The Airport never asked me or let me input a password for the 5 mhz band!
That would be because the AirPort has no setting for this. It uses the same password for both 2.4 GHz and 5 GHz......no matter whether both bands are using the same wireless network name or different wireless network names.
Now the Airport insists that the 5mhz band is the default!
I don't understand what you mean by "default" since there are no settings on the AirPorts to make either the 2.4 GHz band or 5 GHz band a "default" for the AirPort.
If you have been messing with the settings on the AirPort and enabling and then disabling the option to use a separate name for the 5 GHz band.....you are going to need to reset the AirPort and start over again with a new setup.
After the AirPort has been reset, the "default" setting on the AirPort is to produce a dual band 2.4 GHz and 5 GHz wireless network that uses the same wireless network name and password for both bands. It will stay that way if you do not make any additional changes to the wireless settings.
If you use this setting though, you cannot "direct" any Wi-Fi device to connect to a given band. It is up to the Wi-Fi device to choose the band with which it will connect.
Since the 2.4 GHz band signals are stronger than 5 GHz signals, a 5 GHz capable device may connect to the slower 2.4 GHz band, so the device may be noticeably "slower". Unfortunately, nothing you can do about this if you want to continue to have both bands use the same wireless network name.
It is possible that some older 2.4 GHz only Wi-Fi devices will not be able to connect to the AirPort's dual band network. In cases like this, you have no option but to assign different names to each band and then "point" the Wi-Fi device at the 2.4 GHz network name.
