Your satellite spins in circles and can adjust up and down inside the dome. However, HD satellites require that the satellite dish be able to "skew", which means that they "cock" to one side or another after spinning and moving up and down.
With that said, I sold my neighbor my KVH SD sat dome back in 2012. He installed it and amazingly, it's still getting SD stations even though DirecTV said they were turning them off years ago. Eleven years for $200, he got a good deal.