diff --git a/modules/aeolus/datasource.py b/modules/aeolus/datasource.py
index 586d79e32e332911d970363c4f3af2d2b89898b9..1059352f4f9eb29c6687c96874f617b675224132 100644
--- a/modules/aeolus/datasource.py
+++ b/modules/aeolus/datasource.py
@@ -29,10 +29,7 @@ class Files:
         self.flist = self.flist[sidxs]
 
     def get_datetime(self, pathname):
-        filename = os.path.split(pathname)[1]
-        dt_str = (((filename.split('raob_soundings'))[1]).split('.'))[0]
-        dto = datetime.datetime.strptime(dt_str, '%Y%m%d_%H%M').replace(tzinfo=timezone.utc)
-        return dto
+        pass
 
     def get_file_containing_time(self, timestamp):
         k = -1
@@ -54,6 +51,17 @@ class Files:
             return None, None, None
 
 
+class RAOBfiles(Files):
+    def __init__(selfs, files_path, file_time_span, pattern):
+        super().__init__(files_path, file_time_span, pattern)
+
+    def get_datetime(self, pathname):
+        filename = os.path.split(pathname)[1]
+        dt_str = (((filename.split('raob_soundings'))[1]).split('.'))[0]
+        dto = datetime.datetime.strptime(dt_str, '%Y%m%d_%H%M').replace(tzinfo=timezone.utc)
+        return dto
+
+
 class GFSfiles(Files):
     def __init__(self, files_path, file_time_span, pattern):
         super().__init__(files_path, file_time_span, pattern)