Re: what is a proper ground for this
Jacob, the electrical grounds should be at the main disconnect, not at the house. The conduit feeding the panel should contain two hot wires (typ. black), a neutral (white), and a separate ground (bare or green).
Your panel is basically a sub-panel, since it's fed from a remote disconnect, which is why the neutrals are (or should be) separated from the grounds; they only connect to each other at the main disconnect.
It would not hurt for you to add a ground rod at the house, but you should use a solid #6 copper wire between the panel and the ground rod. This wire should be connected to the ground bus where all the bare wires land.
Then you can run your new ground wire to the same rod and attach it using a second ground clamp. You could split-bolt the dish ground wire to the new #6, but a separate clamp on the rod is actually preferable.