diff --git a/lib/qra/q65/q65.f90 b/lib/qra/q65/q65.f90
index 2012af83f..9f89fa2e7 100644
--- a/lib/qra/q65/q65.f90
+++ b/lib/qra/q65/q65.f90
@@ -437,11 +437,16 @@ subroutine q65_ccf_22(s1,iz,jz,nfqso,ntol,ndepth,ntrperiod,iavg,ipk,jpk,  &
 
   ia=max(nfa,100)/df
   ib=min(nfb,4900)/df
-  max_drift=0
-  if(nqd.eq.1 .and. iavg.eq.0 .and. ntol.le.100 .and. ntrperiod.eq.60) then
+  max_drift=0                         !Drift units: bins/TxT
+! Do we need a GUI control to set max_drift ?
+! For now, turn on drift compensation only for submodes 15B amd 60A.  
+  if(nqd.eq.1 .and. iavg.eq.0 .and. ntol.le.100 .and. ntrperiod.eq.60 .and. &
+       mode_q65.eq.1) max_drift=10    !Q65-60A
+  if(nqd.eq.1 .and. iavg.eq.0 .and. ntol.le.100 .and. ntrperiod.eq.15 .and. &
+       mode_q65.eq.4) max_drift=40    !Q65-15C
+  if(max_drift.ne.0) then
      ia=nint((nfqso-ntol)/df)
      ib=nint((nfqso+ntol)/df)
-     max_drift=10                        !Drift units: bins/TRperiod (?)
   endif
 
   do i=ia,ib