wireless beginner

The gear needed for wardriving

5 posts • Page 1 of 1

Postby grim » Sat Sep 13, 2003 11:20 am

Hi, I got wireless in my house with 2 different broadband connects, Im trying to setup a deal where I can get net connect from home, at my job, which is only 1-2 miles away not even, Where I live its marshland so at my house theres alot of trees, but where I work its right off the main road so there is a big clearing without many trees, I wanted to know what would be the easiest most cost effective way so that I can reach my house from work and get on the net without having to use dialup modem at work :P

Postby izzy4505 » Sat Sep 13, 2003 3:08 pm

Line of sight is important in your situation. 2.4GHz waves don't like trees. Especially wet trees. If you have a spot in this clearing where you can put a couple of antennas, then cool. What I'd recommend, is getting 2 24dB parabolic grids from http://www.hyperlinktech.com. They'll go a lot farther than what you need, but at that distance, you'll be sure to have a stable link. Next, you need some device to hook this up to your wired network. Linksys 802.11b WAP11's work great for this, as they can be put in this bridging mode. They're usually cheaper than wireless bridges too. Next, you need a couple pigtails, and maybe some coax to hook up the grids to the wap11's. [more later, class is starting]
Brad Isbell

Postby grim » Sun Sep 14, 2003 1:34 pm

Hey, all I would need is the antenna's and the pigtails then, I already got the WAP11 v2.2 access point in my setup, im just using regular linksys 4 port router with the wap11, i can mount those antennas on top of my house and be set then? sounds pretty easy, just directing them and finding a place for line of sight is the hard part, but we have recently cut alot of trees down in the past year or so, so shouldnt be a problem, So basically what im doing is gonna have to buy 2 pigtails, 2 coax cables and run each antenna to each antenna part on the wap, and this will work up to 2-5 miles, even tho my job is about 1-2 miles if even that? also in the near future, for having something like this going would it be best to up my access point to something nicer, I had my first spin around the city today war driving, and I cant believe the things i picked up from where I live, I would be pissed if someone was actually on my own network. I seen at least 20-30 open wireless networks while driving around town

Postby mycroft » Sun Sep 14, 2003 2:56 pm

I might be missing something, but I believe the two parabolics are meant as one for each site, rather than both at your home. You need two endpoints to the link which is why Brad suggested two atennas, two WAP11's, etc. A bare wifi card will probably not pick up an unamped 24dB parabolic at 2 miles (I'd say absolutely won't, but I'd be proven wrong in a second :) ). Just position one at work and one at home, make sure there's LoS between them, and make sure they're pointed at each other.

All of this assuming that:

1. you're sure that work is ok with this because depending on how you set up the machines accessing the wifi net, you could end up exposing their network through your home broadband (if you have a machine residing on both networks).

2. hooking up a 24dB parabolic to a WAP11 doesn't exceed the FCC limits for unlicensed transmission power.

Postby izzy4505 » Mon Sep 15, 2003 11:26 pm

Yes, you need 2 wap11s. As pointed out in the previous post, one wap11, pigtail, and antenna go on each end. Otherwise there'd be no way to maintain a link at that distance, with a standard 32mW output of a standard card. Also, use LMR400 coax, when running to the grids. Don't use more than 50' of cable. [I'd recommend 20 or less]

Don't quote me on this, but last I checked, wap11's with 24dB gain antennas are legal. I went to linksys's site to double check this, but I couldn't find the specs of power output on their pdf anymore for some reason, so if you're really concerned about it, you'll have to check into that. For this type of setup, you can crank out up to 4 watts. If you're not quite sure how to calculate this:

appowerindbi ^ (1 + ((antennagainindbi-signalloss)/3))

The signal loss is where you factor in loss from cable and stuff. Factor in 1 to 2 dB for every coax connection. Look up the specifics on your cable online somewhere. Even though it may be category 400 cable, it can be different from one manufacturer to the next.

Ya only have to worry about all of that though if you're really concerned about the fcc knocking on your door. The biggest thing is, pick a channel that nobody in your beamwidth is using, and you'll be fine. Get channel 6 if you can get it. It's right in the center of the whole band, and is what antennas are tuned to. It'll help your signal a bit. Also, you may want to experiement with various polarizations. . . If your signal is funky, turn your two parabolic grids 90 degrees, and see if it's better. Play with it. Just keep in mind, that whatever direction one antenna is going, the other one must be pointed the same, otherwise you'll have almost no signal.

Anyway, bottom line is, get one ap, one pigtail, one chunk of coax, and one parabolic grid on each side. [You can get the pigtail, coax, and grid from http://hyperlinktech.com, or http://www.fabcorp.com. fabcorp tends to have cheaper pigtails, but hyperlink has the best grids] As for mounting all this, do whatever is conveinent, and offers line of sight. If it's not line of sight, it'll work pretty poorly, if at all. If you have to put a 20 foot pole on top of your buliding to get it to work, I strongly advise it. At these frequencies, electromagnetic waves are practically like lasers. [Not quite, but if you imagine them that way, it'll work better for you] They don't like to bend around stuff. Everything has to be perfectly aimed at these distances. Also note: Don't just point the antennas visually and be done with it. Even if you had it dead on, sometimes this doesn't always offer the best signal. Plug an orinoco card into the antenna with netstumbler running or something, and watch the levels to get the best signal.

If you wanna get really technical about it, later we can talk about adjusting your standing wave ratio, but it's really not necessary at this point, considering the antenna is commercially made.

Have fun, and post with any questions.
Brad Isbell

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