What Is Very Low Frequency?

Extremely low frequency refers to radio waves with a frequency from 3Hz to 3kHz and 10,000 kilometers to 100,000 kilometers. Most of them are used by the US military and the Russian military for military equipment weapons and submarine communications. ^[1]

Very low frequencies In atmospheric science, alternative definitions from 3Hz to 3kHz are often given. In related

ELF is a radio frequency. Some medical peer-reviewed journal articles refer to ELF in the case of "extremely low frequency (ELF) magnetic field (MF)" frequencies of 50 Hz and 50-80 Hz. US government agencies such as the National Aeronautics and Space Administration describe ELF as non-ionizing radiation at frequencies between 0 and 300 Hz. Said

A typical spectrum of ELF electromagnetic waves in the Earth's atmosphere, showing peaks caused by Schumann resonance. Schumann resonance is the resonance frequency of a spherical earth-ionospheric cavity. The hit causes the cavity to "ring" like a bell, causing peaks in the noise spectrum. The 50 Hz power peak is caused by radiation from the global power grid. The rise in low-frequency noise is due to radio noise caused by the slow process of the Earth's magnetosphere.

Due to their extremely long wavelengths, very low frequency waves can surround large obstacles

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Transmitters in the 22 Hz range were also found in pipeline detectors, also known as "PIG". The signal is generated as an alternating magnetic field, and the transmitter is mounted on or is part of the PIG. PIG is pushed through a pipe, which is mainly made of metal. The ELF signal can be detected by an external metal. You need to check if a PIG passed a certain location and find a stuck PIG.

Some radio monitoring amateurs use antennas ranging from eighteen inches of active antennas to thousands of feet in length, using fences, highway guardrails, and even decommissioned railway tracks to record ELF

Natural ELF waves exist on Earth and resonate in the area between the ionosphere and the surface. They are caused by lightning strikes, which cause the electrons in the atmosphere to oscillate. Although very low frequency signals were generated mainly by lightning discharges, we found observable ELF components (slow tail), followed by VLF components in almost all cases. The basic mode of the Earth-ionospheric cavity has a wavelength equal to that of the Earth, which gives a resonance frequency of 7.8 Hz on the circumference. This frequency and higher resonance modes of 14, 20, 26, and 32 Hz appear as peaks in the ELF spectrum and are called Schumann resonances.

ELF waves were also initially identified on Saturn's moon Titan. Titan's surface is considered a very low frequency reflecting layer, so the waves may reflect the liquid ice boundary of seawater and ammonia below the surface, and its existence is predicted by some theoretical models. Titan's ionosphere is also more complex than Earth. The main ionosphere is at an altitude of 1,200 kilometers (750 miles), but there is an additional layer of charged particles at 63 kilometers (39 miles). This splits Titan's atmosphere into two separate resonance chambers. The source of the natural ELF wave on the Titan is unclear, as there does not appear to be widespread lightning activity.

The huge ELF radiant power output of 100,000 times the visible solar output may be radiated by the magnetizer. Pulsars in the Crab Nebula radiate powers of this order at a frequency of 30 Hz. Radiation at this frequency is an interstellar medium below the plasma frequency, so the medium is opaque to it, and it cannot be viewed from Earth. ^[5]