To enable Master mode in ath5k, do the following:

  1. Make sure you are running kernel 2.6.29 or higher. If not, you need to get the latest patches for ath5k.

  2. Install hostapd. It is available in Ubuntu repositories.

  3. Create a config file for hostapd. A simple one is:

interface=wlan0
driver=nl80211
ssid=test
channel=1
  1. Now you can start hostapd to put the card in master mode:
        sudo hostapd <config_file>