Instead of just hooking up an HDD to your TV which can only record one programme while you are watching it,
why don't you look into a PVR (personal video recorder). These are digital recording devices that usually have more than one tuner in so you can record two programmes while watching a third. TV aerial plugs into the device and then you connect to the TV via RF cable and HDMI cable. Sony used to make these but sadly no longer.
Humax, Panasonic and Manhattan are popular choices. I have a Humax 5000T with three tuners so I can record 3 programmes and watch another.
