From what I understand, HDTV DOES in fact work over the air, and you can recieve HDTV broadcasted signals with a simple antenna. Thats why you see certain TV shows saying "Broadcast by Panasonic HDTV" or something to that effect... All you need is an HDTV Decoder, which is what this card does. Those HDTV decoder boxes, are like pre-recorded shows in HDTV that they use to show off the HDTV capabilities. There are also $800 HDTV decoder boxes, which basically do what the Hauppauge card does that we just ordered. Although the Hauppauge card has less features, and can't do "Hi-Resolution" which I'm assuming means something like it can't output a high-resolution signal through the S-video jack to the TV.