[SunRescue] Suburban Wireless?

[Chris Byrne]

Mike,

I've done this using high gain directional antennae over about half a mile.
Others have gone as far as 11 miles using amplifiers and HIGHLY directional
antennae (power horn and parabolic dish I think). Beyond that you'd need to
build a decent sized tower, and some serious amplification since 2.4ghz
signals a. attenuate quickly in the atmosphere, and b. do not propagate well
over long distance.

Some acces points advertise up to 250 meter range, but with the standard
antennae you are lucky to get 100 meters,and more like 50 with obstructions.
It's illegal to amplify the signal beyond a certain point, where it could
"cause undue interference" which basically means scrambling your neighbors
cordless phones etc... etc... so your best bet here is good antennae design.

With proper antennae selection, good connections, and a good low loss feed
line I figure you could put up a good Omni-directional rig with 1/4 - 1/2
mile range even through the 80 ft trees and other hazards.

The best way I can think of is to have each house with their own access
point in the attic, with as short a feed line as possible running to an
external antennae. Then put each of the access points on the same WLAN with
the same encryption yadda yadda

It is possible to have the system inside the roof but 2.4 ghz signals are
SEVERLY attenuated by common houshold building materials so it would reduce
your range a lot.

As to antennae design I'd go for either a standard vertical, or maybe a
circularly polarized (hoop, cylinder, or box shaped) antennae.

I've never tried using a circularly polarized rig with very high frequencies
before so I'm not sure if there would be a benefit to them or not, but at
lower frequencies they can give you a radiation pattern that reduces
environmental signal attenuation.

As to the nodes themselves I highly recommend the addtron wireless access
point. It's under $300, has 128 bit WEP, and has a good external antennae
connector. Also, addtron uses the prism chipset (in the AP and the cards)
and there are Solaris and Linux drivers available for prism based cards.
They make a PCI card, but I haven't tried it in any Solaris machine so I
don't know if it would work.


Chris Byrne