we have seen increased signal quality issues on both sd and network hd channels, including audio. it's been worse this year vs. last year, getting worse the last three months. june has been especially bad but it started before that. i suspect pushing comedy central to hd (but not wide format) and fox at 360 up to hd/wide format might be when it started to decline.
we get the montery bay area locals, even though we are on the border to san jose local range and would have preferred that.
we have a hr21 and a non-dvr hd receiver, we see similiar issues on both.