I think you are thinking of WRGB-6 in New York. They transmitted CBS audio on 87.9 for a couple of weeks after the transition before the FCC caught them and forced them to turn it off.
IMO, DTV is not good at all. Who wants to watch pixels and "no signal" in the mountains or in a multipathed area? Or on the boat? In the '90s we used to take a little 5'' analog TV on our boat out in Puget Sound and watch 4, 5, 7, etc. from Seattle just fine on analog. We went to Hood Canal a couple of months ago, which can only get one channel (13 KCPQ). Before DTV, most of the local channels came in, albeit some ghosting. There are defects with DTV, IMO.
-crainbebo