I am thinking of getting an FM filter from RadioShack to see if it may help with reception of distant channels. But do you install the filter before the preamp at the antenna, or before the power supply closer to the TV? I am in zip code 29607 in Greenville, SC, and apparently there are some strong FM towers nearby. But I still get some Charlotte, NC channels from 75 miles no problem, but I just wonder if the FM filter would make a difference on some other weak, distant channels. So where is the proper place to install the FM filter?