Is there any TV tuner that can do digital channels from Cable TV... particularly Charter. I cant get any HD over the airwaves in my location and I am limited to the lower 75 channels or so that are analog. I am expecting these will eventually go digital and I will not longer be able to run my ATI TV Theater Pro 550 at all... which would be bad. I heard about some Cable Card stuff years ago... did that ever pan out? Does Charter support anything like that?