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Re: [TowerTalk] There's 'ground', and then there's 'ground'

To: Frank Donovan <donovanf@erols.com>
Subject: Re: [TowerTalk] There's 'ground', and then there's 'ground'
From: Gary Schafer <garyschafer@comcast.net>
Reply-to: garyschafer@comcast.net
Date: Sun, 16 Jan 2005 13:18:10 -0500
List-post: <mailto:towertalk@contesting.com>
I wouldn't put too much credence in the site that you reference. That guy spouts out a lot of mis-information about lightning protection. Most of the references are ok but some are suspect. I have had many conversations with him. He seems to read lots of stuff and doesn't quite understand how to interpret it for a given situation.

As to using braid for grounding, there is nothing wrong with it if it is not corroded and it is indoors. Outside it will corrode and the resistance/ inductance will increase. And worse, when it is corroded you can't clean it properly to make a new connection when it needs to be repaired.
When it corrodes you loose the connection between wires and it becomes a series of crooked individual wires which have a longer length than the sum when everything is shorted to the next.


For high frequency RF braid may not be the best. But it is regularly used in rf gaskets in many applications.

Lighting energy is concentrated from DC to around 1 mhz. There are components that do go into the vhf range but most of the energy is in the dc to 1 mhz range.

73
Gary  K4FMX


Frank Donovan wrote:
Here's a clarification, pointed out by an attentive towertalkian:

My previous e-mail was not intended to refer to cables that use
a braided shield under a jacket. A tight jacket compresses the braid and it's a very effective RF conductor, provided that
the braid is not corroded.


Rather, my comment was intended to apply to to the inappropriate use of braided strap for RF grounding or lightning protection. Its been well proven that braided strap has far too much inductance to be of any utility above 2 MHz.

So... Lets try again:

Discard all forms of "braided" strap. Braid is something a girl does to her hair.
Braided strap is a poor RF conductor and it's a terrible conductor
of lightning energy.
Use braided strap only for DC and audio applications, its just an inductor for RF or lightning protection applications.


Here's an excellent reference from the many industry sources on this topic:
http://members.cox.net/pc-usa/station/ground5.htm

73!
Frank
W3LPL
donovanf@erols.com



_______________________________________________

See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

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_______________________________________________


See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.

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