I've had bad cables too, Laura.
If your line from coach to park post is very old and the fittings pass muster, the cable may be damaged inside. After I finally bought a new length of coax with modern quality fittings instead of cheap crimped-on ones, my intermittent connection issues quit. Then I went to Lowe's and got my own kit of quality coax tool and fittings and retrofitted my multiple home coaxes. The old thin metal sleeved connectors aren't up to clean transmission of today's signals.
I also added fittings on the RV's coax connectors that convert them to simple sleeves, and no longer struggle with cold fingers in cramped conditions or inclement weather trying to get nuts started and tightened to hook up or disconnect TV cable.
As an aside, if you're at Indian RV Park in Buffalo, I've experienced bad electrical components before in their posts. Whose to say it isn't endemic in the park and not exclusive of their Cable TV configuration.
Joel