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Encyclopedia > Ultra low frequency

Ultra Low Frequency (ULF) is the frequency range between 300 hertz and 3000 hertz. Sine waves of various frequencies; the lower waves have higher frequencies than those above. ... The hertz (symbol: Hz) is the SI unit of frequency. ...


This band is used for communications in mines, as it can penetrate the earth. [1]


Earthquakes

Some monitoring stations have reported that earthquakes are sometimes preceded by a spike in ULF activity. A remarkable example of this occurred before the Loma Prieta Earthquake in California in 1989. Researchers are attempting to learn more about this correlation to find out whether this method can be used as part of an early warning system for earthquakes. Global earthquake epicenters, 1963–1998. ... The Loma Prieta earthquake occurred on October 17, 1989, in the greater San Francisco Bay Area in California at 5:04 p. ... Official language(s) English Capital Sacramento Largest city Los Angeles Area  Ranked 3rd  - Total 158,302 sq. ... 1989 (MCMLXXXIX) was a common year starting on Sunday of the Gregorian calendar. ...


See also

Radio spectrum
ELF SLF ULF VLF LF MF HF VHF UHF SHF EHF
3 Hz 30 Hz 300 Hz 3 kHz 30 kHz 300 kHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz
30 Hz 300 Hz 3 kHz 30 kHz 300 kHz 3 MHz 30 MHz 300 MHz 3 GHz 30 GHz 300 GHz


A voice frequency (VF) or voice band is one of the frequencies, within part of the audio range, that is used for the transmission of speech. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ... Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ... Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. ... Part of the aerial of Transmitter Grimeton Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ... This article is being considered for deletion in accordance with Wikipedias deletion policy. ... Mediumwave radio transmissions (sometimes called Medium frequency or MF) are those between the frequencies of 300 kHz and 3000 kHz. ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m). ... This article is about the radio frequency. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... Extremely high frequency is the highest radio frequency band. ...


External articles


  Results from FactBites:
 
Ultra Low-frequency Pulse Generator RR-77 (502 words)
The "Schumann Resonance" is a resonance frequency that exists in the Earth's "electromagnetic" cavity; i.e.
The lowest-frequency ?iand highest-intensity ?jmode of the Schumann Resonance is at a frequency of approximately 7.83Hz.
We substantiate that there are many effects when the frequency of 7.83Hz is generated artificially.
Ultra-low Natural Frequency Vibration Isolatin Workstation - MK26 Series (225 words)
Kinetic Systems manufactures the system utilizing the Minus K patented negative stiffness vibration isolators in order to provide a compact, passive Vibration Isolation Workstation with ultra-low natural frequencies, higher internal structural frequencies, and excellent vertical and horizontal isolation efficiencies.
The Minus K vertical isolator uses a stiff spring and negative-stiffness mechanism to achieve a low net vertical stiffness without affecting the static load supporting capability.
Adjusted to a 1/2 Hz natural frequency, the workstation achieves 93% isolation efficiency at 2 Hz, 99% at 5 Hz and 99.7% at 10 Hz.
  More results at FactBites »

 
 

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