NPR: up the power, but not where interference is increased

In response to iBiquity Digital’s comments filed yesterday (7/8/09 RBR #131), with the FCC in response to its Public Notice soliciting a second round of comments on the proposed one size fits all 10 dB across-the-board power increase, NPR proposed an alternative approach to upgrading HD power that would not interfere with existing analog FMs.  We’ve got more detail:

The proposal supports an interim, immediate power increase of up to 10dB to HD radio broadcasting without doing damage to existing analog broadcast signals.  This plan limits power increases based on station spacing to limit any IBOC (in-band on-channel) interference to the existing 1% power level.

NPR's position on the proposed 10 dB power increase has not changed:  NPR generally supports increasing HD transmission power provided it is based on a managed regulatory policy (spacing rules would apply rather than a free for all without regard to consequences to analog neighbors). This approach is essential to avoid harmful interference to analog radio services, which remains the predominate connection between the public and public radio programming.

NPR’s comments, reflecting the breadth of the 850 station public radio community, suggest that an across-the-board increase is a flawed approach because it requires an unnecessary balancing between improved coverage and increased interference that fails to account for each station's 1st adjacent distance separations.  Public radio regional organizations across the country, including California Public Radio, Western States Public Radio, Public Radio in Mid America and Eastern Region Public Media supported NPR’s proposal as well and provided comment.  Together, the Public Radio Regional Organizations represent over 500 public radio stations across the US.

“NPR is committed to the successful implementation of HD Radio by increasing IBOC power to improve HD Radio coverage in a way that preserves existing analog service,” said NPR President and CEO Vivian Schiller.

NPR’s comments to the Commission yesterday call for the future of HD radio to be built on sound engineering practices that account for the unique broadcasting circumstances of all stations – public and commercial alike. 

“It is indeed possible to boost HD broadcasting power and protect our current analog services that bring radio to 235 million Americans,” said Mike Starling, NPR CTO and Executive Director of NPR Labs.   “It simply isn’t necessary to degrade our analog broadcasting signals as we bring needed improvements to HD radio coverage.”

Additional testing by NPR Labs is currently well under way and will produce the technical basis and methodology for authorizing stations to increase IBOC transmission power.  Given how soon that testing will be completed -- approximately 2 months – NPR urged the Commission to defer acting on any unilateral, across-the-board power increase. 

RBR/TVBR observation: It sounds like a fair approach to an upgrade in power, but coming up with a general spacing plan based off of interference levels may be 1) tough; and 2) leave some in-market FM HD stations with lower power than their less-crowded-on-the-dial competitors. The East Coast will be especially challenging. Perhaps one of the HD sideband signals could be brought up to higher power, while the other one is kept lower--to keep down 1st-adjacent channel interference. We’re not sure if this could be engineered easily, but it seems worth looking into.

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