diff --git a/bf_pulp_utils/bf_pulp_utils/psrfits_requantisation.py b/bf_pulp_utils/bf_pulp_utils/psrfits_requantisation.py
index 8e1acb00fa8f9d89128c77096e000b786bc830ba..dc9804437dac5791f7cd614a1896b5cd18710f77 100644
--- a/bf_pulp_utils/bf_pulp_utils/psrfits_requantisation.py
+++ b/bf_pulp_utils/bf_pulp_utils/psrfits_requantisation.py
@@ -165,9 +165,14 @@ def main():
             # removing the converted file if it's still there (for instance after the crash, etc).
             # otherwise psrfits_subband will not work - can't override the file if it exists already
             os.system("rm -f %s.fits" % (outputbase))
+            outf = open(logfile, 'w')
+            outf.write("=" * 75 + "\n")
+            outf.write("Input PSRFITS file: %s\n" % (ii))
+            outf.write("Command: %s\n" % (cmd))
+            outf.close()
             proc = Popen(shlex.split(cmd), stdout=PIPE, stderr=STDOUT, cwd="%s/%s" % (workdir, rootdir), shell=False)
             (sout, serr) = proc.communicate()
-            outf = open(logfile, 'w')
+            outf = open(logfile, 'a')
             outf.write(sout.decode("utf-8").replace("\r\n", "\n"))
             outf.close()
             for line in sout.decode("utf-8").split("\n"):