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Re: [TowerTalk] verticals in woods vs. in a field

To: "Jim Lux" <jimlux@earthlink.net>
Subject: Re: [TowerTalk] verticals in woods vs. in a field
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Thu, 16 Sep 2004 14:36:32 -0400
List-post: <mailto:towertalk@contesting.com>
> > I actually measured the resistance of a freshly cut pine
> > tree by attaching metal plates to each end of a one foot
> > piece, and it as in the many hundreds of ohms per foot
at
> > radio frequencies.
>
> Interesting measurement.  What was the diameter of the
tree?  Did the metal
> plate cover all the end of the tree, and did you use any
sort of conductive
> gel to make a good contact with the tree (assuming that
the metal was
> flatter than the saw cut).

If you ever saw (pun intended) a Georgia Pine, it is thick
with sap. I used multiple small screws to hold the plates
against the ends, and made sure the cut was flat.
Effectively the plates became glued to the wood.

The "log" was roughly one foot in diameter. This was as
close to living as you can get, it was fresh cut less than
an hour before the measurement. Pines are also very acidic
and very wet inside, so I doubt it was on the less
conductive side of how trees go.

> It would be nice to get some decent HF measurements of
living trees.

It would indeed. For all the interest in this, I'm really
surprised no one has made any meaningful measurements. It is
a very common question, and all we have for answers are wild
guesses. Whoever does this and does this correctly would
really be contributing a great deal towards answering a
common question.

73 Tom


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