FYI on MAC books random WiFi drops: We experienced issues awhile ago with MAC books just dropping WiFi randomly or when roaming. After some trouble shooting we found that the MAC likes to place in multiple certs in the keychain. For example we updated our expired cert (using same cert name for the new one, thinking it would just update the old cert) and saw the MAC put both certs in the key chain. The MAC would either do one of the certs or try to use just the expired cert. This causing the MAC to scan and not connect at random. By deleting the expired cert helped but it wasn't the 100% fix. We found you have to tweak the new cert SSL section on the MAC book and set it to always trust. Have provided a link from our web site that we use in taking our customers step by step on fixing this issue.
https://www.ohio.edu/oit/internet-phones/internet/wifi/how-fix-dropped-wi-fi-connections-mac
Hope this helps all those troublesome random MAC WiFi drops.
Enjoy
Bill