diff --git a/fixhdr/LibTrace.py b/fixhdr/LibTrace.py
index 511fedd199782d3e65323ee23e6ccb3c5f3233f8..49cbda32f1c27cdc4880908f58c6fcaffdc3e91e 100755
--- a/fixhdr/LibTrace.py
+++ b/fixhdr/LibTrace.py
@@ -1461,7 +1461,7 @@ class Mseed(futils):
             tmpchar = ""
             while tmpchar != "~":
                 tupchar = self.sunpack(fmtstr, self.infileread(1))
-                tmpchar = str(tupchar[0])
+                tmpchar = tupchar[0].decode()
                 if tmpchar != "~":
                     char = char + tmpchar
                 length_data_string += 1