yes it is the one that connects the tv to the antenna analog signal will come through coax that a digital signal will not, if I were you I would replace the coax with quad shield coax and that would eliminate any problem most wal marts carry it and 100 foot is about 36.00. and you could try a converter box to see if it was the tuner but I would borrow one as they run around 53.00 and up so I would replace the coax first. I then would do as jay did and get a small db2 antenna an install behind the tv. if you are handy I have posted the plans for a homemade uhf antenna in the antenna reviews section that everyone is raving over you can even make it with coat hangers but copper wire works better and is easier to bend.
