FCC Issues Public Notice on IBOC Sideband Power Increase

June 1, 2009

Washington - May 22, 2009 - In a public notice, the Federal Communications Commission is soliciting public comment on four issues relevant to recent filings in the pending digital audio broadcasting proceeding (MM Docket No. 99-325). On Oct. 23, 2008, the Media Bureau released a public notice soliciting comment on a request filed June 10, 2008, asking the Commission to modify the technical specifications for FM digital audio broadcasting, as well as on two related technical studies. The request was filed by a group consisting of 18 broadcasters that operate more than 1,200 commercial and noncommercial educational FM radio stations throughout the United States and the four largest manufacturers of broadcast transmission equipment, collectively identifying themselves as the Joint Parties.

The Joint Parties requested that the Commission increase the maximum permissible digital operating power of FM stations from the current level of 1 percent of a station's authorized analog power (-20dB) to a maximum of 10 percent of a station's authorized analog power (-10dB). Filed concurrently with and in support of the request was a technical report prepared by Ibiquity Digital.

In addition, National Public Radio submitted on July 18, 2008, its Corporation for Public Broadcasting-supported research on digital radio coverage and interference. The October 23, 2008, Public Notice sought comment on the joint parties' request and these related technical studies.

Developments since the release of the Oct. 23, 2008, public notice prompt the FCC's solicitation of public comment on four issues. Specifically, in response to the October 23, 2008, Public Notice, the Media Bureau has received comments and reply comments both supporting and opposing the power increase request. The joint parties have urged the Commission to move expeditiously on its request to ameliorate the coverage shortfalls and reception difficulties that result from digital transmissions at currently authorized power levels.

NPR has announced the commencement of additional CPB-supported testing of IBOC. NPR states that its additional testing will result in a recommendation of the amount of power increase needed to improve digital radio coverage while also protecting analog FM signals, including subcarrier transmissions, from interference. The study also proposes to consider the minimum spacing distances needed to protect analog signals from higher powered digital operations. NPR states that the findings of its study will be presented in September 2009.

In light of the record before the Commission, as well as NPR's plans for additional testing of FM IBOC, the FCC solicits further comment on the previously submitted Ibiquity and NPR technical studies and on the following issues:

  • Whether the Bureau should defer consideration of the joint parties' requested power increase until the completion of and comment on the further NPR studies.
  • Whether the record in this proceeding, the real-world experience gained from more than 1,400 FM stations operating for several years in the hybrid mode and the record of experimental authorizations at higher digital power levels warrant an increase in maximum digital operating power as proposed by the joint parties or support a provisional power increase of some lesser extent than that requested by the joint parties.
  • If the Commission adopts a power increase, whether it should also establish standards to ensure the lack of interference to the analog signals of stations operating on first adjacent channels. Should such standards apply to, i.e., require the protection of, LPFM stations operating on first adjacent channels?
  • If the Commission adopts a power increase, whether it should also establish more explicit procedures to resolve digital-into-analog interference complaints.

    The joint parties request and the Ibiquity and NPR technical studies are available electronically at http://fjallfoss.fcc.gov//prod/ecfs/comsrch_v2.cgi under MM Docket No. 99-325

    Submit comments on or before 21 days after date of publication of a summary of the public notice in the Federal Register, and reply comments on or before 35 days after date of publication of this public notice in the Federal Register.

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