There is one experiment that might be worth trying. Insert a HLSJ, common and high ports, between the antenna and the input of the preamp. This will block signals below channel 7, including the FM band.
http://www.solidsignal.com/pview.asp?p=zhlsj
Even if your antenna is aimed away from KVCR, I still think it might be too much signal for a 7777, assuming your tvfool report is an accurate prediction of the signal strength arriving at your antenna.