Hello!

I would like to change the bandwidth of the channel I'm using, channel 1 of 802.11g, from 20MHz to 10MHz. But I'm not able to get it, I'm using Backfire 10.03.1 on a tp link WR1043ND. I have tried the following without success.

1- Change the maximum bandwidth that the channel can use defined on the regulatory bin, but it doesn't work. I mean, I have changed the parameter

however, when I measure that the bandwidth is always the same, the point is that I cannot understand how I can set  channel 14 but not changing the bandwidth, if the proccess for changing the parameters is the same.

2-I have gone to this directory

in which is chnbw, and I tried to change it but it didn't work either....

On the other hand, reading in dev.openwrt.org I've found the following post https://dev.openwrt.org/browser/trunk/p … ?rev=31347, where is 512-ath9k_channelbw_debugfs.patch that I guess it's for changing the bandwidth, could I install that patch in my router?? Likewise, I have found another patch https://dev.openwrt.org/changeset/31954 which is to force the atheros chip to use the regualtory.bin that I set,I think.

My configuration is

config 'wifi-device' 'radio0'
    option 'type' 'mac80211'
    option 'macaddr' 'xx:xx:xx:xx:xx:xx'
    option 'htmode' 'HT20'
    list 'ht_capab' 'SHORT-GI-40'
    list 'ht_capab' 'DSSS_CCK-40'
    option 'disabled' '0'
    option 'channel' '1'
    option 'txpower' '10'
    option 'diversity' '0'
    option 'hwmode' '11ng'
    option 'chnbw' '1'
    option 'country' 'NL'

config 'wifi-iface'
    option 'device' 'radio0'
    option 'encryption' 'none'
    option 'ssid' 'it-ah'
    option 'mode' 'adhoc'
    option 'network' 'wlan'

Thanks in advance!!!!!

(Last edited by ndarkness on 10 Aug 2012, 07:46)

That is not supported by mac80211/ cfg80211.

It is possible on trunk through the chanbw parameter but certainly not in backfire.
Valid values for chanbw are 5, 10 and 20.

Hi!!
I have to say that I have achieved to change the bandwidth of the channel using Backfire 10.03.1. What has to be done is changing the value of the file called chanbw, if you set this variable with 0x0000000a the bandwidth changes to 10MHz, and if you set 0x00000005 your bandwidth will be 5MHz.
Here a proof wit chanbw=0x0000000a

Greetings!

(Last edited by ndarkness on 13 Aug 2012, 18:36)

Any guys can clearly the 10MHz is defined in 802.11 spec,i read it but don't find anything.I only see the 20MHz and 40MHz.

The 10MHz and 5MHz bandwidth channels are defined under the term "channel spacing"on the 802.11-2007 standard, on page 593(802.11-2007 standard)

Regards!

(Last edited by ndarkness on 29 Aug 2012, 09:49)

Thank you so much!

Some times ago i check the 802.11-2009:
http://standards.ieee.org/getieee802/do … n-2009.pdf
But it's seems it remove the 5MHz and 10MHz compare with the 802.11-2007,do you know any story about this and why remove it?

PS:
I wait to read the 3000 pages 802.11-2012,more info you can read this:
http://blogs.aerohive.com/blog/the-wi-f … 80211-2012-

No, I don't. Indeed, before reading that version of the standard, I had already read the 802.11g,802.11n & 802.11a in order to lool for these kind of channels... Another curious point, it's that the standard only refers to the 5GHz band and not to the 2.4GHz, and I don't know why either.

regards!

(Last edited by ndarkness on 30 Aug 2012, 07:59)

It looks like it should be possible usign "option chanbw", also this ticket is good resource:
https://dev.openwrt.org/ticket/14916