Yup, I'm one of those people who have noticed it on OTA. Macroblocking on OTA seems completely random on my TiVoHD. I can go days without have problems, then an entire night of programming can be macroblocking-plagued. The only time I get macroblocking thats predictable is when I have multipath (which I can hear, since its always associated with the helicopters that occassionally fly through my line-of-sight). Now before I had the TiVoHD and watched directly on my TV, I never had macroblocking except when I had multipath, which again, only usually lasts 10-15 seconds, not the entire program. I've tried pretty everything, but I'm now convinced this is an encoding issue. Lately, most of the HD shows I've recorded have been off NBC, which happens to be the strongest station I receive (90% or higher, compared to FOX which I get at 70%). The macroblocking usually leads to the picture freezing, but I can always hit "skip forward" to get it unstuck.