Zach said:. The only time I've lost HD from local stations has been due to tropo, which is frequent and strong here on the coast. But that's only happened a few times in a year and a half that I know of, and when it happened it took all the class A's and distant C's out as well.
Tropo is a big problem for a lot of stations without adding HD to the mix. Listeners usually don't understand it, and think you are doing something "to keep them for listening" or that your equipment is at fault.
I can only speak about my analog station, but this time of year, I get several angry emails or phone calls every month about tropo problems. The caller usually calms down after I explain that it is an uncontrollable force of nature. I guess I should be grateful that they care enough to complain.
I suspect that if HD gets obliterated every morning from 7:00 AM until about 10:00 or so, people will simply think "it doesn't work." This would be especially true of HD-2 or HD-3 channels which have no analog fall-back. Probably they will write it off as “another defective product.”
Maybe I'm wrong.