to tell the truth, your probably asking for trouble spitting again as thats going to drop your levels even more, and its not like you can get a cable signal booster down your local DIY (shame that), your far better off getting yourself a DVB-T USB card (with BDA drivers) and setting up a good external tv arial too that DVB.
far easyer and you get the advantage of being able to stuff that DVB direct digital .ts feed through your lan (works nice over wireless 11g,see
http://jtvlan.netsons.org/howto.php) to the other machines or special mpeg2 boxs.