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FCC Takes Comments on FM Digital Power Increase

It also agreed to combine this petition with an earlier one for asymmetric sidebands

The FCC wants to know what you think about the proposal by the National Association of Broadcasters and Xperi to allow many FM HD Radio stations in the United States to raise their digital power levels.

The Media Bureau now is taking comments on the petition submitted by the NAB and Xperi in October. [Read the petition.]

The commission also has combined this petition with another filed in 2019 by NAB, Xperi and NPR. That one would permanently authorize FM stations to use HD Radio with asymmetric sideband power levels without the need for separate or experimental authorization. [Read that petition.]

These two petitions now have been assigned MB Docket Number 22-405. Comments can be filed in the FCC’s Electronic Comment Filing System. Comments are due Jan. 12, replies are due Feb. 13.

Higher power

Xperi and the NAB believe that higher power will improve digital FM coverage and digital FM signal penetration of buildings while minimizing interference to adjacent-channel stations.

The commission originally authorized FM stations to operate with digital ERP equal to 1 percent of analog power or –20 dBc. In 2010 it allowed stations to operate at –14 dBc but to allow stations that meet certain guidelines to increase to –10 dBc, or 10 percent of analog power.

In some cases, to operate above –14 dBc, stations must submit a request with an analysis of its potential to cause interference to adjacent-channel analog signals. It used a technical formula developed by National Public Radio and supported by Xperi predecessor iBiquity Digital.

Xperi and NAB say this approach was intentionally conservative and can be loosened based on field experience. It said the existing approach uses symmetric sidebands for all calculations, eliminating a path for many stations to increase power on at least one sideband and improve digital coverage. Further, they said, real-world experience has shown that the existing formula is too restrictive.

There are approximately 2,600 FM stations using HD Radio in the country.

Randy Stine contributed to this report.