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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: David Jordan <wa3gin@erols.com>
Date: Mon, 17 Jan 2005 09:11:00 -0500
List-post: <mailto:towertalk@contesting.com>
...the only place I've seen braid used commercially for RF shielding is
on aircraft engine spark plug wires...

73,
dave
wa3gin

Frank Donovan wrote:

Keith,

If you work as a professional in the industry, or if
you're interested in spending several hundred dollars,
purchase the EIA/TIA and IEEE grounding and bonding
standards that provide exactly the engineering foundation
 information you are seeking.  If you want to spend the
money, let it be known on the reflector and I'm sure
you will get the specifics.

Otherwise, I suggest you visit a commercial cell site, a
radio transmitter site, or a large computer facility in your
area.

Let us know how many braid straps you find.  If you
find any, let us know how long they are.

73!
Frank
W3LPL
donovanf@erols.com



----- Original Message -----
From: Keith Dutson <kjdutson@earthlink.net>
To: <towertalk@contesting.com>
Sent: Sunday, January 16, 2005 3:59 PM
Subject: RE: [TowerTalk] There's 'ground', and then there's 'ground'



Its been well proven that braided strap has far too much inductance to be

of any utility above 2 MHz.


OK. So where is the proof?

I am thinking any writing you can find is based on the use of braid that

of


poor manufacture or has corroded, or both.  Poor or corroded braid can act
like many very small wires to create substantial impedance.  However, well
constructed braid acts more like a solid bar of metal, but with the
flexibility required for many installations.

Keith NM5G

-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Frank Donovan
Sent: Sunday, January 16, 2005 10:35 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] There's 'ground', and then there's 'ground'

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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_______________________________________________

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.

_______________________________________________
TowerTalk mailing list
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http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________

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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