A while back I sampled WTAW while driving through Brenham on Highway 290. I got a lock about 80% of the time, but it was obvious I was on the fringe of its HD coverage.
At my home in NW Harris County WTAW is listenable with a fair analog signal. The HD indicator glows dimly, indicating the station is in HD but is too weak to lock, which would make the indicator glow brightly.