Project Sanguine

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Clam Lake, Wisconsin ELF transmitter in 1982, part of Project ELF, the downsized successor to Sanguine. Sections of the rights of way for the power lines that make up the two 14-mile-long ground dipole antennas can be seen passing through the forest in the lower left. Clam Lake ELF.jpg
Clam Lake, Wisconsin ELF transmitter in 1982, part of Project ELF, the downsized successor to Sanguine. Sections of the rights of way for the power lines that make up the two 14-mile-long ground dipole antennas can be seen passing through the forest in the lower left.

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″N90°55′03.7″W / 46.084889°N 90.917694°W / 46.084889; -90.917694 and Republic, Michigan 46°20′10.1″N87°53′04.6″W / 46.336139°N 87.884611°W / 46.336139; -87.884611 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.

Contents

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, antiwar and environmental groups concerned about the effects of high ground currents and electromagnetic fields on the environment. [2] [3] [6] [7] The nuclear survivability of the system was made doubtful by Soviet development of MIRV ballistic missiles. [3] After an attempt to resite the project in the Llano Uplift of Texas [8] was also stopped by public opposition, [3] the Navy abandoned Sanguine and proposed a series of increasingly modest variants: Project Seafarer (1975), Austere ELF (1978), and finally Project ELF (1981), which was constructed. [3] [5] This lower power system required 15 minutes to transmit each code group, so it was not used to transmit tactical orders directly but instead served the function of a "bell ringer", ordering a specific vessel to rise near the surface and receive further orders by ordinary radio or satellite communication. [1] [2] [3] The system became nominally operational in 1989, 20 years after it first went online as "test facility," and was used until 2004, when the US Navy declared it obsolete and it was shut down and dismantled.

Project ELF

Map showing location of the US Navy ELF transmitters. The red lines show the paths of the ground dipole antennas. The Clam Lake facility (left) had two crossed 14 mi. ground dipoles. The Republic facility had two 14 mi. dipoles oriented east-west, and one 28 mi. dipole oriented north-south. US Navy ELF transmitter map.png
Map showing location of the US Navy ELF transmitters. The red lines show the paths of the ground dipole antennas. The Clam Lake facility (left) had two crossed 14 mi. ground dipoles. The Republic facility had two 14 mi. dipoles oriented east–west, and one 28 mi. dipole oriented north–south.

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]

Clam Lake ground dipole antenna, showing how it works. The alternating current I in the line is shown flowing in only one direction for clarity. Ground dipole ELF antenna.svg
Clam Lake ground dipole antenna, showing how it works. The alternating current I in the line is shown flowing in only one direction for clarity.

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]

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 extremely low frequency (ELF) band of 30 to 300 Hz can penetrate to a depth of hundreds of meters, allowing them to communicate with submarines at their normal operating depth. [5] The lower the frequency, the longer the wavelength of the radio waves, and transmitters require longer antenna structures to generate them. ELF transmitters use huge antennas called ground dipoles consisting of tens to hundreds of kilometers of overhead cables resembling ordinary power transmission lines. The transmission lines are grounded at the ends, and looping currents deep in the Earth form part of the antenna. Because even these huge antennas are much smaller than the ELF wavelengths, they are extremely inefficient; only a tiny fraction of the input power is radiated as ELF waves, with the rest dissipated as heat in antenna resistance. At their full input power of 2.6 MW, both US ELF transmitters working together only generated about 8 watts of ELF radiation. This weak signal reached submarines over half the globe only because of the extremely low attenuation of ELF waves of 1–2 dB per 1000 kilometers. ELF transmitters are most efficient when sited over certain low conductivity underground rock formations, which forces the currents to spread deeper through a larger volume of rock, forming a larger "antenna". [2] The US system was located in Wisconsin and the Upper Peninsula of Michigan over the Laurentian Shield formation, for that reason. [2]

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]

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

Related Research Articles

Ground waves are radio waves propagating parallel to and adjacent to the surface of the Earth, following the curvature of the Earth beyond the visible horizon. This radiation is known as Norton surface wave, or more properly Norton ground wave, because ground waves in radio propagation are not confined to the surface.

<span class="mw-page-title-main">Very low frequency</span> The range 3–30 kHz of the electromagnetic spectrum

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 as the wavelengths range from one to ten myriameters. Due to its limited bandwidth, audio (voice) transmission is highly impractical in this band, and therefore only low data rate coded signals are used. The VLF band is used for a few radio navigation services, government time radio stations and for secure military communication. Since VLF waves can penetrate at least 40 meters (131 ft) into saltwater, they are used for military communication with submarines.

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.

<span class="mw-page-title-main">Medium frequency</span> The range 300-3000 kHz of the electromagnetic spectrum

Medium frequency (MF) is the ITU designation for radio frequencies (RF) in the range of 300 kilohertz (kHz) to 3 megahertz (MHz). Part of this band is the medium wave (MW) AM broadcast band. The MF band is also known as the hectometer band as the wavelengths range from ten to one hectometers. Frequencies immediately below MF are denoted as low frequency (LF), while the first band of higher frequencies is known as high frequency (HF). MF is mostly used for AM radio broadcasting, navigational radio beacons, maritime ship-to-shore communication, and transoceanic air traffic control.

<span class="mw-page-title-main">Longwave</span> Radio transmission using wavelengths above 1000 m

In radio, longwave, long wave or long-wave, and commonly abbreviated LW, refers to parts of the radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band. The term is historic, dating from the early 20th century, when the radio spectrum was considered to consist of longwave (LW), medium-wave (MW), and short-wave (SW) radio bands. Most modern radio systems and devices use wavelengths which would then have been considered 'ultra-short'.

<span class="mw-page-title-main">High frequency</span> The range 3-30 MHz of the electromagnetic spectrum

High frequency (HF) is the ITU designation for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters. Frequencies immediately below HF are denoted medium frequency (MF), while the next band of higher frequencies is known as the very high frequency (VHF) band. The HF band is a major part of the shortwave band of frequencies, so communication at these frequencies is often called shortwave radio. Because radio waves in this band can be reflected back to Earth by the ionosphere layer in the atmosphere – a method known as "skip" or "skywave" propagation – these frequencies are suitable for long-distance communication across intercontinental distances and for mountainous terrains which prevent line-of-sight communications. The band is used by international shortwave broadcasting stations (3.95–25.82 MHz), aviation communication, government time stations, weather stations, amateur radio and citizens band services, among other uses.

<span class="mw-page-title-main">TACAMO</span> US strategic communications system

TACAMO is a United States military system of survivable communications links designed to be used in nuclear warfare to maintain communications between the decision-makers and the triad of strategic nuclear weapon delivery systems. Its primary mission is serving as a signals relay, where it receives orders from a command plane such as Operation Looking Glass, and verifies and retransmits their Emergency Action Messages (EAMs) to US strategic forces. As it is a dedicated communications post, it features the ability to communicate on virtually every radio frequency band from very low frequency (VLF) up through super high frequency (SHF) using a variety of modulations, encryptions and networks, minimizing the likelihood an emergency message will be jammed by an enemy. This airborne communications capability largely replaced the land-based extremely low frequency (ELF) broadcast sites which became vulnerable to nuclear strike.

Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. Understanding the effects of varying conditions on radio propagation has many practical applications, from choosing frequencies for amateur radio communications, international shortwave broadcasters, to designing reliable mobile telephone systems, to radio navigation, to operation of radar systems.

<span class="mw-page-title-main">Extremely low frequency</span> The range 3-30 Hz of the electromagnetic spectrum

Extremely low frequency (ELF) is the ITU designation for electromagnetic radiation with frequencies from 3 to 30 Hz, and corresponding wavelengths of 100,000 to 10,000 kilometers, respectively. In atmospheric science, an alternative definition is usually given, from 3 Hz to 3 kHz. In the related magnetosphere science, the lower-frequency electromagnetic oscillations are considered to lie in the ULF range, which is thus also defined differently from the ITU radio bands.

Super low frequency (SLF) is the ITU designation for electromagnetic waves in the frequency range between 30 hertz and 300 hertz. They have corresponding wavelengths of 10,000 to 1,000 kilometers. This frequency range includes the frequencies of AC power grids. Another conflicting designation which includes this frequency range is Extremely Low Frequency (ELF), which in some contexts refers to all frequencies up to 300 hertz.

Communication with submarines is a field within military communications that presents technical challenges and requires specialized technology. Because radio waves do not travel well through good electrical conductors like salt water, submerged submarines are cut off from radio communication with their command authorities at ordinary radio frequencies. Submarines can surface and raise an antenna above the sea level, or float a tethered buoy carrying an antenna, then use ordinary radio transmissions; however, this makes them vulnerable to detection by anti-submarine warfare forces.

<span class="mw-page-title-main">Grimeton Radio Station</span> Historic Swedish wireless telegraphy station

Grimeton Radio Station in southern Sweden, close to Varberg in Halland, is an early longwave transatlantic wireless telegraphy station built in 1922–1924, that has been preserved as a historical site. From the 1920s through the 1940s it was used to transmit telegram traffic by Morse code to North America and other countries, and during World War II was Sweden's only telecommunication link with the rest of the world. It is the only remaining example of an early pre-electronic radio transmitter technology called an Alexanderson alternator. It was added to the UNESCO World Heritage List in 2004, with the statement: "Grimeton Radio Station, Varberg is an exceptionally well preserved example of a type of telecommunication centre, representing the technological achievements by the early 1920s, as well as documenting the further development over some three decades." The radio station is also an anchor site for the European Route of Industrial Heritage. The transmitter is still in operational condition, and each year on a day called Alexanderson Day is started up and transmits brief Morse code test transmissions, which can be received all over Europe.

Goliath transmitter was a very low frequency (VLF) transmitter for communicating with submarines, built by Nazi Germany's Kriegsmarine navy near Kalbe an der Milde in Saxony-Anhalt, Germany, which was in service from 1943 to 1945. It was capable of transmission power of between 100 and 1000 kW and was the most powerful transmitter of its time.

<span class="mw-page-title-main">Umbrella antenna</span>

An umbrella antenna is a capacitively top-loaded wire monopole antenna, consisting in most cases of a mast fed at the ground end, to which a number of radial wires are connected at the top, sloping downwards. One side of the feedline supplying power from the transmitter is connected to the mast, and the other side to a ground (Earthing) system of radial wires buried in the earth under the antenna. They are used as transmitting antennas below 1 MHz, in the MF, LF and particularly the VLF bands, at frequencies sufficiently low that it is impractical or infeasible to build a full size quarter-wave monopole antenna. The outer end of each radial wire, sloping down from the top of the antenna, is connected by an insulator to a supporting rope or cable anchored to the ground; the radial wires can also support the mast as guy wires. The radial wires make the antenna look like the wire frame of a giant umbrella hence the name.

<span class="mw-page-title-main">Ground dipole</span> Radio antenna that radiates extremely low frequency electromagnetic waves

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<span class="mw-page-title-main">VLF Transmitter Cutler</span> VLF radio transmitter operated by the US Navy

The VLF Transmitter Cutler is the United States Navy's very low frequency (VLF) shore radio station at Cutler, Maine. The station provides one-way communication to submarines of the Navy's Atlantic Fleet, both on the surface and submerged. It transmits with call sign NAA, at a frequency of 24 kHz and input power of up to 1.8 megawatts, and is one of the most powerful radio transmitters in the world.

<span class="mw-page-title-main">Jim Creek Naval Radio Station</span> United States naval transmission facility near Oso, Washington

Jim Creek Naval Radio Station is a United States Navy very low frequency (VLF) radio transmitter facility at Jim Creek near Oso, Washington. The primary mission of this site is to communicate orders one-way to submarines of the Pacific fleet. Radio waves in the very low frequency band can penetrate seawater and be received by submerged submarines which cannot be reached by radio communications at other frequencies. Established in 1953, the transmitter radiates on 24.8 kHz with a power of 1.2 megawatts and a callsign of NLK, and is one of the most powerful radio transmitters in the world. Located near Arlington, Washington, in the foothills of the Cascades, north of Seattle, the site has 5,000 largely forested acres (2,000 ha).

Naval Radio Transmitter Facility Aguada is a tall guyed radio mast erected by the United States Navy. It is used as a facility of the US Navy for ashore and U.S. and NATO ships, planes, and submarines operating at sea in areas of broadcast coverage near Aguada, Puerto Rico at 18°23′55″N67°10′38″W by using radio waves in the very low frequency range.

Through-the-Earth (TTE) signalling is a type of radio signalling used in mines and caves that uses low-frequency waves to penetrate dirt and rock, which are opaque to higher-frequency conventional radio signals.

<span class="mw-page-title-main">ZEVS (transmitter)</span>

ZEVS is a facility of the Russian Navy to transmit messages to submerged submarines in deep water using extremely low frequency (ELF) waves. It is located near Murmansk on the Kola Peninsula. As ZEVS works on 82 hertz, it can be only used for very rudimentary transmissions. Due to its extreme low frequency, the techniques used by ZEVS are quite different from those of standard transmitters.

References

Footnotes

  1. 1 2 3 4 5 6 Altgelt, Carlos. "The World's Largest 'Radio' Station" (DOC). The Broadcaster's Desktop Resource. Barry Mishkind. Retrieved 17 February 2012.
  2. 1 2 3 4 5 6 7 8 9 10 Jones, David Llanwyn (4 July 1985). "Sending Signals to Submarines". New Scientist. 26 (1463): 37–41. Retrieved 17 February 2012– via Google Books.
  3. 1 2 3 4 5 6 Aldridge, Bob (2001). "ELF History: Extreme Low Frequency Communication" (PDF). Pacific Life Research Center. PLRC-941005B. Retrieved 23 February 2012.
  4. ↑ Sullivan, Walter (13 October 1981). "How Huge Antenna Can Broadcast into the Silence of the Sea". The New York Times. Retrieved 22 May 2012.
  5. 1 2 3 4 5 6 7 Spinardi, Graham (1994). From Polaris to Trident: The Development of US Fleet Ballistic Missile Technology. London: Cambridge University Press. pp. 81–82. ISBN   0-521-41357-5 – via Google Books.
  6. 1 2 Brodeur, Paul (2000). Currents of Death. New York: Simon and Schuster. p. 62. ISBN   0-7432-1308-4 – via Google Books.
  7. 1 2 3 4 Cohen-Joppa, Felice (15 October 2004). "Project ELF Closes". The Nuclear Resistor. No. 135. Felice and Jack Cohen-Joppa. Retrieved 10 July 2014.
  8. ↑ Ellis, Grover (September 1973). "Dr. Strangelove is Back!". Texas Monthly.
  9. 1 2 3 4 "Extremely Low Frequency Transmitter Site, Clam Lake, Wisconsin" (PDF). Navy Fact File. United States Navy. 28 June 2001. Retrieved 17 February 2012– via Federation of American Scientists.
  10. 1 2 3 4 5 6 7 Friedman, Norman (1997). The Naval Institute guide to world naval weapons systems, 1997-1998. New York: Naval Institute Press. pp. 41–42. ISBN   1-55750-268-4 – via Google Books.
  11. 1 2 3 4 5 6 Heppenheimer, T. A. (April 1987). "Signaling Subs". Popular Science. 230 (4): 44–48. Retrieved 17 February 2012– via Google Books.
  12. ↑ "Navy Gets New Facility to Communicate with Nuclear Submarines Prowling Underwater". The Times of India . 31 July 2014.
  13. ↑ 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.
  14. ↑ Jacobsen, Trond (2001). "ZEVS, The Russian 82 Hz ELF Transmitter". Radio Waves Below 22 kHz. Renato Romero webpage. Retrieved 17 February 2012.

Bibliography

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