Yes - but I don't think all of them attenuate.
I have to keep rebooting my modem - ready light keeps dropping to blinking. It coincides with being upgraded from 2MB to 4MB, or whatever it is - I lose track. All I know is my modem speed is faster today than it was yesterday.
[edit] It's now just rebooted itself. Me suspects they might be fiddling again

Unless it's the neighbours.
[edit] Might be a stray egg, Chris W -
http://www.cableforum.co.uk/board/sh...97&postcount=2
Downstream Receive Power Level is -9.4 dBmV - which according to Iggy is too high.