I've been having issues connecting to wifi access points, and I am wondering if the band is messing things up. How do I tell what band a wifi connection is using on the laptop if I don't have access to the router settings?
Hold the option key down and select your WiFi icon in the menu bar.
It lists channel and (5 GHz) or (2.4 GHz) for the current radio settings.
You can get even more information from System Information, but I usually open Wireless Diagnostics and use the utilities / info window to get more detailed WiFi networking or scan for better channels, check for interference, etc...