The FCC’s Media Bureau has announced the start date for new rules allowing for expanded HD Radio coverage. The rules, announced in September, are based on a 2019 petition from Xperi, NPR, and the NAB that has drawn criticism from the aviation industry.
With the publishing of the Report and Order in the federal registry, FM stations will be able to operate their upper and lower digital sidebands at different power levels without needing special permission as of November 20. Previously, operators had to apply for experimental authorization to use asymmetric sidebands each year.
Due to concern about potential interference with aviation navigation systems led by Air Line Pilots Association International, the FCC has temporarily excluded stations on frequencies from 107.1 to 107.9 MHz. Stations on those frequencies will still have to follow the previous rules while safety testing continues.
The new allowance is designed to greatly improve digital signal penetration while causing minimal interference on the analog side. Joint research between Xperi and the NAB found that, “In many cases, the stations that cannot increase power are located in urban and suburban areas with greater population density and more tall buildings. A power increase for those stations would enhance building penetration and significantly improve their listeners’ ability to receive a strong digital signal.”
Under the rules, Schedule 335-FM will be updated to require stations to report the Effective Radiated Power for both the upper and lower digital sidebands, as well as the total digital ERP. Stations increasing total digital ERP above -14 dBc must certify compliance with the maximum permissible power levels outlined in the FCC’s updated table.
The FCC will maintain the current interference mitigation and remediation procedures, deeming them sufficient to address any potential interference while reserving the right to revisit these procedures if interference issues arise, ensuring protection for adjacent analog FM stations.
