matthewsimon
Newbie  Posts: 1 Registered: 23/8/06 Status: Offline |
posted on 23/8/06 at 14:21
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I'm trying to help my aunt set up a wireless
network on her ranch in a remote corner of New
Mexico, and have run into a number of questions
about outdoor and long-range WiFi that I hope
people can help me answer.
The central office building has Internet access via
DSL, to which we would like to provide access
from other locations around the ranch. Digging two
thousand feet of trenches and laying shielded fiber
would be prohibitively labor intensive and expensive,
so wireless seems like the logical answer.
Geography
Many of the buildings and outdoor spaces where we'd
like to have access are clustered within 150
feet of the main office. However, a few key
buildings are spaced further away, up to approximately
600 feet, and one has quite a few trees
between it and the main building.
In the map below, the main office is marked with
a red border, while the primary other buildings
we'd like to provide access to are shown with a
blue border. The blue-marked building in the
upper-right is completely blocked off from the main
office by an area of many trees, but has near
line-of-sight to the workshop, which is marked with
a green border.
matthew.cavalletto.org/wifi_outdoors.html
Other Constraints
There will only be a few simultaneous users, so
I don't expect that bandwidth contention will be an
issue.
There are a fair number of trees on the
property, which will attenuate the signal.
On the upside, the nearest neighbors are quite
distant, so there shouldn't be any interference with
other wireless devices.
All of the computers being used are Macs of
various vintages, and there's no on-site tech guru,
so I'd prefer to use Apple's AirPort base stations
for simplicity, but we could live with third-party
access points if needed.
We don't have a fixed budget, but if it looks
like the price is going to be much over $1,000
they're likely to just settle for getting another
DSL line or satellite-based Internet access at one
or two additional locations.
Ideas and Questions
The first step would seem to be placing a WiFi
access point in the main office, connected to the
DSL router, with an outdoor omni-directional antenna
on the roof to provide access to the main
cluster of buildings.
- Which model of outdoor omni-directional antenna
should we use on the roof of the main office?
- Does it make sense to get an amplifier to
increase the signal strength?
For the building shown on the left side of the
map, which is about 250 feet from the main
office and has some intervening trees, I think we
may need a directional antenna pointed towards the
main building.
- Instead of getting an outdoor antenna, can we
just use an indoor directional antenna and point it
through a window, or does that significantly
attenuate the signal?
The building in the bottom-right corner of the map,
is even further away: about 6-700 feet.
- Is a directional antenna likely to be sufficient
over this kind of distance?
For the building on the upper-right corner of the
map, I'm concerned that even a directional antenna
may not be able to punch through all of trees
that lie between it and the main building, so
I've been thinking of placing another access point
at the workshop, which has line-of-sight to both
the main office and the remote building, and using
that to propagate the signal.
- Is a directional antenna on the remote building
likely to be sufficient, or do we need a
directional antenna on each end of the link?
- Is there a decent wireless-to-wireless bridge with
two antenna ports, so we can connect an
omni-directional antenna to one to pick up the
local signal, and a directional antenna to the
other to connect to the far side of the
property?
Suggestions Welcome!
I've spent a while Googling, which reinforced my
initial impression that it's difficult to predict the
real-world performance of wireless networks.
It may be that our only choice is to engage
in a bit of trial-and-error, starting by placing
the initial base station and omni antenna, then
wondering around the property to see what level of
signal strength we get, and figuring out how to
expand from there.
However, any suggestions or feedback people might have
would be much appreciated. Have you dealt with
these kinds of issues in the past? Any
recommendations for specific equipment, general approaches,
or avenues of further research?
Thanks!
-- Matthew
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