Hi, im working whit 2 AP whit same hardware configuration and same issue. The RB532a has 2 SR2 in ap bridge mode whit 30 clients each and the internet backbone comes from ethernet interface. Everything works just fine (fine is a way to say it) the power of the clients goes from -58 dBm to -72 dBm and all of them are conected at 11Mbps. So were is the problem......the thing is that the ack timeout vary from 30 to 408 and the CCQ goes from 30 to 70. I check everything cables, conectors, configuration, upgrade it to the last version, try using diferents manuals ack, try diferents power outputs, try disabling the worst connected clients and nothing happens always stay the same issue. The thing is that this happens on the two APs so there is no way that this was a hardware failure but because i have some parts in the closet i change the SR2 ........but still the same issue. If anyone can trow some lights on this i will be very happy.

Tnks for now and sorry for my english like always.

Ack timeout displayed at 408us (the Atheros chipset's limit) is a symptom that there's somehing strange... in your case, you have to set the ack timeout as static (calculate yourself the value, based on the longest client), try to improve the LOS between you and your client and try to see if there's interference between you and your client.
Low CCQ indicate that there's some interference or you are not in LOS qith some of your client.

Already try the static ACK and all the clients have exelent LOS and the distance is not more than 2 km.

Which is the working frequency of the two SR2?

Channel 2412 and 2462 there is no interference problem.
The thing is that whit other wireless cards like cm9 or old prism2 everything works just fine, i only have this issue whit ubiquiti cards. When the SR2 dont work i buy XR2 to try it but the problem is worse, now only the 5 more close clients connects to the AP.
Now im going to trow away everything and start again to see if i miss something.
Later post will show what i found......i hope.

Have you tried to poweroff one of your ap and one of the two card on the other?
Is your CPE all the same brand/models? Which?

I tryed whit only 1 card and nothing, the CPE's are Teletronics and Edimax (think this use atheros chips)

I am running an XR2 on my AP and running into the same problem. I think I will change the card out and see what happens.

Hi,

We have this problem in the past, with Lobometrics Miura Basic and Plus. When we have 10-12 clients at one AP, ack up to 408, but when we have only 3-5 ack it's ok (after reboot, sure).

About 6 month ago, change my clients to RB112@R52, all MT and Routerboard, and I have AP with more than 35 clients with better values, ¡25 us!. See attach file.

I've tried ack-timeouts and all, so far no luck for me. Good luck to you sir.