Is your machine dropping the connection, or is your router's wireless 
crashing? From the log section you posted, it looks like your AP's radio 
is going offline.

Ath9K wireless cards are known to cause problems when combined with 
certain linux-based routers --such as the Buffalo WHR* dd-wrt based 
routers-- also running Atheros chipsets.

I ran into this problem about a year ago. It was real fun tracking the 
problem down as it was caused by a laptop I only use when my workstation 
is unavailable. I got snowed with work while rebuilding my workstation 
and switched to my laptop exclusively for several months; magically, the 
previously stable Buffalo WHR-HP-G300N router (with an Atheros chip) 
running DD-WRT began randomly dropping all wireless connections and 
required a power-cycle to turn the radio back on.

Since nothing had changed from my perspective --I had used the laptop on 
the network before, but not as extensively-- it took some effort to 
pinpoint the problem. Replacing the laptop's ath9k wireless card with an 
inexpensive Intel, and throwing out most of my USB Wireless-N adapters 
(many are Atheros based) fixed the issue.

I've only heard of the issue when the client machine is running MS Win 
7x64 with the 'right' version of updated drivers combined an Atheros 
based router with the 'right' set of DDWRT firmware, and large file 
transfers by the client over the local wireless network. If you haven't 
updated the driver in your Windows 7 box to the problem driver version, 
and/or aren't transferring large files (DVD ISO's, etc) the router won't 
display the problem behavior.  I suppose the true moral of the story is: 
don't buy Qualcomm chips, and when possible replace devices that use them?

Here's one of the links that helped me:
http://kinglee.blogspot.com/2010/07/buffalo-whr-hp-g300n-wireless-drop-on.html

Moving away from whatever firmware you're running on your router might 
fix the issue. I replaced my laptop's wireless nic with an intel, and 
tossed my Atheros based USB wireless adapters and am very happy. Best of 
all, the Intel wireless NIC has pretty good bluetooth built in.

Can you send us sterilized sections of your router logs?


--W

On 3/12/2013 11:58 AM, Steven Haigh wrote:
> On 03/13/2013 02:54 AM, Pat Riehecky wrote:
>> On 03/12/2013 05:45 AM, Steven Haigh wrote:
>>> On 12/03/13 21:03, Steven Haigh wrote:
>>>> Hi all,
>>>>
>>>> I've been trying to figure out the cause of this... It seems I'll be
>>>> using the wifi without issue, then NetworkManager will indicate 
>>>> that it
>>>> is reconnecting. It seems to happen randomly with no real pattern.
>>>>



>>>> iw events -t shows:
>>>> 4b:d6:98:14:48 -> 00:0f:66:c5:2d:6b reason 3: Deauthenticated because
>>>> sending station is leaving (or has left) the IBSS or ESS
>>>> 1363082116.240481: wlan0 (phy #0): disconnected (local request)
>>>> ....
>>>> 1363082122.323703: wlan0 (phy #0): auth 00:0f:66:c5:2d:6b ->
>>>> 1c:4b:d6:98:14:48 status: 0: Successful
>>>> 1363082122.344295: wlan0 (phy #0): assoc 00:0f:66:c5:2d:6b ->
>>>> 1c:4b:d6:98:14:48 status: 0: Successful
>>>> 1363082122.347571: wlan0 (phy #0): connected to 00:0f:66:c5:2d:6b
>>>>
>>>> Interestingly, I've only had this problem under linux. The access 
>>>> point
>>>> is stable and works fine with the same card under Windows 7 - as 
>>>> well as
>>>> our smart phones etc etc. The access point hasn't changed in a 
>>>> number of
>>>> years (4+).
>>>>
>>>> At the moment, I'm using the kernel-ml from elrepo until I can get the
>>>> eeepc module re-enabled for 64 bit kernels from our wondering upstream
>>>> provider. (Battery life dies to about 3.5 hours instead of 5+ with 
>>>> it!)
>>>>
>>>> I've tried 'iwconfig wlan0 power off' to disable power management from
>>>> the wifi adapter, but the dropouts still seem to randomly happen. 
>>>> The AP
>>>> is secured with WPA2-PSK (AES+TKIP) - not sure if that makes a
>>>> difference...