Radio Waves Podcast #328

 Radio: February 18, 2022

Years ago, it was relatively common for radio stations to give away special radios that tuned only to one station: theirs. The novelty radios were essentially transistor radios with the normal tuning knob removed and special circuitry that locked on to a single frequency.

Something similar is happening to certain radios in the Seattle, Washington area: some factory-installed radios in 2014-2017 model-year Mazda automobiles are locking on to just one station, KUOW, at 94.9 FM.

Perhaps the slogan for the station should be “The Outer Limits,” since they are taking control of the radio. But I digress.

KUOW is an NPR station that broadcasts using HD Radio technology. According to radio engineering newspaper Radio World (radio world.com) and a statement on the KUOW website (kuow.org), they are aware of the issue but don’t know exactly what is happening. 

Service managers at local Mazda dealerships have — as has the station itself — been inundated with complaints regarding the issue, in which the infotainment systems in the cars go into a cycle where they lock up or continually reboot. For whatever reason, the radios will then lock on to KUOW and only allow for volume changes.

The station has been talking with engineers from Xperi, the company that invented and licenses the HD Radio system to stations and receiver manufacturers, in an attempt to determine what is going on. One theory says that some sort of data may have been sent with the station’s signal, such as images that can be displayed on the screen, and they may have inadvertently corrupted some of the programming code that runs the infotainment systems.

The station shared with Radio World a statement from Mazda, reading in part: “Between 1/24 and 1/31, a radio station in the Seattle area sent image files with no extension, which caused an issue on some 2014-2017 Mazda vehicles with older software … Mazda North American Operations will support impacted customers with replacement parts” … at least once they are available. And perhaps after the issue that caused it is truly identified.

KUOW says that the HD Radio system in the vehicles pulls images from an NPR database, and uses local images from the station when an NPR image is not available. This technically means that the issue could be more widespread than though, and it may affect other areas of the country — and potentially other radios — if a fix isn’t found. 

It is also possible that the KUOW lock may just be a side effect of a programming error caused by another station. Consider that I’ve had digital radios go bad in thew past that locked onto particular stations when they rebooted, just by coincidence.

In the meantime, the great HD Mystery continues. And I guess KUOW’s ratings will benefit!

Rethinking HD

A “questionable” purchase on my part, along with the advancement of other technologies, has me rethinking the future of HD Radio itself. And this came about before the KUOW saga.

Back in the early 1990s, the National Association of Broadcasters got together with Denon to produce what was to be the ultimate tuner, designed to take advantage of all known technologies to help in the reception not only of FM, but AM as well … including a wider, high-fidelity bandwidth, an AM stereo decoder, noise reduction, and more.

It was called the TU680NAB, and it was quite a tuner. I tested one out but ultimately preferred (and bought)  the competing Carver TX11b, partly because I slightly preferred the overall reception, and I was a bit of a Carver snob. But the Denon was considered among the best tunes ever produced, due to its sensitive tuning and extended fidelity, especially on AM.

HD Radio came later, and rendered it essentially obsolete, due to its HD’s improved fidelity, the extra channels on FM, and the complete lack of noise and interference on AM. But problems quickly arose, due to both interference from the HD signals themselves especially on the AM band, and the licensing costs to run HD streams. In the meantime, apps such as Streams HiFi Audio and myTunerRadio have made online apps more reliable and easier to use, and can tune stations from around the world.

While at one time, HD on AM made for a nice listening experience, most AM stations in Los Angeles and nationwide that once ran the HD signals have turned them off, though HD is still common on FM. True counts are hard to come by, but it would not be a surprise to me if there are more stations broadcasting in analog AM stereo than there are using AM HD.

A group on Facebook that I am part of got me interested in that Denon tuner, and I happened to find one relatively cheap.  Just like I remember, it sounds fabulous. I have not compared it to the Carver since the 1990s — I need to get the Carver out of the attic to do so —  but it is impressive. AM stations, even though none are in stereo locally, sound fabulous . Better than I remember… So do FMs.

And unlike HD radio, where AM stations only sound good when receiving the digital signal, AM on the Denon sounds great even in mono. Yes, almost as good as FM.

So it got me thinking: why don’t AM stations turn on the stereo again, and pressure radio manufacturers— through the FCC and the NAB — to make tuners capable of  receiving stereo and the full fidelity AM can have?  It may be only a temporary solution as apps take over broadcasting over the next 20 years, but it would be an easy, inexpensive solution regardless.

As long as AM stations start running formats people want to hear.

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