802.11a/n

[Grant]

>> What a drag. ?So no Linux AP is capable of operating on any 5Ghz channel?
>>
>> For when I travel outside of the US, EU, and Japan, can this be
>> overridden with a kernel patch? ?If so, is such a patch available?
>
> I presume this is driven by the CRDA regulatory stuff? (Please correct me?)
>
> If you are using some modern distro then it's probably done in userspace
> using the crda service (more on the wiki). If you are building your own
> then you can compile into the kernel your own regional settings (ie what
> *you* are allowed to use) by editing: linux/net/wireless/db.txt

I switched to kernel control of regional settings and channels without
editing db.txt and the channels which are supposed to work in the US
without DFS started working: 36, 40, 44, 48, 149, 153, 157, 161, 165.
I noticed in dmesg I had:

cfg80211: Calling CRDA for country: US

Switching back from kernel control to crda again disabled all 5ghz
channels and in dmesg I only get:

cfg80211: Calling CRDA to update world regulatory domain

I noticed that the channel allowances for country 00 match what is
enabled for me under crda.  The kernel must set my country to US and
crda must set it to 00.  I'm using crda-1.1.1 and
wireless-regdb-20101124 which are Gentoo's latest versions.  Does
anyone know what could be wrong?  Are these packages created by
Gentoo, meaning I should file a bug with them?

> However, my reading of the DFS stuff is that it applies to only *some*
> of the 5Ghz channels. ?OK, yours are disabled, but is it not possible to
> implement a 5Ghz AP in the uk if you avoid the DFS channels of 5250-5350
> and 5470-5725?

I think you're right.  Please see above.

- Grant