I am trying to hook up my TV to my Sony surround sound system. The problem is that my TV has no outputs of any sort and I do not use a cable box, thus I have no way of getting an audio signal to my reciever. I bought this thing from Walmart that accepts an RF connection and has audio outputs but apparently it does not pick up the audio from the cable line. Is there any device I can get that will help me out here (minus a cable box)?