I agree with ADTech. You seem to be doing as well as can be expected based on your old tvfool report. Changing to a different preamp might not do any better.
The fact that you were able to pick up WATM doesn't mean that your system is sensitive enough to receive signals weaker than NM -15 dB. The Thermal Noise Floor is at NM -15 dB/-106 dBm, so it isn't likely that you would have received that signal buried in the noise. Antenna gain can not "pull a signal out of the noise," but it can make the NM more positive and improve its SNR.
Your antenna gain is less than 18 dBd and your preamp NF is more than 1 dB, so an actual -15 dB NM signal is beyond your reach.
It is more likely that the WATM signal was much stronger than NM -15 dB, which is common for Tropo signals. Without Tropo or refraction enhancement, there is no WATM signal at your location:
http://www.tvfool.com/?option=com_wr...ALLTV%26n%3d20
Please do a new exact address tvfool and fmfool report so that we can try to help you "tweak" your system.
Here is a new tvfool report I did based on an estimate of your location:
http://www.tvfool.com/?option=com_wr...5134a4e30af4b0
And one for FM signals:
http://www.fmfool.com/modeling/tmp/a...0/Radar-FM.png
FM WAYZ at -16.7 dBm
might be strong enough to interfere with weak TV signal reception.
How close did I come?
The only improvements I can see are an antenna with more gain, and a preamp with a lower NF. But the preamp must be resistant to overload because there is a great difference in signal strength between your strongest and weakest desired signals, which is called the dynamic range. The strong signals can cause partial overload that will create spurious signals from IMD (Intermodulation Distortion) that will damage your weak signals.