I reported this to the linux-wireless list, thread available here: http://news.gmane.org/find-root.php?message_id=%3c4B5CB7AB.7010105%40bzz.no%3e One of the replies suggested installing CRDA (RFP #536502), which fixed the problem. According to Luis R. Rodriguez: "No, Atheros cards by default abide by a custom strict world regulatory domain if CRDA is not present."