Re your little amplified antenna, typically you can't defeat the amplifier. If you unplug it, the internal amplifier turns into an attenuator, and blocks any signal. So it could be overload, or it could be the long wavelength (though RCA says all VHF and UHF channels).
It's possible that you'd get WBRA 3 anyway from a passive VHF high antenna, simply because the signal is very strong. I'm not sure which single antenna to recommend to you.
If this were me, and I had no better recommendations from the experts here, I'd probably buy an Antennacraft Y5713
http://www.antennacraft.net/Antennas/AntennasVHF.html point it at WSET ABC and see if I get WBRA too. The Y5713 is fairly inexpensive, so it might be worthwhile to experiment. Then I'd add a UHF antenna pointed at WDJB, to pick up the remaining majors on UHF.