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[TowerTalk] Shack Equip grounding - second floor shack/rocky terrain/no

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Subject: [TowerTalk] Shack Equip grounding - second floor shack/rocky terrain/no level ground
From: daslin@bayarea.net (David Aslin)
Date: Sat, 24 Nov 2001 15:39:56 -0800
TTers:

Here's the grounding conundrum that faces me at this idyllic (if you
consider the views and house) or lousy (if you consider antenna options)
California QTH:

The house is built on a 35-55 degree slope, on a rock material called
'greywacke'.  Ground rods will penetrate 4-6 inches (yes, inches!) before
meeting total resistance.  The longest radial run I could get would be
about 20 feet.  The shack is on second floor.  Fortunately, this is a low
lightning area, but this fall's big storms have convinced me easily that
'low lightning' does not equal 'no lightning'

So, I thought that I could consult the awesome experience of TT
reflectorites to answer the following:

- how do I best achieve a ground connection?  An 8 foot drill looks a tough
way to get a ground rod inserted - and how would the rod contact what I
assume is poor conductivity rock?  Trying to put fill down the hole
alongside an 8 foot rod looks comparable with cutting the grass of a
football field with nail scissors.  So how would an array of radials work
for station grounding?  I have tons of experience with radials for
verticals on excellent conductivity land in UK, but none for shack
grounding purposes on low conductivity.

- if I can get a decent ground, will big (2 inch?  4 inch?) copper strap
give me a low enough impedance connection to the second floor?  What about
reactance/resonances of the strap?  (Without wishing to open the Artificial
Ground thread again, none of the commercial units operate at 1500W anyhow).
 Will the electric company's ground, plus a set of 1/4 wave counterpoises
at the shack end be adequate? 

All suggestions (serious, non-flaming variety) gratefully received...

Dave
WJ6O G3WGN
ex M6T, G5M





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