Re: Building a wireless network in Iraq

There are several white papers and even some Java applets that show you 
how to computes signal levels (i.e. coverage) as a functions of distance, 
antenna gains, transmitter power, and RX sensitivity.  For instance on 
Proxim website,  the following link will take you to one paper that has 
some simple details,

http://www.proxim.com/learn/library/whitepapers/parameters_802.11g_performance.pdf is an example.

Good luck, by the way,  Are they showing 9/11 Fahrenheit in Baghdad ?.


Mohamed Nezami, 
Florida, USA







Ryan Marsh <[email protected]>
Sent by: [email protected]
07/29/2004 12:26 PM

 
        To:     [email protected]
        cc: 
        Subject:        [BAWUG] Building a wireless network in Iraq


I'm putting together a wireless network for the guys in my company. Let 
me start by saying that I am infantry. So that means I am in an 
infantry unit, so, not much in the way of network guys around to 
help... Besides, Army network guys are usually one certification away 
from my grandmother. In a previous life not too long ago I was a 
software engineer (don't even ask). I have a strong knowledge of 
routers, networks, and the internet... but all from a landline 
perspective.

Right now we're finding a satellite internet provider. Once I get that 
hooked up I'm going to share the connection with our guys wirelessly. 
We can't just run CAT-5 to every hooch I don't have the time or 
resources to do that. I've got a laundry list of questions and I was 
hoping you guys wouldn't mind offering up some advice because they are 
mainly terrain and equipment related questions.

There is a local here that sells D-Link wireless access points and 
routers. He's got B and G routers, and two different D-Link access 
points. One of the access points does load balancing. What that 
requires, or how best to effectively use an access point is new to me. 
I thought a wireless router basically did the same thing as an access 
point. I'm not sure which I should use in my situation.

The situation is about 50 (or fewer) guys with laptops, with D-Link 
WiFi cards or the card that came installed in their laptop, and one 
Airport Extreme card (mine). We are living in small temporary buildings 
about 15 meters long, about the size of a small trailer home and built 
out of most likely the same materials. That means, light metal on the 
outside, and possibly metal studs on the walls. There is no foliage to 
speak of where we are at. Just heat and regular dust storms (which I 
discovered in Kuwait doesn't hurt WiFi signals much). As a matter of 
fact, in Kuwait we could hear a network that the medics had put up at 
least 250 meters away, maybe further. The signal passed fine through 
canvas tent after canvas tent (probably 8 to 10 before it got to us). 
Maybe the less dense hot air helped. That gives me hope, but the metal 
in these buildings bugs the crap out of me. The buildings are spaced 
about two meters apart, with a road about the size of a small two lane 
separating the buildings into rows of two by five buildings. The 
buildings that we occupy probably take up an area no more than 200 x 
200 meters. We are not evenly distributed though. There is another unit 
sprinkled in with us. In a map I've made we actually clump up in to two 
opposite corners of this grid.

So it has become apparent that I might need to put an access point at 
the two opposite corners of our neighborhood just to get a signal 
through these buildings. Has anyone worked with buildings like this? 
How many of these temporary buildings can I expect the signal to 
penetrate? Can I have the AP inside and run a line to an antenna 
outside? If the AP is outside it's going to have to endure dust storms 
and 140 degree temps. Will elevating the antenna above the buildings 
help (they are only one story)? I can't give everyone a Yagi antenna 
and orinco card, that would be impractical and too expensive. I can at 
least run CAT-5 from the gateway/firewall to two AP/Routers.

My questions boil down to this:
Should I use AP's or routers?
How far can I expect the signal to go in said terrain?
What kind of antennas should I use? How should I position them?

Please keep in mind that this is being paid for by all of us with 
laptops so we can't afford alot. The satellite setup is already going 
to stretch us thin.
BTW: If anyone can help me find a satellite provider they know or 
trust, I'd be open to the referral. I only get about an hour on the 
Internet every other day and it's very far away so trying to get info 
from these providers in the UK is going sloooow.

If you are interested in the war and politics, please email me off this 
list, I'd be happy to talk. I might surprise you.

-ryan
--
Let us, then, be up and doing,
     With a heart for any fate;
Still achieving, still pursuing,
     Learn to labor and to wait.
   -- Henry Wadsworth Longfellow

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