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Radio industry journal acknowledges problems with AM HD

Following on the heels of my unimpressive AM HD radio listening test last week, industry stalwart Radio World magazine published a report that comes to terms with the fact that “AM HD radio has stalled.” In fact, I’d say that characterizing AM HD as “stalled” is very optimistic. Instead, reading the same article I come away with the impression that AM HD just barely launched into orbit, and has since fallen.

In terms of statistics, the article notes that there are fewer than a sixth (16%) as many digital AM stations than FM, totaling only about 6% of all AM stations in the US. Furthermore, even amongst the nation’s most powerful big market AM stations that are broadcasting in digital, “most of those transmit their digital signals only during the day.” Tellingly, RW also observes that, “[m]any of the stations on-air with AM HD are owned by members of the HD Digital Radio Alliance.”

The article points to several non-technical factors that might be influencing AM HD’s lack of success. One is the recent FCC decision permitting FM translator repeater stations to be used to rebroadcast AM signals. Another purported cause is the economy (which we can pretty much blame for nearly everything without further explanation). Finally, apparently station groups are waiting for their FM HD signals to start paying off before making further investments on the AM side.

Significantly, it appears that interference issues, including interference with a station’s own primary analog signal, are behind many stations turning off their digital signal. Furthermore, the issue of receivers switching between digital and analog signals when the radio can’t keep locked to the HD data stream is important. On FM the relatively similar fidelity of the analog and digital HD1 channels means that the “blending” between them isn’t particularly noticeable. But on AM the digital and analog programs sound very different, making the blending from one to the other very noticeable and often quite annoying.

Something I didn’t know before is that iBiquity, the owner of the IBOC HD technology, is offering a new “configuration” for AM stations that air mostly talk programming which reduces the digital signal bandwidth in order to reduce interference, heard most prominently on older high performance AM receivers. As a listener, however, I see the bandwidth reduction as a double-edged sword. While it may minimize interference, it also reduces fidelity, which can obviate some of the minimal gains associated with HD technology in the first place.

In a companion piece, Radio World also talked to a number of additional radio engineers not quoted in the first article. While a few, like Clear Channel’s Brett Gilber based in Tulsa, OK, consider the technology a success, others are less sanguine. Harold Beer, who engineers Michigan State University’s WKAR-AM said, “After years of encouraging listeners to get better quality wideband AM radios, we ended up degrading their listening experience with a 5 kHz bandwidth, –35 dB SNR analog signal once we turned on the IBOC digital.”

In the end, whether you read Radio World’s relatively balanced coverage or just listen to AM HD yourself, it’s hard to conclude that this digital medium is anything close to a success. The question is: will the radio industry see fit to throw more cash down the AM HD Radio money pit?


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4 Responses to Radio industry journal acknowledges problems with AM HD

  1. Greg September 6, 2010 at 8:35 pm #

    “FCC Admits Ignorance on Digital Radio”

    “A few questions remain to be settled, including how the IBOC system will function in the real world; what is the potential for and extent of interference that IBOC could cause to existing services; and the technical feasibility of nighttime AM IBOC transmissions.”

    http://www.diymedia.net/audio/mp3fcciboc.htm

    “Statement of Jeff Littlejohn SVP Engineering Services Clear Channel”

    “The current AM allocation rules require Co-Channel stations to provide 20:1 protections to each other and first adjacent channel stations to provide 2:1 protection to each other. While this works fine in an all-analog environment, it does not seem to be sufficient in the presence of IBOC. The energy above 10 KHz from the proposed Hybrid IBOC signal significantly exceeds the energy present in the current analog AM signal. For this reason, the amount of energy provided to a first adjacent station is significantly more detrimental than our current allocation rules allow for.”

    http://www.am-dx.com/clearchannelrprt.pdf

    The FCC and Jeff Littlejohn (who’s now a huge shill for HD Radio) knew about the problems with AM-HD back in 2002, and the radio industry is just now acknowledging these problems! More excuses why AM-HD is a failure – blame it on the economy, FM translators, and a real popular one is that AM radio is just a failure itself.

    “AM-HD Undergoes Radical Redesign”

    “It, in effect, signals iBiquity and its proponents’ firm intention to gradually phase out the notion of long-range listening on the AM band as we’ve known it, and localize the coverage area of all AM radio stations. Apologies to those of you who live in rural areas with no stations of your own, who rely on distant stations as a primary means of radio listenership: you’re out of luck. This is no conspiracy – you simply don’t exist anymore ”

    http://www.diymedia.net/archive/0410.htm#040310

    Some “configuration”, hugh?

  2. Ed Robinson September 7, 2010 at 8:18 am #

    AM HD needs to be put out of its misery.

    It draws negative publicity onto HD from those that don’t distinguish between FM HD and AM HD. FM HD is doing relatively well all things considered, with steady increases in receiver penetration and more and more stations adding HD2 sub-channels, but if iBiquity doesn’t get rid of AM HD, it will remain a drag on HD FM.

  3. Greg September 7, 2010 at 9:31 am #

    @Ed: Have you checked the FCC’s webpage for the number of conversions for FM-HD and AM-HD? For the past couple of years, conversions have virtually stalled. Also, to get past Struble’s receiver sales nonsense, I simply run this Google Trends graph, which says it all:

    http://tinyurl.com/26eaztv

    Try comparing “xm”, “sirius”, and “pandora” against HD Radio. Funny, Struble never mentions the high return rates for HD radios. It’s always quotes about the number of HD chipsets shipped.

  4. Matt P September 12, 2010 at 6:07 pm #

    That’s interesting. I have always had a pleasant experience with AM HD Radio.

    Interesting article on AM HD Radio

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