>So in conclusion, a down conductor is highly recommended.
Agree with statement. But I think it does not provide much benefit unless
you are trying to protect an antenna at or near the tip of the tower.
If you ground each tower leg to a separate ground rod, most of a lightning
strike will be shunted away from equipment to be protected. If earth
surrounding the tower is typically dry and of low conductance, use multiple
ground rods connected by copper wire, extended out from the tower base.
If a vertical antenna, such as one used for a repeater, is mounted to the
top of the tower, the likelihood of a direct strike causing its destruction
is quite high. In this case, mounting a ferrite rod nearby with heavy
copper cable connecting it to a separate ground system will offer a more
attractive path for a strike.
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Wilson Lui
Sent: Monday, June 28, 2004 2:14 AM
To: 'Martin Sole'; towertalk@contesting.com
Subject: RE: [TowerTalk] create cr30 rooftop
Couple of things to remember. Copper has 10X the conductivity of steel with
comparable cross section.
The item from Polyphaser is true to a certain degree. If your have a
substantial tower (like a HUGE steel structure) AND all the connections
between the various steel elements are welded or put together mechanically
extremely well then you may not need a separate down conductor. This is
assuming that all the steel elements are electrically continuous. in other
words free of paint, galvanization etc; this is extremely doubtful.
So in conclusion, a down conductor is highly recommended. This down
conductor needs to also be bonded to the tower at various points along the
way down. Exothermic welds are recommended.
Wilson Lui
ATI Tectoniks
wilsonlui@atitec.com
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Martin Sole
Sent: Saturday, June 26, 2004 7:26 PM
To: 'Jim Naughton'; towertalk@contesting.com
Subject: RE: [TowerTalk] create cr30 rooftop
I'm quite interested in lightning protection. Living in SE Asia we get large
numbers of storms pretty much any time of year, now is a very active time.
I'm not sure that a separate down conductor will be of much use, might
depend on the type of tower you have but Polyphaser produces a document that
suggests this is a rather futile approach unless the cross sectional area of
the wire can approach that of all the other metal work in your tower and
feeders. I guess if it's a rooftop you might need something though.
Martin, HS0ZED
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Jim Naughton
Sent: 27 June 2004 09:16
To: towertalk@contesting.com
Subject: Re: [TowerTalk] create cr30 rooftop
IF your house is located where lightning also occasionally happens, you
don't want any antenna support structure attached to your house!
Thanks for the advice ... I have considered lightning ... My research is
that properly grounded, the tower is just a big ligthtning rod and if
anything your house is safer. I plan on taking an additional step and
installing a lightning rod which glenn martin sells at the top of the mast
above the beam and running a seperate ground off of that. Does anyone out
there have additional information about this ??
Jim
K4SSN
_______________________________________________
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.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
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