Hi Frank:
Ouch ! Seems I hit a nerve there. Now, I have used insulated copper wire on
several occasions and things like copper water piping as a common bus on
which you could connect copper flashing. But now you have me confused on one
point - how can the pressure of insulation (or lack of it) decrease (or
increase) RF impedance ? If it is a simple 'lack of appropriate contact'
without the pressure, it would seem to me that linear stretching would
provide adequate contact - at least intuitively.
Just trying to learn something here. Grounding sometimes gets into the Karma
of Ham Radio ! HI
73, Jamie
WB4YDL
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of
donovanf@starpower.net
Sent: Tuesday, November 22, 2005 6:48 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] station grounding question
Braid is a suitable RF grounding conductor only when
alternatives such as stranded wire or copper strap are subject
to flexure failures, such as grounding of swinging metal doors,
fence gates or movable components in vehicles.
Braid from RG-213 is a suitable RF grounding conductor only if
you do not remove the jacket from the cable. After you
remove the jacket, the RF impedance of the braid increases
dramatically because all of the braid crossovers are no longer
under pressure.
A more appropriate equipment grounding conductor would be
stranded copper wire, 16 AWG or larger would be suitable.
Braid is something little girls do with their hair, it's completely
unsuitable as an RF grounding conductor except when no other
alternative is practical.
73!
Frank
W3LPL
---- Original message ----
>Date: Tue, 22 Nov 2005 18:22:53 -0600
>From: "James C. Hall, MD" <nwtcc@earthlink.net>
>Subject: Re: [TowerTalk] station grounding question
>To: "'Richard W. Harris'" <Richard_Harris@byu.edu>,
towertalk@contesting.com
>
>Richard:
>
>Got some old 213 coax(or similar RG-8) lying around ? Take
the jacket off a
>chosen length of this coax and push up the braid until it simply
slides off
>the dielectric. Use two large solder eyes - one on each end
and give the
>braid a half twist around the solder lug. Clamp and solder the
eyes to the
>braid and you have instant ground strap ! This you can use to
flexibly
>connect your gear to the copper flashing or SPG panel. I've
used this method
>for over 25 years without a single problem.
>
>73, Jamie
>WB4YDL
>
>-----Original Message-----
>From: towertalk-bounces@contesting.com
>[mailto:towertalk-bounces@contesting.com] On Behalf Of
Richard W. Harris
>Sent: Monday, November 21, 2005 9:19 PM
>To: towertalk@contesting.com
>Subject: [TowerTalk] station grounding question
>
>Hi,
>A simple question on station grounding. I have a copper wall
plate for
>common grounding of all of my station equipment. I have 2"
wide copper
>strap to connect each piece of gear to the copper panel. Most
pieces of
>equipment have a simple bolt for grounding. Seems to me
that a single/small
>bolt connection to the copper strap is not a very good
connection. Any
>suggestions here? Should I simply be connecting the 2"
copper strap to the
>grounding bolt of each piece of gear or is there a better
method?
>Thanks,
>Richard Harris - KJ7CU
>
>Also, thanks to all those that gave me advice on my 160M
shunt-fed tower.
>Working great. A lot of work but well worth the effort
>_______________________________________________
>
>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
>TowerTalk@contesting.com
>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.
>
>_______________________________________________
>TowerTalk mailing list
>TowerTalk@contesting.com
>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.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
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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TowerTalk mailing list
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