diff --git a/lib/fsk4hf/watterson.f90 b/lib/fsk4hf/watterson.f90
index 4b6799cb2..f62139247 100644
--- a/lib/fsk4hf/watterson.f90
+++ b/lib/fsk4hf/watterson.f90
@@ -42,8 +42,8 @@ subroutine watterson(c,fs,delay,fspread)
      cs1=cs1/NZ
      cs2=cs2/NZ
   endif
-  
-  nshift=0.001*delay*12000.0
+
+  nshift=nint(0.001*delay*fs)
   c2=cshift(c,nshift)
   sq=0.
   do i=0,NZ-1