No pixelation noticed on channel 5, WTTG at my home. Try checking your connections first, I had a similar problem with channel 50, WDCW and that fixed the pixelation. Good luck.
I replaced the connection going from the coax to the bbc. You will want to make sure all of your connections are tight. If that doesn't fix the problem you might need your dish adjusted in better by a tech. Good luck.