I just bought an ar9170 usb network adapter since I'm running BT4 on VMware and had no luck with my integrated Realtek RTL8187SE. In case you're wondering, I'm running Vistax64 on an alienware m17.

After installing the drivers, I finally got feedback from the airmon-ng command:

Interface Chipset Driver

ath0 AR9001U Otus

Next was to try an airodump, to which I received:

ARP linktype is set to 1 (Ethernet) - expected ARPHRD_IEEE80211,
ARPHRD_IEEE80211_FULL or ARPHRD_IEEE80211_PRISM instead. Make
sure RFMON is enabled: run 'airmon-ng start ath0 <#>'
Sysfs injection support was not found either.

And finally, airmon-ng start ath0 9

Found 2 processes that could cause trouble.
If airodump-ng, aireplay-ng or airtun-ng stops working after
a short period of time, you may want to kill (some of) them!

PID Name
4601 dhclient3
4740 dhclient3
Process with PID 4740 (dhclient3) is running on interface ath0

Interface Chipset Driver

ath0 AR9001U Otus (monitor mode enabled)

But, airodump continues to say give the same response, and I can't get it to work. =\