Higher then the roof , form 25 to 30 feet above ground , try at about 25 feet or so first before going higher , there is very little improvement at 60 feet antenna height.
However Much improved signal strength at 120 feet antenna height.
Install a Winegard HD7084P antenna with a Kitz Tech KT-200-COAX TV Antenna Booster Remote Power Coax Fed.
Aim the HD7084P antenna at about 306 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
As always , the starting aim direction is the -> starting aim direction.
The aim direction can then be adjusted for best reception.
For 1 Tv connected use no splitter.
For 2 Tv's connected use a , HFS-2D , 2 way splitter.
For 3 Tv's connected use a , HFS-3D , 3 way splitter.
Buy the HFS splitters at ,
http://www.hollandelectronics.com ,
http://www.solidsignal.com.
Here are some strong and sturdy 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 ,
http://www.kitztech.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 install a antenna at a location that has the least amount to no amount of obstructions of any type or kind in the directions of reception.
The Tv/s Must Channel Scan for the Digital 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.