Last week I was at Best Buy in Winston-Salem, NC, and they were playing a long message over the PA system extolling the virtues of HD Radio...cd quality audio (their term, not mine), new "hidden" channels that you can only get with an HD Radio (new music formats, more news, etc...the things we listen to radio for), and NO MONTHLY FEES, EVER!
It's about time they started promoting HD Radio like they mean it. The technology (for FM stations, I still have no experience with AM HD) works great. The sound is fantastic. And it truly has brought me programming I can't get anywhere else, even with a 5mbps broadband connection, and an XM subscription.
As for AM HD, I have yet to have anything "lock on" with my Accurian (Radio Shack) HD Radio, including WBT Charlotte (about 80 miles from my home). But when near Charlotte (Statesville, Hickory), I HAVE heard some low level noise on adjacent channels (to two Charlotte stations...1110AM, and 610AM). A friend says the 610AM signal in Charlotte is damaging reception of his analog-only 630AM licensed to Hickory, and I believe him. It's always been a challenge fitting a gallon (high quality audio) in a quart container (a 10khz AM channel). A challenge that stations HAVE been able to meet for many decades. But the extra bandwidth occupied by HD isn't "a gallon", but more like "ten gallons". And the little 10khz-wide AM channel just can't contain it, so it's "spilling over" onto 1st and 2nd adjacent channels. Drip, drip!
So AM HD causes interference to adjacent channels (apparently). And when it works correctly, digital coverage is a lot more restricted than analog (I have no trouble receiving WBT's analog signal!). How badly do we want digital to work in the mediumwave band? And are we allowing that desire to cloud our judgement? I'm a huge believer in digital technology, and that in the future all media (most of it, anyway...I still enjoy print on paper!) will be delivered as packets of data...binary code. What I'm questioning is whether THIS (AM HD) is the best way for AM stations to deliver those packets!