Wireless link between two buildings

Lemo

I'm looking to create a wireless link between small networks in two buildings, about 150m apart with clear line of sight. I'm starting from scratch. I'm basically trying to share a broadband connection between two holiday homes. Any security concerns are external and I plan to use MAC address security.

The easiest thing might be to use a pair of wifi access points with 4-port hubs to create a bridge. I have a Linksys WAP54G lying around that I would like to use if possible.

Some questions...

- What sort of aerials (and boosters?) might I be likely to need? I would prefer to use directional antennas between the buildings. Any suggestions?
- Can the wireless APs that are creating the bridge also act as APs to wireless clients in their vicinity?
- If I use MAC address restrictions as my security do I need to worry about anything else other than people sniffing the unencrypted wireless traffic?

Thanks.

Gone West

Now. this is a nice project.
I set up a bunch of network similar to thid myself.
I find that a pair of satellite dishes either attached as antanea to the access points does the job pretty good. Or If youre feeling adventurous, get a pair of USB wifi dongles, and mount them at the focal point of the satellite dish(for mega gain). These dongles can then be attached to any server you have on the network, and you can make a software bridge.

Or you could use 2 access points. If you access point has 2 antanae, you can attach one to the sector/parabolic/dish/any directional aerial. And you can leave the other as an omnidirectional for use in the buildings.

"Boosters" Operating an unlicsensed networkat 2.4*ghz is fine, as long as you dont try to amplify the signal. Any strength under 250ma(IIRC) is fine. This will be a point to point link, so unless you are thinking of having radio in between the two points which recieves and retransmits the data, boosters are out.

Ill include a basic jpg of the setup.
You will most likely need 2 seperate wireless access points acting in all directions, and 2 seperate access points acting in the 150M link.
This is because an external antenae simply focuses the signal, decreasing its strength in other directions, but focusing the signal in one direction, and sometimes 1 plane.


any questions, feel free to pm me or post it up, Im sure we'll be able to help.


**EDIT: forgot about the encryption question.
Why dont you use WEP encryption? Its compatible with everything, barely slows the network down and is actually quite good. Its nowhere near as easy to crack as people claim. Especially if you use MAC address filtering, and mabye even disable SSID broadcast.
Another point to note is that random people must be within the area covered by your network to be able to get access to it.
Thats why using a pair of satellite dishes will work great. They really concentrate the signal, and in a single plane. So a wardriver/cracker must be pretty close to the actual line of sight between the link. If your dishes are mounted on the 1st floor of higher, this will make it almost impossible for anyone to crack your network.

Lemo

Thanks for such a detailed reply. Very helpful.

The sat dish idea is very interesting but I need to keep things quite neat so I don't mind buying a couple of directional antennae. That said, if money's tight I've seen one made from a Pringles carton :-)

It sounds like I might be able to use that old Linksys WAP54G because it has two antennae so I could use one for local access and another for the link. Maybe getting another Linksys AP would be a good idea.

I really can't see anybody spending days (or even hours) bothering to crak the network so I'll use WEP and MAC addresses.

I'll do some tests over the weekend to test the signal strength along the path between the two houses to get an idea for how much help I will need to get a decent radio signal going between them.

Thanks again.

Gone West

http://www.stelladoradus.com/

This is a good irish shop for antanas.
Try to steer well clear of the pringles yagi.
Whilst a great novelty and all, it is unreliable. You will most likely need a wall-mounted antena.