Coverage and Interference for Second-Adjacent Channel FM Broadcast Stations

The coverage and interference of seven Los Angeles area FM broadcast stations are analyzed. The area and population coverages predicted by the FCC methods described in the rules are compared with a method that considers the intervening terrain in some detail. We also show that the criteria for deciding second-adjacent-channel interference threshold of -50 dB (rather than the present -20 dB) adequately protects modern receivers, based on data available in FCC filings and on the performance of these stations. We believe the techniques used in this analysis could be widely applied, and would result in more efficient spectrun use.