WASHINGTON A proposal to allow digital FM stations to increase power — one that reflects industry negotiations and recent compromise among several major broadcast interests — is now in the hands of the Media Bureau of the Federal Communications Commission.
The goals of the proposal are to improve reception of digital signals significantly, particularly in mobile environments and within buildings, and to match up HD Radio digital coverage areas with stations’ analog footprints. More broadly, advocates hope a power hike will help renew the pace of adoption of HD Radio by broadcasters and send a positive sign to automakers and the consumer electronics industry.
The commission is contemplating the compromise crafted by iBiquity Digital and NPR, with input from the so-called Joint Parties, a group of 18 organizations including major broadcasters and transmission manufacturers. The Joint Parties, iBiquity and the National Association of Broadcasters originally asked the FCC for an increase more than a year ago. Observers believe the FCC preferred an industry consensus before acting on a power hike.
The United States has about 9,560 licensed FMs, according to FCC data. As of November, about 1,650 of those were using HD Radio, according to iBiquity Digital, or about 17 percent.
‘The water is fine’
The compromise worked out in November calls for the commission to allow a voluntary 6 dB hike for FM IBOC broadcasters across the board — meaning stations could quadruple their digital power — with provision for increases beyond that, up to a 10 dB increase in certain circumstances, or 10 times as much power. Initial prediction models suggest most stations would be able to exceed 6 dB.
The compromise also envisions adoption of technical developments — namely, single-frequency networks to fill gaps in digital coverage and asymmetrical digital sidebands to reduce the potential for digital interference to short-spaced first-adjacent analog stations — that would allow more stations to increase power without negative effects on themselves and neighbors.
Both NPR and iBiquity also committed to development of low-bitrate codecs and conditional access crucial to moving radio reading services into the mainstream digital system.
Supporters hope the agency will approve the plan quickly. They say it will show receiver manufacturers and automakers that the industry has a clear path to increased and more reliable digital signal coverage. Such improvement is critical, they say, as more HD Radio portables enter the market.
Backers also hope a power increase will spur adoption of HD Radio among broadcasters that have not transitioned, including many standalone operators and owners in medium to smaller markets.
“What comes out of this is a very strong signal to all of the industry stakeholders, especially the auto manufacturers, that the water is fine,” said Mike Starling, NPR’s vice president, chief technology officer and executive director of NPR Labs.
“Come on in and help us promote and deliver these new products to the American people because they’re going to have a wonderful experience with the benefits of digital technology with services and clarity that we could not deliver with our analog signals.”
Supporters including the four transmission companies in the Joint Parties say indecision over a power boost — along with the need for stations to sense a potential return on investment — has helped to stall the digital rollout.
Also, proponents say an increase would help motivate consumer electronics manufacturers to roll out more receivers, including models made for cars.
Not all agree
The industry, however, is not unanimous on the matter by any means.
Skeptics have argued that only stations in the largest markets will transition to digital because IBOC remains expensive to implement. They also worry that by boosting power, stations will cause interference to their own analog signals, especially at the edge of coverage areas. They wonder how many stations will lack the necessary headroom in their digital transmitters to increase power and be obliged to spend more to upgrade.
Some opponents are concerned about analog interference to stations caused when neighbors raise digital power. Representatives of the Media Access Project and Prometheus Radio, for example, have asked the FCC to deny the increase; they say elevated power testing has not taken into account the impact on low-power FMs and that “parties noted the impact of self-interference to the analog signals” during testing.
Entravision has told the FCC that interference from IBOC stations to rim-shot and lower-powered facilities “simply cannot be tolerated,” noting that KRRN(FM) in Moapa Valley, Nev., which reaches Las Vegas, “has been adversely affected by DAB operations at the –20 dB level.”
Brown Broadcasting, licensee of licensee of stand-alone WBRU(FM) in Providence, R.I., told the agency in comments this summer that it is short-spaced to six other stations and that for various reasons, its station power is being held to 20 kW, only 40 percent of the normal maximum ERP for its class. Brown says the station is one of the ones “that will suffer the most” from IBOC’s “destructive co-channel interference … which wipes out a significant part of a station’s service area.”
Brown also stated: “The giant conglomerates that now dominate radio ownership have some stations that will benefit from an IBOC increase and others that will suffer; but their largest stations are likely to benefit, and they seem willing to trade some burden for what they see as a greater benefit.” It said stand-alones like WBRU “can easily be ‘thrown under the bus’ by the trade-offs that media giants may choose to make.”
‘Reasonable compromise’
What happens with the increase now is up to the FCC.
The commission can accept the compromise and authorize stations to increase digital power. It may decide to use some elements of the negotiated agreement but add changes to any plan after inviting comment on the proposal or on portions of it. Or it could decide to do nothing.
Observers say the last option is unlikely because the agency has recognized an increase is needed. Media Bureau Chief Bill Lake said during the fall NAB Radio Show that the agency wants to support IBOC. Audio Division Chief Peter Doyle has said the current power level “is fraught with problems” and that notifications from owners converting stations to digital have dropped considerably.
Weeks of negotiations began in earnest after the fall NAB Radio Show; together, NPR and iBiquity made their resulting recommendations. They urged the FCC to adopt a plan in which most stations — commercial and noncommercial — that want to increase FM digital power be allowed to adopt a 6 dB increase, from the current level of –20 dB to a power level of –14 dB, as soon as authorized. To go beyond that to a 10 dB increase, broadcasters would use spacing calculations developed by NPR Labs for stations on reserved and non-reserved FM band allocations. See the formula in the box at POSITION.
(The 50 to 60 so-called “Super B” stations eventually would be able to increase their digital power by as much as 10 dB, but their increase would be based on the maximum for their class, and not a super-powered facility, said Milford Smith, vice president of radio engineering for Greater Media, one of the broadcasters among the Joint Parties. The Super B language in the compromise was part of the Joint Party’s original proposal, he said. The language states: For grandfathered super-power Class B stations, the digital power levels should be limited to the higher of: (i) –20 dB relative to their analog carrier as is permitted by the current rules, or (ii) at least 10 dB below the maximum analog power authorized for this class of station as adjusted for height, absent any grandfathered super power.)
NPR and iBiquity crafted the compromise with input from the Joint Parties, who, along with the technology developer, had advocated an immediate 10 dB blanket digital power increase. This summer, iBiquity proposed a 6 dB step in the interim as a compromise.
NPR has been studying the potential effects on analog signals if nearby digital stations raised power. Its initial calculations would have allowed fewer stations to raise power, and it wanted the FCC to wait until NPR completed its elevated power studies before deciding.
Initial NPR study results seemed to predict that short-spaced stations at the low end of the dial that air lightly processed music or talk would suffer interference to their analog signals, especially in a car radio, from an industry digital power hike.
But after walking through the details, NPR’s advisory committee — a group that included non-commercial station engineers as well as engineers from Greater Media and Cumulus — realized there would be tradeoffs, Starling said.
One is that some closely-spaced stations could have reception issues. But the compromise offers ways to handle those, he said.
“All in all, the committee felt it was a reasonable compromise to make sure HD Radio will work up to everybody’s expectations for portable and indoor operation.”
Starling said with its new, final data, NPR Labs completed new power calculations for the spacing recommendations that would allow more stations to raise their power, especially if new methods such as asymmetrical IBOC sideband transmission are used.
NPR projects that overall (both reserved and non-reserved) some 5,132 FMs, or 56 percent, could operate at -10 dBc with symmetrical power. But when you apply the asymmetrical software capability that iBiquity is working on, then approximately 89 percent, or 8,156 FMs can reach -10 dBc on one sideband. Also, while 35 percent of FMs are limited to – 14 dBc with symmetrical radiation, the number drops to eight percent with asymmetrical radiation, according to NPRs calculations.
The asymmetrical software would be installed in station exciters, according to Ibiquity President/CEO Bob Struble.
Smith said several versions of the formula for calculating how many stations can raise power and by how much were discussed in negotiations. “It provides a path for stations that aren’t absolutely minimally spaced.”
NPR previously had filed interim spacing calculations based on initial results of its elevated power tests conducted over the summer. NPR has now completed the study and updated those calculations. It submitted those to FCC in November.
Allowable IBOC Transmission Power Calculator The parties agree that additional power increases beyond 6 dB may be possible depending on conditions that limit harmful interference.
Stations that seek to increase power by more than 6 dB up to a maximum of 10 dB should be required to file an application with the FCC setting out compliance with the following criteria and formula:
Between the maximum IBOC power of –10 dBc and a blanket minimum power of –14 dBc, the allowable digital power for the digital station, toward any point on the 60 dBu contour of any first-adjacent analog FM station, is:
Allowable IBOC power = [2.27 * (60 – (IBOC station F(50,10) dBu)) – 33.6] The pace of change
How fast stations that want to go up to a full 10 dB increase could so, assuming the FCC approves the increase, is unclear and really up to the commission. It may opt to submit the issue of what to do beyond 6 dB for comment, said Starling.
“At that point, assuming they move forward to endorse the proposal, they will define how the notification or request process might work.”
The plan includes elements of what Starling calls a “managed power increase strategy.” The recommendations include the joint development by iBiquity and NPR of the technical upgrades NPR wanted, such as digital FM boosters for single-frequency networks, the software for asymmetrical sidebands and a variable-bitrate coder including conditional access for stations that air radio reading services.
NPR and iBiquity would give the FCC regular updates on these proposed technology developments.
Concrete steps to resolve legitimate analog interference complaints regarding the increase are included in the proposal. The parties say these steps would remediate harmful interference from any stations increasing power above the existing –20 dB power level.
Critics say similar interference mitigation procedures haven’t worked well on the AM dial, where several interference complaints have not resulted in agency action.
What’s next?
Struble and others said that, if the FCC does give stations the authority to increase power, implementation will not happen overnight; each station would need to evaluate its situation. But he characterized the compromise as “an important first step” in which improvements can be accomplished on the station end of the transmission chain, requiring no changes on the part of receiver manufacturers.
“Major advances” in upgrading broadcaster transmission facilities for higher power likely would take place in 2010 but that there was no set timetable, Struble said.
“The Media Bureau has been patient with the industry in working through each party’s concerns. A compromise has to help move things along because the issue is not contentious anymore,” he said.
Smith of Greater Media said the compromise is “enough to make a real difference and large enough to significantly improve the coverage of digital radio as opposed to analog.” Both he and Struble called the agreement a milestone.
Smith said only a couple of his company’s stations could raise digital power immediately upon FCC approval; most of the rest would need additional equipment. But he believes Greater Media, as well as other Joint Parties like CBS Radio and Clear Channel, would act as fast as possible to increase power on their stations if approved.
NPR surveyed member station managers to get a handle on how many facilities might increase their digital power. Of 183 responding, 70 percent indicated they’d raise IBOC power “the maximum they would be allowed to over the next year,” Starling said. Some, like WAMU(FM), Washington and KUVO(FM), Denver, already have purchased higher power transmitters in anticipation of an increase.
