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Unread 31-01-2010, 13:22
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Re: Using non KOP router, possible cause of wireless communication issues?

Quote:
Originally Posted by Isaac501 View Post
Find out what networks are strong where the team practices. The networks will be on channels 1/6/11 (if the school IT people have any clue what they're doing). Pick another channel, preferably as far from (in channel number) from the networks present.
The reason they pick 1/6/11 is because of the way spread-spectrum radio works. The channel specified is the "home" frequency. The actual signal hops from frequency to frequency very rapidly across a range of several channels. It follows a known pattern, so the receiving unit can follow along.

The reason they pick channels 1/6/11 is that those are separated enough that they won't overlap and are always clear to each other. A unit on channel 1 won't reach up to the lower limit of one on channel 6, for example.

Putting another unit on in the 2-5 range at a distance where it is far enough away from the channel 1 or 6 unit will work, but if it is in close proximity, they will still overlap and interfere with each other.

In a school or other building where they want to saturate it with multiple access points, they will stagger them so if one unit is on channel 1, the next closest is on 6, then the next is on 11, then back to 1. If they are a couple hundred feet apart, by the time you get another channel 1, it is 600-1000 feet away from the first.

But if your router is right near a strong access point, you might receive interference on several channels. If you are between access points on all three channels, you might not be able find a channel that is clear.

But chances are you are only primarily being bothered by one and careful selection of the channel manually may help. Using a sniffing tool (Google Wardriving, or Netstumbler) might help you find out what is happening. I have also seen router firmware that shows you what "Neighbor" nodes it is hearing and the channels they are on.

Or, get a Type-N router...
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