What's the best Wi-Fi channel to use?
There are 11 channels available in the 2.4GHz Wi-Fi. Some channels overlap and interfere with the channels on either side of them.
Example: channel 6 actually spans across channels 4, 5, 6, 7, and 8 while channel 3 spans across channels 1, 2, 3, 4, and 5.
This means that if you select channel 3, you will get interference from other Wi-Fi devices using channels 1 and 6. If you want to avoid the congestion, choose 1, 6, or 11 since these three channels don't overlap with each other.