This post is cable centric, but the programming is HD. I didn't see an equivalent HD (cable source - technical) forum. If there is, let me know and I'll move the post.
I live in NYC and have Time Warner digital cable. On some channels and when using their Start Over service, I tend to get pixelation or complete dropout.
I called TWC, who send over a technician. He told me that the cable I have running in the walls was RG59, and it really should be RG6U (IIRC).
Replacing the cable in the walls would be a huge, expensive, and difficult project. Is there any way to boost the signal through the RG59, or otherwise improve the signal getting to the box?