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243:), scientists were unwilling to believe the speed in the ionosphere could be higher. Nevertheless, Marconi had received signals in Newfoundland that were broadcast in England, so clearly there must be some mechanism allowing the transmission to reach that far. The paradox was resolved by the discovery that there were two velocities of light, the
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proposed the name "Heaviside Layer" for the radio-wave reflecting layer in the upper atmosphere, and the name has subsequently been widely adopted. The name
Kennelly–Heaviside layer was proposed in 1925 to give credit to the work of Kennelly, which predated the proposal by Heaviside by several
194:) side of the Earth, the solar wind drags the ionosphere further away, thereby greatly increasing the range which radio waves can travel by reflection. The extent of the effect is further influenced by the
237:, which in turn would require that the speed of light in the ionosphere would be greater than in the atmosphere below it. Since the latter speed is essentially the same as the speed of light in vacuum (
271:, and that makes total internal reflection possible, and so the ionosphere can reflect radio waves. The geometric mean of the phase velocity and the group velocity cannot exceed
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183:" or "skip" propagation technique has been used since the 1920s for radio communication at long distances, up to transcontinental distances.
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standard model of absorption and reflection of radio waves by the
Heaviside Layer was developed by the British Ionospheric physicist
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Existence of a reflective layer was predicted in 1902 independently and almost simultaneously by the
American electrical engineer
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occurring roughly between 90km and 150 km (56 and 93 mi) above the ground — one of several layers in the
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presses this layer closer to the Earth, thereby limiting how far it can reflect radio waves. Conversely, on the night (
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Proceedings of the Royal
Society of London, Series A, Containing Papers of a Mathematical and Physical Character,
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175:. Because of this reflective layer, radio waves radiated into the sky can return to Earth beyond the
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Philosophical
Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences,
218:(1850–1925), as an explanation for the propagation of radio waves beyond the horizon observed by
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Physicists resisted the idea of the reflecting layer for one very good reason; it would require
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in 1901. However, it was not until 1924 that its existence was shown by
British scientist
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493:"On some direct evidence for downward atmospheric reflection of electric rays"
267:. The phase velocity for radio waves in the ionosphere is indeed greater than
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L.M. Muggleton (1975). "A method of predicting foE at any time and place".
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412:"Atmospheric Pressure and the Ionisation of the Kennelly-Heaviside Layer"
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Nobel Prizes for 1947: Sir Edward
Appleton, G.B.E., K.C.B., F.R.S."
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Propagation is affected by the time of day. During the daytime the
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first mapped the
Heaviside layer's variations in altitude. The
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Appleton, Edward V., and
Barnett, M. A. F. (1 December 1925).
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523:, pp. 703–704 (22 November 1947) doi:10.1038/160703c0
400:, No 1586, pp. 540 DOI: 10.1126/science.61.1586.540
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Proceedings of the
Institute of Radio Engineers, 4,
49:. Unsourced material may be challenged and removed.
255:. The phase velocity can in fact be greater than
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129:. The Kennelly–Heaviside layer is the E region
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344:Oliver Heaviside and the Heaviside layer"
109:Learn how and when to remove this message
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355:https://doi.org/10.1098/rsta.2017.0459
342:Griffiths, Hugh (15 November 2018). "
214:(1861–1939) and the British polymath
47:adding citations to reliable sources
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389:McAdie, Alexander (22 May 1925) "
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471:Russell, A. (24 October 1925). "
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473:The “Kennelly-Heaviside” Layer"
34:needs additional citations for
16:Layer of the Earth's ionosphere
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369:Marchant, E. W. (Dec. 1916). "
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391:The Kennelly-Heaviside Layer"
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164:. It is also known as the
58:"Kennelly–Heaviside layer"
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235:total internal reflection
139:Kennelly–Heaviside layer
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410:Martyn, D. F. (1934).
228:Nobel Prize in Physics
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212:Arthur Edwin Kennelly
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371:The Heaviside layer"
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547:1975ITUTJ..42..413M
430:1934Natur.133R.294M
377:No. 6, pp. 511–520.
282:In 1925, Americans
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502:.752 pp. 621–641.
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41:Please help
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541:: 413–418.
173:radio waves
567:Ionosphere
561:Categories
327:References
202:activity.
188:solar wind
162:ionosphere
127:ionosphere
69:newspapers
448:0028-0836
302:Etymology
179:. This "
395:Science,
315:See also
311:months.
249:and the
166:E region
543:Bibcode
426:Bibcode
206:History
200:sunspot
181:skywave
177:horizon
151:ionised
83:scholar
517:Nature
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