Re: [TCML] Grounding rods

[sparktron01@xxxxxxxxxxx]

Gary, all 

The method to gauge ground integrity basically is to inject AC current into two ground rods separated by 
a standard distance, then measure the voltage drop and compute ground resistance directly (R = E / I). 

At our work , we usually use a DLRO (Digital Low Resistance Ohmmeter), typical fare for testing 
high power CB's and switchgear. Typical building steel grounding is < 1 milliohm (0.001 ohms), 
while utility ground rods for residential applications can be anywhere from 5 to 50 ohms. 

I just spent > $1,000 US upgrading and bring up to current NEC standards my home wiring. I have a 
concrete incased (UFER) ground system in my home, and ran #2 THHN as a ring bus between all grounding 
points on system, rather then a daisy chained #6 system. Did this because one #4 ground absorbed a 
significant lightning event (damaged insulation melted into conductor), but forunately no fire or other 
electrical damage. And the wife wonders why I over build everything, especially electrical (but I think 
I cured her of that way of thinking... ;^D ) 

The above is typical methodology for utility (60Hz) grounding as prescribed by the National Electric Code. 
How this performance would or could be translated into RF performance would be problematic. I think 
ground counterpoises as used for LF, MF antennae systems would be significantly better then ground 
rods. Oh, I drove the ground rods to satisfy the AHJ, its just that the REAL grounding system is in the 
crawl space... ;^D 

Best Regards 
Dave Sharpe, TCBOR/HEAS 
Chesterfield, VA. USA 

----- Original Message ----- 
From: "Gary Lau" <Gary.Lau@xxxxxx> 
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx> 
Sent: Friday, July 24, 2009 2:24:46 PM GMT -05:00 US/Canada Eastern 
Subject: RE: [TCML] Grounding rods 

The short answer is, no, I haven't tried using a chemical ground. 

The problem is, I'm unaware of any means to gauge the "goodness" of a ground system. The truth is, the spark performance of a Tesla coil is relatively (maybe completely) unaffected by the quality of an RF ground system. What IS affected is the degree to which RF and HV transients are coupled into one's mains wiring, but again, I'm unaware of any means to measure or compare mains corruption. 

If you can detect a performance difference with different grounds in receiving VLF radio, you may be able to teach us something! 

Regards, Gary Lau 
MA, USA 

> -----Original Message----- 
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On 
> Behalf Of Mike Thompson 
> Sent: Friday, July 24, 2009 2:03 PM 
> To: Tesla Coil Mailing List 
> Subject: [TCML] Grounding rods 
> 
> Hello All, 
> 
> I was wondering if anyone had played with a chemicle ground in the past. This is 
> basically a copper pipe with holes drilled in it and then hammered into the ground. 
> At that point brine solution is poured into the pipe to "activate" it. I have played with 
> these in the past regarding ground antennas and have had decent success and 
> was wondering if anyone had use one for a Tesla Coil ground. 
> 
> I am currently keep a small blog on my progress with building a Tesla Coil if 
> anyone is interested in seeing the ground rod I am proposing to use. 
> 
> http://z0rb.livejournal.com/tag/teslacoil 
> 
> Thanks 
> Mike T. 
> 
> Homepage 
> http://home.comcast.net/~mikethompson236/index.htm 

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