The latest is WSRO-AM, a low powered jazz station in Boston that operates on 650 AM. Like most of these experimental digitized signals, they lose whatever listeners they have - except, of course, they all have FM repeaters that lets the audience continue to hear them.

Will this thing ever actually catch on? I just can't see it, given that most radios are still not equipped to receive these signals and I doubt a lot of people will go out and buy a brand new set just to hear one or two outlets they may not listen to in the first place. 

Still, an interesting development and worth watching to see if others follow suit. 

New England Gets Its First All-Digital AM