The Digital Tv Channel Signal strengths at your location are Ok. The situation at your location is the adjacent channel warnings and co-channel warnings , most of them are Analog Tv channels that can cause possible interference to Digital Tv channels. In Florida the FCC can put more pressure on those analog stations to switch to digital. Read and understand this about Real Digital Tv Channels and Virtual Digital Tv Channels ,
http://forum.tvfool.com/showthread.php?t=695 . Ok the Tv antenna is a Winegard HD7698P with a Winegard HDP269 preamp mounted on the roof or a tower and pointed at 334 magnetic compass. This antenna is sharply forward directive so as to reject interfering signals on the sides and back of the antenna. I do not expect there will be a problem with interference but won't know until yea try it. Here is how to aim Tv antennas
http://www.kyes.com/antenna/pointing/pointing.html The 40 feet you have for antenna height is fine. Do you have newer model Digital Tv's ?? Or will you be using Digital to Analog converter boxes??