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Ronoboogie's avatar
Ronoboogie
Aspirant
Jan 02, 2017
Solved

In general should the 20/40 coexistance box be checked?

New Nighthawk R7800, In general should the 20/40 coexistance box be checked?  I've seen some posts that say yes but others say no. I noticed that it was checked while reviewing the default setup configuration. Thanks    

  • In general, yes, it should be checked.  Wi-Fi standards require that routers support 20/40 coexistence, which is functionality to ensure that routers fall back to using 20 MHz wide channels either when devices request it or when neighboring Wi-Fi networks that overlap with the current channel are detected.  Disabling coexistence can interfere with these functions.

     

    Note, that the 20/40 MHz coexistence mechanism only applies to the 2.4 GHz band.  Unless you live in a rural area with no other Wi-Fi networks present, there's no point trying to use 40 MHz channels at 2.4 GHz.  A 40 MHz channel uses 2/3rds of the frequency spectrum available at 2.4 GHz, which is very unneighborly.  You would be better off using the 5 GHz band, whenever possible, because 40 MHz channels are allowed, even 80 MHz.  You also can take advantage of 802.11ac Wi-Fi which uses superior modulation schemes for overall faster speeds.

     

4 Replies

  • Yes, you should. It's called a "Good neighbour policy". You can clobber other 2.4ghz wifi user's in your neighbourhood, with interference. Here's an SNB discussion on the subject. In this instance, take the narrow band! (20mhz)..

  • In general, yes, it should be checked.  Wi-Fi standards require that routers support 20/40 coexistence, which is functionality to ensure that routers fall back to using 20 MHz wide channels either when devices request it or when neighboring Wi-Fi networks that overlap with the current channel are detected.  Disabling coexistence can interfere with these functions.

     

    Note, that the 20/40 MHz coexistence mechanism only applies to the 2.4 GHz band.  Unless you live in a rural area with no other Wi-Fi networks present, there's no point trying to use 40 MHz channels at 2.4 GHz.  A 40 MHz channel uses 2/3rds of the frequency spectrum available at 2.4 GHz, which is very unneighborly.  You would be better off using the 5 GHz band, whenever possible, because 40 MHz channels are allowed, even 80 MHz.  You also can take advantage of 802.11ac Wi-Fi which uses superior modulation schemes for overall faster speeds.