Thanks a lot, for your moral support if nothing else...
I finally received some meaningful images and then discovered the next set of problems but I am making headway.
Sometimes the image turns into what you saw in my previous screenshot. There is some source of electrical noise that I can't control. Everything is turned off in my boat but I am in a Marina and next to a Navy base so who knows...
It just had happend that on previous trials the noise had been there the whole time.
In the attached image (besides a loss of synchronicity) you can see the noise hitting in the middle of a reception.