SUPPLEMENTARY INFORMATION:

This is a summary of the Media Bureau's Public Notice in MB Docket No. 22-405; DA 24-154, released on February 21, 2024. The full text of this document is available electronically for public inspection via the Commission's Electronic Comment Filing System (ECFS) at https://apps.fcc.gov/​ecfs and the FCC's website at https://docs.fcc.gov/​public/​attachments/​FCC-24-154A1.pdf. Documents will be available electronically in ASCII, Microsoft Word, and/or Adobe Acrobat. Alternative formats are available for people with disabilities (Braille, large print, electronic files, audio format), by sending an email to fcc504@fcc.gov or calling the Commission's Consumer and Governmental Affairs Bureau at (202) 418-0530.

Synopsis

1. The Commission initiated this proceeding on August 1, 2023, with the release of an Order and Notice of Proposed Rulemaking seeking comment on a proposal to change the methodology used by digital FM stations to determine whether they can increase FM digital power, and to allow asymmetric sideband operation. Modifying Rules for FM Terrestrial Digital Audio Broadcasting Systems, MB Docket No. 22-405, Order and Notice of Proposed Rulemaking, FCC 23-61 (rel. Aug. 1, 2023) (NPRM). A Federal Register summary published on August 22, 2023, 88 FR 57033. The time period for filing comments and reply comments on the NPRM closed on October 6, 2023. Comment and Reply Comment Dates Set For FM Digital Power NPRM, Public Notice, DA 23-741 (MB rel. Aug. 22, 2023). Comments and reply comments were filed in ECFS under Media Bureau Docket No. 22-405.

2. On February 2, 2024, the National Association of Broadcasters (NAB) and Xperi Inc. (Xperi), two of the parties that filed Petitions for Rulemaking that led to release of the NPRM, filed with the Media Bureau (Bureau) a Petition for Rulemaking Addendum—Request for Clarification (Petition for Clarification), which is available in the Commission's Electronic Comment Filing System at https://www.fcc.gov/​ecfs/​document/​10202290960928/​1. In the Petition for Clarification, NAB and Xperi state that they have “identified an important ambiguity that requires clarification regarding the maximum allowable operating power of a digital FM signal.” Petition for Clarification at 2. The NPRM and the Commission's past discussions of digital power levels have considered only the power level for the digital FM carriers of the primary HD Radio MP1 hybrid service mode of operation. Id. In particular, the Commission has considered the total integrated power level for all digital carriers used to transmit MP1 standard hybrid service. NAB and Xperi note, however, that the HD Radio system is not limited to the MP1 mode, and the Commission has authorized extended hybrid modes of operation, which increase the number of digital subcarriers. Petitioners assert that the optimal operation of the extended hybrid modes requires an increase in the total integrated power above that of the MP1 mode so that all the digital carriers individually operate at the intended power. Id. at 2-5. (The MP1 mode consists of 10 digital partitions, each with 19 subcarriers. Extended hybrid modes add partitions between the MP1 partitions and the analog signal: for example, the MP2 mode adds one partition to the MP1 partitions; the MP3 mode adds two partitions; and various other modes, such as MP11, MP5, MP6, MP1X, DSB1, MP1XOV, MP6OV, and DSB1OV, add four partitions. These additional partitions increase the total digital power by 10, 20 and 40%, respectively. Id. at 4-5.) Otherwise, individual carriers would have to operate with less than the intended power level to keep the total integrated power at the intended level. Petitioners therefore seek to clarify the maximum digital FM power levels permitted for hybrid and extended hybrid service modes, including adding clarifying text to the NPRM, and textual changes to the proposed new § 73.404(e) of the rules. Id. at 6-7.

3. In light of this requested clarification, and to provide a complete record on this issue, the Bureau encourages public comment on NAB and Xperi's proposed clarifying language and changes to proposed § 73.404(e) of the rules. The Bureau notes that NAB and Xperi ask the Commission to incorporate a reference in the rules to the NRSC-5 standard, which is subject to modification, as an appropriate means to implement the proposed change. Because it is unusual for the Commission to incorporate outside standards into its rules, the Bureau states that commenters should offer alternative means to incorporate the proposed clarification directly into the Commission's rules. The Bureau further seeks comment on whether the additional digital power necessitated by use of extended digital modes would increase potential interference to first adjacent channel analog FM stations, to the host analog station, or to other users of the FM broadcast spectrum or adjacent to that spectrum. The Bureau notes that the Petition for Clarification does not reference any technical studies ( printed page 14799) of the impact of extended hybrid modes with a total integrated digital power level more than −10 dBc. Are such studies needed to determine whether or not to adopt this proposal? Commenters also should consider that if the Commission adopts this proposed change for stations operating with less than −10 dBc, should the Commission limit the total overall digital power for any station operating in extended hybrid mode to a maximum of −10 dBc? The Bureau notes that doing so would require stations that convert from MP1 to an extended hybrid mode to reduce the power of the individual subcarriers in the primary digital sidebands, in order to accommodate the power added by the extended digital sideband partitions. The Bureau further invites commenters to suggest modifications to petitioners' clarifying suggestions, as appropriate. It also seeks comment regarding the number of stations operating in the various extended hybrid modes, including whether those stations operate at a power level with more than −14 dBc, in order to determine the scope of this issue. Finally, the Bureau also offers an opportunity to commenters who wish to supplement or amend their previous comments in light of more recent additions to the record.