Here was my problem. I have a cable-in jack on the back of my RV. The coax connects to that fitting which is connected to the interior coax on the back side if the trim plate. The interior run of cable had wiggled loose from that little connector behind the trim plate. I'm ashamed of how much time I spent chasing a wild goose before I finally tried connecting cable from dome directly to receiver through door and found it worked fine. In any event, all is well that ends well. Thanks for those offering suggestions!
Big Mike