[TowerTalk] Lightning protection - length of grounding rodsruns from tower?

[Roger (K8RI) on TT]

On 1/30/2015 12:02 PM, Mike Fahmie via TowerTalk wrote:

And 60 degrees is the only included angle that will give such a simple 
solution.

73

Roger (K8RI)


> An equilateral triangle has equal sides so that means that the rods on adjacent radials will be spaced the same as the length of the radial, ie, at 16' from the center, adjacent rods will be 16' apart.
> -Mike-
>   
>        From: Roger (K8RI) on TT <K8RI-on-TowerTalk at tm.net>
>   To: towertalk at contesting.com
>   Sent: Friday, January 30, 2015 6:00 AM
>   Subject: Re: [TowerTalk] Lightning protection - length of grounding rodsruns from tower?
>     
> You are also limited on more shorter runs as the distance between runs
> will have the first rod or two on adjacent runs fairly close.  The
> first rods a couple of feet out will by necessity be close.
>
> Refresh your math skills and try to do it with trig <:-))  They come
> from a common point (center of the tower.  6 radials would be 360/6, or
> 60 degrees forming the vertex of an equilateral triangle and that about
> exhausts my math abilities. So that's where my refreshing would start.
> Refreshing?  What am I saying?  I never had Trig in the first place!  I
> have a math minor without ever having taken trig and I graduated in 90.
> I never had to use a bit of it since then. So the sum of my knowledge is
> the same as before I took all those classes.  It looks good on a resume,
> but I never claimed to be any good at it.
>
> 73
>
> Roger (K8RI)
>
>
> On 1/30/2015 1:24 AM, Ray Benny wrote:
>> Thanks to all who made comments.
>>
>> My take away is to use more shorter ground rod runs from the tower, say 30
>> - 40 ft, than a smaller number of longer runs.
>>
>> I will see how many 30 ft radial runs I can make using 8 ft ground rods
>> while keeping 16 ft separation between the rods. Guess I could pull out a
>> drawing compass and scale the radials lengths, then measure between the 16
>> ft points. Boy, this make me old! Haven't done this in ages, especially on
>> paper...
>>
>> Ray,
>> N6VR
>>
>>
>>
>> On Thu, Jan 29, 2015 at 11:36 AM, john at kk9a.com <john at kk9a.com> wrote:
>>
>>> Less effective than what?  Two 8' ground rods 8' apart are less effective
>>> than a single 8' rod?
>>>
>>> John KK9A
>>>
>>>
>>> To:    "Jim Lux" <jimlux at earthlink.net>
>>> Subject:        Re: [TowerTalk] Lightning protection - length of grounding
>>> rodsruns from tower?
>>> From:  charlie at thegallos.com
>>> Date:  Thu, 29 Jan 2015 11:37:40 -0500
>>>
>>>
>>> I can't think of a good way to word it - except may to say a pair of rods
>>> closer than 2x is less effective -
>>>
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>


-- 

73

Roger (K8RI)


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