Channel 40 cannot set under 11ac 80MHz

Dear All,

im trying to set a qca9880 radio to channel 40 with 80Mhz bandwitdh, but after save&apply, i saw its working in channel 36.

btw: is it posible that disable all dfs channel?


An 80 MHz signal covers all 4 channels of the lower block anyway.

If you set a fixed channel outside of the DFS range, it will stay on that channel and not change frequency.

Dear mk24,

idont know why just 40 cannot set.. ive testted all others channel, seems all right..

i mean is it posible to disable dfs channel in driver and luci, so that user cannot set them at all.. some fcc problem


This thread might be very helpful: Linksys WRT3200ACM only transmits with 20 MHz on the AC radio

It addresses:

  • Why you see 36 when set to 80 MHz
  • Information regarding DFS and regulatory settings

Incorrect, many countries require DFS, not just the US-FCC. Changing some radio configurations (e.g. DFS) can cause your device to transmit with a configuration that is illegal, causes interference, etc.

If you're allowed to use WiFi without DFS in your nation, that will be configured by changing the country setting.

Dear lleachii

I'm curious about why other channel can set ( 44, 48,52,56 ....) but only 40 go back to 36

i saw the hostapd.conf generate by, there`s nothing different. is that shoud be and ath10k bug?


Channel 36 pairs with channel 40 to allow 80 Mhz with 802.11ac

Called channel bonding.