For reception of the Philadelphia Tv stations channels install a Winegard HD7084P antenna with a Winegard AP8700 preamp above the roof aimed at about 55 degree magnetic compass.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing.html.
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 places to buy antennas and etc. ,
http://www.solidsignal.com ,
http://www.winegarddirect.com ,
http://www.amazon.com.