Archived from groups: alt.internet.wireless (
More info?)
On Fri, 17 Sep 2004 09:22:49 -0400, "Mike" <mikebegin@hotmail.com>
wrote:
>I have a Cisco AP350 with a T1 coming into my
>house. I would like to provide access for my neighbors. What do you
>recommend for an outdoor antenna? My house sits on a high spot, but the
>problem is a lot of tall tree and thick woods between houses.
Dunno. The best I can do is offer some general clues and rhetorical
questions.
Mini rant: No numbers = no specific answers.
What are the distances involved?
How much difference in vertical elevation?
Is this going to be a neighborhood LAN (everyone joins in) or are you
going to do this point to point, one house at a time?
Is price an issue?
Are there wired alternatives?
Trees and woods are a serious problem. 2.4Ghz does not go through
anything with water inside. If you have a view of the *TOPS* of the
trees, you can possible mount the client radios (for the neighbors) in
the tops of the trees, and run PoE (power over ethernet) to the
treetop. The major problem with this is maintenance. Climbing a
100ft tree, in the middle of a storm, to remove an ant colony, was not
my idea of fun. Basically, you need to get line of sight somehow.
Perhaps this would be a good excuse to do some tree thinning or
logging.
I helped with a neighborhood LAN similar to yours, where the view from
the central hilltop was nothing but tree tops. Looking from above,
that's all you see. However, trees tend to not have branches at
ground level, so there was a few between the trunks at ground level.
The access points were moved to ground level and located so there was
some semblence of line of sight between the tree trunks. I had to use
multiple access points on the central hub to cover all the neighbors,
but it did work.
Another way of going through trees is to use 900MHz. We had quite a
bit of experience with Metricom in the area. 900MHz is blocked by
trees, but nowhere as bad as 2.4GHz. The problem is that 900MHz
equipment is difficult to find. The available speeds are also limited
to about 1.5-3.0Mbits/sec depending on manufacturer. The band is also
full of interference from other devices. The only currently
manufactured 900MHz hardware I know about is Motorola Canopy system.
One thing you shouldn't do is install a very high gain omnidirectional
antenna. The problem is that the vertical radiation angle is very
narrow. From even a modest hill, you will be sending the signal over
everyone's head. Think multiple access points, sectored antennas,
panels, dishes, or anything directional.
I live in an overgrown redwood/fir/oak forest. We have a crude 2.4GHz
neighborhood LAN that barely works through the trees. However, we
also have a buried coax and fiber distribution system that works well
enough. You can go about 1000ft point to point with CAT5 or coax
between two switched ports at 10baseT-HDX. Some drivel I wrote on the
subject:
http://www.google.com/groups?selm=39isj0995dp2gsk180n1hd22ff620tmda8%404ax.com
http://www.google.com/groups?selm=onatj01td5ilomf5dd436e50v7r521f2k7%404ax.com
--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
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