Matches in DBpedia 2016-04 for { <http://dbpedia.org/resource/Tropospheric_propagation> ?p ?o }
- Tropospheric_propagation abstract "Tropospheric propagation describes electromagnetic propagation in relation to the troposphere.The service area from a VHF or UHF radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. Viewers living in such a \"deep fringe\" reception area will notice that during certain conditions, weak signals normally masked by noise increase in signal strength to allow quality reception. Such conditions are related to the current state of the troposphere.Tropospheric propagated signals travel in the part of the atmosphere adjacent to the surface and extending to some 25,000 feet (7,620 m). Such signals are thus directly affected by weather conditions extending over some hundreds of miles. During very settled, warm anticyclonic weather (i.e., high pressure), usually weak signals from distant transmitters improve in strength. Another symptom during such conditions may be interference to the local transmitter resulting in co-channel interference, usually horizontal lines or an extra floating picture with analog broadcasts and break-up with digital broadcasts. A settled high-pressure system gives the characteristic conditions for enhanced tropospheric propagation, in particular favouring signals which travel along the prevailing isobar pattern (rather than across it). Such weather conditions can occur at any time, but generally the summer and autumn months are the best periods. In certain favourable locations, enhanced tropospheric propagation may enable reception of ultra high frequency (UHF) TV signals up to 1,000 miles (1,600 km) or more.The observable characteristics of such high-pressure systems are usually clear, cloudless days with little or no wind. At sunset the upper air cools, as does the surface temperature, but at different rates. This produces a boundary or temperature gradient, which allows an inversion level to form – a similar effect occurs at sunrise. The inversion is capable of allowing very high frequency (VHF) and UHF signal propagation well beyond the normal radio horizon distance.The inversion effectively reduces sky wave radiation from a transmitter – normally VHF and UHF signals travel on into space when they reach the horizon, the refractive index of the ionosphere preventing signal return. With temperature inversion, however, the signal is to a large extent refracted over the horizon rather than continuing along a direct path into outer space.Fog also produces good tropospheric results, again due to inversion effects. Fog occurs during high-pressure weather, and if such conditions result in a large belt of fog with clear sky above, there will be heating of the upper fog level and thus an inversion. This situation often arises towards night fall, continues overnight and clears with the sunrise over a period of around 4 – 5 hours.".
- Tropospheric_propagation wikiPageExternalLink dx_faq.htm.
- Tropospheric_propagation wikiPageExternalLink tropo.html.
- Tropospheric_propagation wikiPageExternalLink channels_2-6.html.
- Tropospheric_propagation wikiPageExternalLink DXPhotos.
- Tropospheric_propagation wikiPageExternalLink fmdxua.
- Tropospheric_propagation wikiPageID "22416553".
- Tropospheric_propagation wikiPageLength "13629".
- Tropospheric_propagation wikiPageOutDegree "121".
- Tropospheric_propagation wikiPageRevisionID "676154748".
- Tropospheric_propagation wikiPageWikiLink Africa.
- Tropospheric_propagation wikiPageWikiLink Algeria.
- Tropospheric_propagation wikiPageWikiLink Amasya.
- Tropospheric_propagation wikiPageWikiLink Analogy.
- Tropospheric_propagation wikiPageWikiLink Arkansas.
- Tropospheric_propagation wikiPageWikiLink Atmosphere_of_Earth.
- Tropospheric_propagation wikiPageWikiLink Atmospheric_duct.
- Tropospheric_propagation wikiPageWikiLink Atmospheric_pressure.
- Tropospheric_propagation wikiPageWikiLink BBC_Radio_Scotland.
- Tropospheric_propagation wikiPageWikiLink Bahrain.
- Tropospheric_propagation wikiPageWikiLink Brazil.
- Tropospheric_propagation wikiPageWikiLink Bucharest.
- Tropospheric_propagation wikiPageWikiLink Bulgarian_National_Radio.
- Tropospheric_propagation wikiPageWikiLink Burgas_Province.
- Tropospheric_propagation wikiPageWikiLink Burnt_River,_Ontario.
- Tropospheric_propagation wikiPageWikiLink California.
- Tropospheric_propagation wikiPageWikiLink Canada.
- Tropospheric_propagation wikiPageWikiLink Category:Radio_frequency_propagation.
- Tropospheric_propagation wikiPageWikiLink Channel_One_Russia.
- Tropospheric_propagation wikiPageWikiLink Clear-channel_station.
- Tropospheric_propagation wikiPageWikiLink Co-channel_interference.
- Tropospheric_propagation wikiPageWikiLink Contour_line.
- Tropospheric_propagation wikiPageWikiLink Cyclone.
- Tropospheric_propagation wikiPageWikiLink Density.
- Tropospheric_propagation wikiPageWikiLink Digital_television.
- Tropospheric_propagation wikiPageWikiLink Electromagnetic_radiation.
- Tropospheric_propagation wikiPageWikiLink FM_broadcasting.
- Tropospheric_propagation wikiPageWikiLink Federal_Standard_1037C.
- Tropospheric_propagation wikiPageWikiLink File:TV-4-NZch4-Auckland-tropo-1975.jpg.
- Tropospheric_propagation wikiPageWikiLink File:Tropo.png.
- Tropospheric_propagation wikiPageWikiLink Florida.
- Tropospheric_propagation wikiPageWikiLink Fog.
- Tropospheric_propagation wikiPageWikiLink Ghosting_(television).
- Tropospheric_propagation wikiPageWikiLink Goldsboro,_North_Carolina.
- Tropospheric_propagation wikiPageWikiLink Gulf_of_Mexico.
- Tropospheric_propagation wikiPageWikiLink Góra_Kalwaria.
- Tropospheric_propagation wikiPageWikiLink HD_Radio.
- Tropospheric_propagation wikiPageWikiLink Hawaii.
- Tropospheric_propagation wikiPageWikiLink High-pressure_area.
- Tropospheric_propagation wikiPageWikiLink Horizon.
- Tropospheric_propagation wikiPageWikiLink Humidity.
- Tropospheric_propagation wikiPageWikiLink Illinois.
- Tropospheric_propagation wikiPageWikiLink Indonesia.
- Tropospheric_propagation wikiPageWikiLink Interference_(communication).
- Tropospheric_propagation wikiPageWikiLink Inversion_(meteorology).
- Tropospheric_propagation wikiPageWikiLink Iowa.
- Tropospheric_propagation wikiPageWikiLink Kansas.
- Tropospheric_propagation wikiPageWikiLink Keaau,_Hawaii.
- Tropospheric_propagation wikiPageWikiLink Line-of-sight_propagation.
- Tropospheric_propagation wikiPageWikiLink Looming_and_similar_refraction_phenomena.
- Tropospheric_propagation wikiPageWikiLink Louisiana.
- Tropospheric_propagation wikiPageWikiLink Low-power_broadcasting.
- Tropospheric_propagation wikiPageWikiLink MW_DX.
- Tropospheric_propagation wikiPageWikiLink Massachusetts.
- Tropospheric_propagation wikiPageWikiLink Mediterranean_Sea.
- Tropospheric_propagation wikiPageWikiLink Mexico.
- Tropospheric_propagation wikiPageWikiLink Miami.
- Tropospheric_propagation wikiPageWikiLink Michigan.
- Tropospheric_propagation wikiPageWikiLink Missouri.
- Tropospheric_propagation wikiPageWikiLink Monterrey.
- Tropospheric_propagation wikiPageWikiLink Mountain.
- Tropospheric_propagation wikiPageWikiLink Nazran.
- Tropospheric_propagation wikiPageWikiLink Netherlands.
- Tropospheric_propagation wikiPageWikiLink New_Zealand.
- Tropospheric_propagation wikiPageWikiLink Ohio.
- Tropospheric_propagation wikiPageWikiLink Oklahoma.
- Tropospheric_propagation wikiPageWikiLink Orkney.
- Tropospheric_propagation wikiPageWikiLink Outer_space.
- Tropospheric_propagation wikiPageWikiLink Pajala.
- Tropospheric_propagation wikiPageWikiLink Pakistan.
- Tropospheric_propagation wikiPageWikiLink Palm_Beach,_Florida.
- Tropospheric_propagation wikiPageWikiLink Pennsylvania.
- Tropospheric_propagation wikiPageWikiLink Persian_Gulf.
- Tropospheric_propagation wikiPageWikiLink Poland.
- Tropospheric_propagation wikiPageWikiLink Poltava.
- Tropospheric_propagation wikiPageWikiLink Portsmouth,_Virginia.
- Tropospheric_propagation wikiPageWikiLink Pyrgos,_Elis.
- Tropospheric_propagation wikiPageWikiLink Radio_Data_System.
- Tropospheric_propagation wikiPageWikiLink Radio_propagation.
- Tropospheric_propagation wikiPageWikiLink Raleigh,_North_Carolina.
- Tropospheric_propagation wikiPageWikiLink Refraction.
- Tropospheric_propagation wikiPageWikiLink Refractive_index.
- Tropospheric_propagation wikiPageWikiLink Rila.
- Tropospheric_propagation wikiPageWikiLink San_Antonio.
- Tropospheric_propagation wikiPageWikiLink Skywave.
- Tropospheric_propagation wikiPageWikiLink Stereophonic_sound.
- Tropospheric_propagation wikiPageWikiLink Sweden.
- Tropospheric_propagation wikiPageWikiLink Tampa,_Florida.
- Tropospheric_propagation wikiPageWikiLink Television.
- Tropospheric_propagation wikiPageWikiLink Temperature.