Setting up wireless network

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eye_suc

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You know, decent information about wifi is pretty hard to come by on the net, or perhaps i'm looking in all the wrong places.

Anyhow, things i would like to know is what type of antenna to use in our situation, but cannot get a straight answer from anyone! Basically, its a 1.2km range connection with (i think) LOS. If there is anything in the way it would be some minor trees, nothing a few molotov coctails wont fix during the weekend.

Also, i tried to get hold of graphical representation of the beamwidth for the different types of antennas (basically wanted to see the area a antenna would cover). Hard to find, and the information i could muster was also sketchy.

Are there any decent links for learning these things the right way?

Thanks
 
20 dBi for 1.2 km?? Wow...

See, this is the problem I i thought we are gonna have. The sales people recommended 8dBi flat panels, or perhaps 14's if theres too much interference...

Yagi would be point to point type connection, right? And what would the beamwidth be of a medium strength yagi? Erm, or the broadcast area, or whatever you call it :/
 
There are two broad categories of atennae:

Directional, or semi/non-directional.

Directional antennae like Yagi's or Grids, or flat Panels, typically have a beamwidth between 18-40 degrees, depending on the model.

More nondirectional antennae like Sectors or Omnis range from 60 degrees to 360 degrees.

Your post didn't divulge a lot of information about your application, but from the sounds of it you're interested in a point to point link between two locations. For that application, directional antennae are almost always the best choice. So, go for a Yagi, or a Grid.

For a point to point connection through some obstructions, a directional antenna will probably serve you better, due to the fact that the signal loss over the distance will be much less.

It's like using a laser, versus a widebeam torch. 8db flat panels are essentially useless, I wouldn't even consider them.

In your scenario, I would recommend either two Yagi's or two 24DB grids. Unfortunately there's no "magic bullet" formula for saying which will work the best. This depends entirely on how much obstruction and interference there will be.

I can however say that the Miro 12Db Yagi's work quite well, and are quite cheap. This would be my first option for a short distance link of that nature. If the Yagi's can't make it through the obstruction, then 24db Grids are your next best choice. They're about double the price of the Yagis.

The length of cable between your antenna and your WiFi device will also be a deciding factor in the dBm rating of antennae you need. If you have a long cable, there will be much signal loss, and you will have to compensate for this with an antenna with a higher dBm rating. If the length of cable is short, then a lower rated antenna should do the job. Once again, there's no magic formula here. It depends on the kind of cable in use, the number of connectors involved, and the length of cable itsself.

Have a look at http://www.miro.co.za/ 's antennae section. They actually specify the horizontal/vertical widths of their antennae.
 
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do yourself a favour, give miro in CT a call. I have bought some stuff there and they are very helpful. They tested an X-Micro AP for me that i bought else where. (021) 555 3207. Rather have all the info before you go and purchase the hardware, rather expensive mistake. Climb up on the roof and have a look if there is line of site(LOS). Trees will effect the signal.
 
12dbi yagi's should do the job great, i am at current running a 1km link with them, los is the most important thing! i moved my one yagi about 4 meters back from the window, and things went to hell, stuck it back against the window and bananas!
my yagi's are from poynting(spelling?) they have a website in sa!
 
Ah, thank you kindly all!!! It helps to know people in high places ;)
/me bows down to TheRodent

Shouldve come to you guys first!

We shall give this a go and I shall report back after implementation.

And Mufasa, thanks for Miro's details, i'm dialing as we speak!

bboy, on the LOS issue. If there are some minor leaves from crappy trees in the way, will it make that much of a difference? We are gonna test this weekend in the dark if we have DEFINITE LOS by me jumping up and down on the roof with a mowerse big flashlight. Hope it comes out good!
 
well i have a row of bluegums in the way, they don't bother me much!
 
/me hugs bboy

Thanks for the info :) getting more confident by the minute
 
eye_suc,

Mossie and myself are currently busy with implementing a 7.3km link...

Should be possible with the right hardware... still in testing phase though...

and believe me, u need a moerse big torch.
 
hehehe, i believe you :)

we also gonna try the mirror thing, that might actually work better if the sun is high enough.

but with 7.3 km i think you should rather get a telescope
 
too far for a telescope.

We have a really long piece of string which we each tug on depending on signal strength... only problem is that it keeps getting tangled up at Makro.
 
We had success this weekend. We were able to connect at 2MBPS although the speed was very unstable.

The ping times were awesome, at an average of 4ms.

To attempt to fix this i will be adjusting my antenna a bit, we suspect its not 100% lined up. We also have potential interference with trees, but nothing that creative destruction cannot fix.

We were able to 1. Share internet access and 2. Play a nice long game of Soldat. Copying files were nearly impossible. We still trying to figure out why.

Thanks for all of your help guys, your inputs have been invaluable. We will soon publish all the things we have learned in this process, since we could not find a definitive collection of all this information. We shall find hosting and report back with the links. What a damn steap learning curve!
 
I had a similar problem with copying files over a Wifi link with samba ( Windows Shares).
Setup an FTP ,HTTP server to share files. Scp is actually the best. something a bit less prone to errors.
 
thanks bboy!!!! That is what we were hoping was the problem, for after we put away the ladders (was after dark already) we noticed the antenna was a bit skew. Will set that right this evening.

Crash, we tried ftp with a small file and that worked, but larger files (still sub 50MB) struggled. We wanted to transfer about 7GB, and failed. Will try again after we reset the antenna. And we will also look into SCP as well, thanks for the suggestions :)
 
Well, i tried jumping on the roof to adjust the antenna aim, but i proved much to short. Damn genetics!

So we just fiddled around with some settings. After our connection died when i got an SMS, we checked what channel we were on. Default 11. Or maybe we set it to 11, i dunno anymore, but after changing to channels 13 and 1 (we tried both) we had a solid connection. We tried up tp 18MPBS, and tonight we will try going faster.

Thanks for the help guys. Will keep posting our findings here.
 
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