On Sun, 17 Feb 2008 15:26:29 -0500, "Robert11"
wrote:

Hello,

New at this.

I guess radio waves can go through wood just fine, as I can har signals from
my Discone that's in my attic.

But, there is, I imagine, some attenuation as a function of type, thickness
(of the wood) and the frequency involved.

Are there any good links explaining Attenuation as a function of frequency
for different materials, etc. ?

Hi Bob,

Yes. I've even calibrated products that measure the percent moisture
content of wood using RF probes. However, most of what you might find
is in terms of nearfield (much like my probes); or as forest. Of
course, the attenuation of 2x4s falls somewhere in between, but I
would hazard to guess, it doesn't amount to much.

Nearby trees, on the other hand, do represent a significant wavelength
of wetter wood (dry wood is about 15-22% water, and standing wood is
significantly wetter). We have, in the past, found postings here on
how to drive a nail into a tree for a feedline connection, lay out
radials, and use the tree as a radiator for HF. I suppose it was as
efficient as a 160M antenna the size of two shoeboxes. That is to say
it is not so amazing that it works, as it is to say that someone tried
it.

When you consider how much bulk wood is in a house, and how much
volume the house occupies, the loss would seem to be inconsequential
at HF. As you mention a Discone in the attic, I must expect you are
more concerned with VHF/UHF. This will alter the loss landscape, and
I doubt there is a lot of accessible data about wood's loss in those
bands as it is so easy to avoid (putting an antenna near timbers, that
is).

73's
Richard Clark, KB7QHC