile (45 km),[1] in the shape of the letter "F" (the shape is not significant and was dictated by land availability).[11] The lines, made of 1.5-centimeter (0.59 in) aluminum cable supported on insulators on 40-foot (12 m) wooden utility poles, resembled ordinary power transmission lines.[2] The ends of the transmission lines were grounded by 1 to 3 miles (1.6 to 4.8 km) of buried copper cable and ground rods,[2] later replaced by arrays of electrodes in deep 300-foot (91 m) boreholes[1] The transmitters sent alternating currents of 300 amperes through the lines, which passed through the buried electrodes deep into the Earth.[2]
The transmitters operated at a frequency of 76 Hz in the extremely low frequency band, with an alternate capability at 45 Hz[2] and used a combined power of 2.6 megawatts.[5] They could communicate with submarines over about half the world's surface. The system transmitted continuously, 24 hours a day, sending an "idle" message when it was not being used so that submarines could verify they were within communication range.[9][11]
Because of the extremely small bandwidth of the ELF band, the transmitters had a very slow data rate. They couldn't transmit voice (audio) but only short coded text messages of a few letters.[5][10] Reportedly, it took 15 minutes to transmit a single three-letter code group.[10][11] Therefore, the system was not used to relay operational orders but served a "bell-ringer" function, ordering specific submarines to the surface to receive detailed orders by ordinary radio and satellite communications links.[10]
The system was controversial and was the target of legal attacks, suits, and protests throughout its operating life.[6][7] On five occasions, protesters cut down transmission line poles, interrupting operation briefly.[7]
In 2004, the Navy shut down both transmitters, with the explanation that very low frequency (VLF) communication systems had improved to the point that the ELF system was unnecessary.[7]
How ELF communication works
Submarines are shielded by seawater from all ordinary radio signals and, therefore, are cut off from communication with military command authorities while submerged.[11] However, radio waves of very low frequency can penetrate seawater; the lower the frequency, the deeper in the ocean they can penetrate.[9] Waves in the VLF range of 3 kHz to 30 kHz can penetrate to a depth of about 10 to 30 meters,[10] and since WWII navies have used VLF transmitters to communicate with submarines. To receive VLF signals, subs must rise to just under the surface or trail a shallow antenna buoy, making them vulnerable to detection by the enemy.[5][10]
Radio waves in the
Such ELF transmitters cannot be installed on submarines because of the antenna size and high power requirements. So ELF communication is one-way, with a receiver in the submarine receiving orders from a shore station but unable to reply. The low attenuation of ELF waves with distance allows a single ELF station to send messages to submarines worldwide.
Another drawback of ELF is that the ELF band has very small bandwidth and, therefore, can only transmit very simple messages very slowly.[5][10] ELF signals cannot carry audio (voice) like other types of radio and can only carry short text messages consisting of a few letters. The US Navy system (above) reportedly uses three-letter code groups and requires 15 minutes to transmit one group.[10][11] So, the systems were not used to transmit detailed orders but served a "bell ringer" function to order a specific vessel to surface and receive further orders by ordinary radio or satellite communication.[10]
Other ELF transmitters
The US, Russia, India, and China are the only nations that have constructed ELF communication facilities. The Indian Navy has an operational ELF communication facility at the INS Kattabomman naval base to communicate with its Arihant class and Akula class submarines.[12][13] The Russian Navy reportedly operates an ELF transmitter, ZEVS, located northwest of Murmansk on the Kola Peninsula in northern Russia.[14]
See also
- Extremely low frequency
- Ground dipole
- Communicating with submarines
- JASON Defense Advisory Group
- Through the earth mine communications
References
Footnotes
- ^ a b c d e f Altgelt, Carlos. "The World's Largest 'Radio' Station" (DOC). The Broadcaster's Desktop Resource. Barry Mishkind. Retrieved 17 February 2012.
- ^ a b c d e f g h i j Jones, David Llanwyn (4 July 1985). "Sending Signals to Submarines". New Scientist. 26 (1463): 37–41. Retrieved 17 February 2012 – via Google Books.
- ^ a b c d e f Aldridge, Bob (2001). "ELF History: Extreme Low Frequency Communication" (PDF). Pacific Life Research Center. PLRC-941005B. Retrieved 23 February 2012.
- ^ Sullivan, Walter (13 October 1981). "How Huge Antenna Can Broadcast into the Silence of the Sea". The New York Times. Retrieved 22 May 2012.
- ^ ISBN 0-521-41357-5– via Google Books.
- ^ ISBN 0-7432-1308-4– via Google Books.
- ^ a b c d Cohen-Joppa, Felice (15 October 2004). "Project ELF Closes". The Nuclear Resistor. No. 135. Felice and Jack Cohen-Joppa. Retrieved 10 July 2014.
- ^ Ellis, Grover (September 1973). "Dr. Strangelove is Back!". Texas Monthly.
- ^ ISBN 1-55750-268-4– via Google Books.
- ^ a b c d e f Heppenheimer, T. A. (April 1987). "Signaling Subs". Popular Science. 230 (4): 44–48. Retrieved 17 February 2012 – via Google Books.
- ^ "Navy Gets New Facility to Communicate with Nuclear Submarines Prowling Underwater". The Times of India. 31 July 2014.
- ^ Hardy, James (28 February 2013). "India Makes Headway with ELF Site Construction". IHS Jane's Defence Weekly. Archived from the original on 23 February 2014.
- ^ Jacobsen, Trond (2001). "ZEVS, The Russian 82 Hz ELF Transmitter". Radio Waves Below 22 kHz. Renato Romero webpage. Retrieved 17 February 2012.
Bibliography
- Baker, RE (1974). "Project Sanguine: An overview and status of the Navy's ELF communications system concept". In Llaurado, JG; Sances, A; Battocletti, JH (eds.). Biologic and Clinical Effects of Low-Frequency Magnetic and Electric Fields. Springfield, IL: Thomas. pp. 83–90. ISBN 9780398030247.
- Becker, Robert O. (1990). Cross Currents: The Promise of Electromedicine, the Perils of Electropollution (1st ed.). Los Angeles: J.P. Tarcher. pp. 201–2, 233–4. ISBN 9780874775365.
- Jones, David Llanwyn (4 July 1985). "Sending signals to submarines". New Scientist. 26 (1463): 37–41. ISSN 0262-4079. Retrieved 17 February 2012 – via Google Books.
- PMID 17735468.
- Wait, James R. (April 1977). "Propagation of ELF Electromagnetic Waves and Project Sanguine / Seafarer". IEEE Journal of Oceanic Engineering. 2 (2): 161–72. ISSN 0364-9059.