Just for your consideration ...
You can have as many fixed antennas as you want, if you have the budget, the room on the roof and a tuner for each. You don't need a rotator if your fixed antennas cover the channels you want. Connect the tuners to a HTPC (home theatre PC) working as a DVR and send saved or live programming from any of the covered channels to any TV in the house. The Silicon Dust tuners are very popular -
http://www.silicondust.com/