You didn't provide TVFool Results for your location, but I'm guessing that you MIGHT be located within a few miles of zipcode 49501 (downtown, near I-196 Exit 77C):
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3df1f0cc8c50f97b
Note that there are three TV Stations within 5 miles of this downtown location....you should enter your exact location into TVFool and copy/paste the Results URL (webaddress at top of Browser) so we all can see it....you probably have TV signal Overload issues that need to be considered...
I also entered zipcode 49501 into
www.FMFool.com to see where your FM Stations are located....only a FEW are in same direction as the Major TV Network stations....and the others are scattered in ALL Directions with half a dozen within a few miles, SURROUNDING downtown that can cause Interference problems into Hi-VHF Band. So I'm curious as to whether you use a Rotator or not. If you enter your exact location into FMFool, you will PROBABLY find that there are VERY NEARBY FM Stations that can generate Second Harmonic Interference into the Hi-VHF Band due to Overload....esp. if you are using a Preamp (you didn't say) or if you add a Distribution Amp (as recommended above). If you have Hi-VHF Band reception problems, you should add a (FULL) FM BAND REJECT FILTER from Antennas-Direct (NOT Radio Shack's, it doesn't attenuate lower end of FM Band very much):
https://www.antennasdirect.com/store/FM_band_rejection_filter.html
I would recommend that you use a SEPARATE FM Antenna with a SEPARATE Coax downlead system (could be Stacked on same Rotator). This will 1) eliminate TV Splitter Loss from the FM network, 2) eliminate 7-8 dB FM Splitter Loss from the TV distribution network thereby eliminating the NEED for a Distro Amp, and 3) allow the use of a FULL BAND FM FILTER on the TV distribution network to minimize interference to Ch7, 8, 11 and 13.