Even two same make and model TV's may perform differently.
Another possible issue is the splitter.. I assume it is the winegard wall plate that is a good one) and the LENGTH of the coax..
I rather like my Winegard Sensar III with added wingman and Sensar Pro "Wall plate".. Nothing beats it, I mean NOTHING.
One possible issue is the antenna connector on the TV. See comments on TV (Same make and model may be different) this is one of the differences.. Some need a bit longer center wire on teh cable