You're on the right track. A corrosion resistant grounding clamp sized to match your mast, some #10 AWG copper and an appropriate clamp to make the connection at the electrical service takes care of the mast ground. But you will also want to be sure to ground the coax shield... See http://forum.tvfool.com/showthread.php?t=901, post #20

Thanks again GroundUrMast. :)

Back to my grounding questions..................

On the side of the house closest to the antenna, there is an old ground rod that's been there for years. On the other side of the house closest to where the RG6 goes through the wall, that is where the Service Entrance is.

Can the antenna be grounded to the rod and the grounding block for the coax to the service entrance? That would be two grounding locations quite a distance apart. What's the problem by doing this if any?

If the ground rod near the antenna is not bonded to the rest of the electrical service grounding system via #6 AWG copper (or heavier), I would not trust it to provided a reliable low resistance connection to the grounding system in your house. A reliable low resistance connection is vital if you want to avoid undesirable or even dangerous voltage differences between items that connect to the grounding system.

If the rod is bonded correctly, it can serve as the mast ground.

The ideal situation is to connect at a common point. This reduces resistance between different sub systems to nearly zero. I think the term grounding tends to make people think that a connection to earth is some sort of 'be all and end all'. The most important thing you are trying to achieve is not a connection to earth, but rather, a low resistance between each 'grounded' object. A connection to earth is an important, but secondary goal.

Thank you GroundUrMast, your replies have been most helpful. :)

So, i guess i should run two seperate ground wires to the service entrance. One for the mast and one for the coax.

That's the ideal method. First, for the superior ability to avoid unintended voltage differences and secondly, both runs can be done using #10 AWG copper, which is much less expensive than #6 AWG. (Ideally, the #10 link from the coax ground block to the electrical service ground would be no more than ten feet long.)