Thanks for your help Tom. I also explored the links you provided and found
them helpful. In fact, part of the reason I started looking into this is
because I have lost a modem. Although I have no reason to believe there
have been multiple grounds in the past, I'll be sure everything goes to the
same place before I'm done.

Ground block is really nothing more than a connector that
attached to CATV cable and that permits a 10 AWG ground wire
to be connected. It is even sold in Home Depot with other
CATV cable accessories. Best to put grounding block on cable
outside building and as close to new ground rod as is
possible. Make distance from CATV to ground rod shorter with
minimal bends, etc. Yes that grounded RCA splitter
accomplishes same for human safety and NEC reqirements. But
transistor safety wants that connection to earth ground to be
closer to central earth ground. Also an outside ground block
to ground rod connection makes it easier to keep that ground
wire separate from other non-grounded wires.

Hmm. Well, I checked and there's no ground whatsoever coming off the CATV
line at the point it enters the house. I'd have to install a new one
outside in order to run a ground line from the entrance point, and that side
of the house is the exact opposite of where I plan to put the ground rod.
The CATV comes from the street to the top of my house and then runs down
before meeting a splitter and entering the house. Becuase I don't currently
subscribe to Cable (and don't plan to), I think I'll just disconnect the
cable so that it never even enters the house and then I'll just forget about
grounding it. Is there any reason why this would be unsafe or cause
electrical trouble?


Telco provides a "Service's accessible grounding means" in a
box called NID. Their 10 AWG earth ground wire connects their
NID box mounted outside (so that it is accessible) to that
earth ground rod. Some installers want to make that 10 AWG
wire look neat. They will even 'split bolt' attach it to the
breaker box ground wire. However better trained installers
will run their ground wire directly to the top of that ground
rod - as should be the CATV wire ground. All grounds should
run indepenently until they all meet at central earth ground.
This last requirement is not required in code but creates a
more robust and effective earth ground.

Well, the Network Interface Box I have now is really old and in bad shape.
There's no NID or block or anything outside of house. The line comes
straight in. (I'll spare you the details, but let me just say that I'll be
calling Telco as soon as I get my electrical troubles in order.) Even so,
I'm glad you mentioned it. I can leave the top of the ground rod exposed
and that way Telco can have the option to run a conductor straight to it,
rather than using the split-bolt method. At this point I have no idea what
they will do or if they will even install an outside NID. One way or the
other, the current telephone junction box needs replacing.

If I'm following your line of thinking, then wouldn't it be slightly better
to run the TV Antenna ground straight to the grounding rod tip as opposed to
split-bolting it to the main ground (coming from the service panel and
heading towards the rod)?

Oh, an in case I don't hear from Thomas Horne, is bare 4 gauge copper
conductor appropriate for grounding the service panel to the grounding rod,
or must it be insulated with plastic? (I was just at Lowes and the
"x-electrician" there says I only need the bare wire)

Thanks. Sorry for being so caught up in the details. I really want to do
this right and do it safe, and I'm not getting the same answers from the
local "Pros".

As a reminder to others, smart move to have all utilities
located before pounding down the rod.