First.
To , Prove Reception.
Run a -->New<-- loooong coax from the antenna through a open window or door direct to 1 Tv.
No amplifiers , No amplifier power supply or power injector , No splitters , No couplers , No nothing.
Aim the ANT751 antenna at about 205 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
As always , trees and tree leaves do a good job of , reflecting , reducing , blocking , Digital Tv reception , and so do buildings and other obstructions including your own roof and house.
It is best to install the ANT751 antenna at a location that has the least amount to no amount of obstructions of any type or kind in the direction of reception including your own roof and house.
The signal strengths are strong.
Remove the CM7777 preamplifier , the preamp power injector , the preamp power supply.
Try reception with passive splitters.
And install a , 6 way splitter for 6 Tv's connected.
Or a 8 way splitter for , 7 or 8 , Tv's connected.
-->If<- required , use a Channel Master CM3418 distribution amplifier.
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Coax cables are Always Suspect of being Bad.
Amplifiers are not a substitute or replacement for bad coax and bad coax connections.
Amplifiers will not make bad coax or bad connections , good.