This afternoon the Commission released an Order authorizing FM radio stations to increase power on their hybrid digital radio operations. This power increase is a welcome boost to HD radio operations and was eagerly awaited by many FM stations broadcasting in digital.  In a nutshell, the rule change allows stations to increase from the current maximum permissible level of one percent of authorized analog effective radiated power (ERP) to a maximum of ten percent of authorized analog ERP.  In raising the power permitted for digital radio operations, the Commission acknowledged that the current digital power levels are insufficient to replicate stations’ analog coverage and that indoor and portable coverage are particularly diminished.  Building on proposals advocated by National Public Radio (NPR) and iBiquity, the Commission has provided for an immediate voluntary 6 dB increase in Digital ERP (except for super-powered FM stations, as discussed below).   In addition, stations will be allowed to seek authority for increases over 6 dB up to a maximum of 10 dB using an informal application process.

Once the Order becomes effective, eligible FM stations may commence operations with FM digital operating power up to -14 dBc (that is, up to a 6 dB increase), consistent with the existing IBOC notification procedures.  Stations availing themselves of the voluntary power increase must notify the FCC electronically of the increased digital power within 10 days of commencement using the Digital Notification form via the Commission’s Consolidated Database System (CDBS).   The exception to this is super-powered FM stations, which, regardless of their class, are limited to the higher of either the currently permitted -20 dBc level or 10 dB below the maximum analog power that would be authorized for the particular class of station, as adjusted for the station’s antenna height above average terrain.   The Audio Division’s web site contains an FM Super-Powered Maximum Digital ERP Calculator available here to assist super-powered stations with determining the maximum permissible Digital ERP.  Licensees of super-powered FM stations must file an application, in the form of an informal request, for any increase in the station’s FM Digital ERP. 

For power increases over 6 dB, licensees will be required to submit an application to the FCC, in the form of an informal request, for any increase in FM Digital ERP beyond 6 dB. Licensees wishing to operate with an FM Digital ERP in excess of -14 dBc must make a calculation and determine the station’s max permissible Digital ERP as detailed in paragraphs 17 through 20 in the Order, available here.  Continue Reading FCC Gives Digital FM Radio a Power Boost