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Relationship of the atmosphere and ionosphere. The ionosphere (/ aɪ ˈ ɒ n ə ˌ s f ɪər /) [1] [2] is the ionized part of the upper atmosphere of Earth, from about 48 km (30 mi) to 965 km (600 mi) above sea level, [3] a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar ...
Musica universalis—which had existed as a metaphysical concept since the time of the Greeks—was often taught in quadrivium, [8] and this intriguing connection between music and astronomy stimulated the imagination of Johannes Kepler as he devoted much of his time after publishing the Mysterium Cosmographicum (Mystery of the Cosmos), looking over tables and trying to fit the data to what he ...
Musicians working in a recording studio An audience watching a concert. The music industry refers to the individuals and organizations that earn money by writing songs and musical compositions, creating and selling recorded music and sheet music, presenting concerts, as well as the organizations that aid, train, represent and supply music creators.
TEC plot for the continental USA, made on 2013-11-24. Total electron content (TEC) is an important descriptive quantity for the ionosphere of the Earth. TEC is the total number of electrons integrated between two points, along a tube of one meter squared cross section, i.e., the electron columnar number density.
Sporadic E (abbreviated E s or SpE) is an uncommon form of radio propagation using a low level of the Earth's ionosphere that normally does not refract radio waves above about 15 MHz. Sporadic E propagation reflects signals off relatively small ionization patches in the lower E region located at altitudes of about 95~120 km (50~75 miles).
Grundig Satellit 400 solid-state, digital shortwave receiver, c. 1986 [1]. Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (approximately 100 to 10 metres in wavelength).
Van Zandt started TeachRock to help keep music and the arts in K-12 public schools by creating and providing lesson plans that integrate music history into state education standards, covering math ...
Because of changing the Ionosphere during day and night, during daytime higher frequency bands under critical Frequency work best, but during nighttime the lower frequency bands work best. The D layer is present during the day and it is a good absorber of radio waves, increasing losses, Higher frequencies are absorbed less, so higher ...