Very unlikely. Even barrels rated for only OTA frequencies will have virtually no effect on the DirecTV signal, and if they did it would simply affect the signal strength. It would not directly affect signal quality.
far more likely HD channels are not selected in the receiver setup, or 1080i/720p are not selected as supported resolutions.
EDIT: Replied to the wrong post, but my comment still stands. Using the wrong barrel in a cable from the dish to the receiver can at worst reduce the signal strength, and if the receiver still shows signals in the high 70s/80s you would still get a perfectly good picture. It's a digital signal so you either get it or you don't.