Why Channels 1, 6 and 11?

By now you’ve probably learned that selecting the proper Wi-Fi channel can significantly improve your network coverage and performance. But perhaps you don’t know why you should choose between channels 1, 6 or 11. Currently, many wireless routers automatically select the channel for you upon initial setup, and eventually this leads to slow Wi-Fi speeds and interference. This article will describe what interference you're dealing with and takes you through the steps to selecting the right channel.

There are three main causes of Wi-Fi interference: Co-Channel, Adjacent-Channel and Non-Wi-Fi interference:

Co-channel - Every client and access point on the same channel competes for time to talk. Adjacent-Channel - Every client and AP on overlap channels talk over each other. Non-Wi-Fi - Non-802.11 devices compete for medium access

Co-Channel interference isn’t a huge deal until the point when there are too many Wi-Fi devices on the same channel. Adjacent-Channel interference on the other hand is where you run into problems and channel selection becomes critical. Luckily,these channel related interference can be reduced or eliminated by selecting the proper Wi-Fi channel for your network with inSSIDer. Ultimately, this will improve your 2.4 GHz Wi-Fi network performance.

Each channel on the 2.4 GHz spectrum is 20 MHz wide. The channel centers are separated by 5 MHz, and the entire spectrum is only 100 MHz wide total. This means that the 11 channels have to squeeze into the 100 MHz available, and in the end, overlap.

20 MHz wide channels

However, there are three channels that don’t overlap: 1, 6 and 11, as you can see in the image below. Co-channel interference is where devices take turns talking, so the more devices on one channel, the longer it takes for a device to talk since it has to wait for its turn.

Channels 1, 6, & 11 don't overlap.

Armed with the above information, you’ve narrowed your selection down to three channel choices (1, 6 and 11) without using any software! Using inSSIDer will help you visualize the networks to finalize your decision. If you want to get more in depth about the types of channel interference, check our Webinars. The dual-band slide will give you more information.

The great thing about inSSIDer is that it will automatically recommend the optimal channel for you. It’s also easy to do on your own, just launch inSSIDer, and start out by counting how many networks are active on each channel. The first step is to click the “Channel” header to sort the channels in order. What you are looking for is the channel (out of 1, 6 and 11) that has the least amount of networks present. If there are several networks on each of these channels, you will want to choose the network whose average RSSI (signal strength) is -75dBm or lower. An RSSI at this level or below indicates that the conversations being held by the access point(s) aren’t very loud. A good rule of thumb to remember is that the closer to -20dBm a signal is, the stronger it is.

MetaGeek inSSIDer Screenshot

Notice in the above image that the network called “bba” is running on channel 9, which is overlapping channels 6 and 11. There is only one active network on channel 1, and its signal strength is very low. If you are deciding which channel would be the best for a new access point, channel 1 has the fewest amount of networks and there aren’t any partially overlapping networks. In this example, the best channel to choose is 1.

Don’t forget that inSSIDer 4 and inSSIDer Office both provide you with a recommended channel automatically. As your wireless environment is constantly changing, inSSIDer will keep you updated on which channel is best. You can read how to easily find the recommended channel in inSSIDer as well as the Knowledge Base.

Using inSSIDer to help you choose which channel to run your wireless network on is one of the best things you can do to improve Wi-Fi performance. On the other hand, if you're still experiencing issues with your network, there are more advanced techniques for combating wireless issues that Chanalyzer or Eye P.A. can resolve.

Again, more information and other helpful facts are located on our Knowledge Base where you’ll find a variety of FAQs, documents, videos, webinars, etc. that will help you on your way to becoming a Wi-Fi pro!


Small Office

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