Some of the better paneling adhesives would probably support a DISH.
If that is what has been used, heat should help you get the glue to release. We're talking heat gun heat at least as you're going to have to get the entire foot hot enough that you can't touch it.
If it is on there with silicone-based glue, you should be able to brute force it off with a pry bar. Be careful to protect the facia from whatever you're prying with.
I don't recommend yanking on the mast because most adhesives won't let go if the entire bonded surface remains intact. Prying up the corners or the middle is the only way you're going to get a mechanical advantage over the vacuum-like bond.