In my case, I traced the problem to the connector that runs through the roof. Both of the center wires (the antennae, and booster) were completely corroded away at the ends. I had to pull the microwave out to get to the wire that runs to the booster. I cut off an inch from the faulty ends, and installed new connectors, and all works well now.
I originally just fixed the antennae wire, as it was easier to get to. But after still not getting TV reception, I plugged the antennae directly to the booster, and got good reception, leaving the wire from the roof coupler to the booster as the additonal suspect.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263