Ken,
The lightning protection grounding electrode system is required to be bonded to the electrical system grounding electrde. 810.21 requires that the dish be connected to the electrical grounding system. The minimum size of the bonding conductor from the dish to the electrical system ground is #10. If you install a ground rode for the dish, then 810.21(J) will require that you install a #6 from the dish ground rod to the electrical grounding electrode system.
Don
