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  2. Schumann resonances - Wikipedia

    en.wikipedia.org/wiki/Schumann_resonances

    The global electromagnetic resonance phenomenon is named after physicist Winfried Otto Schumann who predicted it mathematically in 1952. Schumann resonances are the principal background in the part of the electromagnetic spectrum [2] from 3 Hz through 60 Hz [3] and appear as distinct peaks at extremely low frequencies around 7.83 Hz (fundamental), 14.3, 20.8, 27.3, and 33.8 Hz.

  3. Extremely low frequency - Wikipedia

    en.wikipedia.org/wiki/Extremely_low_frequency

    The fundamental Schumann resonance is at approximately 7.83 Hz, the frequency at which the wavelength equals the circumference of the Earth, and higher harmonics occur at 14.1, 20.3, 26.4, and 32.4 Hz, etc. Lightning strikes excite these resonances, causing the Earth–ionosphere cavity to "ring" like a bell, resulting in a peak in the noise ...

  4. Earth–ionosphere waveguide - Wikipedia

    en.wikipedia.org/wiki/Earth–ionosphere_waveguide

    Earth–ionosphere waveguide. The Earth–ionosphere waveguide[1] is the phenomenon in which certain radio waves can propagate in the space between the ground and the boundary of the ionosphere. Because the ionosphere contains charged particles, it can behave as a conductor. The earth operates as a ground plane, and the resulting cavity behaves ...

  5. Winfried Otto Schumann - Wikipedia

    en.wikipedia.org/wiki/Winfried_Otto_Schumann

    Technical University of Munich. Doctoral advisor. Engelbert Arnold. Doctoral students. Fritz Borgnis. Winfried Otto Schumann (May 20, 1888 – September 22, 1974) was a German physicist and electrical engineer who predicted the Schumann resonances, a series of low-frequency resonances caused by lightning discharges in the atmosphere. [1][2]

  6. Orders of magnitude (frequency) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude...

    Orders of magnitude (frequency) The following list illustrates various frequencies, measured in hertz, according to decade in the order of their magnitudes, with the negative decades illustrated by events and positive decades by acoustic or electromagnetic uses. Acoustic – frequency of G −7, the lowest note sung by the singer with the ...

  7. Resonance - Wikipedia

    en.wikipedia.org/wiki/Resonance

    Increase of amplitude as damping decreases and frequency approaches resonant frequency of a driven damped simple harmonic oscillator. [1][2] Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration that matches its natural frequency. When this happens, the object or system absorbs energy from ...

  8. Radio propagation - Wikipedia

    en.wikipedia.org/wiki/Radio_propagation

    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. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]

  9. Fundamental frequency - Wikipedia

    en.wikipedia.org/wiki/Fundamental_frequency

    Fundamental frequency. The fundamental frequency, often referred to simply as the fundamental (abbreviated as f 0 or f 1 ), is defined as the lowest frequency of a periodic waveform. [1] In music, the fundamental is the musical pitch of a note that is perceived as the lowest partial present. In terms of a superposition of sinusoids, the ...