If you are getting rid of satellite service and connecting 2 Tv's. . Yes 115 degree magnetic compass is a good direction to point a Winegard HD7696P antenna. For 2 Tv's no amplifier will be needed. How many Tv's are connected?? If 2 Tv's are connected in the house then it is likley that the 2 black coax cables go to the 2 Tv's. A simple 2 way splitter can be connected to the 2 black coax cables. The Tv antenna needs to clear the roof and not be pointed into the roof. Also the HD7696P antenna needs to be level with the ground , not pointed up at the sky , not pointed down at the ground and not tilted at odd angles. Here is how to point Tv antennas ,
http://www.kyes.com/antenna/pointing/pointing.html . Yes 18 feet should provide good reception.