Which Antenna?
I have both the Scantenna and a Discone mounted in the attic.
(from gound level, approx. 32 feet to the top of my antenna in the attic.)
They both are exactly at the same height and spaced 50 feet apart using the same coax LMR-400
The discone does not perform well at all compared to the scantenna.
My Scantenna pulls in signals from 130 miles away and I am not using an amplifer. My experience with the scantenna is excellent and in my opinion it is the best antenna for the bang!
I know of one person using the scantenna and he has it mounted sixty feet in the air with much better signal gain than my setup.
Good luck