sounds simple, but did you try #ifconfig ath0 up?
also, is your wifi card turned on, maybe there is a hardware switch to enable the device? bios setting perhaps?
I just tested your commands on heron Ubuntu and they work fine on my atheros card. try my above suggestions.
the output of my #lspci showsas my atheros card.Code:02:03.0 Ethernet controller: Atheros Communications Inc. AR5212/AR5213 Multiprotocol MAC/baseband processor (rev 01)