Thermal fade

Thermal fade

A thermal fade is a phenomenon of wireless signal degradation (fading) caused by temperature and relative humidity factors. As the prevailing environmental conditions change, for example, from hot to cool, humid to arid or day to night, the electromagnetic waves refract differently thus altering the power distribution and possibly the direction of the signal. This is the same process that causes visible light to "bend" on hot days over a road or other surfaces.

This is a serious problem for AM broadcasting but less so with FM broadcasting. Thermal fading can occur in almost any frequency band.

ee also

*Atmospheric duct
*Ducting
*Refractive index


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • Thermal paper — is paper that is impregnated with a chemical that changes color when exposed to heat. It is used in thermal printers and particularly in cheap, lightweight devices such as adding machines, cash registers, and credit card terminals.The paper is… …   Wikipedia

  • Thermal printer — For the type of printer which uses sparks and aluminised paper (and is sometimes referred to as a thermal printer ), see spark printer. Part of a series on the History of printing …   Wikipedia

  • Brake fade — Vehicle braking system fade, or brake fade is the reduction in stopping power that can occur after repeated application of the brakes, especially in high load or high speed conditions. Brake fade can be a factor in any vehicle that utilizes a… …   Wikipedia

  • Fading — This article is about signal loss in telecommunications. For the poetry book, see Fading (book). For other uses, see Fade (disambiguation). Frequency selective time varying fading causes a cloudy pattern to appear on a spectrogram. Time is shown… …   Wikipedia

  • List of radio propagation topics — This is a list of radio propagation terms. NOTOC A a index A index aa index active prominence active prominence region (APR) active region active surge region (ASR) active dark filament (ADF) AE index Air Force Geophysics Laboratory (AFGL) arch… …   Wikipedia

  • Atmospheric duct — Fata Morgana of Farallon Islands with clearly seen duct In telecommunication, an atmospheric duct is a horizontal layer in the lower atmosphere in which the vertical refractive index gradients are such that radio signals (and light rays) (a) are… …   Wikipedia

  • TV and FM DX — TV DX and FM DX is the active search for distant radio or television stations received during unusual atmospheric conditions. The term DX is an old telegraphic term meaning long distance. VHF/UHF television and radio signals are normally limited… …   Wikipedia

  • запас на замирание относительно теплового шума — (МСЭ R F.1108 4). [http://www.iks media.ru/glossary/index.html?glossid=2400324] Тематики электросвязь, основные понятия EN thermal fade marginTFM …   Справочник технического переводчика

  • Disc brake — Close up of a disc brake on a car On automobiles, disc brakes are often located with …   Wikipedia

  • Label — For other uses, see Label (disambiguation). Shirt with labels …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”