I've been testing on the 5Ghz range, currently iwlist wlan0 channel only allows (EU):

Channels 1-14 (2.4Ghz)
36-48 (5.18Ghz - 5.24Ghz)
149-165 (5.745Ghz - 5.825Ghz) - These are not allowed in EU!

It should be capable of the following (http://www.alfa.com.tw/in/front/bin/...egory=105483):
5.150-5.350 (Channels 34-64)
5.470-5.850 (Channels 100-165)

These are dependent upon country but channels 48-116, 132-140 should be available to Europe and America but are not showing up with current drivers. They have some restriction to do with dynamic frequency seleciton and tranmission power control between 52-140 but I'm not sure if thats why they aren't being picked up by drivers.

In Windows 7 it detects up to channel 64. Fails to see 100,116,136 (the highest my router will go to).