Kandiru,
I've got one of those set-top antenna's on my TV and the closes tower is about 40 miles away. Whats funny is the closer towers I can't get using the 811's crapy tuner. I can get the ones that are 70 miles away with 80 and above % signal strength.
It is a amplified antenna from Wal-Mart for $30, I think (it has been awhile since I looked) it has 30db gain on VHF and UHF. Anyways, I'm able to pull in something like 9 real stations, plus the sub-stations. Then there is a couple others that I can adjust my antenna and pick up ok, sometimes they drop.
Garys,
On the 811 anything at 60% or below, does NOT lock, I can view something when it is at 60%, but usually it doesn't do to good unless I'm at 62% or above.
Andy01,
Picture quality depends on what station you are viewing and what content they are broadcasting, etc... Different stations my not be broadcasting full resolution, which will cause the PQ to be below what you expect.
On the stations that I get, most of them have Sub channels, usually the main HD channel is *.01 channel, however, there is couple of them that are on the .02 channel.
When viewing the same programming on the HD channel and the channel that is not HD, I see a big PQ difference. This may be what you are seeing, it may be that the channels in question, are not broadcasting the HD signal, or the HD signal is only broadcasted certain hours of the day. My two local PBS stations (Tulsa and OKC) only broadcast HD signal certain hours, and their Digital stream is only broadcasted from like 12-12. It could be that the channels that you notice a PQ problem, are not broadcasting their HD signal at that time in other words.
If you have side bars on your screen on these channels that PQ is bad, that is a good sign that the signal isn't really HD. Whenever I see side bars on my screen for my locals, the PQ is great, but your local station may not be upconverting the analog (which is what the side bars tell you, HD should fill your 16x9 TV).