Install above the roof so the reception is not blocked buy the roof and house in the directions of , north west , south west , south.
Install a ANT751 antenna aimed at about 210 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
No preamplifier is required.
For 1 Tv connected use No splitter.
For 2 Tv's connected use a simple common 2 way splitter.
Here are some places to buy antennas and ect. ,
http://www.solidsignal.com ,
http://www.amazon.com.
As always , trees and tree leaves do a good job of , reflecting , reducing , blocking , OTA=Over The Air , Digital Broadcast Tv stations/channels and so do buildings and other obstructions in the directions of reception including your own roof and house.
It is best to install the ANT751 antenna at a location that has the least amount to no amount of obstructions of any type or kind in the directions of reception including your own roof and house.