8.2 and 8.1.5 AP's can't be co-located

We recently ran into a problem where I had upgraded all of our towers to 8.2v2 we then purchased some new AP’s to increase our coverage and installed them at 2 of our towers that already had other AP’s. (All of our radios are 5.7) The new AP’s came from Moto with and our towers were running 8.2v2. I installed the new AP’s figuring that I would upgrade them when I had time to get to it.

As soon as the new AP’s running were turned on speeds at the SM’s of all the radios connected to both the old and new radios dropped from 5Mbps to less than 500Kbps! As soon as I turned the new AP’s off the speeds came back. It kept seeming like a timing issue. I went round and round double checking that I had everything set correctly. Same downlink, max mile, and control slots etc. etc. no difference. I finally decided to upgrade all the AP’s at these towers to 8.2.1 since that was the only difference I could find…the problem vanished.

Figured I’d pass this along because this may impact not only radios that are co-located but it may cause problems for towers that are close enough to hear each other.