How do I find out if my wireless card supports 5 GHz?

Question

I have the

03:00.0 Network controller: Intel Corporation Centrino Wireless-N 2200 (rev c4)

How do I find out if that card/driver support 5 GHz?

Solution 1

Find out the interface name, by running iwconfig

$ iwconfig
eth0      no wireless extensions.

lo        no wireless extensions.

wlan0     IEEE 802.11bgn  ESSID:"EvanCarroll"  
          Mode:Managed  Frequency:2.437 GHz  Access Point: D8:50:E6:44:B2:C8   
          Bit Rate=19.5 Mb/s   Tx-Power=15 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=61/70  Signal level=-49 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:1  Invalid misc:80   Missed beacon:0

In this case it is wlan0, then run iwlist <interface> freq,

$ iwlist wlan0 freq
wlan0     13 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
          Current Frequency:2.437 GHz (Channel 6)

None of these channels are outside of 2.4 GHz. It does not support 5 GHz.

Solution 2

If you're trying to discover what your card supports, iw phy is a nice solution with a lot more information (including supported bands).

iwlist is showing more what's available and/or allowed in your locale, what was disabled due to DFS channels, etc., not what your device supports. From the iwlist man page:

   freq[uency]/channel
          Give  the  list of available frequencies in the device and the number of defined channels. Please note that usually the
          driver returns the total number of channels and only the frequencies available in the present locale, so  there  is  no
          one-to-one mapping between frequencies displayed and channel numbers.

Comments

[Admin]

Related: How to set wifi driver settings to prefer 5 GHz channel above 2.4 GHz

[derobert]

It'd be nice if you also showed how to do this with the iw tool as well. I think the others are possibly considered obsolete...

[stef]

right. iw phy shows detailed capabilities. beside of this you may also find wifi cards that are capable of 5ghz, but the driver isn't.

[Daniele Segato]

and does this means the Linux driver does not support it or the card itself does not? Or to rephrase it: can this mean the driver simply does not support it?

[Brandon Condrey]

@DanieleSegato I am unsure of how to answer that. The whole thing is predicated on there being a card with specific bands not supported by driver. That may exist. However, it sounds theoretical and it's another question.

[Brandon Condrey]

That's simply factually incorrect, as 802.11n /can/ support 5ghz, even though it isn't require to support 5ghz by the spec.

[toliveira]

@DanieleSegato, I don't know that answer for your question, but you can check the manufacture's website if your are in doubt. For the OP, for example: ark.intel.com/products/66888/…. It says it is single band.

[Mark Twain]

What if before switching to Ubuntu I was using 5Ghz Wi-Fi network on same laptop on Windows and after installing Ubuntu iwlist <interface> freq displays only 2.4 Ghz channels?

[Brandon Condrey]

@colotiline it is totally possibly your wifi driver itself doesn't support 5ghz. I would be interesting in knowing your output to LSPCI, you should ask another question about that. specifically, "does <card> support 5ghz in linux"