Wireless networking and distances.

dolbz

Right I'm looking into getting a wireless access point to allow my girlfriend access broadband because dialup costs her and is wayyyyyy too slow. I was thinking of getting one anyway but this came into the equation just today so now I'm wondering how much the terrain affects the signal.

Ok. So the access point I've been looking at is quoted as having the following spec:

DefconAlpha · Posted: Mon Jun 09, 2003 9:16 pm Post subject: well

in "open area" they mean really just that. if you could run a wire (perfect wire, no bends, no curves, no slack, etc) between the two points, is there *anything* there? no trees? no cars? no houses? well, then you should be fine to go.

The point that you see objects in the way is when you invest in a few towers and slightly higher power antennae than the standard 2.2dBi "duckies" that are shipped with most wireless AP's. There is something just up on /.: http://slate.msn.com/id/2084046/ However you may be looking for something more like: http://www.d128.com/wireless/

Just for shits-n-giggles, i managed to get my ibook about 200ft from my d-link wireless cable/router through one wall and part of a tree and still listen to grapeshot.net's pink floyd station.

hope this helps
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metalac · Posted: Mon Jun 09, 2003 9:26 pm Post subject:

which ever way you go 300m is a fairly long distance and you will not be able to run any of the standard CAT5 cabling without some repeaters or something in the way. Also with cable the weather and such outside factors become a huge issue, since most cables are not built to be used like that. As far as wirless goes I'd go with a home built point to point antena. I've seen these babies built for as little as $20 and having a rage of 1-2km the onli disadvantage you have to point it at the other antena, but if you have clean view of her house or balcony or something, then it wouldn't be problem.

go to www.seattlewireless.net for more info about this.
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dolbz · Posted: Mon Jun 09, 2003 9:39 pm Post subject:

Well I've got no plans on cabling at all but I'll look at the links. Thanks guys. Anybody else?

EDIT: metalac, I'm not much of a radio expert so sorry if this is a bit of a newb question but could just my end have an antenna and she still use a standard wireless card?

dolbz · Posted: Tue Jun 10, 2003 9:42 pm Post subject:

Right. It's time for a little update.

So I've decided that I'm gonna do this. I'll attach my access point to a directional antenna and point that at my girlfriends window which is just within sight. I'm assuming that if my antenna is good enough quality it should easily cover this range without having a recieving antenna at the other end (well just the standard small one on the back of the wifi card). Are my assumptions correct? Also by connecting a directional antenna does this mean that a machine on the other side of the antenna will not even have any kind of chance of getting a connection? I'd like to know your thoughts

Thanks.
Dolbz

khel · Tux's lil' helper Joined: 07 Mar 2003 Posts: 80

It should work... Just make a small cantenna and see what will happen :-)

dolbz · Posted: Wed Jun 11, 2003 8:06 am Post subject:

Oh and another question.

I've got a whole heap of cable that the nice cable guy left me for if I wanted to rearrange my room and extend the length of cable that my cable modem is on. My question is this.........

Is that cable suitable for connecting to antennas? I know the connectors aren't right but I'm sure that can be sorted?

Thanks again
Dolbz

fgarbrecht · n00b Joined: 27 May 2003 Posts: 43 Location: Philadelphia

You should probably skip the homegrown cable; you will suffer signal losses if you use inappropriate cable and connector types. You can find fairly reasonable prices for directional Yagi antennas, pigtails and connectors various places on the web; I got a cheap Yagi on Ebay that works very well. I can tell you from experience that unless you have some expensive diagnostic equipment, it's difficult to troubleshoot faulty wi-fi connections so save yourself some grief and get decent correct connectors, cables and antenna made for the job.

BlueShift · Posted: Wed Jun 11, 2003 9:54 am Post subject:

You can't use that cable for antenna cable but you can use it between your pc and the access point.
A few days ago there was this article on slashdot about building a super cheap directional antenna http://slashdot.org/article.pl?sid=03/06/07/1633252&mode=thread&tid=137&tid=193
one of the more interesting links in this article seems to be http://www.esiee.fr/~dormardj/ but it's in French.
I also think you will need 2 directional antennas. just 1 won't work (I think, not an expert either)
Greetings,

Jan.

khel · Tux's lil' helper Joined: 07 Mar 2003 Posts: 80

As I said - it should work IF you have LOS (line of sihgt), no trees in between and your friend doesnt roam far away :-)

But as BlueShift mentioned, it's more common when ppl use two directional antennas or omni+directional.
Hm... cable... You should use LMR cable (for ex. Times Microwave LMR 240 coax) otherwise the signal loss would be too big.

Anyway, if you want more info on wireless, antennas etc. check out the forum on www.netstumbler.com

khel

fgarbrecht · n00b Joined: 27 May 2003 Posts: 43 Location: Philadelphia

A little off topic, but to be considered as well.... I don't know about telecommunications law in the UK, but I know that US cable companies get pissy when you share your bandwidth with non-subscribers.

Also, make sure you secure your wi-fi setup adequately; very easy to sniff, and wep keys can be easily cracked.

fg

Dracnor · Guru Joined: 08 Jun 2003 Posts: 397 Location: Pennsylvania

I agree with the LMR cable. We use LMR-400 and LMR-600 cable at work and it has very little loss (esp. the 600). As for an antenna, you can use a directional (YAGI) antenna or a sector antenna, just make sure that the degrees spread on the antenna is very narrow. You don't want to push signal out to the sides if you want to go a far distance. In terms of signal strength, it really depends on the Access Point and the receiving end of the client. If worse comes to worst, put an amplifier on the Access Point to boost the signal to her house. Also, I would put a Lightning Arrestor between the antenna and the AP (we've had a few antennas get struck, and would have fried the AP if there wasn't one.) Also make sure you use WEP - and a different ESSID than from out of the box.

As for objects in the way...trees really won't bother the signal too much. It will have real problems trying to penetrate metal. If you still can't get signal to her house, perhaps you could set up a wireless bridge - point to point. It's just like having a backbone, and you can put the remote end of the bridge into a small switch/hub and plug in from her house, or if it has dual channels, use the other channel (not the bridge channel) to give local coverage all around her house.

Hope this helps.

dolbz · Posted: Wed Jun 11, 2003 9:11 pm Post subject:

Ok. So I've read a bit more on the subject and I'll post my assumptions / thoughts and you can correct me ok?

So. a wireless bridge will still have to be in line of sight but because of higher power then small obstructions of a non metallic nature will be ok? (so would that include a few rooftops to prevent putting up a huge mast?)

Also I've found the following (too good to be true in price) bridge:
clicky
So do I need 2 of these to make a connection or could one end just have a standard wifi card?

Sorry for all the questioning but I've never even looked into wireless before and googling for info isn't amazingly resourceful

Thanks a ton or two.

Dolbz

khel · Tux's lil' helper Joined: 07 Mar 2003 Posts: 80

Dracnor · Guru Joined: 08 Jun 2003 Posts: 397 Location: Pennsylvania

Yes, if you did have a lot of trees in the way, it may impede the signal. That is why you use a booster/amplifier

In terms of a point to point bridge I was referring to something that creates a backbone:

http://hardwarecentral.dealtime.com/xPO-Proxim_ORiNOCO_Point_to_Point_Radio_Backbone_Kit_Wireless_bridge_700002485~FD-96292

This one's expensive, but you can probably find ones that are cheaper than this kit.

You can think of this point to point as another way to connect to buildings together (instead of strining wire or fiber optics).

/B

samokk · Posted: Fri Jun 13, 2003 1:40 pm Post subject:

since we're speaking about wifi, I'm wondering about something....

is there a difference between a commercial Access Point, and a Linux Box + WiFi card ?

sam