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254:), 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
205:) 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
248:, 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 (
282:, 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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194:" 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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186:. 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,
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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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504:"On some direct evidence for downward atmospheric reflection of electric rays"
278:. 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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423:"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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534:, pp. 703–704 (22 November 1947) doi:10.1038/160703c0
411:, No 1586, pp. 540 DOI: 10.1126/science.61.1586.540
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Proceedings of the
Institute of Radio Engineers, 4,
60:. Unsourced material may be challenged and removed.
266:. The phase velocity can in fact be greater than
140:. The Kennelly–Heaviside layer is the E region
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355:Oliver Heaviside and the Heaviside layer"
120:Learn how and when to remove this message
290:, the group velocity must go below it.
286:, so when the phase velocity goes above
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366:https://doi.org/10.1098/rsta.2017.0459
353:Griffiths, Hugh (15 November 2018). "
225:(1861–1939) and the British polymath
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58:adding citations to reliable sources
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400:McAdie, Alexander (22 May 1925) "
237:, for which he received the 1947
482:Russell, A. (24 October 1925). "
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484:The “Kennelly-Heaviside” Layer"
45:needs additional citations for
27:Layer of the Earth's ionosphere
493:, p. 609. doi:10.1038/116609c0
380:Marchant, E. W. (Dec. 1916). "
1:
546:ITU Telecommunication Journal
402:The Kennelly-Heaviside Layer"
583:Radio frequency propagation
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175:. It is also known as the
69:"Kennelly–Heaviside layer"
368:. Retrieved 14 June 2019.
246:total internal reflection
150:Kennelly–Heaviside layer
148:, sometimes called the
421:Martyn, D. F. (1934).
239:Nobel Prize in Physics
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223:Arthur Edwin Kennelly
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382:The Heaviside layer"
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54:improve this article
558:1975ITUTJ..42..413M
441:1934Natur.133R.294M
388:No. 6, pp. 511–520.
293:In 1925, Americans
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272:special relativity
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552:: 413–418.
184:radio waves
578:Ionosphere
572:Categories
338:References
213:activity.
199:solar wind
173:ionosphere
138:ionosphere
80:newspapers
459:0028-0836
313:Etymology
190:. This "
406:Science,
326:See also
322:months.
260:and the
177:E region
18:E region
554:Bibcode
437:Bibcode
217:History
211:sunspot
192:skywave
188:horizon
162:ionised
94:scholar
528:Nature
488:Nature
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101:JSTOR
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303:ITU
203:lee
171:'s
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