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<div class="moz-cite-prefix">We don't have good data on trees. We
should certainly develop some. How much attenuation does a trunk
of X diameter present? Is there a variation between trees? How
does it scale with diameter? What about branches/needles? I can
tell you that I shoot through trees about a mile away, but the
fresnel zone helps me out there. I can also tell you that rain
affects me, but not because of the rain itself! On a clear shot
with rain, there's hardly any signal degradation. It's the fact
that the rain coats the trees in a film of water, and that seems
to be the killer of signal. In my case, I think I lose about 8dB,
but we don't have good data on this either. It's gonna take a
while to build it since we don't control the weather...yet. :)<br>
<br>
Where are you located? We can do a path analysis and see if we
can help you do a site survey.<br>
<br>
--Bart<br>
<br>
<br>
On 10/5/2013 6:09 PM, Allen wrote:<br>
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<div><font face="Comic Sans MS">So looking at that profile I see a
small rise close by that is probably less than my tower. But I
have a lot of fir and ceder all around me that are higher than
the tower. How well will 5ghz pass through the fir and cedar?</font></div>
<div> </div>
<div><font face="Comic Sans MS">73,</font></div>
<div><font face="Comic Sans MS">Allen</font></div>
<blockquote style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT:
5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<div style="FONT: 10pt arial">----- Original Message ----- </div>
<div style="FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color:
black"><b>From:</b> <a moz-do-not-send="true"
title="apolloeme@gmail.com"
href="mailto:apolloeme@gmail.com">Patrick Barthelow</a> </div>
<div style="FONT: 10pt arial"><b>To:</b> <a
moz-do-not-send="true" title="psdr@hamwan.org"
href="mailto:psdr@hamwan.org">Puget Sound Data Ring</a> ; <a
moz-do-not-send="true" title="esarfl@gmail.com"
href="mailto:esarfl@gmail.com">esarfl@gmail.com</a> ; <a
moz-do-not-send="true" title="apolloeme@gmail.com"
href="mailto:apolloeme@gmail.com">Patrick Barthelow</a> ; <a
moz-do-not-send="true" title="jeff@gritch.org"
href="mailto:jeff@gritch.org">jeff@gritch.org</a> </div>
<div style="FONT: 10pt arial"><b>Sent:</b> Saturday, October 05,
2013 10:38 AM</div>
<div style="FONT: 10pt arial"><b>Subject:</b> Re: [HamWAN PSDR]
HamWAN portable</div>
<div><br>
</div>
<div dir="ltr">Hello Guys,<br>
<br>
I have been following the threads from the eaves here, with
interest, because I do/have done this intervisibility/path
loss kind of stuff a lot. I recently discovered a very
powerful program that can assist in this pursuit. Check out:
<a moz-do-not-send="true" href="http://www.heywhatsthat.com">http://www.heywhatsthat.com</a>
. This program will construct, file and store a skyline
horizon from any location on the planet, looking in any
direction. And it will identify nearby intervening terrain
peaks. It will answer questions such as range, and
elevations, intervisibility profile plots, bearings,
distances, fresnel zones, path loss, etc.. Make your
viewshed maps, and file them, in a library of such, on-line,
or send them to your colleagues.<br>
. Try it out. Enjoy..<br>
<br>
Best, 73, Pat <br>
<br>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Sat, Oct 5, 2013 at 9:41 AM, Tom
Hayward <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:esarfl@gmail.com" target="_blank">esarfl@gmail.com</a>></span>
wrote:<br>
<blockquote style="BORDER-LEFT: #ccc 1px solid; MARGIN:
0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class="gmail_quote">On Sat, Oct 5, 2013 at 9:26 AM, Jeff
Francis™ <<a moz-do-not-send="true"
href="mailto:jeff@gritch.org">jeff@gritch.org</a>>
wrote:<br>
> <a moz-do-not-send="true"
href="http://plane.gritch.org/plane/tn/2013-09-08%2014.18.42.jpg.html"
target="_blank">http://plane.gritch.org/plane/tn/2013-09-08%2014.18.42.jpg.html</a><br>
><br>
> If you look in the back of the truck, you can see
precisely the same<br>
> antenna setup that Tom is using laying on top of
the spare tire (next to the<br>
> stool). From the park, I was close enough I just
propped the antenna up and<br>
> did it that way. No need for the tripod (and the
strange looks from other<br>
> park-goers).<br>
<br>
From that photo, I can tell you that it won't work.
You're aimed at<br>
the sky. The beamwidth of these dishes is very narrow
and they must be<br>
aimed precisely in both azimuth and elevation.<br>
<br>
Here's my algorithm for aiming:<br>
- First, I calculate the bearing from my current
location to a HamWAN<br>
site (your APRS client should be able to do this for you
with the<br>
HamWAN* objects).<br>
- Then I sight that bearing with my compass.<br>
- With the Poynting on the tripod mast, I sight down the
feedhorn of<br>
the Poynting and line it up with the same landmark I
spotted with the<br>
compass, being sure to keep the feedhorn level in the
elevation axis.<br>
- At this point the signal LEDs on the modem have
usually registered<br>
something (I'm connected) and I can pan and tilt
slightly in each<br>
directly to maximize signal.<br>
<br>
This works really well for me because I have a sighting
compass<br>
accurate to 1 degree and I know how to use it. Another
technique is to<br>
plot the path on Google Earth and look for landmarks
along the path.<br>
I've done this and sighted "between the two water
towers." This<br>
technique requires more patience and panning.<br>
<br>
This is microwave. It's a lot harder to get a signal
than VHF, but<br>
it's really satisfying when you do (and faster than 1200
baud!).<br>
<br>
Tom KD7LXL<br>
<br>
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</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
Best, Pat Barthelow <br>
<a moz-do-not-send="true" href="mailto:apolloeme@gmail.com"
target="_blank">apolloeme@gmail.com</a><br>
<br>
Google Lunar X prize Team, SYNERGY MOON <br>
<a moz-do-not-send="true" href="http://wwww.synergymoon.com"
target="_blank">wwww.synergymoon.com</a> <br>
<a moz-do-not-send="true"
href="mailto:pat.barthelow@synergymoon.com"
target="_blank">pat.barthelow@synergymoon.com</a> </div>
</div>
<p> </p>
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