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I'd like to have a network connection between two buildings, but can't use wires so I'm looking into other solutions:

  • Are there some sort of directional WIFI antennas that I can place in the outside of the building and are durable to heat/rain etc?

  • Long time ago I had read an article about Free Space Optics, have these things been in production use?

  • Any other ideas?

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How far apart are the buildings? Do you have a clear LOS between them? –  Oesor Aug 28 '09 at 17:58
    
Why can't you use wires? –  endolith Oct 11 '09 at 17:45

8 Answers 8

up vote 4 down vote accepted

The antenna type you're probably looking for are called yagi antennas; directional antennas to help focus your signal. They can be a pain to aim sometimes though.

Make sure you have proper grounding or you're going to have a nice and expensive lightning rod.

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Do you know of any examples? I've never seen a yagi for the frequencies used by wireless network devices. –  John Gardeniers Aug 14 '09 at 21:59
1  
cantenna is a type of yagi...netscum.com/~clapp/wireless.html –  Bart Silverstrim Aug 14 '09 at 23:11
    
    
    
Avoid yagis for outdoor use. If you're located anywhere the temperature drops to freezing, they can get coated in ice and detune. While a radome helps, quality yagi antennas with a radome tend to cost as much as an equivalent gain panel antenna, and are more unwieldly to install and align. –  Oesor Aug 28 '09 at 17:57

There are alot of hacks online that deal with sending wireless internet across long distances. Some of them are even simple and affordable, but I dont know how reliable.

By 'cant use wires' I assume that you cant run wire from building to building.

I would recommend obtaining internet service for both locations and setup a VPN/VLAN-type connection. My company manages a few setups like this and they all work perfectly, like being on a LAN.

There is a free piece of software that will accomplish this, although I would hesitate to use it permanently. Its called Hamachi and is here: https://secure.logmein.com/products/hamachi/vpn.asp?lang=en

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+1 for the VPN suggestion. Just seems like it would be easiest to do VPN tunnel between the two location's firewalls and not have to go shopping for the wireless gear. –  Chris_K Aug 28 '09 at 17:55

I recommend giving serious thought to getting a consultant for this. A few factors that come to mind in choosing the right wireless solution:

  • Line of Sight: Some frequencies go through things like trees better than others if the wave is longer.
  • FCC Licensing Concerns (USA): You need a approval to use certain frequencies, if you want a tower you might need permission from the local government as well. If it is not licensed, someone else could start using your frequency as well.
  • Cost: The equipment required to chose the right solution is often expensive, which is why a consultant might be good.
  • Existing Wireless Noise: If you live in an area with potential noise on that frequency, you might not get good quality.

Unless this is a really small shop, the cost of consultant will probably be worth the risk of a wrong decision when you are talking the price of good wireless networking equipment. Wireless networking is a pretty complex topic, at least, seems that way to me.

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Go to Blackbox. Years ago they helped me with RF Wireless Bridges to connect to buildings, that my company leased, so we could not pull cables underground. We were able to create a 3-5 MBs connection between the buildings. This was in the late 90s so I'm sure things have gotten faster. Talk to a Sales Engineer, they really knew what they were talking about, and helped specify the correct antennas, and lighting arresters for our application.

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+1 for Blackbox. Been using them for a decade, perhaps 2. –  Knox Aug 14 '09 at 18:45
    
The other thin Blackbox is great for is custom cables, if you need to replace a cable, and everybody tells you that they've never seen anything like it, Blackbox will make it for you. You can specify the connectors, the pin-outs, and the cable length. Very Cool. –  BillN Aug 14 '09 at 23:45

If you're looking for a high-throughput connection, that is very reliable, and you're willing to spend the money, consider a Bridgewave AR60. It can do 1 Gbps traffic across short links, and can be set up with redundant equipment.

We were considering linking two buildings across the street from each other, and a VPN over public internet wouldn't cut it due to speed and latency. We decided on a Bridgewave AR60 connected with a Motorola PTP600 as a backup/failover link. It was quite impressive, but the quote totalled over $45000. The project was cancelled though, so I can't say exactly how it would perform.

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You may want to look into other wireless techs if available in your area.

  1. PTP microwave - really cheap using dis-continued Sprint network equipment ($50 = 2+ miles)
  2. Laser PTP - faster, no FCC licensing required, less lawsuits than radio or microwave
  3. Infrared PTP - wider beam than laser, better for tall buildings or trees in line of sight, no FCC licensing required
  4. BRI or whatever your telco calls it these days. It's a PTP leased line between buildings. Used to be real popular. Probably cheaper to install another ISP and VPN between the two. Useful for admin and security concerns keeping external access (internet) in one location only.

Check with you local laws and regulations. Many areas don't allow radio or microwave near schools, high density living, etc.. It's often done illegally anyway and can open you and company up to a class-action lawsuit later.

I prefer infrared but have used microwave often for tradeshows, fairs, concerts, etc.. Microwave is easier to setup and align. Infrared is faster and less regulated.

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