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Digital Radio Cranks Up the Juice

The FCC knows a good compromise when it sees one

The Federal Communications Commission did well when it decided on Jan. 27 that most U.S. FM stations airing HD Radio signals may now increase their digital power.

The breadth of industry backing for a carefully managed increase is impressive and includes numerous radio owners and transmitter manufacturers. The move will help broadcasters deliver a better product to the new class of HD Radio receivers, particularly portable devices and indoor radios, without causing undue harm to neighboring stations.

Further, no one can argue that this power hike is being done willy-nilly, thanks to the cautionary effect of NPR’s testing and the FCC’s care in how it is adopting most of the compromise recommendations it eventually received from iBiquity Digital and NPR. Though I do have some worries about the interference remediation, overall this ruling is appropriate.

The gist is that FM stations running HD Radio may, if they choose, increase their hybrid digital effective radiated power from the current limit of 1 percent of analog ERP, which is 20 decibels below carrier. Most will be able to increase by 6 dB, a four-fold digital power hike, to –14 dBc, right away; further, some will be able to seek approval to increase digital power as much as 10-fold, to 10 percent of a station’s analog power, or –10 dBc.

The FCC also set up interference mitigation and remediation steps to resolve cases of digital interference to full-service FMs resulting from this power hike.

Here are major points I take away from the much-anticipated order, released by William T. Lake, chief of the FCC’s Media Bureau:

• “Virtually all” of the 1,500 or so FMs using HD Radio have concluded that their digital coverage doesn’t match that of their analog, and that indoor and portable reception “are particularly and significantly diminished,” the FCC wrote. Both iBiquity and NPR support that conclusion, as you know from past issues of Radio World.

• The FCC is well aware that the HD Radio rollout is stalled and thinks that’s a bad thing: “The number of notifications of the commencement of hybrid FM digital operations has dropped significantly over the past two years,” it wrote. “Based on these findings, we conclude that it is important to increase FM digital ERP to improve FM digital coverage and to eliminate regulatory impediments to FM digital radio’s ability to meet its full potential and deliver its promised benefits.”

• FM digital in more than five years’ time has not produced a mess of interference (despite self-assured predictions from some critics, I would add). In fact, the FCC stated flatly: “Since the commencement of 1 percent FM IBOC power operations in 2004, the bureau has not received any well-documented complaints of interference to analog FM stations from digital signals.”

iStockphoto/Sergei Popov It further noted that since 2006, it had issued 15 experimental authorizations for operations at the highest contemplated digital power level, including authorizations for 10 grandfathered short-spaced stations with as many as four first-adjacent channel short spacings, some severe.

• Even though most now have spent three-plus years at the higher digital power, “the bureau did not receive any complaints of interference to analog FM stations from licensees of analog FM stations or the listening public as a result of the experimental operations.” (It acknowledged that Rhode Island Public Radio, in filed comments, did mention interference to the analog of WRNI from higher digital power at WKLB in Massachusetts.)

• Based on the data available to it, as well as “five years of interference-free FM hybrid digital operations by approximately 1,500 stations,” the commission approved the immediate 6 dB increase for all FMs except super-powered stations.
The latter may still be able to increase power under certain circumstances. (Super-powered FMs enjoy effective radiated powers or reference contours in excess of the usual maximums for their class. Fewer than 200 stations are super-powers. Not sure if you are a super-powered FM? Go here:

The commission felt it was “imperative for us to implement a power increase promptly” and believes its digital power limits will protect analog FMs properly. But it rejected arguments that all stations should be allowed a blanket 10 dB increase, that the “structured increase” compromise is cumbersome or that grandfathered, super-powered stations should also enjoy a blanket increase.

As I write, the FCC order is awaiting regulatory paperwork to take effect; but stations can request an STA to raise power if they don’t wish to wait. Once the order takes effect, eligible FMs can make the increase in digital power up to –14 dBc and must notify the Media Bureau within 10 days using a form in the CDBS filing system.

• In considering this decision, the commission heard suggestions that it approve or reject a digital power hike flat-out. It heard backing as well for incremental or limited approaches. It should decide case by case, some people argued, or on the basis of minimum distance separation or contour protection standards.

Some commenters talked about the potential of using asymmetrical sideband power levels to limit the impact on first-adjacent analog stations or of using single-frequency networks and synchronous boosters to improve FM digital coverage instead of hiking digital power. Again, these are all issues familiar to Radio World readers.

• The commission ultimately set up a mechanism for a station to seek an increase beyond the blanket 6 dB; and it established a formula to determine maximum allowable FM digital ERP, following the idea proposed by NPR.

If anything, the formula is conservative, but the commission feels the resulting protection to first-adjacent stations lets it set up “an expeditious ‘go-no go’ mechanism for many FM stations to obtain significant digital power in excess of the 6 dB for which most stations will qualify.”

• The commission was not swayed by arguments that it should set up protection rights for low-power FMs, despite the possible impact of HD Radio signals on nearby LPFMs.

“Adoption of these recommendations would constitute a dramatic change in LPFM licensing rules and the relationship between LPFM and full-service stations,” it decided. Because analog LPFMs and FM translators are secondary services, they are not entitled to protection from existing full-service analog FMs.

“One aspect of secondary service licensing would make this change particularly problematic,” the Media Bureau continued. The rules now permit LPFM stations (unlike others) to operate at locations where they may receive interference from other stations. “The ability to ‘accept’ received interference is enormously beneficial to the LPFM service, providing greater flexibility in choosing transmitter sites and, in many instances, permitting the licensing of stations that would not be possible under full-service rules.”

If LPFMs operate at “substandard spacings,” the commission said, it’s because of voluntary decisions they made to accept interference.

• “Out of an abundance of caution,” the FCC also adopted steps to deal with interference resulting from the digital power hike, as Leslie Stimson reports.

The FCC promises that action on valid complaints will be relatively swift. Notably, if the FCC doesn’t respond right away to your legitimate interference complaint, your station can demand that the other guy back the digital power down — and you presumably can expect the commission’s support until the matter is decided officially.

• None of this affects digital AM stations. The FCC made no mention of AM IBOC, an entirely separate ball of wax with its low penetration and history of interference concerns.

• Given the whole IBOC debate and HD Radio’s relative lack of uptake by smaller broadcasters, I also was interested in a note I spotted among the “small print” language in the order regarding the possible impact of the FCC decision on small entities:

“We acknowledge that an argument could be made by smaller entities that they could face an unacceptable disproportionate burden because of a comparative lack of capital and other resources. This argument suggests that the adopted rule changes place smaller entities at a resultant disadvantage in relation to larger entities.

“However,” the commission staff stated, “we reject such an argument because allowing such voluntary upgrades will ultimately provide: (1) improved digital coverage; (2) the advancement of digital radio technology; (3) increased listenership; (4) greater regulatory certainty; (5) flexibility to licensees in the timing and scope of the rollout of their digital radio services; and (6) the facilitation of informed decisions regarding equipment purchases that will best serve licensees’ needs. Allowing licensees to voluntarily increase their digital ERP will, in the long run, prove to impose a lesser burden on smaller entities than alternative measures, such as making digital power increases compulsory or prohibiting increases altogether.”

• Last, the commission left itself an out:

“We believe that the FM digital ERP increase and the FM digital interference remediation procedures that we are adopting will not result in numerous or non-resolvable cases of objectionable interference to analog FM stations. Nonetheless, if implementation of the adopted increases in FM digital ERP results in a widespread level of interference to existing analog FM stations that we deem unacceptable, we will promptly revisit the maximum permissible FM digital ERP values in the future.”

In all, I feel the FCC took a moderate path here and acted wisely.

The outcome also further demonstrates how influential the work of NPR Labs has become within engineering and regulatory circles in the few years since it was created. When I hailed NPR and Mike Starling at the time for developing that concept, I could not have imagined a better example of the salutary role of an engineering-based radio broadcast R&D organization. Witness how NPR Labs has helped mold what might otherwise have been a flat-out rush to approve an unlimited 10-fold digital power hike.

I do hope that while celebrating their “win” and spinning up their power dials, HD Radio backers pause to acknowledge that strong anti-IBOC feelings remain in the marketplace, and that many good, well-intended, intelligent broadcasters remain worried about interference despite the confident language from proponents and the FCC.

Some broadcasters frankly also feel steamrolled by what they view as a digital radio bandwagon driven by big forces beyond their reach or control. That’s unfortunate; industry engineers and executives who have worked in good faith to build a success out of IBOC understandably feel that such sentiments are grossly unfair. But I’m here to tell you, for some broadcasters that taste, fair or not, is bitter and long-lasting.

So the worst thing that could happen now would be for valid interference complaints to end up in a bureaucracy, for the remediation steps laid out by the FCC to end up as window dressing.

HD Radio proponents got what they wanted when they won FCC approval of the system as a de facto standard, at the digital injection levels they requested. They later won approval to use their extended hybrid mode. Now they’ve won approval to crank up the power dial a lot. They have been given, and have earned, remarkable support from our nation’s regulators.

Now both the FCC and digital broadcasters need to make sure cases of interference are handled quickly and fairly. I’m dubious that the commission can respond fast to interference complaints — this is an organization that sometimes takes years to issue decisions in public file cases — though I appreciate the good intentions and its recent attempts at being more responsive.

And we’d better hope the FCC is serious about being ready to revisit this power hike if it suddenly starts hearing about widespread interference to existing analog FM stations. The day has not yet come when digital FM has earned priority over analog.

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