If you don't need HD then there is only 1 satellite required to receive all of the DirecTV SD programming. The only need for the other 2 satellites is for HD. If you can live without a roof mounted automatic you can use a ground mounted tripod based antenna which WILL get you all of the DirecTV programming including HD. If you want a roof mounted antenna that will get you the DirecTV HD programming you will need to pay the big bucks for a Winegard Trav'ler.
The portable domes combined with the Dish Network service WILL get you their full package including HD but there are some limitations on the type of receiver you can use.