[TowerTalk] ground rod depth problem - and understanding ground rods

[K4SAV]

Jim, I think maybe you misunderstood the reason for my questions.  I 
wasn't asking what the rules and regulations say.  I have that data 
already.  I'm not constructing anything and want to know what to do.  I 
have done that already and it has proven to work very well for many 
strikes, with no damage so far.  It's the basis for some of the 
regulations I wanted to know more about.  Maybe those regulations are 
based on experimental data, I'm not sure but I suspect they are, however 
I would think by now some have tried to make some sense of them 
analytically.  Anyone that wants to write some software to analyze some 
of this stuff is going to have to understand the mechanisms.  I was 
looking for that kind of information (not that I'm developing software, 
but I'm very curious).  Grounding regulations don't describe the 
mechanism of ground rod underground plasma, when it exists, and what 
that does to the impedance of a ground rod.   Dave Robbins gave some 
excellent data references to help with that understanding.  Thanks Dave.

Then the thought of encasing a ground rod in concrete came up, and I 
don't think I have ever heard of anyone doing that.  Ufer grounds are 
not exactly the same thing.  Rules for Ufer grounding aren't very 
similar.  I know some use bentonite around a ground rod but what would 
happen if someone used only one ground rod encased in concrete as the 
ground for a tower?  Yeah that's probably dumb, but what would happen?  
Would it explode?  A strike can go right thru a concrete wall.  What's 
the difference? (It also goes right thru many other building materials, 
including tile, if those are in the path where the strike wants to go.)  
There doesn't seem to be any rules for this kind of grounding, or any 
data or description to help understand what will happen.  I can guess 
what would happen, but I would rather not.

And I agree that the way the ground connections are made is the most 
important part of a grounding system, but that subject is easy to 
understand, and not so difficult to analyze.

I realize most people don't ask these kind of questions.  As long as 
they know what to do to solve the problems, most don't care how it 
works.  Guess I'm just different.

Jerry, K4SAV