I live about 65 miles as the crow flies from Red Mountain, where all of the transmitters for the Birmingham TV stations are located.
I have a tower antenna about 60 feet high. If I unplug the power supply to my preamp I get absolutely no signal at all. With the preamplifier I get 100% on all stations except for two, that I get about 75-80% on.
There is one station WCFT 33 thats transmitter is located to the SW of Birmingham, not where the others are, even not being directly aimed at it, I still get 100% signal.
I said all of that to say this, instead of going with multiple antennas now, since you are so close to the transmitters, try tuning up what you have and you might be surprised how well it will work.