Unable to set my channel with hostapd

Francisco Cuesta ndarkness at gmail.com
Mon Apr 29 05:24:43 EDT 2013


Hi Luciano,

Thanks in advance,

I have modified my regulatory data base for USA in order to be able to
use that channel

 iw reg get
country US:
    (2412 - 2484 @ 40), (3, 27)
    (4400 - 4940 @ 40), (N/A, 31)
    (4910 - 4990 @ 20), (N/A, 31)
    (5170 - 5250 @ 40), (N/A, 31)
    (5250 - 5330 @ 40), (N/A, 31), DFS
    (5490 - 5600 @ 40), (N/A, 31), DFS
    (5650 - 5710 @ 40), (N/A, 31), DFS
    (5735 - 6480 @ 40), (N/A, 31)

But even though, I was getting the same error, do you have another good idea?

thanks again!




2013/4/29 Luciano Coelho <coelho at ti.com>:
> On Mon, 2013-04-29 at 12:01 +0300, Luciano Coelho wrote:
>> Hi Francisco,
>>
>> On Mon, 2013-04-29 at 10:27 +0200, Francisco Cuesta wrote:
>> > Hello,  thanks for replying,
>> >
>> > I'm using ath9k driver in openwrt with hostapd v2.0-devel.
>> >
>> > iw reg get
>> >     (2412 - 2472 @ 40), (3, 27)
>> >     (5170 - 5250 @ 40), (N/A, 31)
>> >     (5250 - 5330 @ 40), (N/A, 31), DFS
>> >     (5490 - 5600 @ 40), (N/A, 31), DFS
>> >     (5650 - 5710 @ 40), (N/A, 31), DFS
>>
>> Here you can see that the channel you want to use is not allowed by the
>> regulatory code.  It seems that you're using "00" as the country
>> (world).  From the regulatory database [1], you can see that channel 196
>> (4980 MHz) is only allowed in Japan (regulatory country "JP").
>
> Forgot to paste the link to the regulatory database:
>
> http://git.kernel.org/cgit/linux/kernel/git/linville/wireless-regdb.git/tree/db.txt
>
>>
>> > iw list
>> >
>> > Frequencies:
>> >             * 5180 MHz [36] (17.0 dBm)
>> >             * 5200 MHz [40] (21.0 dBm)
>> >             * 5220 MHz [44] (17.0 dBm)
>> >             * 5240 MHz [48] (17.0 dBm)
>> >             * 5260 MHz [52] (17.0 dBm) (radar detection)
>> >             * 5280 MHz [56] (17.0 dBm) (radar detection)
>> >             * 5300 MHz [60] (17.0 dBm) (radar detection)
>> >             * 5320 MHz [64] (17.0 dBm) (radar detection)
>> >             * 5500 MHz [100] (17.0 dBm) (radar detection)
>> >             * 5520 MHz [104] (21.0 dBm) (radar detection)
>> >             * 5540 MHz [108] (21.0 dBm) (radar detection)
>> >             * 5560 MHz [112] (21.0 dBm) (radar detection)
>> >             * 5580 MHz [116] (21.0 dBm) (radar detection)
>> >             * 5600 MHz [120] (disabled)
>> >             * 5620 MHz [124] (disabled)
>> >             * 5640 MHz [128] (disabled)
>> >             * 5660 MHz [132] (17.0 dBm) (radar detection)
>> >             * 5680 MHz [136] (17.0 dBm) (radar detection)
>> >             * 5700 MHz [140] (17.0 dBm) (radar detection)
>> >             * 5745 MHz [149] (21.0 dBm)
>> >             * 5765 MHz [153] (21.0 dBm)
>> >             * 5785 MHz [157] (21.0 dBm)
>> >             * 5805 MHz [161] (21.0 dBm)
>> >             * 5825 MHz [165] (20.0 dBm)
>> >             * 4915 MHz [183] (21.0 dBm)
>> >             * 4920 MHz [184] (21.0 dBm)
>> >             * 4925 MHz [185] (21.0 dBm)
>> >             * 4930 MHz [186] (21.0 dBm)
>> >             * 4935 MHz [187] (21.0 dBm)
>> >             * 4940 MHz [188] (21.0 dBm)
>> >             * 4945 MHz [189] (21.0 dBm)
>> >             * 4960 MHz [192] (21.0 dBm)
>> >             * 4980 MHz [196] (21.0 dBm)
>>
>> This shows that the driver supports 4980, but it won't be able to use it
>> if the regulatory doesn't allow it.
>>
>>
>> > But, could you explain me the reason behing I get this error, I mean,
>> > what does it mean, for instance  problem with the interface, the
>> > channel isn't supported by the driver ..., I would like to understand
>> > it, not just resolve it.
>>
>> This is because the radio regulations in the country you're choosing
>> ("world" is a set of frequencies that is valid in *every* country)
>> doesn't allow WiFi operation on the channel you want to use.  You can
>> only legally use channel 196 in Japan.  So, if you are in Japan, you can
>> do this:
>>
>> iw reg set JP
>>
>> And hostapd should work on that channel.  If you're not in Japan, doing
>> this is not legal, so you should better choose a different channel
>> instead. ;)
>>
>>
>
> --
> Luca.
>


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