I hope I can explain this right ... There is a wall plate behind the TV that has the connections for the antenna, video and audio. I found the antenna connection to be a bad design. They take the coax down to the core wire and soldier to coax connector. They do this so that cover will over the back of the wall plate. I felt that would cause interference.
I took that connection out of the wall plate and replaced it with a regular female - female wall plate connector. I connect the coax from the amplifier back up to the new wall plate connector. To put the cover back on, I had trim the plastic cover a little.
After doing this, my picture quality improved greatly on both TVs on either air or cable. I would take pictures but the trailer is at the dealership.
2012 F150 Ecoboost, 3.55, tow package
2009 Flagstaff V-Lite 30WRLS
1982 16' Glastron Ski boat