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[TowerTalk] Re: Lightning ground "Holy Wars"

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Subject: [TowerTalk] Re: Lightning ground "Holy Wars"
From: (Tom Rauch)
Date: Mon, 01 Jun 1998 09:26:23 +0000
To: <>
> Date:          Sat, 30 May 1998 16:18:37 -0700
> From:          Bob Wanderer <>

Hi Bob,

You wrote: 
> > Flat copper conductors present a lower inductance path than round ones!
I wrote: 
> Can you give me a reference for that? I've been looking for years, 
> and find no data on conductor shape vs inductance.

You wrote:
> It's in the "Grounds" book. Poly also sells a slide rule which will show you 
> the
> voltage drop difference and resistance between the various lengths and 
> types of conductors both round and flat. The formula is in the book and 
> there's
> a slide used in the presentation which graphically shows this information. Try
> calling the technical assistance types at Poly and see if someone can make a
> photocopy of it. See if you can either talk to or leave a voice mail for Ken 
> Rand.

It is very well known and well documented that time-varying current 
tends to move to the edges of a flat strip, causing a wide flat strip 
to have higher resistance for rapidly changing currents than a round 
conductor of similar surface area. That info is in several reliable 
engineering texts (including Terman).

I've even directly measured the effect here during experiments, it's 
quite easy to observe that effect.

I haven't been able to find any engineering text that supports the 
claim a flat strip has less inductance than a round conductor of the 
same length, as long as the length is much longer than the width.

If anyone has a reliable source for this information I'd appreciate 
a reference. I've been looking off and on for years.

73, Tom W8JI

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