I'm wondering if I limit my channel width on a really nice (Meraki WAPs capable of 802.11ac) WAPs, to 20 MHz to stop them from overlapping, or if the Auto Width channel setting is making that change. if the limit of 54 Mbps will be reached. Or, is there something about the newer 802.11n protocol that allows for faster bitrate, even with that 20 MHz wide channel, and we've disabled 2.4 GHz radios.

For reference to the theoretical limits I speak of, this is one resource, but I'm not sure about what happens if you've turned off the 2.4 ghz radio use.

My reading of it is that by limiting an 802.11ac capable device, to 5 Ghz and to 20 MHz width, you're effectively downgrading 802.11ac to 802.11n 1X1, and the limit is actually about 72.2 Mbps, but I'm not sure I'm deducing that correctly.



1 Answer 1


Other than the addition of 256-QAM [MCS 8], and (optional) 5-8 streams, you are correct. 802.11ac's advantages are small when limited to 20MHz. In the 5GHz band, there's no real reason to limit it to 20MHz. There's plenty of channels and not a lot of overlap. (which is why 160MHz is even possible)

[See Also: Data Rates and Speeds Table (Wikipedia)]

  • 1
    It's true that there a lot more channels, but if one is avoiding DFS range, at 80 MHz , and even 40 MHz, in a crowded RF space, it starts to feel pretty limited. That's the context for my question, exploring how narrow to allow the channels of a 5 GHz radio network, with three floors right on top. So, thanks so much for your input. I think 20 MHz is a no go, but some of the waps were auto-correcting to 20 MHz, which I'm theorizing was causing at least some of the throughput tests to return under 70 Mbps. Wired is normally 200 mbps.
    – beauk
    Commented May 8, 2018 at 13:12

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