Ground wire partly around the building is better than what
exists. However ground wire completely encircling the
building makes earth beneath building equipotential. That
Cinergy information says same. Three pictures (as I recall).
One is bad, very bad. Second is improvement. Third is most
preferred.

IOW protection required is a function of geology and other
factors - best determined by neighborhood history. Typically
a potentially destructive transient occurs once every eight
years. How often does the neighborhood suffer a lightning
strike? If a few events (even to trees) have occurred in the
past decade, then consider a full halo ground.

But an earthing wire only part way around building and
connecting to all incoming utilities is a major improvement
over what you now have. Major improvement, I say, again.

Running a ground block to one point then using that
connection to make the earthing connection? It comes back to
a simple question. How many feet from that incoming wire,
connecting to other wires, then all way back to central ground
point. Add more feet for every sharp bend and splices. If
those wires are bundled with other wires, (ie safety ground
wire in romex), then that is more system compromises.
Distance from incoming utility wire to single point earth
ground must be 10 feet or less for effective transistor
protection.

Same applies to a ground on water faucet. Important is not
distance from incoming wire to faucet. Significant is
distance from incoming wire, through all those pipes, and then
on connecting wires (if they exist) to single point earth
ground. Again, soldered pipe joints and 90 degree turns in
that copper pipe only add more feet to that distance.

Do if only for human safety. You must get all those widely
separated grounds interconnected.

Also, repeating a previous post for the benefit of all,
measuring conductivity with meter (ie 1 ohm) does not prove a
good ground. Meter can only detect a bad ground; not prove a
good ground. Same for those three light receptacle testers.
They too can identify a defect. They cannot prove an outlet
is properly or sufficiently safety grounded. Repeated here
only because it demonstrates that logic process (thinking
binary instead of ternary) can lead to incorrect conclusions.

Important - you entered this with appropriate attitude.
Bonding all electrical services and safety grounding all metal
pipes is important, first and foremost, for human safety.
Human safety is your most important objective.

Minnie Bannister wrote:
Or, now that I think about it further, it seems it would be much
better to run my own ground wire from the dish to a ground rod
connected to the halo ground.

And when I looked again at the diagram on the Cinergy Website, I
saw that it does depict a ground that goes only partway round the
building. I was confusing it with another diagram showing the
ground wire going all the way around the building.

MB