Re: [Madwifi-devel] CHANNEL_HALF / CHANNEL_QUARTER. Changing channel Bandwidth. Help...

[John C. <jc...@me...>]

Douglas Diniz schrieb:
> Hi, i'm working in a project that is using madwifi driver. We need to 
> change the channel bandwidth, but we saw that there isn't a iwpriv 
> command that do this. So, we began to code the new comand.
> After studing the driver, we saw that CHANNEL_HALF and 
> CHANNEL_QUARTER  should do the thing. I get the last driver on the 
> branch svn, with Hal 0.9.30.13 <http://0.9.30.13>.
> To test this feature, i forced the flags in function ath_chan_set. I 
> did this:
>
> hchan.channelFlags |= CHANNEL_HALF;

A few months ago, when the HAL was released that supported the 
half/quarter channel options, I setup a FreeBSD system
to have a look.

It seems to me, that at the moment, these options are only valid for 
those devices that can operate in a couple of
'regions'. One region being the 4.9 'Public Safety Band'. I did not see 
any region, and I cycled through them all, that
appeared to permit/allow a configuration of narrow bandwidth in the 2.4 
region.

I have not followed up with how Madwifi has been modified to select the 
narrow bandwith options, even
when a supporting region has been selected.

About a year ago, I got all excited about a Ubiquiti(*) 900 MHz 
interface, which alleged to also support the 5/10 MHz
bandwidths, but then read the 'fine print' which seemed to suggest that 
only one particular version of 'linux', with
some alternative drivers, was required to really support these options.

What bothers me most about this, is I'd rather just have the HAL itself 
as the only dependency on 'binary only'
distributions. I'd rather keep up with versions of Linux that I choose, 
and not have to 'wait' for a linux
release from some entity, on their own schedule, because I'm dependent 
on their binary driver.

And of course, it goes without say... or maybe not... that the Chip can 
be setup to have narrow bandwith options
in the 2.4 band, and not violate some FCC rule of use in the band... but 
Atheros has been pretty unsupportive by
not giving those who do have access to the source of the HAL sufficient 
documentation, to allow this type of
configuration.

*Someone here did make contact with someone at Ubiquiti, but there was 
virtually no follow up in terms of our
technical questions. I tend not to promote companies that don't follow 
up on requests for technical info on their
products.

John Clark.