[TowerTalk] Naive question about lightning protection

[Tom Rauch]

> Upon further thought, I will throw out this suggestion, using commonly
> available materials and Ham frugality (cheap!). Let's expand on Tom's 
> copper pipe idea. Now suppose you pound 12 inches of the end of the pipe
> flat, creating a sharper edge on one side, and place this edge parallel to
> the tower leg. This, in effect, creates a large, parallel path for
> potential arcs that will form sooner that on the more rounded,
> un-flattened edge. 

A rounded conductor is more immune to increase in breakdown 
voltage as the sharp point goes away from repeated arcs. It also 
handles more current without damage.

That's why BC towers have balls instead of points. Sharp points 
increase the voltage gradient, and reduce the voltage breakdown, 
but blunt surfaces are just as fast responding. You just need to set 
a blunt surface closer, that'll make response identical.    

By the way, someone made a good suggestion to also include a 
shunt choke. I do use a single layer choke from a HF PA on one 
tower, because it has no feedlines or power wiring going up the 
tower. That's a good idea, to prevent an annoying pop pop pop 
every time the weather gets the least bit bad.


73, Tom W8JI
w8ji@contesting.com

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