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tparker
Asked: 2022-04-12 06:48:58 +0800 CST

Is there a way to check whether my device is currently using the 2.4 GHz or 5 GHz WiFi band?

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If my Ubuntu device is connected to a dual-band WiFi SSID that uses both 2.4 GHz and 5 GHz WiFi, then my understanding is that it will automatically switch between the two bands depending on which one has a stronger signal/better data rate. Is there any way to check which band my device is currently using?

Ubuntu 20.04.

wireless

1 Answers

  1. Best Answer

    If your router is set, by default, to use the same network name (SSID) and login credentials and your wireless card is capable of both bands, then the router will, indeed, automatically switch as it deems necessary. Please check:

    nmcli device wifi list

    One of the listed networks will have an asterisk next to it * indicating it is in use. Here is an example from my machine:

    IN-USE  BSSID  SSID  MODE   CHAN  RATE   SIGNAL  BARS  SECURITY
    xxxx  GBR1   Infra  11    540 Mbit/s  99      ▂▄▆█  WPA2 WPA>

    •   xxxx  GBR5   Infra  149   540 Mbit/s  92      ▂▄▆█  WPA2 WPA>
  xxxx  --     Infra  3     130 Mbit/s  74      ▂▄▆_  WPA2    >
  xxxx  DIRECT-Infra  149   130 Mbit/s  67      ▂▄▆_  WPA2

    I have redacted the BSSIDs (MAC addresses). As you see, I am connected to GBR5; its channel is 149, indicating it’s a 5 gHz channel.

    You can also find out with:

    iwconfig

wlp3s0    IEEE 802.11  ESSID:"GBR5"  
          Mode:Managed  Frequency:5.745 GHz  Access Point: xxxx  
          Bit Rate=866.7 Mb/s   Tx-Power=22 dBm   
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=67/70  Signal level=-43 dBm

    As you see, the frequency is 5.745 gHz, obviously a 5 gHz frequency.

    Because 5 gHz is always faster, I recommend that you rename the segments of your router; something like myrouter2.4 and myrouter5.

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