What public stations should consider about upgrading HD Radio power

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Two of NPR’s top technologists recently back from the NAB Show share the microphone to weigh the pros and cons for stations that might boost their digital signals to improve listeners’ reception of HD Radio.

Dennis: Digital radio broadcasting is a reality now in most American communities, though adoption is still modest. About 2.5 million receivers have been sold, but assuming multiple receivers for early adopters and counting methodologies, household penetration might be roughly 2 percent — about as many households as in  a market the size of Washington.

Public radio has aggressively invested in digital radio transmission. Some stations, such as WAMU in Washington, have also made significant programming investments in new channels. But general managers and their boards are asking: Where is this all going? Should we upgrade to a higher power level? What would that mean for analog coverage? Mike Starling and I are going to try to provide some answers.

Where is HD Radio going?

HD Radio has been buried by commentators more times than Nosferatu (Mike and I have even touched a shovel once or twice), yet was very much alive at this year’s NAB Show.  The pace of consumer acceptance is slow and we’re an impatient bunch. No one really knows where this is all going, but a couple of examples from broadcasting’s past will provide some context.

FM stations now get 80 percent of radio listening, but the technology didn’t always look like a winner. The first FM station went on the air in 1938 when broadcasting itself was less than two decades old, and it took roughly 40 years before FM overtook AM to become the dominant aural medium. You could start in radio, have a full career, and retire in that time. Stereo, first available in 1961, contributed to the eventual disruption of AM, but even that took more than 15 years.

The first digital television station in the U.S. went on the air in 1996, but it was a full decade later before a fourth generation of decoder chips delivered receiver performance that even approached an acceptable level. Fourteen years later, penetration of receivers with HD-capable tuners is only 17 to 40 percent, depending on the market. If you look at what was happening in the consumer video world during that lost decade and shortly before, you’ll see that American TV broadcasters were hugely disrupted by competition from cable and satellite providers, videocassettes and DVDs.

Radio broadcasting has been disrupted for decades by television, tapes, CDs and digital music players. We’ve survived, but have been changed.

The disruption continues. A large number of Internet radios have been released to the marketplace, and new services including the enormously successful streaming service, Pandora, and its competitors are bringing customizable music to multiple platforms. And what about the news/talk listener? Stitcher and RadioWeave stream podcasts that users can assemble into their own on-demand “stations.” The iPhone and other smartphones have taken locality out of portable radio, providing access to any station anywhere. In December, Pandora had 300,000 “average active sessions” online — almost as many as CBS Radio and Clear Channel combined.

This past year was a good one for digital radio in the U.S. Receiver manufacturers came out with the first digital radios that didn’t require a giant “wall wart” to power them, including Microsoft’s well-reviewed Zune upgrade. And they’ve learned more about how to build digital radios with less internal noise. More car manufacturers have signed on. And at year’s end, NPR and iBiquity Digital negotiated a compromise, which the FCC adopted, enabling a meaningful power increase (four-fold or, in some cases, up to ten-fold) for digital radio while providing important protections for analog FM reception.

These are all necessary — though not sufficient — steps for success. Radio needs to show that it’s ready to provide value to listeners in a very competitive and disruptive marketplace.

One brilliant thing about the U.S. digital radio standard is that it rather easy to develop new capabilities for it — more or less like developing new web pages. There are many exciting innovations in the works that will make today’s receivers look rather pedestrian. Visual and data elements are coming. And it would be surprising if we don’t, within very few years, see hybrid radios incorporating analog, HD Radio and IP radio in one dashboard unit.

HD Radio is neither DOA, nor is it assured of success. Rather, it has a plausible shot at market acceptance if we’re patient and learn from our disruptors. Disruptive technologies don’t need to overtake radio, they just have to skim our margin — and margins are pretty skinny where they exist at all.

Mike will explain the new digital radio power increase and what general managers and their boards should know about this important development. As with stereo, there is “no free lunch” with in-band on-channel (IBOC) digital — not even at current power levels. But we believe the FCC’s balanced approach will moderate the costs to analog reception, permitting digital radio services to grow while protecting analog services and their far greater number of listeners.

Upgrading HD v. analog coverage

Mike: It should come as no surprise that there are tradeoffs when you add power in the FM band. The power increase for IBOC FM stations resides on each station’s first-adjacent channel. Therefore, the roughly 10 to 15 percent of stations that operate with minimum spacing may suffer interference with their fringe reception (near or beyond their protected contours). So, for stations that rely on coverage beyond their protected contours, an HD power increase by a closely spaced first-adjacent neighbor could be particularly problematic.

Digital stations have been operating at a power level that is 1 percent of the analog level. The FCC now allows a blanket 6 dB (four-fold) power increase from this level, but that’s expected to cause some new instances of first-adjacent HD Radio stations interfering with neighboring analog FM stations.

The FCC, in adopting these rules, stated that it had received “no bona fide complaints of interference” after HD Radio had operated several years at the 1 percent power level. And they stressed again that interference beyond protected contours is not actionable. So if your station relies on listening beyond your protected contour, you should consult with qualified engineering personnel to determine the likelihood of new interference from stations increasing IBOC power nearby — and consider targeting important communities in such areas as priorities for translator or repeater upgrades.

Contrary to what you’d expect, we don’t expect worsened interference from stations that go for the greatest power increases — those that boost power up to ten-fold (to as much as 10 percent of analog power). Those stations will have to operate under tougher anti-interference rules.

Interference is more likely to occur with the closely spaced HD Radio signals with smaller power increases (those going to 4 percent of their analog power). Many but not all of these stations are in the congested Northeast.

Again, remember that regardless of separation criteria, detecting IBOC interference is highly dependent on modulation density masking and the most vulnerable stations are those programming talk or lightly processed music.

The bottom line is: be on the lookout for stations that are likely to upgrade power on your first-adjacent frequencies. We expect these to initially be stations that are participating in traffic services, such as Clear Channel or Broadcast Traffic Consortium outlets, or others that are investing heavily in the success of the HD offerings, whether multicast streams — or emerging datacast services. Here again, qualified engineering help can point out where these moves are likely.

There has been discussion about the need for a systematic means of tracking increases as filed with the FCC for stations that might reasonably be on a “watchlist” of most vulnerable stations. Remember that the NPR Labs testing (www.nprlabs.org) showed that the most vulnerable stations are those running news/talk or lightly processed, high-fidelity music with extended passages at low volume levels. If you operate a moderately processed jazz format, you will be less susceptible than if you are operating a news/talk or classical station. And monaural stations will be less susceptible than stereo stations.

Should we upgrade?

If you’re running a multicast format important to your station’s community mission on HD2, HD3 or HD4, you should plan an upgrade to the highest available power at your earliest opportunity. If you would like to maximize your opportunity to participate in emerging HD data services, a power upgrade should be important to you, too.

Because the rules will trigger 3-dB power step-downs when six or more bona fide complaints cannot be resolved between affected stations, it would be advantageous to have your station on the air before the launch of a potentially interfering new analog station.  In addition, listeners will be more likely to complain about IBOC interference, which is indistinguishable from noise, if it begins after they develop expectations about the sound of an analog station.

At the very least, every station should ask its HD equipment manufacturer what it would cost to upgrade power to 4 percent of analog power, as well as to the maximum power allowable.

Many stations will be able to eke out a further increase in power when iBiquity releases new software to transmitter manufacturers later this year. That will enable them to increase HD Radio power asymmetrically — more on the side where there’s less potential interference. Stations will benefit by determining a.s.a.p. how much they can increase power symmetrically and asymmetrically, and what it costs, so they can take advantage of matching funds offered by CPB. There’s no guarantee that the funds will always be available or that you’ll continue to have any elbow room among nearby frequencies.

Dennis: In its 90-year existence, radio has proven amazingly adaptable to both technology and competitive challenges. However, never in that time has our industry faced so many disruptors as we have now. Even the disruptors have disruptors.

Surely, radio must adopt multiple distribution strategies for web and mobile devices, and we’ve made notable inroads in that regard. But since our “gross tonnage” of listening will come from over-the-air broadcasting for many years to come, we must look at modernizing its technology and business strategies as well.

The IBOC radio standard has the flexibility and initial take-up to be an important tool in this effort to continue and increase service to our audiences.  The collaborative RadioDNS project (radiodns.org) is developing exciting new ways to combine radio broadcasting with Internet Protocol capabilities. It’s also entirely feasible now to give HD Radio a back channel  for interactivity by building broadcast radio receivers that can also send and receive 3G or 4G wireless services. The more HD Radio can assume the capabilities of Internet services such as Pandora and Stitcher, the sooner our investments in digital transmission will pay off.  If radio broadcasters as a group are smart, the receivers of the relatively near future will have interactivity as well as the scalability of radio broadcasting.

Dennis Haarsager is NPR’s senior v.p. for system resources and technology and former acting chief exec, and the author of the blog Technology360.com. Mike Starling is NPR v.p. and chief technology officer and executive director of NPR Labs.

More power for HD Radio means more buzz on analog FM, NPR finds, September 2008.

WAMU manager Caryn Mathes writes: For WAMU and its listeners, HD Radio means more slices of pie to go around, September 2009.

NPR and iBiquity agree: raise HD Radio power four-fold, November 2009.


Audio samples on NPR Labs’ site approximate the sound of interference by the hybrid analog/digital signal with regular FM reception.

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