You tested the antenna in the attic and picked up all the channels in the list.
With the antenna above the roof with the antenna mounted in such a manner that the roof is not in the way of reception , You were saying that ABC is a little weak , NBC is weak also??
Now that I see how the house is wired with coax.
A better amplifier setup is a Antennas Direct CPA-19 preamp.
For 1 Tv connected use no splitter.
For 2 Tv's connected use a , HFS-2D , 2 way splitter.
For 3 Tv's connected use a , HFS-3D , 3 way splitter.
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