[TowerTalk] Lightning protection

[Paul Playford]

Thanks David.  I had a similar reply formulated but it hit the garbage bin.

de Paul, W8AEF

---------------------------------------
ZF2TA  ZF2JI FO8DX  FO0PLA  8Q7AA  XZ0A
---------------------------------------

----- Original Message ----- 
From: "David Robbins K1TTT" <k1ttt at arrl.net>
To: "reflector -tower" <towertalk at contesting.com>
Sent: Monday, March 22, 2004 6:25 PM
Subject: RE: [TowerTalk] Lightning protection


> > Just think what the power lines are:
> > bunch of towers with spikes on the top, prone to attract discharge.
> > Yes, long wires, but insulated from the towers, grounded where?
> > So they do not form the "umbrella" effect. The "umbrella" has to be an
> all
> > metal structure with good grounding. Power lines are not that.
> 
> Obviously you do not work with large power lines.  The top shield wires
> are normally at the highest point and are connected to either the steel
> structure or to a ground wire that runs down the poles for other lines.
> The effect of an approaching downward leader on the power conductors is
> the same as if they were grounded... charge on the wires is attracted to
> the downward moving stepped leader just as it is on the ground and on
> the grounded shield wires.  
> 
> 
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://www.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
>  


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.576 / Virus Database: 365 - Release Date: 1/30/2004