Wi-Fi Antennas and equipment

[mwidner]

I searched the threads and found some items "close" to this, but felt I needed to start a new thread.

I work in a park which has a building where our DSL line comes in and we have hooked a LinkSys WRT54G wireless router. We have an area in front of the building where park volunteers park their RV's and beyond that another building with an office etc. There are a few trees to one side, but no others.

We want to put up an omnidirectional wi-fi antenna (since there are 1 or two employee trailers "behind" the building housing the DSL.)

My question is, will the LinkSys router, then connected to a WAP54G and then to an outdoor 12dBi omni-directional antenna be pretty much all that we need in terms of equipment?

I realize that we need to do a site survey etc. but having never installed an "outdoor"" wireless system, I was unfamiliar with the equipment part of it. We cannot afford anything over $500, so we're hopeing this will do the trick.

Thanks in advance.

 

[americanmcneil]

A couple of points,

The WAP54G is NOT and outdoor unit. The Linksys outdoor unit is the WAP54GPE and from my experience with about 20 of them, they are NOT reliable.

My suggestion would be this, keep your Linksys router inside, get a Deliberant 2100 2.4GHz radio (these are outdoor units with good solid case, easy to use interface, solid documentation, good support and run about $180 or so). Mount this outside and if you get the right omni antenna (N-Male connection I believe but I would have to double check) it can mount directly to the case. Run outdoor Cat5 from the Deliberant to the Linksys which will control DHCP and internet access.

Tadaaa... outdoor wireless for well under your $500.00 budget!

Scott "Thrown to the Wolves" McNeil

http://www.epproach.net

 

[DrGreen26]

You may want to invest a little more money and get a commercial grade access point and either have it be designed for outdoor use, or put it in a NEMA enclosure. Make sure you also include lightning protection as this is required by the NEC for outdoor RF. You cannot install it without it.

As for the antenna, though it is true that the receive sensitivity is identical to transmit power, you still have to keep in mind that this is 802.11. In other words, you also need to consider the transmit power of your clients. Since the receiver is truly the access point, you want to make sure your clients can get back to the AP and not just hear it. This is a design mistake that many people make, put a high gain antenna on, but if you would imagine this.

Suppose you and another person stand on each side of the grand canyon. One with a bull horn (high gain antenna) and one without. The person without the bull horn can hear the person with the bull horn quite easily, but when the person without the bull horn communicates back, the one with the bull horn cannot hear him. This is essentially what happens in the 802.11 world. Your clients will hear the AP but the AP will not be able to hear your clients if they are too far away.


Mark C. Greenwood, CNE, CCNA, BICSI II


With more than 16 years experience to share.