WLAN Green horn request for help

[jameade]

I have been tasked to install some Cisco Aironet 350 Access Points. We are utilizing our Raduis server for authentication at a site connected via 3MB WAN.

I've been told that I can only have 3 access points at our site because of site survey that was performed. The reasoning was that we are only able to utilize channels 1, 6 and 11, with 100Mw tansmit power.

Our building is 200' X 350 '. From testing we have been able to cover almost 50% of our building with one access point.

Why can't I use all 11 channels?

Thanks for your patience.....

[pries]

You actually are using all channels. There is an overlap of channels and ultimately, you only get 3 distinct channels that you can use in one area (or cell) that don't interfere with one another. 1,6, and 11 are the only channels you would practically use if you're using 3 or more APs in a deployment.

[blue.modal]

With the right antenna configuration, you can create a coverage 'cell' of any size and shape (well, up to a 1 mile radius).

As long as you have 75 users or less, your 3 APs (and the right antennas) should give you good coverage. The other response on channelization is correct - the overlap in the 802.11b spec only gives you three channels that you really want to use. Actually, the truth is worse than that because of the side lobes - see www.bluemodal.com/spectrumcal.pdf for a visual.

If you need help getting the right antennas to give you bullet-proof coverage from your APs, let me know.

Matthew Wheeler

Chief Wireless Architect

www.BlueModal.com