Why do only some channels from my cable TV pixellate and some don't?

I had that problem a few years ago. Turns out - squirrels had been chewing on a jumper wire on a pole. The damage affected the higher-frequency channels first while the lower frequency channels still looked good.

So call your cable company for a service call. Either wires are going bad or they need to install or fix an amplifier.

That has to do with the amount of allotted memory. Each channel is allotted so much band width and when they try to fit more into it, it causes pixelation. The same thing happens if you try to fit four movies onto a 4.7 GB blank dvd.

Could indicate a weak signal from your cable... You may need a tech. to come and check out the signal strength to your box or TV..! (Should be -3db. minimum in most cases.)