Thank you guys for your efforts!
GroundUrMast -
I linked the wrong analysis (40 ft).
20 ft. Signal Analysis I can not get as high as 40 ft.
Using GroundUrMast's "lower limits" of WOPX & WTGL, at 20 ft. they are still marginally positive NM at 5.3 & 3.4 dB with Power -85.5 & -87.5 dBm. Is the signal NM the probable determinant with the low Power requiring the pre-amp?
What other site/book should I read to begin my education at the Novice/Dummy level?