diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3c1bedfee..6cb21cf97 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -169,6 +169,7 @@ set (fort_qt_CXXSRCS
   )
 
 set (wsjt_qt_CXXSRCS
+  helper_functions.cpp
   qt_helpers.cpp
   widgets/MessageBox.cpp
   MetaDataRegistry.cpp
diff --git a/helper_functions.cpp b/helper_functions.cpp
new file mode 100644
index 000000000..706c427eb
--- /dev/null
+++ b/helper_functions.cpp
@@ -0,0 +1,33 @@
+#include "helper_functions.h"
+
+double tx_duration(QString mode, double trPeriod, int nsps, bool bFast9)
+{
+  double txt=0.0;
+  if(mode=="FT4")  txt=1.0 + 105*576/12000.0;      // FT4
+  if(mode=="FT8")  txt=1.0 + 79*1920/12000.0;      // FT8
+  if(mode=="JT4")  txt=1.0 + 207.0*2520/11025.0;   // JT4
+  if(mode=="JT9")  txt=1.0 + 85.0*nsps/12000.0;  // JT9
+  if(mode=="JT65") txt=1.0 + 126*4096/11025.0;     // JT65
+  if(mode=="Q65")  {                                      // Q65
+    if(trPeriod==15) txt=0.5 + 85*1800/12000.0;
+    if(trPeriod==30) txt=0.5 + 85*3600/12000.0;
+    if(trPeriod==60) txt=1.0 + 85*7200/12000.0;
+    if(trPeriod==120) txt=1.0 + 85*16000/12000.0;
+    if(trPeriod==300) txt=1.0 + 85*41472/12000.0;
+  }
+  if(mode=="WSPR") txt=2.0 + 162*8192/12000.0;     // WSPR
+  if(mode=="FST4" or mode=="FST4W") {               //FST4, FST4W
+    if(trPeriod==15)  txt=1.0 + 160*720/12000.0;
+    if(trPeriod==30)  txt=1.0 + 160*1680/12000.0;
+    if(trPeriod==60)  txt=1.0 + 160*3888/12000.0;
+    if(trPeriod==120) txt=1.0 + 160*8200/12000.0;
+    if(trPeriod==300) txt=1.0 + 160*21504/12000.0;
+    if(trPeriod==900) txt=1.0 + 160*66560/12000.0;
+    if(trPeriod==1800) txt=1.0 + 160*134400/12000.0;
+  }
+  if(mode=="MSK144" or bFast9) {
+    txt=trPeriod-0.25; // JT9-fast, MSK144
+  }
+  if(mode=="Echo") txt=2.4;
+  return txt;
+}
diff --git a/helper_functions.h b/helper_functions.h
new file mode 100644
index 000000000..e62e23b7d
--- /dev/null
+++ b/helper_functions.h
@@ -0,0 +1,7 @@
+#ifndef HELPER_FUNCTIONS_H
+#define HELPER_FUNCTIONS_H
+#include <QString>
+
+double tx_duration(QString mode, double trPeriod, int nsps, bool bFast9);
+
+#endif // HELPER_FUNCTIONS_H
diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 1ebd022cf..a7f5c1188 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -45,6 +45,7 @@
 #include <QRandomGenerator>
 #endif
 
+#include "helper_functions.h"
 #include "revision_utils.hpp"
 #include "qt_helpers.hpp"
 #include "Network/NetworkAccessManager.hpp"
@@ -1031,6 +1032,7 @@ MainWindow::MainWindow(QDir const& temp_directory, bool multiple,
 
 void MainWindow::not_GA_warning_message ()
 {
+  /*
   MessageBox::critical_message (this,
                                 "This is a pre-release version of WSJT-X 2.5.0 made\n"
                                 "available for testing purposes.  By design it will\n"
@@ -1039,6 +1041,7 @@ void MainWindow::not_GA_warning_message ()
   if (now >= QDateTime {{2021, 8, 31}, {23, 59, 59, 999}, Qt::UTC}) {
     Q_EMIT finished ();
   }
+  */
 }
 
 void MainWindow::initialize_fonts ()
@@ -2203,7 +2206,7 @@ void MainWindow::keyPressEvent (QKeyEvent * e)
     break;
   case Qt::Key_X:
     if(e->modifiers() & Qt::AltModifier) {
-//      qDebug() << "Alt-X" << WSPR_message();
+      qDebug() << "Alt-X" << revision();
       return;
     }
   }
@@ -3858,6 +3861,9 @@ void MainWindow::guiUpdate()
     if(m_transmitting) m_bEchoTxed=true;
   }
 
+  Q_ASSERT(txDuration == tx_duration(m_mode,m_TRperiod,m_nsps,m_bFast9));
+  Q_ASSERT(m_mode==m_modeTx);
+
   if(m_mode=="WSPR" or m_mode=="FST4W") {
     if(m_nseq==0 and m_ntr==0) {                   //Decide whether to Tx or Rx
       m_tuneup=false;                              //This is not an ATU tuneup
@@ -4381,6 +4387,7 @@ void MainWindow::guiUpdate()
 //Once per second (onesec)
   if(nsec != m_sec0) {
 //    qDebug() << "AAA" << nsec;
+
     if(m_mode=="FST4") chk_FST4_freq_range();
     m_currentBand=m_config.bands()->find(m_freqNominal);
     if( SpecOp::HOUND == m_config.special_op_id() ) {
diff --git a/wsjtx.pro b/wsjtx.pro
index 04c0ce68e..1cf2a1295 100644
--- a/wsjtx.pro
+++ b/wsjtx.pro
@@ -65,6 +65,7 @@ SOURCES += \
   getfile.cpp \
   WFPalette.cpp \
   WsprTxScheduler.cpp \
+  helper_functions.cpp \
   main.cpp decodedtext.cpp wsprnet.cpp \
   WSPRBandHopping.cpp MessageAggregator.cpp SampleDownloader.cpp qt_helpers.cpp\
   MultiSettings.cpp PhaseEqualizationDialog.cpp \
@@ -72,6 +73,7 @@ SOURCES += \
   LotWUsers.cpp TraceFile.cpp
 
 HEADERS  += qt_helpers.hpp qt_db_helpers.hpp \
+  helper_functions.h \
   pimpl_h.hpp pimpl_impl.hpp \
   ExceptionCatchingApplication.hpp Logger.hpp WSJTXLogging.hpp \
   Radio.hpp NetworkServerLookup.hpp revision_utils.hpp \