All of the preamplifier must be disconnected removed , the preamp unit , the power injector , the power supply.
What channels are dropping out , use the Tv station call sign and programing to identify , example , WGCL CBS.
Aim the ANT751 antenna at about 145 degree magnetic compass direction.
The ANT751 antenna receives to the front of the antenna at angles to the front of the antenna , back of the antenna and angles to the back of the antenna.
The least amount of reception is on the sides of the antenna.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
As always , the antenna is to be installed mounted in such a manner that the roof or the house is not restricting or blocking reception.
At your location the reception is , North , North east , East , , South east , South.
As always , trees and tree leaves do a real fine job of reducing or blocking reception and so buildings and other obstructions including your own house.
It is best install the antenna at a location that has least amount to no amount of obstructions of any type or kind in the directions of reception including your own house.