[Elecraft] I need some grounding-strap guidance, if'n you please

[Jim Brown]

You assume wrong. :)  Concrete is a conductor, and metal that makes 
contact with it forms a Ufer ground (that is, a ground electrode). 
By virtue of having a lot of surface area in contact with the 
earth, the Ufer ground can have a fairly low impedance to earth. 
The tower is bonded to that copper and to ground rods that surround 
the tower. Thus, the total impedance to earth is the parallel 
combination of all of those electrodes. 

Again, the fundamental principal is that all grounds MUST be bonded 
together for lightning safety. In the event of a lightning hit, the 
potential of all rise together, so it is much less likely that 
something bad will happen in the building. We say "less likely" 
because those bonding conductors have resistance and inductance, so 
the potential difference won't be zero, but it will be lower than 
if there were no bonding. 

73,

Jim Brown K9YC

 --Original Message Text---
From: Ken Kopp
Date: Tue, 1 Sep 2009 06:47:39 -0000

Hi Jim, 

I assume the straps in the concrete were an experiment 
to measure the resistance of concrete and -not- intended 
to be for lightning grounding.