5 GHz Frequency – How Many Non-Overlapping Channels?

ieee 802.11

So I read that the 5 GHz frequency (in the EU) can have 19 channels without overlapping. The 5 GHz frequency goes in the EU from 5.150 to 5.725 GHz, so total 575 MHz. The width of one channel is 20 MHz. 575 MHz / 20 MHz = 28,75 ~ 28 Channel.

I also don't get where this site has this channel partition:
https://www.welotec.com/files/CMS%20Landingpages/5ghz-kanalverteilung-80211ah-1.jpg

(From 5,150 GHz to 5,350 GHz with 20 MHz channel-wide, i'll get 10 channels + From 5,470 GHz to 5,725 GHz with 20 MHz channel-wide, i'll get 12 channels)

For 19 channels, each channel should have a channel-wide of ~ 30,25 MHz (575 MHz / 19 channel)

Edit: Ok i see we have unused channels between channel 65 – 99 (5320 – 5500 MHz). Why are these unused?

Best Answer

This Wikipedia article has a table to summarize that:

enter image description here

Note that

The wide of one channel is 20 MHz

is a false assumption. A channel can be 20, 40, 80 or even 160Mhz wide. So the actual number of non-overlapping channels is dependent of the width used.

we have unused channels between channel 65 - 99 (5320 - 5500 MHz). Why are these unused?

This is the U-NII-2B band, which is not allocated for unlicensed use by the FCC not the ETSI, so cannot be used for WiFi.

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