Tropospheric propagation describes electromagnetic propagation in relation to the troposphere.
The service area from a television (TV) or frequency modulated (FM) radio transmitter extends to just beyond the optical horizon, at which point signals start to rapidly reduce in strength. Listeners or 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.
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Tropospheric Ducting Forecasts:
Tropospheric Ducting explanation and how to use: