TV card problems - help me please!
 

Got a TV card today. I can get pictures downstairs when I hook the card up to a wire direct from an aerial socket, but when I go upstairs to my room and just hook it up with an external aerial the picture is very random.

Also, whilst I can get picture fine downstairs, on 70% of the channels I can't any sound. On the others it is fine!

HELP

Dean