Hi - I've just sent the following through to support but wondered if anybody could also confirm what I'm seeing please (probably relevant to 2865/2866/2927 owners I think) : -

I have a 2866Lac and 2x AP903's. All set to 20/40MHz Channel Bandwidth on the 5GHz range.

Regardless of channels chosen (i.e. auto-select, specified, etc) ALL wifi-scanners I have tried state that the 2866Lac is only utilising 20MHz channel bandwidth whereas the AP903's correctly show 40MHz.

Issue also existed on firmware 4.4.2 (and I suspect all previous firmwares).

I can provide screenshots if required although this ought to be very simple to confirm in-house.

Interesting.

What about 80Mhz? Do you get the same result?

Yes, nothing changes - almost as if the router can't actually do anything other than 20MHz.

I've also tried with 20/40/80 on a 2866ax (same firmware version 4.4.3) and that works correctly.

...and another thing I've just noticed is that when I make that change to the 5GHz band it kicks ALL clients off BOTH bands when the setting applies - why are the 2.4GHz clients affected ?

I noted in my post here https://forum.draytek.co.uk/viewtopic.php?t=24888 that with the setting on Auto 20/40 all devices connect at 20, whereas with the setting on 40 some connect at 40 and some still at 20. Odd.

Thanks for that - if you use something like WiFiman to scan the WiFi I am assuming you see the same as me then - all APs show 40MHz whilst your router is only 20MHz?

Draytek support came back asking if it was resolved...presumably by some magical means!

When I said not, they came back asking me to reduce the RTS Threshold to 255 on all three devices. Now to me this is a sure sign they've totally misunderstood the issue because as far as I'm concerned RTS Threshold and channel bandwidth aren't linked (unless somebody wants to tell me I'm wrong?)

I really need another 2866Lac user to test the issue for me....anyone?