40MHz question

[freshwater]

Can someone explain what are the advantages of using higher MHz, we have option of 20, 20/40 and 40 on the settings.

 

[connorm]

first i will go over 2.4 - where 40MHz is normally not recommended unless you have almost 0 neighboring networks. then i will quickly over 5GHz where you should almost always be using 40MHz

1 2.4GHz Channel (ex. channel 6) @20MHz gives you 75mbps of theoretical throughput. assuming you stay on channel 6. and you go to 40MHz, another channel will be used. you get to choose whether it is the upper channel (something like channels 8-9) or if its using the lower channel (channels 3-4)

adding 2 20MHz channels like 6+9, 6+3, 6+4 or 6+8 is how you get 40MHz channels

you got 75mbps for 1 channel @20MHz. so you create 2 channels like i said above. bring them together to create 1 big channel and you get a total of 150mbps link. the device connecting must support 40MHz channels tho and if not it will probably just grab the main channel and have a 75mbps link @20MHz rather then 150mbps link @40MHz.

so depending on how many spacial streams your router has (2 seems to be standard now. 3 is also commonly available and what i use, with 4 stream router coming soon)

so if you have a 300N router that claiming it has the potential to create 1 40MHz channel for 150mpbs throughput. and then having 2 separate spacial streams sent through 2 separate antennas doubles this 150 to 300N.

just like how u needed the device to support the 40MHz. you will need the device to support 2 spacial streams aswell.

so 2 streams @20MHz = 150mbps. 2 streams @40MHz = 300mbps

if you had 3 stream it would be @20MHz = 225mbps. 2 streams @ 40MHz = 450mbps.

as i said earlier you probably dont wanna use 40MHz on 2.4 unless you are in an area where you have almost no neighboring routers. but by all means try 40MHz if you want. but 2.4 wasnt originally designed for 40MHz and 5GHz was. in 5GHz i recommend always using 40MHz as i believe each channel is a full 20MHz apart so unless someone is using 1 of the 2 channels you are on you shouldnt see problems. also since 5GHz has less range. interference is even less common

hopefully i made sense. if not sorry. lol

 

[freshwater]

^^ thanks for your detail info, make sense to me..
I have 20Mhz for 2.4 and 40Mhz for 5.0.

I do see 6-8 networks in my neighborhood.

 

[connorm]

glad i could help enjoy your wifi.