sigh.
the last thing you want to do is plant a high gain omni on high ground.
here's the thing with antennas, they have the same gain in both
directions.
here's the thing with wifi, there are more of them then there are of
you.
Thus, if you employ a high gain omni with a clear LOS to a lot of
area, that area will have other WiFi devices in it.
If you can reach out far enough to communicate with one, it (or one
at the same or shorter range) will be able to, at the very least,
wreck havoc.
APs are like insects, where you find one, there are more, lurking,
waiting to cause interference with packets you're trying to receive.
They can't 'hear' each other (because the path loss at ground level
is too high), but they can all hear *you*, and, as a consequence, you
can hear *all* of them.
This is what killed Vivato.
I've tried explaining it to Matt and co up in Seattle (just like I
told them early on that their efforts with OSPF as a wireless routing
protocol were doomed, and that mesh was going to be the only way
forward.) In both cases, my mistake has been attempting to explain
'why' with mathematics to a crowd who are suspicious of mathematics
(potentially because they don't understand them) and always wants to
"see it in real life".
Matt eventually asked me to leave the Seattle Wireless lists because
he didn't want me to "spout off" about why he was wrong, when he was
wrong. I've stayed on the other community wireless lists (Austin,
PTP (Portland), here, and NYCwireless).
Community wireless (or rather Community Networking) has a chance(*),
but its not going to happen with high EIRP setups and people who
aren't willing to deal with the actual physics of RF.
Jim
(*) See, for example:
http://www.smallworks.com/archives/00000365.htm
http://www.smallworks.com/archives/00000372.htm
Begin forwarded message:
From: "Frank Keeney" <[EMAIL PROTECTED]>
Date: January 19, 2006 11:46:46 PM HST
To: <[email protected]>
Subject: [SOCALWUG] Wi-Fi Underground Revolutionaries
Reply-To: [email protected]
A very good summary of the grass roots community wireless Internet
movement:
"The idea of building citywide wireless networks from the community
level was suspiciously simple back in 2000, though the plans
sounded like the work of underground revolutionaries.
"All of us were very idealistic, and all quite strongly
opinionated," said Adam Shand, founder of The Personal Telco
Project, which had visions of such a network in Portland, Ore.
Seattle Wireless probably represents one of the highest
achievements in the area of neutrality, because they’ve built a
network of what looks like now over a dozen nodes that use an open-
source mesh routing protocol to create a neutral medium....."
Read the New York Times Article also at Cnet
Glenn Fleishman's Blog
Frank Keeney
Antennas, Cables and Equipment:
http://www.wlanparts.com
Blog: http://www.unwiredadventures.com
