Hi
I just tried a second USB WLAN-adapter since the first one turned out to be atheros based. Guess what, the second one is also atheros based! 
My own personal guess is that dual band adapters are different in the US and in Europe due to frequency restrictions in the 5 GHz band. So we end up with different chipsets here in Europe. Can anyone confirm if this is the case?
So, if anyone from WD is reading this.
We really need Atheros-chip support in the wdtv live!
