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I have been toying with the idea of creating a wireless community network.
Most people in this space are interested in sharing Internet, however I'd
like to do something a bit different.

My idea is to bring together local residents in much the same way as BBSes
did years ago. Applications such as chat, games, a community web page, etc
is what I have in mind. This would all be non-Internet based.

Looking at antennas, I was wondering what kind of range (very generally
speaking) something like an 18dbi omni mounted on my roof would give. Is
this even doable considering the "donut-shaped" pattern of an omni? Would
tress interfere too much?

Has anyone done anything like this?

On Sun, 02 May 2004 18:38:04 GMT, "Seeker"
<(E-Mail Removed)> wrote:

>I have been toying with the idea of creating a wireless community network.
>Most people in this space are interested in sharing Internet, however I'd
>like to do something a bit different.

Make sure you have some thoughts about "bandwidth hogs."

>I was wondering what kind of range (very generally
>speaking) something like an 18dbi omni mounted on my roof would give.

All depends upon where you live...etc...etc...etc...etc...there are
theoretical specs....and also, how long your cable is and type...and
output of your transceiver.


>Would
>tress interfere too much?

Yep....line of sight.....

>Has anyone done anything like this?
>My idea is to bring together local residents in much the same way as BBSes
>did years ago.

http://www.austinwireless.net/cgi-bin/index.cgi/AboutUs

http://www.bawug.org/about/
>

Seeker wrote:

> I have been toying with the idea of creating a wireless community network.
> Most people in this space are interested in sharing Internet, however I'd
> like to do something a bit different.
>
> My idea is to bring together local residents in much the same way as BBSes
> did years ago. Applications such as chat, games, a community web page, etc
> is what I have in mind. This would all be non-Internet based.
>
> Looking at antennas, I was wondering what kind of range (very generally
> speaking) something like an 18dbi omni mounted on my roof would give. Is
> this even doable considering the "donut-shaped" pattern of an omni? Would
> tress interfere too much?
>
> Has anyone done anything like this?

18dbi would be a VERY flat doughnut. It would be mostly a matter of luck
to hit someone's antenna. Think more in terms of either a flexible 8dbi
omni - or use multiple sector antennas, such as four 90° sector antennas.

Up close, trees aren't a big deal. When I say up close, I mean like
200-500 feet. Going out further, trees are not only a big deal, they are
a deal-killer. Get a clear line of sight and you can go for miles with
either setup. Throw in a few trees and you are dead in the water.

I'd be surprised if you'd find much interest in a local-only BBS type
of wireless system. If, coupled with Internet access, you'd probably
have something. But, if you do toss in Internet access, one thing you
should be very careful of is --- Does your ISP agreement allow for it.
Read the fine (and even, not so fine) print. Otherwise, you could find
yourself in a heap of trouble, you never saw coming.

Okay, on to the antenna question. In general, yes. trees (and anything
else in the way) is going to limit your effective range. No matter how
much gain your antenna is spec'ed for. Also keep in mind that (in
general) the more gain an antenna is rated for, the narrower the
beamwidth. For example, say for instance you mount an 18 dBi omni
antenna (with no downtilt rating) 20 or more feet above your roof
line. A very good percentage of the radiated power is going to be
directed straight out in all directions (but, not downward where the
people are).

There are ways to counter this. 1) Buy an omni/gain antenna with
downtilt. 2) Get a few of your neighbors to put up some repeaters on
their homes. This may sound like a BIG deal. But, it doesn't need to
be. I'm mounting D-Link DWL-2100AP's in NEMA 3R outdoor enclosures
(and weather-proofing them). They're relatively inexpensive, and they
work well as repeaters and bridges. If you have a number of them, well
placed within your community, coverage would be vastly improved. Note
that the root AP would have to have an unobstructed view of the
repeaters. Of course, there are a few other ways (and more expensive).
But, this would be the most simple and inexpensive.

Chet

On Sun, 02 May 2004 18:38:04 GMT, "Seeker"
<(E-Mail Removed)> wrote:

>I have been toying with the idea of creating a wireless community network.
>Most people in this space are interested in sharing Internet, however I'd
>like to do something a bit different.
>
>My idea is to bring together local residents in much the same way as BBSes
>did years ago. Applications such as chat, games, a community web page, etc
>is what I have in mind. This would all be non-Internet based.
>
>Looking at antennas, I was wondering what kind of range (very generally
>speaking) something like an 18dbi omni mounted on my roof would give. Is
>this even doable considering the "donut-shaped" pattern of an omni? Would
>tress interfere too much?
>
>Has anyone done anything like this?

I don't think your idea will go very far (sorry). Without providing
internet access, you are going to require your neighbors to have two
network feeds - one for your local net and one for the internet. The
roadblock will be getting the "non-computer-savvy" people set up to
join both networks.

If, OTOH, you were to create your own network with it's own domain on
the internet, you could probably make more progress except that now
you'll have to pay commercial rates for a connection to "the cloud"
and bill your neighbors for their fair share while guaranteeing you
can be a better provider than the one they already have.

Greg