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Extremely low frequency (ELF) is the ITU designation [1] for electromagnetic radiation (radio waves) with frequencies from 3 to 30 Hz, and corresponding wavelengths of 100,000 to 10,000 kilometers, respectively. [2] [3] In atmospheric science, an alternative definition is usually given, from 3 Hz to 3 kHz.
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.
A U.S. Navy TACAMO EC-130Q of VQ-4, in 1984. The acronym was coined in 1961 [citation needed] and the first aircraft modified for TACAMO testing was a Lockheed KC-130 Hercules which in 1962 was fitted with a VLF transmitter and trailing wire antenna to test communications with the fleet ballistic missile submarines (see communication with submarines).
Data were obtained in real-time only, at frequencies of 136 and 400-MHz at 100 bit/s (or 200 bit/s with convolutional coding) plus wideband Very low frequency (VLF) data. [6] It was designed, built, and tracked by personnel at the Department of Physics and Astronomy, University of Iowa whose sports teams are the Iowa Hawkeyes.
The transmitters include those designed to operate at Very Low Frequency (VLF). The submarines pick up the message via special antennas. Nuclear-capable forces will then be expected to carry out an EAM without fail. Crewed bombers may be recalled, but missiles fired from land-based silos or from submarines cannot be recalled.
Noise-induced neurologic disturbances in scuba divers exposed to continuous low-frequency tones for durations longer than 15 minutes has involved in some cases the development of immediate and long-term problems affecting brain tissue. The symptoms resembled those of individuals who had suffered minor head injuries.
Sound (extremely high volumes, dynamic range, low frequency, high pitched noise, intended to interfere with rest, cognition and concentration) Stabbing Starvation
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 ...