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.
In the SFNPRM, the Commission affirms its commitment to exploring some degree of reduction in the interference protections afforded to clear channel stations to enable improvements to local service by other station classes. Accordingly, the FCC presents one new proposal for the protection of clear channel stations during the day, two alternative proposals for critical hours protection, and two alternative proposals for protection of clear channel stations at night. Specifically:
Daytime hours proposal:
- During daytime hours, Class A AM stations would be protected to their 0.5 mV/m daytime groundwave contour, from both co-channel and first-adjacent channel stations.
Critical hours proposals:
- Alternative 1: During critical hours (i.e., the two hours after sunrise and the two hours before sunset), Class A AM stations would be afforded no protection from other AM stations; or
- Alternative 2: During critical hours, Class A AM stations would be protected to their 0.5 mV/m groundwave contour.
Nighttime hours proposals:
- Alternative 1: During nighttime hours, there may be no overlap between a Class A AM station’s 0.5 mV/m nighttime groundwave contour and any interfering AM station’s 0.25 /m 10 percent skywave contour (calculated using the single station method); or
- Alternative 2: During nighttime hours, Class A AM stations would be protected from other AM stations in the same manner as Class B AM stations are protected (i.e., interference may not be increased above the greater of the 0.5 mV/m nighttime groundwave contour or the 50 percent exclusion nighttime root-sum-square (RSS) nighttime interference-free (NIF) level (calculated using the multiple station method)).
The Commission seeks comment on these alternative proposals, including the effects on licensees and listeners of each type of station that could result from reduced protection to Class A stations and power increases by co- and adjacent-channel stations. In addition, the agency asks for specific comments addressing the effect its proposals would have on the functioning of the EAS and IPAWS systems – in particular, the ability of other radio stations to receive EAS alerts from clear channel stations that function as Primary Entry Points. Finally, although the Commission states that it is not revising proposals set forth in the 2015 Further Notice of Proposed Rulemaking pertaining to the calculation of nighttime RSS values of interfering field strengths and NIF service, it does request that “in light of the alternative Class A protection proposals …, commenters state whether they would revise their previously submitted comments regarding calculation of RSS values and changes to Class B, C, and D daytime protection and, if so, in what way and for what reasons.”