The overlap is where the simplified explanation confuses people. Technically if people didn’t use channel 6 and instead used 4 or 8 you would have 4 channels, 1, 4, 8, and 11 that could be used that would not “overlap.” The problem with overlap is it is similar to distance and in ways works with or against distance. The closer your channel is to another channel the more overlap you have. But also the closer your distance is the more overlap you will have. So if you have a person 10 feet from you using channel 6 and you use channel 5 you might as well be both using channel 6 due to the overlap and distance being so close. Now if the two points are over say 100 feet away using channel 5 and 6 it would be similar to using a router on channel 1 and 6 that are only 10 feet apart in range. There will be little to no interference. That is why some people are experiencing huge gains from dropping 1 channel. On the flip side if there was truly zero overlap you could have two routers on channel 1 and 6 with antennas an inch apart and not see drops in signal quality, which is not the case. The case is that minor distance overcomes the overlap interference of the traditional 1, 6 and 11 channels or 1, 4, 8, 11 and that is why they call it non overlapping channels, 1, 4, 8, 11 take more distance then the 1, 6, 11 but not by much.

The reason you might be on channel 11 by yourself and experiencing very poor connections with no overlapping channels can be due to some of the outside interferences you cannot see with typical scanners. Using inSSIDer’s dBm to measure signal strength will show you interference levels in a channel but not tell you what is causing them outside of wireless a,b,g and n adapter.

Now with that being said, the reason you want to use 1, 6, 11 or 1, 4, 8, 11 is to avoid interference with others, call it wireless manners if you will. If you are close to someone and you are using channel 3 and they are also close to someone using channel 9 they realistically may not have a channel to use that wouldn’t experience some form of interference. Though realistically this won’t work in all residential situations as well as it does in an office that you control the entire wireless network for that area.

Often times I find in residential areas channels will be set on 1, 6, and 11. Often I will find that using 1, 6 and 11 will all resort in some sort of dropped signal. So I look for the two weakest interference channels. If 1 and 6 have the weakest signals compared to 11 I can offset it to say 4 to minimize interference and have the best performance. Which is probably similar to why some of you have experienced increases in performance on an odd channel. Though the flip side to this is that the interference from the amount of users in that area can amount to more than either using 1, 6, or 11. Typically this is never the case and just finding that sweet point where your signal is the strongest is all that it takes.

The following pictures show how signals fade through the channel spectrum.
http://img.tomshardware.com/us/myimages/NTK/superg_ntk_11b_adjacent_chans_alt.gif

http://img.tomshardware.com/us/myimages/NTK/superg_ntk_11b_1_6_11.gif

From the pictures you can see that technically 6 barely overlaps with 1 and 11.

If you use a non-overlapping channel, that’s arguably “the best solution”.

If you don’t then you may be causing problems for other folks (on the overlapped channels), but it might be “the best solution” (for you)

And, of course, proximity has a good deal to do with it.

In my case, NetStumbler worked for me, and it gave me the info I wanted/needed, and that helped me choose an “unoccupied” channel, and that’s working well for me.

That said, the issues of “noise” from “other devices” in the 2.4Ghz range is a related factor. I switched my 2.4Ghz phones out for 5.8Ghz phones, and that helped, too.

It has been working significantly better. No drops now in 3 days…

So, to any real RF experts out there… doesn’t my approach make more sense as it minimizes my overlap? Wouldn’t setting my channel to 1,6,or 11 result in total (100%) overlap of signal?

http://www.metageek.net/products/wi-spy-comparison

The lowest priced Wi-Spy is the 2.4i at $99