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

[David Jordan]

...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 at erols.com
> 
> 
> 
> ----- Original Message -----
> From: Keith Dutson <kjdutson at earthlink.net>
> To: <towertalk at 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 at contesting.com
>>[mailto:towertalk-bounces at contesting.com] On Behalf Of Frank Donovan
>>Sent: Sunday, January 16, 2005 10:35 AM
>>To: towertalk at 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 at 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.
> 
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