You've gotten the best DTV tuner, but after seeing a very ugly explosion during an action movie, you think something might be off that caused that heavy pixellation with trailing effects when that garden shed blew up.

It's not your setup. It's the station's own.

These pixellations, twittering, stairstepping, etc are more visible on scenes with lots of action, fast camera switches, rapid lighting effect, as well as cartoons.

One factor is that it could be more action than the encoder's processor can handle. Another factor - some stations are capping the amount of data transmitted on one channel to favor another channel in their network.

This is greatly apparent on NBC's station family here in Los Angeles- it tends to favor the NBC-HD 1080i broadcast over the other NBC channels as well as the other stations they own, Univision, Ion/PaxTV, among other UHF channels they own. Other stations with less channels appear cleaner since they don't have so much to deal with at once. The image sometimes, but not always, clears up when the "ring frame" is transmitted.

So if it's okay on the other channels, stop fiddling around with the already-perfect setup. If it bothers you too much, you already know how to use a remote, right?