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Community Member

connect 3 buildings with wireless

I have 3 buildings I want to connect with wireless and I am looking for the best solution. Building A is 6/10th of a mile from building B and C. I have an antenna between B and C. All three sites can see the Antenna. Can you give me a solution.

bldg. B

bldg. A--------6/10Mile------ ^


Building B does not have a direct line of site to building C or A but all three can see the antenna. Thanks for any help with this.

Cisco Employee

Re: connect 3 buildings with wireless

If I understand you correctly there is NO line of site between the buildings but you are using some kind of antenna mast and there is a line of site between these. That is ok as line of site is Antenna to Antenna.

If there is a direct line of sight from the 2 sites to the 3rd then the best solution is to use BR350's in a point to multi point set up.

If A can see B but not C and C can see B but not A or some other combination then the best design is



------------ is a radio link

---|--- is a ethernet link (could be a cross over cable)

You could replace the 2 Bridges on B with one Bridge in Repeater mode but this will half your throughput and will not provide you a LAN connection into building B if you need that.

You will need to do a full site survey to work out the best option. You should never expect to run a reliable radio link if you do not do a site survey, in my opinion a site survey is NOT optional but a vital part of the installation process

Community Member

Re: connect 3 buildings with wireless

Building A B and C cannot see each other but they all can see the mast. what type of antenna will I need on the Mast. The mast is 180 degrees between B and C and 90 degrees between building A. Thanks

Cisco Employee

Re: connect 3 buildings with wireless

This sounds like a case that will need a site survey to give 100% sound answers to your questions.

My suggestion would be to consult a intergration partner for this as every environment has challenges that can not be seen in a forum like this and only people on site will be able to fore see these challenges

For example on your mast a omni direction may do the job or you may find that it will not give the range needed and you need to use 2 bridges on your mast to cover the 2 areas. A site survey will reveale this.

I am sorry that I can not give you a direct answer

Community Member

Re: connect 3 buildings with wireless

The real ? is how far are the builds from the mast. You will want to put up a Vertical or omnidirectional antenna. This will give you a pattern of , well a donut. Some have more of a degrees down than others.

At the Buildings you will need a Yagi or dish (parabolic). These will give you a tear drop pattern, with the big end going to the target.

This makes the mast the head end. Your network should be off of this, or some router or switch. As the antenna will not regenrate or pass on the building to building. It has to regenrated back out of the mast to all, for others to hear.

Now, 2500 + feet to the mast? . Your power output, antenna gains and the length of your cable. All pay a big part. FCC rules play to.

O'Reilly has a great book on 802.11x

Cisco is coming with one in March '03

Good luck and take your time. Power in mW's is everything!!

Phil Muller

INAP Field Eng.

Community Member

connect 3 buildings with wireless

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