[TowerTalk] Lightning... and pointed rods!

[Bob Wanderer]

Sorry, Norm, but the spline balls working that way (as they
were originally touted) is just not true (please substitute
a much stronger but politically incorrect term).  When I was
at PolyPhaser, we used to provide a video from two TV
stations and the FAA in Tampa proving the incorrectness of
these beliefs.  The one from the FAA (just before the camera
stopped running) clearly shows one of these "hedgehogs"
being hit.  The FAA was interested in them (for obvious
reasons) until the truth became obvious.  Then they were
touted in another manner.

The reason everybody thought that they worked as claimed is
because usually the site had a poor grounding system (the
grounding system is the "make or break" of any good
protection system).  When the hedgehogs were installed, the
grounding system was improved at that time.  Now lightning
damage became minimal or non-existant.  Ergo, it must be the
hedgehog.

73
Bob AA0CY/3
PolyPhaser Technical Consultant, 1994-1997

-----Original Message-----
From: owner-towertalk@contesting.com
[mailto:owner-towertalk@contesting.com]On Behalf Of Norman
Hockler
Sent: Wednesday, October 25, 2000 12:01 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Lightning... and pointed rods!


It helps to have many pointed rods on the top of the tower.
Commercial
towers use "spline balls" on the tower.  They are melon
shaped metal ball
with hundreds of sharp points.  These points help to
dissipate the charge
build up and therefore prevent the ground leader from going
up to meet the
cloud charge.   This is why a uhf/vhf antenna stack is less
likely to be
hit than a single vertical or a HF tribander.

de Norm  N8NH


At 09:52 PM 10/24/00 -0400, you wrote:
>As long as we're on this subject, I notice all the
lightning rods on
>buildings have sharp points upwards...so... does it help to
have a pointed
>rod at the top of the tower mast? If so, why?
>Jerry K3MGT
>
>
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