802.11g connection w/o LOS

G

Gauvain

Limp Gawd
Joined
Apr 24, 2003
Messages
128
I am trying to determine what I would need to set up to connect my buddies apartment to mine. For connection sharing, LANning, ect.

Issue: His apartment, while only being about 50 feet away, is at a 60 degree angle to mine. The front of our apartments facing the apex of the angle.

I know that I could try bridging the two networks, but my friend doesn't want to run a cable from his living room, across the length of his apartment, to the kitchen window.

Now, I either need to find a:
1: passive antenna solution to allow the signal to make that hard left and just run a single network, or,
2: an active solution to bridge my wired network to his currently wired and soon-to-be wireless network without cluttering his house with cables. (S.O. would have a bovine).
3: Determine whether a single access point would work for the situation. I am dubious about this one due to the LOS issues.

Does anyone know of a passive solution that will handle that kind of a relay? If that grail can be found, I can run my wired network and forward through a bridge to his AP.

Thanks!

Gauvain
 
Originally posted by Gauvain
I am trying to determine what I would need to set up to connect my buddies apartment to mine. For connection sharing, LANning, ect.

Issue: His apartment, while only being about 50 feet away, is at a 60 degree angle to mine. The front of our apartments facing the apex of the angle.

I know that I could try bridging the two networks, but my friend doesn't want to run a cable from his living room, across the length of his apartment, to the kitchen window.

Now, I either need to find a:
1: passive antenna solution to allow the signal to make that hard left and just run a single network, or,
2: an active solution to bridge my wired network to his currently wired and soon-to-be wireless network without cluttering his house with cables. (S.O. would have a bovine).
3: Determine whether a single access point would work for the situation. I am dubious about this one due to the LOS issues.

Does anyone know of a passive solution that will handle that kind of a relay? If that grail can be found, I can run my wired network and forward through a bridge to his AP.

Thanks!

Gauvain
Click to expand...

A few things you may want to look into:

There are these things called "waveguides". They're basically designed to do what you need: Take a radio wave, and bend it around corners. If you Google a bit, you should find instructions for building one. A word of caution, however: When manufacturing antennas or anything else that interacts with radio waves, exact measurements are extremely important.
With a waveguide, you and your friend could use directional antennas, pointed at either side of the waveguide.

Citizens can amplify radio signals up to a maximum power of 1W. You might want to look into finding an amp. With an amp on the base station, connected to an omnidirectional antenna, and with your friend using an omnidirectional antenna as well, he shouldn't have too much trouble getting a solid signal.
 
Unfortunately, Googling waveguide ends up with a lot of articles on cantennas. While I have researched Cantennas quite a bit, it's a totally different premise than I am looking for.

Any other suggestions on how to find these devices and/or instructions on making them?

/edit

waveguides as discussed above, not cantennas

/end edit
 
Hm. I looked around, and couldn't find the reference I was thinking of. I do remember seeing a discussion of a waveguide to get around corners and such in either the BAWUG mailing lists, or the Seattle Wireless mailing lists.

That said, at that close distance, you may be able to get away without a waveguide. Microwave radiation (802.11b/g is microwave) diffracts around corners. So, with directional antennas aimed at a corner of a structure blocking the LoS between you and your neighbor, you should be able to take advantage of this.

Don't think in only two dimensions, either. You could diffract around the edge of a roof if necessary. :)
 
Would a simple reflctor work? Billiard shot with the signal off of a metal plate of some variety?

Am I getting too complicated with all the extra gear? I mean, I'm fairly certain we can get signal, but not the full possible speed, so all that's needed is a signal increase.
 
Just in case your are not familiar with this site

www.seattlewireless.net

they have a lot of links to different antennas and even have a mailing list where you could post this question. They have a lot of experienced Wi-fi guys. Good luck
 
Originally posted by Gauvain
Would a simple reflctor work? Billiard shot with the signal off of a metal plate of some variety?
Click to expand...

Could do, yes. Just make sure it's at least one wavelength in width, and one in height. (In fact, it may be best to make it exactly one wavelength in width and in height, or some integer multiple thereof, for best performance).
 
Apparently I have more problems that I thought. Two obstacles to Line-Of-Sight. The stairway leading up to my apartment is directly between the two windows!

This definitely means that I need an external antenna to get around impediment #1, then I still need to figure out how to get good signal to their PC's. New access point too, the antennas don't seem to come off of mine.

/sigh
/more sigh
/end sigh
sleel network diagram.JPG
 
Yes you are. Low power microwave, even amped or added gain with directional antennas may not penetrate what he is trying to get through. It might. Depends on a few things but if the stairs is cinder block filles with concrete then it most likely aint happening. Higher gain or more power can overcome some things but they're not cure-alls. Won't hurt to try it though it might cost him a few pennies. Homemade "cantenna" might be a solution and help with the cost.
 
The walls of the staircase are wood covered with that false flagstone slab that was used so heavily about 20 years ago. Not terribly signal transparent. With the single access point, I get about a 1mbps signal from my friends front door. No IP though.

I think I will try the cantenna route first, although about where the word "Stairs" is in the diagram there is a tree, so I might try my bounce trick from there with my first cantenna.

If I can convince the apartment complex that the cantennas and/or access points are ok under the provenance of satellite dish laws, this will be a much easier project.


If anyone else has any other suggestions, PLEASE fire away.
 
Well if you have money to burn, you would check out:

http://www.hyperlinktech.com/web/amplifiers_2400.php

1 watt should transmit through that wall unless you live in a rfi/efi shielded building... i doubt you do though..lol

A directional antenna like the ones at http://www.cantenna.com/ or a home made one will do the trick I would think... I would bet that the issue is more of a signal to noise ratio... If that is the case, the cantenna will do the trick. I just can not imagin any type residential construction causing this type of loss. Now, a conifer tree.... that can suck up the power! Those needles just happen to be the right wavelength.
 
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