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R: Wet Trees?



Hi Tony, KT2Q and All

Signal attenuation due to foliage environment is probably the most
difficult to accurately quantify.

Please search just on the WEB foliage attenuation and you will get
4413 articles on this matter.

Choose "Publications"

Click on Radio Dinamics on Line Publications

Choose and download the article  "The impact of Dust and Foliage on
Signal Attenuation in the Millimeter Wave Regim by Gary Comparetto

This article is very interesting in general and particularly for the 10 GHz
band
and above.

References 16 and 18 at the end of this article are also very interesting
for our purposes for frequencies belove 10 GHz

Best 73" de

i8CVS Domenico

----- Original Message -----
From: KT2Q <dxdx@optonline.net>
To: <amsat-bb@amsat.org>
Sent: Friday, January 28, 2005 5:55 AM
Subject: Re: [amsat-bb] Wet Trees?


> Emily,
>
> I asked a similar question a while back about AO-40's S-mode downlink. The
> answer I got was that most satellite communications text books state that
> attenuation at 2.4Ghz was about 3db per meter of foliage. Assuming that
> foliage attenuation varies with the square of the frequency, there should
be
> much less atennuation at 435mHz than 3db per meter.
>
> I'm sure Dominico ( I8CVS) would have the answer to this one.
>
> 73, Tony KT2Q
>
>
>
> > On Thu, 27 Jan 2005 08:01:51 -0800, Emily Clarke <w0eec@amsat.org>
wrote:
> >> In the past few months I've noticed that there are days when I just
can't
> >> work SO-50 below 12 degrees
>
> >> After testing power out/VSWR and passing the test, the next thing that
> >> came
> >> to mind is that the wet trees, mostly thick pines and laurels which
still
> >> have their leaves, are attenuating the signal more than when they are
> >> dry.  Does that seem possible?
> >>
> >> 73,
> >>
> >> Emily
> ----
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