Some of the Tv transmissions are still to weak for a one antenna setup at 25 feet.
So that being the situation , to receive the -Most- receivable channels (both directions) with the antennas at about 25 feet above ground.
Install a Winegard HD7698P antenna with a Antennas Direct CPA-19 preamp aimed at about 120 degree magnetic compass direction for reception of the south east group of Tv stations/channels.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
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And install a Winegard HD9095P antenna with a CPA-19 preamp aimed at about 330 degree magnetic compass direction for reception of the north west group of Tv stations/channels.
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These are 2 Separate antenna systems and will not be connected on to one coax.
The 2 separate antenna systems coaxes will go the the location of the Tv and be connected to a remote control A/B antenna switch.
http://www.radioshack.com , #15-1968 , or ,
http://www.mcmelectronics.com , #32-4425 .
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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.winegarddirect.com ,
http://www.amazon.com.