Radio horizon: Difference between revisions

Latest revision as of 04:50, 27 March 2024

The locus of points at which direct rays from a radio transmitter become tangential to the earth's surface.

The radio horizon extends beyond the geometric and visible horizons in conditions of normal atmospheric refraction. It may be decreased or increased in particular cases as standard propagation is replaced by substandard propagation or superstandard propagation, respectively. Beyond the radio horizon, surface targets cannot be detected under VHF atmospheric conditions although significant radio power is sometimes detected in the diffraction zone below the horizon. This power is a result of scattering by turbulence-produced atmospheric inhomogeneities. Assuming a smooth surface, the distance of the radio horizon is given approximately by the equation , where R is the distance in kilometers and h is the height in meters of the antenna above the surface.
See effective earth radius, scatter propagation.

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+{{Term
+|Display title=radio horizon
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+|Definitions={{Definition
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+|Meaning=The locus of points at which direct rays from a radio [[transmitter]] become tangential  to the earth's surface.
-<div class="termentry">
+|Explanation=The radio horizon extends beyond the geometric and visible horizons in conditions of [[normal]]  atmospheric [[refraction]]. It may be decreased or increased in particular cases as [[standard propagation]]  is replaced by [[substandard propagation]] or [[superstandard propagation]], respectively.  Beyond the radio horizon, surface targets cannot be detected under VHF atmospheric conditions  although significant radio [[power]] is sometimes detected in the [[diffraction zone]] below the [[horizon]].  This power is a result of [[scattering]] by turbulence-produced atmospheric inhomogeneities. Assuming  a [[smooth surface]], the distance of the radio horizon is given approximately by the equation  [[File:ams2001glos-Rex02.gif|link=|ams2001glos-Rex02]], where ''R'' is the distance in kilometers and ''h'' is the height in meters of the antenna  above the surface. <br/>''See'' [[effective earth radius]], [[scatter propagation]].
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+}}
-== radio horizon ==
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-  </div>
-<div class="definition"><div class="short_definition">The locus of points at which direct rays from a radio [[transmitter]] become tangential  to the earth's surface.</div><br/> <div class="paragraph">The radio horizon extends beyond the geometric and visible horizons in conditions of [[normal]]  atmospheric [[refraction]]. It may be decreased or increased in particular cases as [[standard propagation]]  is replaced by [[substandard propagation]] or [[superstandard propagation]], respectively.  Beyond the radio horizon, surface targets cannot be detected under VHF atmospheric conditions  although significant radio [[power]] is sometimes detected in the [[diffraction zone]] below the [[horizon]].  This power is a result of [[scattering]] by turbulence-produced atmospheric inhomogeneities. Assuming  a [[smooth surface]], the distance of the radio horizon is given approximately by the equation  <div class="inline-formula">[[File:ams2001glos-Rex02.gif|link=|ams2001glos-Rex02]]</div>, where ''R'' is the distance in kilometers and ''h'' is the height in meters of the antenna  above the surface. <br/>''See'' [[effective earth radius]], [[scatter propagation]].</div><br/> </div>
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