Description of problem:
ath5k stops network connection every 2 minutes for 8 seconds

Version-Release number of selected component (if applicable):
modinfo ath5k | grep version
version:        0.6.0 (EXPERIMENTAL)
srcversion:     15721B3A1DE45C04BEBE82D

How reproducible:
Always

Steps to Reproduce:
1. Start WLAN connection with Atheros AR5001X+ card using the ath5k driver.
2. Use the WLAN connection.
3. Wait two minutes.
  
Actual results:
WLAN connection stops 7 % of the time.

Expected results:
WLAN connection works 100 % of the time.

Additional info:

I have a Atheros AR5001X+ Wireless Network Adapter using the ath5k
driver with NetworkManager on a Fedora 11 laptop. My problem is that
every 2 minutes the WLAN connection effectively stops for
about 8 seconds in both directions. Afterwards the connection again
works normally for two minutes again. Effectively the network card 
is inoperable for 7 % of the time. 

The WLAN card has two LEDs shaped like two parenthesises (). When the
freeze occurs the left of these leds blinks fast. Otherwise that LED is
steadily on when there is a WLAN connection.

When the problem occurs the load on the system rises about 30 % and
there is a command phy0 run by root which is taking most CPU according
to top.
  789 root      15  -5     0    0    0 S 30.7  0.0   0:33.65 phy0 

I do see some of these error messages with dmesg:

ath5k phy0: noise floor calibration failed (5595MHz)
ath5k phy0: noise floor calibration failed (5605MHz)
ath5k phy0: noise floor calibration failed (5595MHz)
ath5k phy0: noise floor calibration failed (5605MHz)
ath5k phy0: noise floor calibration failed (5595MHz)
ath5k phy0: noise floor calibration failed (5605MHz)
ath5k phy0: noise floor calibration failed (5595MHz)
ath5k phy0: noise floor calibration failed (5605MHz)

But these error messages are not time correlated with the
moment when the problem occurs.

uname -a
Linux pchip78 2.6.30.8-64.fc11.i586 #1 SMP Fri Sep 25 04:30:19 EDT 2009
i686 i686 i386 GNU/Linux

lspci -v -v -v
02:00.0 Ethernet controller: Atheros Communications Inc. Atheros AR5001X+ Wireless Network Adapter (rev 01)
        Subsystem: Device 1804:0010
        Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
        Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
        Latency: 168 (2500ns min, 7000ns max), Cache Line Size: 32 bytes
        Interrupt: pin A routed to IRQ 11
        Region 0: Memory at 38000000 (32-bit, non-prefetchable) [size=64K]
        Capabilities: [44] Power Management version 2
                Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
                Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=2 PME-
        Kernel driver in use: ath5k
        Kernel modules: ath5k

What is the ath5k driver doing every 120 seconds that is causing this problem and how could this problem be solved?