How to switch between 2.4 Ghz and 5 Ghz wifi

Issues related to configuring your network
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bonedome
Posts: 166
Joined: 2017/04/22 08:11:04

How to switch between 2.4 Ghz and 5 Ghz wifi

Post by bonedome » 2020/02/16 12:42:41

Hello
I had a new router on Friday and decided to check the default settings and noticed my laptop auto connects to 2.4 Ghz where all the smart phones in the house connect to 5 Ghz.
I am interested in seeing if 5 Ghz performs any better on my laptop, so spent most of the day trying to switch over.
According to

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iwlist wlp2s0 freq
my wireless card (broadcom BCM4313 802.11bgn Wireless Network Adapter, using wl driver) can use the 5 Ghz range.

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wlp2s0    32 channels in total; available frequencies :
          Channel 01 : 2.412 GHz
          Channel 02 : 2.417 GHz
          Channel 03 : 2.422 GHz
          Channel 04 : 2.427 GHz
          Channel 05 : 2.432 GHz
          Channel 06 : 2.437 GHz
          Channel 07 : 2.442 GHz
          Channel 08 : 2.447 GHz
          Channel 09 : 2.452 GHz
          Channel 10 : 2.457 GHz
          Channel 11 : 2.462 GHz
          Channel 12 : 2.467 GHz
          Channel 13 : 2.472 GHz
          Channel 36 : 5.18 GHz
          Channel 38 : 5.19 GHz
          Channel 40 : 5.2 GHz
          Channel 42 : 5.21 GHz
          Channel 44 : 5.22 GHz
          Channel 46 : 5.23 GHz
          Channel 48 : 5.24 GHz
          Channel 52 : 5.26 GHz
          Channel 56 : 5.28 GHz
          Channel 60 : 5.3 GHz
          Channel 64 : 5.32 GHz
          Channel 100 : 5.5 GHz
          Channel 104 : 5.52 GHz
          Channel 108 : 5.54 GHz
          Channel 112 : 5.56 GHz
          Channel 116 : 5.58 GHz
          Channel 120 : 5.6 GHz
          Channel 124 : 5.62 GHz
          Channel 128 : 5.64 GHz
          Current Frequency:2.462 GHz (Channel 11)
I have tried using network manager (originally set to automatic, so set that to 5Ghz) , but as soon as I click save it creates a new profile (same essid appended with 1) back with the default settings.
If I disconnect and do

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sudo iwconfig wlp2s0 channel 36
iwconfig shows 5.18 GHz but as soon as I reconnect iwconfig shows Frequency:2.462 GHz (Channel 11)
I also tried turning 2.4 Ghz off in the router settings, but laptop refused to connect.
After an enormous amount of searching there doesn't seem to be a lot of solutions (mostly ubuntu/windows stuff) on the web.
I wouldn't mind betting network manager is the problem here but no idea how to connect to the net without it.
If anyone can point me in the right direction, I'd love to hear it.

aks
Posts: 3007
Joined: 2014/09/20 11:22:14

Re: How to switch between 2.4 Ghz and 5 Ghz wifi

Post by aks » 2020/02/16 19:58:17

How to switch between 2.4 Ghz and 5 Ghz wifi
Generally you don't.
There's something called "band steering" in which your AP "tells" the connecting client to switch to 5GHz on channel X (if it can).
I am interested in seeing if 5 Ghz performs any better on my laptop
Interesting, do the same thing at a high frequency ... that's usually more about what other nodes are doing. To (attempt) to clarify, at home, 99% of people have a (crappy) consumer APs. They all default to 2.4 GHz (sometimes they have band steering on by default, but it's a "later" thing, so often it's nopt - for "maximum compatibility" - well it usually depends on when the hardware was made). Anyway, the 2.4GHz band is fairly crowded around here, so I've switched to 5GHz for all clients that can, and since that is practically empty, all my nodes can (almost) talk when they like.
Wireless is a shared medium (like classic Ethernet before the advent of switches).
If 5GHz is less crowded then performance "should" improve, but that has nothing to do with 5GHz itself.

Given some nodes "work" on 5GHz, but this particular node doesn't, perhaps the affected node can not do 5GHz on the channel(s) told (or ignores/has a really crappy implementation of band steering).

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