The following is a Teleview recommendation for broadcast Tv reception.
Above the roof install a Winegard HD7000R antenna with no preamp , aimed at about 164 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
For 1 Tv connected use no splitter.
For 2 Tv's connected use a common simple 2 way splitter.
For 3 Tv's connected use a common simple 3 way splitter.
Here are some above the roof antenna mounts ,
http://www.ronard.com/909911.html ,
http://www.ronard.com/34424560.html ,
http://www.ronard.com/ychim.html ,
http://www.ronard.com.
Buy the ronard antenna mounts at solidsignal by typing the word ronard in the solidsignal search box.
Here are some places to buy antennas and etc. ,
http://www.solidsignal.com ,
http://www.amazon.com ,
http://www.winegarddirect.com.
As always , trees and tree leaves do a real fine job of reducing or blocking Tv reception and so do buildings and other obstructions.
It is best to locate the antenna at a place that has the least amount to no amount of obstructions in the directions of reception.
The Tv Must Channel Scan for the Broadcast Tv Channels , sometimes named the 'Air Channels' or 'Antenna Channels' in the Tv setup menu because the Tv transmissions travel through the air from the transmitting antenna to the receiving antenna.
DO NOT channel scan for cable tv channels.