Gary:
Several on this list have grounded their parasitic elements of their
F12 design Yagis. Nathan (W6XR?) of F12 posted here ca Summer/Fall of 2001
that such grounding was indeed possible at the boom/element junctions with
his designs.
My Bencher Skyhawk is of eerily similar design to F12's. To improve
the top-hat loading of the Skyhawk on my tower, I grounded the parasitics
with 3/4 inch by 5 inch pieces of aluminum flashing. I used stainless
self-tapping #10 screws through the PVC insulator to fasten the metal to the
element. I used SS hose clamps, NoAlOx and Scotch 88 tape to fasten the
other ends of the flashing to the boom. Seems to work for my intended
purpose (cap loading on 160 and 80M.)
I did not install inductors in shunt with the feedpoints, though. But
recall that I grounded the parasitics for loading, not to preclude a
lightning strike. Grounding will also eliminate any arc-over that might be
caused by shunt-feeding the tower and running QRO on Topband using the Yagi
as capacitive loading. FWIW.
73 de
Gene Smar AD3F
----- Original Message -----
From: "StellarCAT" <RXDesign@ssvecnet.com>
To: "tower" <towertalk@contesting.com>
Sent: Friday, February 10, 2006 4:08 PM
Subject: [TowerTalk] lightning and insulated elements..
> has there been any previous discussion on the merits (or lack
> thereof) of insulated
> elements visa vie lightning? I recently installed a tower system
> will 5 f12 antennas -
> all having insulated elements... the tower I believe is well
> grounded as are the cables.
>
> Last night we had a storm pass by maybe 5 miles away and I was
> standing outside
> watching - wondering.... and there was a bolt that was well
> maybe a few miles away
> and almost immediately I heard kind of a slow sizzling sound
> from around the tower.
> I was standing - 200' from it (next to the house). Nothing
> visible... all was disconnected
> (in the house) at the time and all works fine today.... but it
> made me wonder. Normally
> a well grounded tower is LESS likely to get hit (I have never in
> many years with towers
> been hit on the tower) but with insulated elements - one would
> think a charge could
> readily build up on these things!
>
> thoughts?
>
> Gary
> K9RX
>
>
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