I have a WiFi access point at my place.

I used this App - WiFi Analyzer App to check the signal strength and the channels which I am using.

While using, I had this question which google was not able to provide an answer.

Question :

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If you check the above image - Mine is the Last peak occupying channels 9-13.

I am connecting only my mobile to my WiFi. So, why is my WiFi using 4 channels (From Channel 9 to Channel 13) to transmit the information to my connected mobile device?

Or in general, what does the width of the channels actually indicate? If I connect 5 or more devices to my WiFi access point, does the WiFi access point use more channels?


2.4GHz Wi-Fi uses channels that are 20MHz (or 40MHz) wide, but the channel center frequencies are only 5MHz apart, which means channels can overlap. It's best practice to limit your 2.4GHz APs to using only 20MHz-wide channels, and putting them only on channels 1, 6, and 11, so that they don't overlap.

Your network is using a 20MHz channel. It's on channel 11 so its center frequency is 2.462GHz, and it extends 10MHz above and below that. So its lower edge is at 2.452 GHz, which happens to be the center frequency of channel 9, and its upper edge is at 2.472 GHz, which happens to be the center frequency of channel 13.

If you set your AP for 20MHz channel width, it will always use 20MHz-wide transmissions. Then number of clients has nothing to do with this.

Using 40MHz-wide channels allows for twice the throughput. Said another way, twice the radio-frequency bandwidth allows for twice the bits-per-second bandwidth. However, the 2.4 GHz band isn't very wide overall, so using 40MHz-wide channels doesn't leave enough room for Bluetooth and other users of the band.

  • Thank you for the answer. But the Bluetooth using Frequency hopping, right? So, it won't be that much a problem for bluetooth to operate on the WiFi band itself right? – Newbie May 16 '20 at 8:38
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    @Newbie Bluetooth hops all over the entire ~80MHz-wide band. Taking up half the band for a single Wi-Fi network hurts that. Originally it didn't have the ability to avoid interference, but now it has Adaptive Frequency Hopping, but having only half the band (or less due to neighbor networks) is still too little. – Spiff May 17 '20 at 1:04

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