diff --git a/lib/qra/q65/q65_sync.f90 b/lib/qra/q65/q65_sync.f90
index 2c1d2e8f0..892f60c78 100644
--- a/lib/qra/q65/q65_sync.f90
+++ b/lib/qra/q65/q65_sync.f90
@@ -37,6 +37,7 @@ subroutine q65_sync(nutc,iwave,ntrperiod,mode_q65,codewords,ncw,nsps,   &
   data sync(1)/99.0/
   save sync
 
+  irc=-2
   idec=-1
   snr1=0.
   dat4=0
@@ -308,6 +309,7 @@ subroutine q65_dec1(s3,nsubmode,b90ts,codewords,ncw,esnodb,irc,dat4,decoded)
   decoded='                                     '
   call q65_intrinsics_ff(s3,nsubmode,b90ts,nFadingModel,s3prob)
   call q65_dec_fullaplist(s3,s3prob,codewords,ncw,esnodb,dat4,plog,irc)
+  if(sum(dat4).le.0) irc=-2
   if(irc.ge.0 .and. plog.gt.PLOG_MIN) then
      write(c77,1000) dat4(1:12),dat4(13)/2
 1000 format(12b6.6,b5.5)
@@ -332,6 +334,7 @@ subroutine q65_dec2(s3,nsubmode,b90ts,esnodb,irc,dat4,decoded)
   decoded='                                     '
   call q65_intrinsics_ff(s3,nsubmode,b90ts,nFadingModel,s3prob)
   call q65_dec(s3,s3prob,APmask,APsymbols,esnodb,dat4,irc)
+  if(sum(dat4).le.0) irc=-2
   if(irc.ge.0) then
      write(c77,1000) dat4(1:12),dat4(13)/2
 1000 format(12b6.6,b5.5)
diff --git a/widgets/plotter.cpp b/widgets/plotter.cpp
index fd7cb173c..52bb97be7 100644
--- a/widgets/plotter.cpp
+++ b/widgets/plotter.cpp
@@ -293,12 +293,14 @@ void CPlotter::draw(float swide[], bool bScroll, bool bRed)
      if(m_bQ65_MultiSync) pen0.setColor("orange");
       painter2D.setPen(pen0);
       painter2D.drawPolyline(LineBuf2,k);
-      QString t;
-      t = t.asprintf("DT = %6.2f",xdt);
-      painter2D.setPen(Qt::white);
-      Font.setWeight(QFont::Bold);
-      painter2D.setFont(Font);
-      painter2D.drawText(m_w-100,m_h2/2,t);
+      if(m_bQ65_Sync) {
+        QString t;
+        t = t.asprintf("DT = %6.2f",xdt);
+        painter2D.setPen(Qt::white);
+        Font.setWeight(QFont::Bold);
+        painter2D.setFont(Font);
+        painter2D.drawText(m_w-100,m_h2/2,t);
+      }
     }
   }
   update();                                    //trigger a new paintEvent