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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.
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.
As frequency surveillance and direction finding became more sophisticated, these devices enjoyed some success. However, submariners soon learned not to rely on such transmitters in dangerous waters. Home bases can then use extremely low frequency radio signals, able to penetrate the ocean's surface, to reach submarines wherever they might be.
The magnetic field spectrum was measured in eight discrete, logarithmically spaced channels from 1.78 Hz to 5.62 kHz. The bandwidth of these channels varied from 7.5% to 30% depending on frequency. The dynamic range was 100 dB, and the sensitivity ranged from 0.1-nT at 1.78 Hz to 3.4E-4 nT at 5.62 kHz. The wideband receiver described above ...
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).
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.
Ultra low frequency (ULF) is the ITU designation [1] for the frequency range of electromagnetic waves between 300 hertz and 3 kilohertz, corresponding to wavelengths between 1,000 to 100 km. In magnetosphere science and seismology , alternative definitions are usually given, including ranges from 1 mHz to 100 Hz, [ 2 ] 1 mHz to 1 Hz, [ 3 ] and ...