[TowerTalk] Re: Lightning ground "Holy Wars"

[Tom Rauch]

> Date:          Fri, 29 May 1998 00:39:58 -0700
> From:          Kurt Andress <NI6W@yagistress.minden.nv.us>
 Hi All,

> A lightning strike does not respect "A nice low impedence path from the
> tower to the house." It just has a @#@#$$%^& of a lot of energy trying to
> find a ground connection. It is merely looking for the lowest inductance
> path to a low resistance connection to the earth ground! 

It's looking for that collection or source of opposing charges.

In my installation, I  prefer it do that out at the tower.

> Impedance may be great for RF grounding, but lightning doesn't care!

Impedance isn't great for any grounding--RF or otherwise, the lack of 
impedance is the goal. 

> Flat copper conductors present a lower inductance path than round ones!

Can you give me a reference for that? I've been looking for years, 
and find no data on conductor shape vs inductance.

I do know...
Smooth conductors have less resistance and impedance (that is 
published data and evident in practical applications). Braiding is 
not a good choice when low impedance is required for RF or 
lightning. 

In flat wide conductors spaced some distance from an opposing current 
carrying conductor, excited with rapidly time-varying currents, 
current bunches up at the very edges with very little current down 
the center (measured it with a current probe and also as lower 
Q than a round conductor of the same surface area). The wide 
strip might as well be a pair of parallel conductors with air in 
between for RF. 

73, Tom W8JI
w8ji.tom@MCIONE.com

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