Hi, My HD set has a built in tuner Ive been using since I went on antenna again. Ive always gotten 6 channels or so. For the heck of it I connected my converter box up to it just to fool around. Instead of 6 channels I got 35 channels with thier sub-channels! Can there be that much difference in tuner sensitivity. Im cosidering getting a outboard tuner that can throw a high def signal to my tv, but I hav'nt seen alot of choices. Anybody know of any? Thanks