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Contours are used as a standardized method to generally predict the coverage area of a broadcast station as well as the areas where a station could cause interference to other stations.  The calculations are based on whether a signal can be received at the field strength indicated on 50% of the receivers, 50% of the time.  This is known as the F(50, 50) curves.  This curve measurement is used mainly to determine coverage of FM radio, analog television and analog televisionLand Mobile Radio (LMR).  The F(50, 10) curve is a similar theory, except that it is 50% of the receivers, 10% of the time.  F(50, 10) is used to determine interference.  Digital television also uses an F(50, 90) curve as signal strength for TVDTV coverage.  

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How to Generate FCC Contours in Signal Pro

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