This limitation on LPFM station power to 50 watts in specific areas like San Diego, Tucson, El Paso, Brownsville, and Yuma is a result of a longstanding agreement with Mexico that predates the LPFM service. In these regions, non-directional LPFM stations are restricted to 50 watts within 125 kilometers of the Mexican border. To maximize the service area while maintaining this power limit, LPFM stations operating in this “strip zone” are advised to have an antenna height of 42 meters above average terrain (HAAT). Operating at lower antenna heights may reduce the station’s coverage area. However, exceeding 42 meters HAAT requires reducing power to meet the 5.6-kilometer service contour limitation.