On October 5, 2018, the Federal Communications Commission, as part of its ongoing efforts to revitalize AM radio, released a Second Further Notice of Proposed Rulemaking(SFNPRM) seeking comment on revised proposals regarding interference protection to Class A AM stations (so-called “clear channel” stations). The SFNPRM is a follow-up to the Commission’s Further Notice of Proposed Rulemaking released in 2015, in which the agency sought comment on technical proposals to reduce the nighttime protection afforded to Class A stations so as to enable more local AM stations to increase their nighttime service. Comments are due 60 days after the item is published in the Federal Register; reply comments are due 90 days after publication.
Clear channel stations, of which there are 57 in the continental U.S. and 16 in Alaska, are currently authorized to broadcast at up to 50 kW daytime and nighttime and are designed by rule as providing primary and secondary service over extended areas. Accordingly, these stations are afforded extensive daytime and nighttime protection from interference by co- and adjacent-channel AM stations. Specifically, clear channel stations in the continental U.S. are protected during the day to their 0.1 mV/m groundwave contour from co-channel stations, and to their 0.5 mV/m groundwave contour from adjacent-channel stations. At night, clear channel stations are protected to their 0.5 mV/m-50 percent skywave contour from co-channel stations and to their 0.5 mV/m groundwave contour from adjacent-channel stations.
The issue of clear channel station protection has been a contentious one since the FCC raised it in 2015, largely pitting Class A station owners against the operators of less powerful, more local AM stations. Class A licensees have resisted proposals to reduce their extensive interference protection, citing the vital role of clear channel stations in national emergencies and other benefits of wide-area AM stations listenable at night across large portions of the country. Owners of smaller AM stations, on the other hand, have pointed to their need to curtail or entirely eliminate their locally-based service at night to protect Class A stations hundreds of miles away. Continue Reading