My wife is from Santa Barbara and I was there three weeks ago for a wedding. While there, I set up my sister-in-law's plasma with the Cox SA 8300. Believe it or not, Cox set it up using the RF so my sister-in-law was not watching HD for 8 months and thought she was. Anyway, after setting it up for them, I noticed the artifacts on the CBS SEC game, Florida-LSU I think. They were much much worse than what I see here on our CBS affiliate in Philadelphia which does not multicast. I believe your CBS affiliate multicasts. If that is the case, what you were seeing was due to the bit starving of the HD signal by your affiliate and is why I am so dead set against multicasting. Complain to them about it. It can't hurt although it will most likely fall on deaf ears.
Louder is NOT better!