diff --git a/lib/calibrate.f90 b/lib/calibrate.f90
new file mode 100644
index 000000000..0ecef3805
--- /dev/null
+++ b/lib/calibrate.f90
@@ -0,0 +1,31 @@
+subroutine calibrate(app_dir,data_dir)
+
+! Frequency calibration driver routine for WSJT-X
+  
+  character*(*) app_dir
+  character*(*) data_dir
+  character*256 fmtave,fcal,infile,avefile,calfile
+  character*512 cmnd
+  
+  fmtave=app_dir//'fmtave'
+  fcal=app_dir//'fcal'
+  infile=data_dir//'fmt.all'
+  avefile=data_dir//'fmtave.out '
+  calfile=data_dir//'fcal.out'
+
+  print*,trim(fmtave)
+  print*,trim(fcal)
+  print*,trim(infile)
+  print*,trim(avefile)
+  print*,trim(calfile)
+
+  cmnd='"'//trim(fmtave)//' '//trim(infile)//' > '//avefile//'"'
+  print*,trim(cmnd)
+  call system(trim(cmnd))
+
+  cmnd='"'//trim(fcal)//' '//trim(avefile)//' > '//calfile//'"'
+  print*,trim(cmnd)
+  call system(trim(cmnd))
+  
+  return
+end subroutine calibrate