[Make-wifi-fast] tweak tx-power to make wifi sta prefer 5G

[Erkki Lintunen <ebirdie@iki.fi>]

Antoine Beaupre blogged: <https://anarc.at/blog/2022-04-13-wifi-tuning/>

> After listening to an episode of the 2.5 admins podcast, I realized 
> there was some sort of low-hanging fruit I could pick to better tune
>  my WiFi at home.

One gets my attention, though, a fading thought, could there be any left?

> So I was surprised to hear one of the podcast host say "it's all 
> about airtime" and "you want to reduce the power on your access 
> points" (APs). It seemed like sound advice: better bandwidth means 
> less time on air, means less collisions, less latency, and less
> power also means less collisions. Worth a try, right?

Right. Have heard that before. Old news coming, perhaps?

> 2. Power

...

> On 5GHz, power was about 20dBm (100 mW) -- and more on the Turris! --
> when I first looked, so I tried to lower it drastically to 5dBm 
> (3mW)just for kicks. That didn't work so well, so I bumped it back up
> to 14 dBm (25 mW) and that seems to work well: clients hit about
> -80dBm when they get far enough from the AP, which gets close to the
> noise floor (and where the neighbor APs are), which is exactly what I
> want.

> On 2.4GHz, I lowered it down even further, to 10 dBm (10mW) since it's
> better at going through wells, I figured it would need less power. And
> anyways, I rather people use the 5GHz APs, so maybe that will act as an
> encouragement to switch. I was still able to connect correctly to the
> APs at that power as well.

What?! Why haven't I come to think about that before... Chasing my way 
to the knobs of my AP.

Both 2.4GHz ja 5GHz radios were already set to 10dBm, not left to auto. 
All associated stations were listing on the 2.4GHz radio. Moved 5GHz 
radio power to 14dBm just to see, how it affects the list. Immediately 
most associated stations moved to the 5GHz radio. There are couple 
only-2.4 sta's in my wifi network, those ought to not move, I think.

Thank you Antoine! Very nice. Me thought, wifi-dog old enough not to 
learn new tricks. And so simple not to need 802.11r, .11k... .11v. 
Veeery nice, indeed.

May this little effective tweak discovery give joy to some other as well.

Best regards,
Erkki