802.11a/n

Grant emailgrant at gmail.com
Mon Aug 15 14:30:37 EDT 2011


>> I'm using a Ubiquiti SR71-E 802.11abgn card and I've tried specifying
>> many different channels for 802.11a mode but I always get this error:
>>
>> wlan0: IEEE 802.11 Configured channel (36) not found from the channel
>> list of current mode (2) IEEE 802.11a
>> wlan0: IEEE 802.11 Hardware does not support configured channel
>
> It sounds like your card could be calibrated as a world roaming card and
> it does not allow AP mode to be started on 5 GHz channels. You can check
> the available channel list with "iw list". The channels that are marked
> "disabled" or "passive scanning" won't be available for hostapd to use
> in AP mode.

Something must be wrong with the config on my router.  I have two of
these SR71-E cards, one in my laptop and one in my router.  The one in
the laptop says:

# dmesg|grep cfg80211
...
cfg80211: Calling CRDA to update world regulatory domain
cfg80211: Calling CRDA for country: US
cfg80211: Calling CRDA to update world regulatory domain
...
# iwlist wlan0 channel
wlan0     20 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 36 : 5.18 GHz
          Channel 40 : 5.2 GHz
          Channel 44 : 5.22 GHz
          Channel 48 : 5.24 GHz
          Channel 149 : 5.745 GHz
          Channel 153 : 5.765 GHz
          Channel 157 : 5.785 GHz
          Channel 161 : 5.805 GHz
          Channel 165 : 5.825 GHz
          Current Frequency:2.462 GHz (Channel 11)

The one in the router says:

# dmesg|grep cfg80211
cfg80211: Calling CRDA to update world regulatory domain
# iwlist wlan0 channel
wlan0     14 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 14 : 2.484 GHz
          Current Frequency:2.462 GHz (Channel 11)

The thing is, I've tried switching them and the US card when installed
into the router no longer says "cfg80211: Calling CRDA for country:
US".  There must be some kind of a misconfig on the router but I don't
know what it could be.  I think it used to work properly and stated
CRDA US in dmesg on the router.  crda is installed and I have
country_code=US in hostapd.conf.

- Grant


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