diff --git a/Configuration.ui b/Configuration.ui
index 36a96d66f..9701fb633 100644
--- a/Configuration.ui
+++ b/Configuration.ui
@@ -2469,7 +2469,7 @@ Right click for insert and delete options.</string>
        <item row="1" column="0" colspan="2">
         <widget class="QGroupBox" name="gbSpecialOpActivity">
          <property name="title">
-          <string>Special operating activity:  Generation of FT8 and MSK144 messages</string>
+          <string>Special operating activity:  Generation of FT4, FT8, and MSK144 messages</string>
          </property>
          <property name="checkable">
           <bool>true</bool>
@@ -3078,13 +3078,13 @@ Right click for insert and delete options.</string>
   </connection>
  </connections>
  <buttongroups>
-  <buttongroup name="TX_mode_button_group"/>
-  <buttongroup name="CAT_data_bits_button_group"/>
-  <buttongroup name="CAT_handshake_button_group"/>
-  <buttongroup name="PTT_method_button_group"/>
-  <buttongroup name="split_mode_button_group"/>
   <buttongroup name="CAT_stop_bits_button_group"/>
+  <buttongroup name="CAT_handshake_button_group"/>
+  <buttongroup name="split_mode_button_group"/>
+  <buttongroup name="TX_mode_button_group"/>
+  <buttongroup name="PTT_method_button_group"/>
   <buttongroup name="special_op_activity_button_group"/>
+  <buttongroup name="CAT_data_bits_button_group"/>
   <buttongroup name="TX_audio_source_button_group"/>
  </buttongroups>
 </ui>
diff --git a/lib/ft4/ft4_downsample.f90 b/lib/ft4/ft4_downsample.f90
index 819b10fbc..d3760a506 100644
--- a/lib/ft4/ft4_downsample.f90
+++ b/lib/ft4/ft4_downsample.f90
@@ -38,7 +38,7 @@ subroutine ft4_downsample(dd,newdata,f0,c)
    endif
    i0=nint(f0/df)
    c1=0.
-   c1(0)=cx(i0)
+   if(i0.ge.0 .and. i0.le.NMAX/2) c1(0)=cx(i0)
    do i=1,NFFT2/2
       if(i0+i.le.NMAX/2) c1(i)=cx(i0+i)
       if(i0-i.ge.0) c1(NFFT2-i)=cx(i0-i)
diff --git a/lib/ft4/getcandidates4.f90 b/lib/ft4/getcandidates4.f90
index 5d42ca740..badbbcfb5 100644
--- a/lib/ft4/getcandidates4.f90
+++ b/lib/ft4/getcandidates4.f90
@@ -69,6 +69,7 @@ subroutine getcandidates4(dd,fa,fb,syncmin,nfqso,maxcand,savg,candidate,   &
         del=0.
         if(den.ne.0.0)  del=0.5*(savsm(i-1)-savsm(i+1))/den
         fpeak=(i+del)*df+f_offset
+        if(fpeak.lt.0.0 .or. fpeak.gt.4910.0) cycle
         speak=savsm(i) - 0.25*(savsm(i-1)-savsm(i+1))*del
         ncand=ncand+1
         if(ncand.gt.maxcand) then
diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 98768c4d2..5deb0c4fe 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -4108,8 +4108,7 @@ void MainWindow::stopTx2()
     on_stopTxButton_clicked ();
     m_nTx73 = 0;
   }
-  if(((m_mode.startsWith("WSPR") and m_ntr==-1) or m_mode=="FT4") and
-     !m_tuneup) {
+  if((m_mode.startsWith("WSPR") and m_ntr==-1) and !m_tuneup) {
     m_wideGraph->setWSPRtransmitted();
     WSPR_scheduling ();
     m_ntr=0;
@@ -4219,7 +4218,7 @@ void MainWindow::on_txrb4_doubleClicked ()
   auto const& my_callsign = m_config.my_callsign ();
   auto is_compound = my_callsign != m_baseCall;
   m_send_RR73 = !((is_compound && !shortList (my_callsign)) || m_send_RR73);
-  if(m_mode=="FT4") m_send_RR73=true;
+  if(m_mode=="FT4" and (m_config.special_op_id()==SpecOp::RTTY)) m_send_RR73=true;
   genStdMsgs (m_rpt);
 }