I have a 4th generation TC that I use as my main router it is conected directly to my ISP modem a Motorola Surfboard SB5100i and it has a wired conecction to my iMac, I also have an Aiport Extreme 802.11ac latest generation that I just bought to extend my network to a far corner of my house were the wireless signal is very pour making it unusable the Airport is conected to the TC via RJ45 and it extends my main wireless network very well I have no issues there.
I decided to create a guest network to keep guests away from the resources inside my main network (adding some extra security), the guest network gets repeated as well by the Aiport and when a client is conected via the TC to the guest network it works perfectly as fast as the main network, however when a client gets conected to the guest network via the Airport extreme the speed they get out of it goes down to around 0.50 Mbps (I have a 9.0 Mbps connection) in other words:
Speed in main network conected to TC: 9.0 Mbps
Speed in main network connected to Airport Extreme: 9.0 Mbps
Speed in guest network connected to TC: 9.0 Mbps
Speed in guest network connected to Airport Extreme: 0.5 Mbps.
I have done everyting from restoring both the TC and the Airport Extreme to changing the wireless security leaving the guest network open, play around with the frecuencies and nothing seems to work no matter what I do I get very slow speed on the extended guest network but excelent speed on the extended main network. TC is runing firmware 7.6.4 and Airport is runing firmware 7.7.1.
I have look for information on the web and on apple support comunities but must of the similar cases i have found are related to slow speed on main and not guest extended networks.
I´ll really apritiate any help that anyone can provide. Thanks in advance.