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Re: Wet Trees?



I had a Monterey Cypress tree in the direction of many repeaters. It was 
about 20' away from the antennas, and covered about 30 degrees beamwidth of 
the antenna.
When it was wet and rainy, the signals were down up to 20db depending on 
frequency,
440 was 20db down, and 1.2 was poor at best! Least affected was 2 meters.

A year later, the tree was chopped down.
ALL frequencies were 100% full scale!!
Was a day and night difference!
For weak signal work, all must be line of sight to work well.

73, Scott WA6LIE
Salinas, Ca.


----- Original Message ----- 
From: "KC6UQH" <kc6uqh@cox.net>
To: "AMSAT BBS" <amsat-bb@amsat.org>; "Emily Clarke" <w0eec@amsat.org>
Sent: Thursday, January 27, 2005 7:49 PM
Subject: Re: [amsat-bb] Wet Trees?


> Re Wet Trees,
> We ( PARC) have noticed and are careful to locate all antennas for 70 cm 
> and
> higher frequencies above the tree line on Palomar Mountain. 6 M and 2 M do
> not seem to be affected, but the difference on 70 cm is very noticeable.
> Another effect is when the temperature inversion layer is well formed 
> making
> it impossible to bring up our repeaters from some locations. Our repeater
> site is at 5600 feet and about 30 miles from the coast. During the summer
> the output from our repeaters on 2 M measured from a site that has line of
> site, can vary as much as 10 dB during the day.
>
> Art, KC6UQH
> ----- Original Message -----
> From: "Emily Clarke" <w0eec@amsat.org>
> To: "AMSAT BBS" <amsat-bb@amsat.org>
> Sent: Thursday, January 27, 2005 8:01 AM
> Subject: [amsat-bb] Wet Trees?
>
>
> > In the past few months I've noticed that there are days when I just 
> > can't
> > work SO-50 below 12 degrees (normally getting down to 5 to 6 depending 
> > on
> > the azimuth.) The signal seems to fade in and out as the satellite moves
> in
> > azimuth, sometimes becoming stronger at a lower elevation.  It usually
> > seems to happen after there has been a rain.
> >
> > 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
> >
> >
> >
> > ---------------------------------
> > W0EEC - CM87tm
> > AMSAT Area Coordinator - San Francisco Bay Area
> > http://www.projectoscar.net    http://www.PlanetEmily.com
> >
> > Join AMSAT!  http://www.amsat.org
> > ----
> > Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> > Not an AMSAT member? Join now to support the amateur satellite program!
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> ----
> Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
> Not an AMSAT member? Join now to support the amateur satellite program!
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----
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