Does someone know what the reason could be if a radio disables itself?

We use more than 8 AP-bridges with AR5212 & AR5213 cards, using version 2.8.24 or above.

Sometimes the problem doens't come up for weeks, sometimes more then 1 time a day.

When I click on disable and then click on enable (in winbox), the radio comes up again.

We use simple queues on some radio's. I cannot see much traffic going on the specific radio when this problem accures.

We've had the same problem in some of our Access Points. When we changed the radiocard with a new one (same brand, same model) the problem disappeared.

(Note: The radiocard which failed in one AP has been stable in another AP, which has puzzled me a bit).

sometimes i run for months with no problems, sometimes the card disables itself several times in short period of time. I have a 2nd problem with wds. I used to link 2 wireless bridges using EOIP, then i upgrade my system to use wds, sometimes one bridge will not "see" the other. I have to reboot the machine to get the bridges talking again. Most important thing is, the wds connection (/interface/wireless/wds) show no sign of a lost connection.

my opinion is that the problem is hardware related or ambient related.
You can fix this out doing a script which disables and enables wlan card if the next router goes down.

here is a pasted script from my experience.
/ system script
add name="disable" source="/interface wireless disable wlan1" \
policy=ftp,reboot,read,write,policy,test
add name="enable" source="/interface wireless enable wlan1" \
policy=ftp,reboot,read,write,policy,test

/ system scheduler
add name="Enable" on-event=enable start-date=jan/26/2005 start-time=05:29:56 \
interval=5s comment="" disabled=no

/ tool netwatch
add host=192.168.8.1 timeout=1s interval=5s up-script="" down-script=disable \
comment="" disabled=no

The reasom might be all sorts of hardware-related problems. First I would suggest to insert the card in a different slot (and tripple-check that the card has indeed a good contact with the slot)