I have a question about 802.11n wlan cards in general: if they support 802.11n radio types, shouldn't they be able to connect to 802.11n 5ghz bands transmitted by routers? I read into this online, and I learned that the 802.11a radio type must be supported by the 802.11n wlan card as well to be able to use 5ghz, but I also got conflicting/confusing information stating that if the wlan card supports 802.11n, then it can work on 2.4ghz or 5ghz bands.
802.11n is a break with the prior 3 major standards, in that it can function on both 2.4GHz and 5GHz. Compliant devices may support either (they tend to support either 2.4GHz only, or 5GHz as well as 2.4GHz). It happens that 802.11a uses 5GHz, and in consequence many device manufacturers add 802.11a support despite that almost no 802.11a APs can be found anywhere. Support for 802.11a is a very strong indication that the device will support 802.11n on 5GHz, but there are lots of devices out there supporting 802.11n on 2.4GHz only, and probably quite a few that support it on 5GHz as well but don't advertise 802.11a support.