WiFi networks and channel selection

OK, it’s been a while since I’ve waxxed all techie here at HoodaThunk? so I figure I’m due. Today’s topic: WiFi networks and the importance of channel selection.

Most home users of WiFi tend to not worry about the radio channel their wireless routed is using. The router is usually smart enough to seek an unused channel by itself. The problem crops up when there are so many WiFi routers in the area that there is no unused channel. Let me show you what that looks like. This picture was taken by my Kindle Fire’s WiFi analyzer app:

image

While the are 11 channels in the radio spectrum space permitted for WiFi, only 3 of them don’t overlap, channels 1, 6, and 11. Almost all wireless routers out there will aim for those channels and you can see that in this graph. The different routers are assigned different colors and you can see their transmission arcs rising to different levels, the higher the peak the stronger the transmission. This reading was taken near an apartment complex and there are something close to 2 dozen routers showing here. So many of them are on the middle channel (6) that that arc is turning white. What does that do?

A good way to picture WiFi is to imagine having a conversation in a crowded restaurant. Everone’s talking and you can only hear you dinner partner because they are closest and their voice is “louder” than anyone else. But, the same volume would be understandable from much further away if the other conversations weren’t going on.

In wireless that means your range is reduced the more people are sharing the same channel. Routers can look for channels with no other transmissions, or lower-power transmissions but they can’t really tell if there are a bunch of users on the channel at the same power, like what you see above.

If you’re not getting the range out of your router that you used to, you might need to help it out and try another channel.

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