I just installed a Radio Shack $99 antenna. The thing is huge (14')and my signal strength went from 60 to 90 (it replaced an old RS antenna that was 1/3 the size).
One problem with a large antenna like this is that they can get chewed up by frequent high winds.
I'm not sure if the Winegard that DirecTV installs is the same as the one that I got with Voom. I'm using my "Voom" Winegard with DirectTV about 45 miles from the towers. I ended up buying a power supply because the signal strength was much lower that it had been with my Voom receiver - nearly every OTA channel is 97-99% even from that distance.