Jul 25, 2013

Why are channels “x+7” available for some WiFi networks?

I asked a question yesterday about choosing a wireless WiFi channel. Thanks for the help, btw! I downloaded WiFi Analyzer for my Android phone and installed inSSIDer on my PC. The two worked great together to not only identify a better channel than I was using, but also to learn that moving my AP about 3 feet made a huge difference in signal strength. However, when analyzing channels, there were a couple signals that were showing channel 11+7, which covered a large portion of the available channels (1-11). Mine didn’t. How are some people able to select a 7 channel spread?

Some interesting info on wifi channels here:


"802.11b, 802.11g, and 802.11n-2.4 utilize the 2.400 – 2.500 GHz spectrum, one of the ISM bands. 802.11a and 802.11n use the more heavily regulated 4.915 – 5.825 GHz band. These are commonly referred to as the "2.4 GHz and 5 GHz bands" in most sales literature. Each spectrum is sub-divided into channels with a center frequency and bandwidth, analogous to the way radio and TV broadcast bands are sub-divided.

The 2.4 GHz band is divided into 14 channels spaced 5 MHz apart, beginning with channel 1 which is centered on 2.412 GHz. The latter channels have additional restrictions or are unavailable for use in some regulatory domains."

What you are seeing is the march of progress. They must have an 802.11n compliant AP. You probably have an 802.11g device.

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