[AbMagFab]

Cable signal is great! Comcast measured it outside, inside and at the Tivo. Comcast did their job. I wish I could say this of Tivo Service.

Why do you assume they are doing their job? If he finds a low signal, he has a lot of work in front of him.

Comcast is notorious for spending a lot of time saying the signal is good, when it isn't.

Try a quality signal amplifier and see if that resolves your problem.

(Also, not that it really tells you much, but what does the Tivo say the signal strength is for the problem channels?)