[TowerTalk] [Bulk] Re: RF Ground is a Myth

[Drax Felton]

What is the conductivity value of concrete? 




Sent from my iPhone

> On Jan 21, 2015, at 9:07 AM, Paul Plants <w3plp at verizon.net> wrote:
> 
> Please use the correct tool not a ohm meter but a merger.
> Paul
> W3PLP 
> 
> Sent from my iPhone 6 plus
> 
>> On Jan 21, 2015, at 8:29 AM, Patrick Greenlee <patrick_g at windstream.net> wrote:
>> 
>> I have a triangular tower with legs on 14 ft centers, yes, 14 feet, not inches.  I built it with three separate concrete foundations, one per leg.  It is currently tilted over so one leg is not touching its concrete embedded mechanical connection/mount.
>> 
>> It would seem that if I take an ohm meter reading between the unconnected leg's mount and one of the other mounts I will be getting a valid estimate of the Ufer ground quality of my tower installation's foundations.  It could be argued that I am actually measuring two Ufer grounds in parallel as two of the attachment points are bridged together by the tower.  I suppose I will also unbolt one of the hinged legs so I can measure independently from the non hinged leg mount to each hinged mount in turn.
>> 
>> There is plenty of rebar in the foundations.  The rebar cages are welded with allowances for the effect of welding on rebar (welded at ends and overlaps so no structural degradation.)  Each leg's foundation has three each pier holes augered with a 12 inch tractor mounted auger.  I moved the tractor a little while augering to get a larger hole. There is rebar in each pier hole and a rectangular cage connecting the three holes.  All rebar is welded so there is good conductivity throughout the rebar armatures.
>> 
>> Each set of three pier holes is topped by a 2'x2'x7' horizontal concrete beam with an extensive rebar cage that is well connected by welding to the rebar in the augered holes.  All rebar is at least 2 inches (typically 3) from the dirt/concrete interface.
>> 
>> Am I missing something?  Will a simple ohm meter test give a reasonable measure of Ufer ground quality, sufficient to decide the question of whether or not multiple copper clad ground rods need to be installed and interconnected?
>> 
>> Is it too much of a leap of faith or otherwise to assume the inter-leg resistance is an adequate predictor of tower mount to Mother Earth conductivity?
>> 
>> Just write your opinion on the back of a US $20 bank note and mail to my QSL address in QRZ.com including a SASE if you want a receipt and or thank you note.
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