We have been running Mikrotik as a AP for serveral years now. Up until recently, we have been using PCMCIA cards or just regular B Mini-PCI (NL2511’s). All is working well. We want to take advantage of using B/G and upgrade our APs. I have NEVER had success with a B/G card 
We will install the card but can never get everyone to authorize or log in over PPPoE.
Current example -
Replaced a NL2511 PCMCIA system with a SR2 system. All 53 users came in fine and seemed to be working.
Made a minor change to wireless card and then changed my mind and changed it back. Wireless card reset. Only about 5 radios registered and log was showing a bunch of deauths. Put antenna back on old system and all users registered just fine, back on new system and they all came back in.
System was running great for about 48 hours. Power problem caused a reboot, after reboot only handful of wireless registrations, no PPPoE logins. Tried changing Freq, rebooting, etc. Same deal, bunch of deauth’s in log and minimal registrations.
Finally when back and swapped out SR2 with NL2511 and we were back in business running great. Nosie level in the area is VERY low. Mikrotik reports -99 noise floor.
I have tried SR2 and NMP8602 PLUS with no success, the old NL2511 just keeps working. Was thinking about trying one of the new Mikrotik High Power cards, but don’t feel like just throwing away more money
BTW - We use SR2 & SR5 on our backhauls and they seem to work great.
Any Ideas.
TIA
Mark