On Fri, 24 Dec 2004 16:29:03 -0500, Scott Piper <piper@ij.net> wrote:
> 1/4 mile is nothing if there is line of sight. Here are some links to
> check out
Yes but you want to make sure you have enough power to get through
rain fading, inclined inversions and other such obnoxious things that
can pop up at the most inopportune time.
Proper siting done once is much better than pulling your hair out because
you did not do it because you based coverage on a good day (the sort of
day we tend to test these things on) and in that quarter mile you can have
a obsticle that sticks up into the first fresnel zone, if you can see
the far end
with your eyes you still may be taken down a bad path, the fresnel zone
changes depth as you go along the path, being widest at mid path.
I will give you a good example of this, given the path is long, but it shows
what happens when you do your testing based on a simple "I can hear it"
or "I can hit it" type test. The local amateur packet group has a link
to Sarasota,
this link runs gang busters during the summer time, and of course that was when
the test were done to check the link. During the winter time it goes to pieces
particularly when we get a very dry air mass and the refractivity of the air
changes. The testing was done based on summer conditions, had the path
been modeled properly the problem would have been known. Of course
it is now known and the fix is a switch somewhere mid point between Tampa
and Sarasota. What I am describing is a hobby activity though it supports
disaster recovery and other emergency activity.
If you are trying to set up a internet connection you certainly do not want the
thing dropping out in the middle of something important, and even a 1/4 mile
path can be a real problem particularly with the power and spectrum used.
Indeed if Mike will send me that lat/lon data on the two ends I can run a path
profile and see if there are any NATURAL obstructions along the path. I have
the topo files for the whole country at 30 and 300m intervals.
-- Chuck Hast To paraphrase my flight instructor; "the only dumb question is the one you DID NOT ask resulting in my going out and having to identify your bits and pieces in the midst of torn and twisted metal." ----------------------------------------------------------------------- This list is provided as an unmoderated internet service by Networked Knowledge Systems (NKS). Views and opinions expressed in messages posted are those of the author and do not necessarily reflect the official policy or position of NKS or any of its employees.
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