On April 5, 2014 at 17:48, vwpower44 said...
There are so many channels because you may need them. we all know that WiFi should be on channels 1,6 and 11.
No, It shouldn't always. Just looking at what channels you see a system on, doesn't tell you enough to make good decisions. Until you know the signal strengths, you are likely to make bad decisions.
I ran into a problem the other day installing an Aruba system at a clients house. Their neighbors system was on 2 and 7. No other wifi was within range of the house. This meant that the best scenario for me was to throw all three access points on 11, or put them on 2 and 7. Since I had Sonos, I put Sonos on 11, and put the AP in the basement on 2, AP on first fl on 7, and AP on second fl on 2.
The reasoning for this is that Access Points can handle Co-channel interference much better than over lapping channel interference. I could have just gone to the neighbors and asked to adjust their system properly, but that wouldn't be right.
Since we really should only be on 1,6 and 11, it doesn't mean that we cant use the other channels. Using 1,6, and 11 allows you to utilize three channels without over lapping. You can use the other channels, but you would only be able to utilize 2 channels. If it was a high density area, this is not ideal since most people will be on 1, 6, and 11. Having the extra channels does allow you to compensate for other peoples stupidity.
I'm afraid you are one of those perpetuating the myths. For example in your example you assume the neighbor should have chosen 1, 6, or 11, yet at their location, they may be picking up signal you can't see at your location, causing the router to choose those other channels. Other possibilities are baby monitors or cordless phones that weren't on at that moment. The routers are pretty smart, and keep track of what sources they see. So having other channels available isn't about other people's stupidity.
Having channels spaced closer than the bandwidth allows to fit more communications channels that don't interfere in a given space, as it assumes there will be a large reduction in signal strength at the peripheral of the channel bandwidth. If you look at the communications spectrum used in these sytems with a spectrum analyser, you would better understand why the extra channels are present, and are not about fixing others stupidity. If it was only about fixing others stupidity, then there never should have been a choice of more than 3 channels. Using only 3 channels would necessarily reduce the number of possible communication channels, making the system work less well in crowded locations. This is why they engineered the system to have more channels. This is a pretty common technique in best utilizing spectrum.
