No it is not just you. It seems Comcast is unable to maintain an acceptable signal quality on their lines. It seems they cannot keep people from tapping their lines (badly) and introducing noise. This has been my theory on our troubles since we started using them. All this so some cheap bastard can get HBO (or whatever) for free. We had good signal on Saturday while comcast staff were patrolling the lines where they have been consistently been having people steal cable but it seems as soon as the trucks left the thiefs were right back at it. I'm not postitve this is the problem, but everything points to it and Comcast has admitted they have had a recurring problem with this in the area. It also could be other comcast customers uncapping their modems. We have abysmal upload numbers (~20K when we're paying for 1M) and hideous signal to noise.
My comment on the subject in private discussions:
Did comcast tell you where their cable thief is? I'm tempted to come down there and shove his bad coax tapping job up his ass so far that he'll be getting HBO direct to the brain. 
This barely describes my frustration about this, poor Frey has been busting his ass trying to resolve it with Comcast when we have known what the issue has been all along. From observing the patterns I can almost tell you when this thief gets up in the morning, when he gets home from work, when he gets up to take a crap and when he goes to bed at night. Its getting ridiculous.
