Switching band of a dual-band WiFi device

[Christian Gagneraud <chgans@gna.org>]

Hi there,

I am using a TP-Link TL-WDN3200 on a ubuntu 13.04 (kernel 
3.8.0-27-generic), and I have install relevant modules with 
backports-3.11-rc3-1.

I would like to switch my WiFi stick to 5GHz, I tried iwconfig wlan0 
freq 5G, but I get ENOTSUPP.
Is the freq settings suppose to handle this 2.4 vs 5GHz band or is it 
only for selecting channel frequency within a given band?

Does linux-wireless provides a way for selecting 2.4 or 5GHz band?

"iw phy phy11 info" tells me that in band 2, all the frequencies are 
disabled except:
                         * 5745 MHz [149] (30.0 dBm)
                         * 5755 MHz [151] (30.0 dBm)
                         * 5765 MHz [153] (30.0 dBm)
                         * 5775 MHz [155] (30.0 dBm)
                         * 5785 MHz [157] (30.0 dBm)
                         * 5795 MHz [159] (30.0 dBm)
                         * 5805 MHz [161] (30.0 dBm)
                         * 5825 MHz [165] (30.0 dBm)

As well, my understanding of WiFi might be a bit limited but, does a 
dual-band WiFi device provides 2.4 and 5GHz services at the same time or 
do I need to select one or the other myself? Or maybe I can just 
enable/disable them manually (and separately)?

Hope someone can shed some light at this.

Regards,
Chris