diff --git a/Configuration.cpp b/Configuration.cpp
index e7b9882ad..f4b8f445c 100644
--- a/Configuration.cpp
+++ b/Configuration.cpp
@@ -673,6 +673,12 @@ QString Configuration::rig_name () const {return m_->rig_params_.rig_name;}
 bool Configuration::pwrBandTxMemory () const {return m_->pwrBandTxMemory_;}
 bool Configuration::pwrBandTuneMemory () const {return m_->pwrBandTuneMemory_;}
 
+void Configuration::adjust_calibration_parameters (double intercept, double slope_ppm)
+{
+  m_->frequency_calibration_intercept_ += intercept;
+  m_->frequency_calibration_slope_ppm_ += slope_ppm;
+}
+
 bool Configuration::is_transceiver_online () const
 {
   return m_->rig_active_;
diff --git a/Configuration.hpp b/Configuration.hpp
index b0c219167..aca0736c8 100644
--- a/Configuration.hpp
+++ b/Configuration.hpp
@@ -159,6 +159,11 @@ public:
   QColor color_NewCall () const;
   bool pwrBandTxMemory () const;
   bool pwrBandTuneMemory () const;
+
+  // Adjust the current calibration parameters, both arguments are in
+  // Hertz. They will be added to the current values.
+  void adjust_calibration_parameters (double intercept, double slope_ppm);
+
   // This method queries if a CAT and PTT connection is operational.
   bool is_transceiver_online () const;
 
diff --git a/lib/calibrate.f90 b/lib/calibrate.f90
index 199beba1f..a27c400a0 100644
--- a/lib/calibrate.f90
+++ b/lib/calibrate.f90
@@ -24,7 +24,7 @@ subroutine calibrate(data_dir,iz,a,b,rms,sigmaa,sigmab,irc)
   n=0
   j=0
   do i=1,99999
-     read(10,*,end=10) cutc,nkHz,ncal,noffset,faudio,df,dblevel,snr
+     read(10,*,end=10,err=995) cutc,nkHz,ncal,noffset,faudio,df,dblevel,snr
      if((nkHz.ne.nkHz0) .and. i.ne.1) then
         ave=sum/n
         rms=0.d0
@@ -84,6 +84,7 @@ subroutine calibrate(data_dir,iz,a,b,rms,sigmaa,sigmab,irc)
   enddo
   go to 999
 
+995 irc=-4; iz=i; go to 999
 996 irc=-1; go to 999
 997 irc=-2; go to 999
 998 irc=-3
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 189bd78ab..a97705b55 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -2110,16 +2110,34 @@ void MainWindow::on_actionSolve_FreqCal_triggered()
   double a,b,rms,sigmaa,sigmab;
   strncpy(data_dir,dpath.toLatin1(),len);
   calibrate_(data_dir,&iz,&a,&b,&rms,&sigmaa,&sigmab,&irc,len);
-  QString t1;
-  t1.sprintf("Slope:     %10.3f ±%7.3f ppm\nIntercept:  %7.2f ±%5.2f    Hz\n\nN:   %18d\nStdDev:  %8.2f  Hz",
-             b,sigmab,a,sigmaa,iz,rms);
-  QString t2{"Solution looks good."};
-  if(irc<0) t1="";
+  QString t2;
   if(irc==-1) t2="Cannot open " + dpath + "fmt.all";
   if(irc==-2) t2="Cannot open " + dpath + "fcal2.out";
   if(irc==-3) t2="Insufficient data in fmt.all";
+  if(irc==-4) t2 = tr ("Invalid data in fmt.all at line %1").arg (iz);
   if(irc>0 or rms>1.0) t2="Check fmt.all for possible bad data.";
-  MessageBox::information_message(this,t1,t2,0);
+  if (irc < 0 || irc > 0 || rms > 1.) {
+    MessageBox::warning_message (this, "Calibration Error", t2);
+  }
+  else if (MessageBox::Apply == MessageBox::query_message (this
+                                                           , tr ("Good Calibration Solution")
+                                                           , tr ("<pre>"
+                                                                 "%1%L2 ±%L3 ppm\n"
+                                                                 "%4%L5 ±%L6 Hz\n\n"
+                                                                 "%7%L8\n"
+                                                                 "%9%L10 Hz"
+                                                                 "</pre>")
+                                                           .arg ("Slope: ", 12).arg (b, 0, 'f', 3).arg (sigmab, 0, 'f', 3)
+                                                           .arg ("Intercept: ", 12).arg (a, 0, 'f', 2).arg (sigmaa, 0, 'f', 2)
+                                                           .arg ("N: ", 12).arg (iz)
+                                                           .arg ("StdDev: ", 12).arg (rms, 0, 'f', 2)
+                                                           , QString {}
+                                                           , MessageBox::Cancel | MessageBox::Apply)) {
+    m_config.adjust_calibration_parameters (a, b);
+    // discard fmt.all as we have consumed the resulting calibration solution
+    QFile f {m_config.writeable_data_dir ().absoluteFilePath ("fmt.all")};
+    f.remove ();
+  }
 }
 
 // This allows the window to shrink by removing certain things