Range of antenna to antenna 802.11b?

[Swanny]

Hello all. I've got a question a friend asked me on if a project he has in mind is possible. He'd like to be able to network his house to his office via 802.11b. He'd have 24dbi gain antenni on towers that are above tree level. The house and office are about 1 mile away. Is this possible? If so, he'd also like ideas on how to get the wire from the antenna down the tower and into the base station. Also, is the a certain brand of base station that's better for external antenna use?

Thanks a lot for your ideas!


Swan

 

[pyrobecks17]

I would say that it wouldn't work because there are many other wireless items such as cordless phones which operate on the same 2.4 ghs frequency's. You may look into a 5ghs wireless networking solution, I know that Linksys makes one, but even then a mile is a long way for a low powered antenna.

 

[Abzstrak]

look into getting cisco aironets on each end, and make sure you have a line of site connection between the two buildings.

You'll probably want to use a couple of dishes on each end, and if memory serves the aironets of sufficient software tools to line up the dishes.

its definitely possible.

 

[wlee]

With a clear "line of sight" and 24db gain on each end, he could get 20+ miles range. There is a guy out in Hawaii doing just that. I can't find the URL for his page at the moment though.

 

[JackMDS]

The following is an abstract from: http://www.craig-bartell.com/

Craig did a very nice job, and there is detailed pdf file of the Project.

?This paper was written in an effort to demonstrate the applicability of professional microwave engineering techniques to consumer wireless networks using unregulated spectrum by documenting the design and implementation of a 7-kilometer 802.11b bridge. The wireless revolution is in full force. The 802.11b standard adapted in 1999 created the first wireless standard to break through the important 10 mbps barrier. Shortly after adoption, inexpensive consumer wireless devices became widely available. At first, these were used for the predicted purpose of creating a local network at home. Later people discovered that using directional antennas allowed these devices to communicate over long distances. In a quest to spread the broadband revolution, some users started building point-to-point links several miles long. Many of these links were built using trial-and-error. However, the science of engineering microwave networks is not new. Professionals have been designing long distance links using regulated microwave frequencies for years. With improved scientific knowledge of microwave engineering, individuals will be able to create even more amazing wireless feats.?

Pdf file of the 7 killometer (4.3 miles) 802.11b Bridge.

 

[ktwebb]

24 dB antennas are ridiculously powerful for a one mile link. However, you will want to get above the trees as much as possible. Even with line of sight you want fresnel zone clearance. As for the cable run to the Bridge, it really depends on how high you go and what path it takes to the bridge. In other words, total cable length, tower and if it needs to snake into the house/office or control room. As a rule of thumb, we use LMR400 up to around 60 feet. After that we use LMR600 to a point. LMR900 or 7/8th are for extremely long coax runs. You'll need to have the cable premade unless you plan on making the connectors yourself and if your doing it right thats a few connectors because you will want to use lightening arrestors and grounding points. You can use Cisco bridges if money is no object They are far and away the best 802.11b bridges available but they are sold at a premium. 1000 bucks a piece new, give or take. At a mile with 24 dBi antennas you could use just about anything you wanted to with a good line of sight and fresnel zone clearance. Coax will introduce loss as will connectors which you will need to do anyway since even a 30 mW radio (15 dBm) puts you well over the legal transmission limit (36 dBM or 4W).