diff --git a/libm65/qra64zap.f90 b/libm65/qra64zap.f90
index 114fe3bbd..63b3fecd5 100644
--- a/libm65/qra64zap.f90
+++ b/libm65/qra64zap.f90
@@ -32,6 +32,8 @@ subroutine qra64zap(cx,cy,nzap)
      nw=3
      do n=1,3
         nw=2*nw
+        if(ipk-2*nw.lt.-1312) cycle
+        if(ipk+2*nw.gt. 1312) cycle
         s1=maxval(s(ipk-2*nw:ipk-nw))
         s2=maxval(s(ipk+nw:ipk+2*nw))
         if(smax.gt.slimit .and. s1.lt.sbottom .and. s2.lt.sbottom) then
@@ -42,7 +44,6 @@ subroutine qra64zap(cx,cy,nzap)
            ib=(i0+nw)*nadd
            cx(ia:ib)=0.
            cy(ia:ib)=0.
-!           print*,'!',nzap,ipk*df,nw
            exit
         endif
      enddo
diff --git a/mainwindow.cpp b/mainwindow.cpp
index f9361fb62..3cc26360a 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -1,4 +1,4 @@
-//--------------------------------------------------------------- MainWindow
+//---------------------------------------------------------------- MainWindow
 #include "mainwindow.h"
 #include "ui_mainwindow.h"
 #include "devsetup.h"
diff --git a/plotter.cpp b/plotter.cpp
index bff636a20..fc79260a8 100644
--- a/plotter.cpp
+++ b/plotter.cpp
@@ -139,18 +139,21 @@ void CPlotter::paintEvent(QPaintEvent *)                    // paintEvent()
     if(f) {
       int x,y;
       float freq,sync;
+      float slimit=6.0;
       QPen pen0(Qt::red,1);
       painter2.setPen(pen0);
       for(int i=0; i<99999; i++) {
         f >> freq >> sync;
         if(f.eof()) break;
         x=(freq - m_ZoomStartFreq)/df;
-        y=(sync-1.5)*2.0;
-        if(y>15.0) y=15.0;
-        if(x>=0 and x<=w) painter2.drawLine(x,0,x,y);
-        x=XfromFreq(float(fQSO()+0.001*freq));
-        painter1.setPen(pen0);
-        painter1.drawLine(x,0,x,y);
+        y=(sync-slimit)*3.0;
+        if(y>0) {
+          if(y>15.0) y=15.0;
+          if(x>=0 and x<=w) painter2.drawLine(x,0,x,y);
+          x=XfromFreq(float(fQSO()+0.001*freq));
+          painter1.setPen(pen0);
+          painter1.drawLine(x,0,x,y);
+        }
       }
       f.close();
     }