On startup or resuming from suspend, it takes a pretty long time to activate, around 10 to 15 seconds.
On Windows it comes on instantly.

I posted on kubuntu forums (takes even longer on kubuntu) and was given this advice:
Code:
sudo sh -c "echo 'options ath9k nohwcrypt=1' >/etc/modprobe.d/ath9k.conf"
It didn't make any difference though.

Code:
Network controller: Atheros Communications Inc. AR9287 Wireless Network Adapter (PCI-Express) (rev 01)