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Wireless connection between two buildings

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Squires
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I'm looking to setup a wireless connection to connect 2 LAN's in 2 seperate buildings to make a single LAN(a church office and a school office). What I need to accomplish is:
1. be able to share files between the 2 offices
2. the church office has a DSL connection, the school office will need the wireless connection to connect to the church office LAN and be able to use the DSL connection there.

The two buildings are about 150-200 feet apart, there are some trees in between. If that will cause too much interferance, it could be setup to go from the church office, to the church, the church then has clear line of sight to the school office.

What wireless devices would best accomplish this? Would 2 access points do the trick, or is something more needed? Is it possible to set this up indoors, or will outdoor devices be needed to ensure a consistent connection?

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cmwood
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Is there any direct line of sight between the 2 buildings?

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zeroth
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Well, you are just over the distance curve regarding the use of an inexpensive wireless setup. It probably could be done but without paying for a site survey, you would just have to try it. The distance is only a matter of available bandwidth, though.

You need to be more explicit about a couple of points. How many users (computers) are on the two networks. If you go up on the roof, can you see a clear path between the buildings, or are the trees just under you or what.

If you mount antennas on the roof, even if there is a clear line of site between them, you can still experience interference from trees. If you imagine the space between the antennas as being an elongated football with it's two points at the antennas, that is the fresnel zone. Within this fresnel zone, anything that intrudes will cause interference (so the trees can be below the line of site and still be a problem). Now, with the distance being so short (for radio bridges or routers anyway) you can afford some interference, if the number or users is not great.

The total cost of such a bridge or router radio system can be in the $2-3K range, depending on the quality of the radios and antennas (these range widely in price) so if that is in your budget, let us know.

Having stated that, you might get away with the inexpensive setup if your user number is small. Having never set up an access point bridge, I can't give you detailed help on that. But it will probably have to be 802.11b rather than g. g will not give you the range you want with 54Mbps but your internet connection isn't going to give you anything like that speed anyway.

Here's another idea also. You can get adapter cards that use external antennas, which when mounted on the window can give you access. Or you can use a normal antenna but when you start this, you could end up more expensive than the bridge radios. But anyway, you wouldn't have to use but one access point. Again, the whole things hinges on how many computers you are going to be using, so...let us know.

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Libertate
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There are a ton of inexpensive solutions out there.

First, search for non-licensed outdoor bridges. You can get one with a directional antenna for about $1,500. It will reach without problem at least 3 miles. I know D-Link, Terabeam, RadWin, RadioLAN, 4RF, etc makes some.

These bridges are all made for outdoors, and will definitely span your 200 feet. Some of the bridges also provide ports for voice channel transfer too. i.e. you can plug some trunk or station ports on one end and out comes on the other end. Some even work with various PBX and digital systems.

Alternatively, purchase two directional antennas, and connect them to standard, generic, vanilla, run-of-the-mill bridges. A single directional antenna will cost you from $30 to $75, and will work with almost any bridge that has removable antenna. Make sure the cable between the bridge and the antenna is as short as possible and is the right kind. You can push it as far as a mile.

I would seriously reconsider using wireless at such a short span. A very very simple way to create a 50Mbps link is taking two SDSL (note : SDSL) modems and run a single pair of cross connected wire between them. This will work for several thousand feet!

I have done the following with great success - ordered "dry lines" between two locations from the Telco. These lines are simply a pair of copper wires, and they are physically connected to each other at the CO, with no electricity or any devices, or services connected to them. The last time it was $9.99/month on each end. I twisted on end, slapped two SDSL modems on their ends, and I got a 24Mbps link between two locations about 3000 feet apart. One catch is both location have to be from the same CO. In your case this is true since they are so close.

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cmwood
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If you have line of sight between the 2 buildings an access point with an external omni antenna about 12dbi and a wireless bridge with an external antenna either omni or directional same dbi will work fine. You can use about 20 feet of pigtail or antenna lead to move the antenna around for line of sight and the access point and bridge can be anywhere on your respective lans. Should be able to accomplish for around $350.00

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BobCochran
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I'm trying to do exactly the same thing as Squires -- I need to set up a wireless link between 2 buildings about 400 feet apart. This is my first wireless project of this type. It does not look like I will be able to get a line of sight between the antennas. Numerous trees and 2 rows of concrete buildings stand between the transmitter and the reciever. The reciever sits in the shadow of a taller concrete building. I've already purchased a 12 dBi omni antenna for the transmitting location and did a firmware upgrade on the access point (a Linksys WRT54G version 2.0). I wasn't able to broadcast enough signal for the reciever (who is just one person in a laptop computer) get a connection. I didn't realize that both the transmitter and reciever need antennas. Also I didn't appreciate the need to get the access point outside in a weatherproof box and keep my coaxial cable runs short. (I have a 50 foot length of LMR 400 cable connected to the WRT54G). I'm wondering how to proceed.

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zeroth
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I need to set up a wireless link between 2 buildings about 400 feet apart. --- I've already purchased a 12 dBi omni antenna for the transmitting location --- wasn't able to broadcast enough signal for the reciever.

An omni antenna doesn´t have a lot of distance because it´s broadcasting in all directions. If you are only broadcasting to one receiver, you are wasting all that power.

In any case, you can go around a building with a simple relay point, which is just two access points connected by a short ethernet cable and two antennas pointing the opposite directions (actually at both connection APs). With this range, you can just use very cheap parabolic (directional) antennas to relay the signal.

Also I didn't appreciate the need to get the access point outside in a weatherproof box and keep my coaxial cable runs short. (I have a 50 foot length of LMR 400 cable connected to the WRT54G). I'm wondering how to proceed.

As I´ve explained above, if the connection is that important, though a trifle more expensive, it will work. If you have a weatherproof AP, then you can run powered ethernet cable up to the box (this run can be a hundred feet or more without losing signal strength, and then the antenna is mounted just above the box, because that distance is critical to power.

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tahaora
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Thank you Mr.Zeroth

I have big broject to connect a wireless in new hotel containing 7 big roof
and i need 4 access point in every roof
how can i connect that, give me your advice plz
thank you

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popepius
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i want to connect two buildings together on wireless points, can any one give a good option. the building are 10mile apart.

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mjdodd
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A word from experience on a similiar problem was actually solved and very reliable by using ethernet cable! I know if you haven't got access for a cable then wifi, but over distance cable and repeater / routers can be a very cheap and reliable solution.
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