Get external storage

Hi, how do I get a path to the external SD card on a Samsung device?
GetExternalStoragePublicDirectory and ExternalStorageDirectory always return /storage/emulated/0/ which is the internal storage.
I would like to have my app save backup files to the external card, but I cannot find a way to find the path to the external card.
I am using xamarin but code in java is fine, any help would e appreciated.
I googled for it but all the info seems to indicate that this is not possible on samsung devices?