[TowerTalk] Thoughts on a Grounding System for my new tower

[Jim Lux]

On 9/2/12 7:35 PM, K8RI wrote:
> On 9/2/2012 8:59 PM, Jim Lux wrote:
>> On 9/2/12 5:20 PM, Jim W7RY wrote: Keep the
>>> rods spaced at lest 1.5 to 2.0X length of the rod. Installing rods on
>>> the ground conductor as it runs between the house and tower base is also
>>> a good idea.
>>
>>
>>
>> I'm wondering what the theory behind that would be.  The ground wire
>> itself provides a fairly good connection to "earth" for the lightning
>> impulse, especially after the soil has settled in a bit.
>
> Until you have a dry spell.  Currently the water table here is around 5
> to 6 feet while the surface foot or so is powder dry.  In the spring the
> water table is about 6" down in the back yard.  Note the clay "chips"
> http://www.rogerhalstead.com/ham_files/tower10.htm
>


Yes, but the vast majority of ground rods are installed where the water 
table is nowhere near the bottom of the ground rod.  Just because the 
soil appears dry doesn't mean it's zero conductivity (that whole 13/5 
"normal" soil thing)..