For reception of KDKA , install the DB8 antenna above the Peak of the Roof in such a manner that the roof and house are not blocking reception to the south east at 148 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Leave the reflector screens on , do not remove the reflector screens from the antenna.
The CPA-19 preamp has been discontinued , if can not find a CPA-19 preamp then use a Winegard HDP-269 preamp.