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WiFi channels - why only 11 of them?
Posted: 08 May 2012, 08:36
by GodfatherB
Hi,
I have noticed (with 2.3 update) that the number of WiFi channels got reduced from 13 (or 14 I am not sure) to 11 now.
I just updated to 2.4.2, hoping to have this resolved, but no such joy. I am suspecting now, since noone reported any similar problem, that this has something to do with my configuration.
I have B3 2TB WiFi. I use 2.4 GHz n + g Wireless. I can only choose among first 11 channels. I would like to use 13, since it is the most isolated from other WiFi singals in the area.
Any ideas of what I could do?
Re: WiFi channels - why only 11 of them?
Posted: 08 May 2012, 10:01
by RandomUsername
I'm not near my system to confirm what I've got, but some countries only allow usage of channels up to 11 (USA for example) so that would be why they're missing.
Re: WiFi channels - why only 11 of them?
Posted: 08 May 2012, 13:08
by fereous
I too was wondering about this. My old Linksys WRT54G router (which the B3 now has replaced) had 13 channels in the standard firmware. I'm located in Sweden.
Re: WiFi channels - why only 11 of them?
Posted: 09 May 2012, 02:02
by GodfatherB
Well, as I said... when I got my unit (december last year), it had all the channels. At that time it was on firmware version 2.2.x.x. This only changed with 2.3.x (I think) and latter.
It would be great if some of you could check the possible channels you have, and a statement from Excito representative would be welcome as well... if this is a known issue of course.
Re: WiFi channels - why only 11 of them?
Posted: 09 May 2012, 11:06
by johannes
Yes, this is a good question. We know we had 13 channels before, then we did a major update of the wifi system and then we got 11. We haven't had time to dig into why yet, but it is related to the reg-database with is the matrix of allowed frequencies for all the geographical locations. We have it set up as a bug report and will look into it as soon as we can.
Is this urgent or making things difficult for you? Asking so I know how to prioritize.
Re: WiFi channels - why only 11 of them?
Posted: 09 May 2012, 13:30
by GodfatherB
It's difficult to say, since I can't use the channel 13 to make a comparison.
At the far end of the appartment I am catching a stronger signal from my neigbhour that is set to channel 9. The throughput is quite lower (and it breaks up quite often) at that particular point, so it might have to do something with it.
Re: WiFi channels - why only 11 of them?
Posted: 09 May 2012, 15:31
by jallee
GodfatherB wrote:It's difficult to say, since I can't use the channel 13 to make a comparison.
At the far end of the appartment I am catching a stronger signal from my neigbhour that is set to channel 9. The throughput is quite lower (and it breaks up quite often) at that particular point, so it might have to do something with it.
So it does not work to edit hostapd.conf ?
Just try and change the channel= line to " channel=13 " and then restart hostapd.
Re: WiFi channels - why only 11 of them?
Posted: 10 May 2012, 03:21
by Gordon
Manually inserting channel 13 won't work.
return from 'dmesg':
Code: Select all
[ 26.388934] ath: EEPROM regdomain: 0x60
[ 26.388943] ath: EEPROM indicates we should expect a direct regpair map
[ 26.388960] ath: Country alpha2 being used: 00
[ 26.388967] ath: Regpair used: 0x60
and return from 'iw list'
Code: Select all
Frequencies:
* 2412 MHz [1] (22.0 dBm)
* 2417 MHz [2] (22.0 dBm)
* 2422 MHz [3] (22.0 dBm)
* 2427 MHz [4] (22.0 dBm)
* 2432 MHz [5] (22.0 dBm)
* 2437 MHz [6] (22.0 dBm)
* 2442 MHz [7] (22.0 dBm)
* 2447 MHz [8] (22.0 dBm)
* 2452 MHz [9] (22.0 dBm)
* 2457 MHz [10] (22.0 dBm)
* 2462 MHz [11] (22.0 dBm)
* 2467 MHz [12] (22.0 dBm) (passive scanning)
* 2472 MHz [13] (22.0 dBm) (passive scanning)
* 2484 MHz [14] (22.0 dBm) (passive scanning)
So what this says is that the NIC's hardware is programmed to support roaming on every possible frequency but can only be an AP on world-safe frequencies. Now apparently you can write a driver that ignores this 'advisory' setting, and being on Linux this is not really much of a challenge (and you can do it yourself because the driver is loaded as a module). Problem is that the driver (and crda) as it is also doesn't do what it is supposed to do; e.g. my local regulatory domain (NL) should have imposed a further limit to disallow channel 14, but it doesn't.
Some additional reading can be found here:
http://smorgasbord.gavagai.nl/tags/atheros/
Re: WiFi channels - why only 11 of them?
Posted: 10 May 2012, 10:03
by jallee
Thanks for the info Gordon and for the informative link.
Re: WiFi channels - why only 11 of them?
Posted: 16 Jul 2012, 17:37
by philgaskin
Is there any update on this? I was using channel 13 too and although everything is working on channel 11, it is not as reliable for me as channel 13 was; probably because nobody else ever seems to use channel 13 in my area.