diff --git a/Bands.cpp b/Bands.cpp
index 3759b634d..d182eb1dd 100644
--- a/Bands.cpp
+++ b/Bands.cpp
@@ -195,3 +195,29 @@ QVariant Bands::headerData (int section, Qt::Orientation orientation, int role)
 
   return result;
 }
+
+QString Bands::const_iterator::operator * ()
+{
+  return ADIF_bands[row_].name_;
+}
+
+bool Bands::const_iterator::operator != (const_iterator const& rhs) const
+{
+  return row_ != rhs.row_;
+}
+
+auto Bands::const_iterator::operator ++ () -> const_iterator&
+{
+  ++row_;
+  return *this;
+}
+
+auto Bands::begin () const -> Bands::const_iterator
+{
+  return const_iterator (0);
+}
+
+auto Bands::end () const -> Bands::const_iterator
+{
+  return const_iterator (table_rows ());
+}
diff --git a/Bands.hpp b/Bands.hpp
index 1b61b4283..adfe21309 100644
--- a/Bands.hpp
+++ b/Bands.hpp
@@ -32,6 +32,23 @@ class Bands final
 public:
   using Frequency = Radio::Frequency;
 
+  // an iterator that meets the requirements of the C++ for range statement
+  class const_iterator
+  {
+  public:
+    const_iterator (int row)
+      : row_ {row}
+    {
+    }
+
+    QString operator * ();
+    bool operator != (const_iterator const&) const;
+    const_iterator& operator ++ ();
+
+  private:
+    int row_;
+  };
+
   explicit Bands (QObject * parent = nullptr);
 
   //
@@ -40,6 +57,10 @@ public:
   QString find (Frequency) const; // find band Frequency is in
   static QString const& oob ();
 
+  // Iterators
+  const_iterator begin () const;
+  const_iterator end () const;
+
   // Custom role for sorting.
   static int constexpr SortRole = Qt::UserRole;
 
diff --git a/FrequencyList.cpp b/FrequencyList.cpp
index f9f7b8436..015dfd3c2 100644
--- a/FrequencyList.cpp
+++ b/FrequencyList.cpp
@@ -173,8 +173,26 @@ int FrequencyList::best_working_frequency (Frequency f) const
   auto const& target_band = m_->bands_->find (f);
   if (!target_band.isEmpty ())
     {
-      // find a frequency in the same band that is allowed for the
-      // target mode
+      // find a frequency in the same band that is allowed
+      for (int row = 0; row < rowCount (); ++row)
+        {
+          auto const& source_row = mapToSource (index (row, 0)).row ();
+          auto const& band = m_->bands_->find (m_->frequency_list_[source_row].frequency_);
+          if (band == target_band)
+            {
+              return row;
+            }
+        }
+    }
+  return result;
+}
+
+int FrequencyList::best_working_frequency (QString const& target_band) const
+{
+  int result {-1};
+  if (!target_band.isEmpty ())
+    {
+      // find a frequency in the same band that is allowed
       for (int row = 0; row < rowCount (); ++row)
         {
           auto const& source_row = mapToSource (index (row, 0)).row ();
@@ -553,3 +571,23 @@ auto FrequencyList::end () const -> FrequencyList::const_iterator
 {
   return const_iterator (this, rowCount ());
 }
+
+auto FrequencyList::all_bands () const -> BandSet
+{
+  BandSet result;
+  for (auto const& item : m_->frequency_list_)
+    {
+      result << m_->bands_->find (item.frequency_);
+    }
+  return result;
+}
+
+auto FrequencyList::filtered_bands () const -> BandSet
+{
+  BandSet result;
+  for (auto const& item : *this)
+    {
+      result << m_->bands_->find (item.frequency_);
+    }
+  return result;
+}
diff --git a/FrequencyList.hpp b/FrequencyList.hpp
index 0be83abe1..c5c001a8d 100644
--- a/FrequencyList.hpp
+++ b/FrequencyList.hpp
@@ -14,18 +14,21 @@ class Bands;
 //
 // Class FrequencyList
 //
-//  Encapsulates a collection of frequencies.  The implementation is a
-//  table  containing the  list of  Frequency type  elements which  is
-//  editable  and  a  second  column  which  is  an  immutable  double
-//  representation  of  the  corresponding Frequency  item  scaled  to
-//  mega-Hertz.
+//  Encapsulates a  collection of  frequencies with  associated modes.
+//  The implementation is a table containing the list of Frequency and
+//  mode tuples which  are editable. A third column is  modeled in the
+//  model  which   is  an  immutable  double   representation  of  the
+//  corresponding Frequency item scaled to mega-Hertz.
 //
-//  The list is ordered.
+//  The list is ordered.  A filter on mode is available  and is set by
+//  the filter(Mode)  method. The  Mode value  Modes::NULL_MODE passes
+//  all rows in the filter.
 //
 // Responsibilities
 //
-//  Stores internally a list  of unique frequencies.  Provides methods
-//  to add and delete list elements.
+//  Stores  internally  a  list   of  unique  frequency  mode  tuples.
+//  Provides methods to add and delete list elements. Provides range
+//  iterators for a filtered view of the underlying table.
 //
 // Collaborations
 //
@@ -47,6 +50,7 @@ public:
     Mode mode_;
   };
   using FrequencyItems = QList<Item>;
+  using BandSet = QSet<QString>;
 
   enum Column {mode_column, frequency_column, frequency_mhz_column};
 
@@ -81,16 +85,26 @@ public:
   // Note that these iterators are on the final sorted and filtered
   // rows, if you need to access the underlying unfiltered and
   // unsorted frequencies then use the frequency_list() member to
-  // access the underlying list of rows
+  // access the underlying list of rows.
   const_iterator begin () const;
   const_iterator end () const;
 
+  // Bands of the frequencies
+  BandSet all_bands () const;
+  BandSet filtered_bands () const;
+
   // Find the row of the nearest best working frequency given a
-  // frequency and mode
+  // frequency. Returns -1 if no suitable working frequency is found
+  // in the list.
   int best_working_frequency (Frequency) const;
 
+  // Find the row  of the nearest best working frequency  given a band
+  // name. Returns -1 if no suitable working frequency is found in the
+  // list.
+  int best_working_frequency (QString const& band) const;
+
   // Set filter
-  void filter (Mode);
+  Q_SLOT void filter (Mode);
 
   // Reset
   Q_SLOT void reset_to_defaults ();
diff --git a/mainwindow.cpp b/mainwindow.cpp
index e874fdf57..9cfcc5393 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -52,6 +52,9 @@ namespace
   Radio::Frequency constexpr default_frequency {14076000};
   QRegExp message_alphabet {"[- @A-Za-z0-9+./?#]*"};
 
+  // These 10 bands are the hopping candidates and are globally coordinated
+  QStringList const hopping_bands = {"160m","80m","60m","40m","30m","20m","17m","15m","12m","10m"};
+
   bool message_is_73 (int type, QStringList const& msg_parts)
   {
     return type >= 0
@@ -390,20 +393,8 @@ MainWindow::MainWindow(bool multiple, QSettings * settings, QSharedMemory *shdme
   m_uploading=false;
   m_hopTest=false;
   m_bTxTime=false;
-  m_band00=-1;
   m_rxDone=false;
 
-  m_fWSPR["160"]=1.8366;                //WSPR frequencies
-  m_fWSPR["80"]=3.5926;
-  m_fWSPR["60"]=5.2872;
-  m_fWSPR["40"]=7.0386;
-  m_fWSPR["30"]=10.1387;
-  m_fWSPR["20"]=14.0956;
-  m_fWSPR["17"]=18.1046;
-  m_fWSPR["15"]=21.0946;
-  m_fWSPR["12"]=24.9246;
-  m_fWSPR["10"]=28.1246;
-
   signalMeter = new SignalMeter(ui->meterFrame);
   signalMeter->resize(50, 160);
 
@@ -2224,16 +2215,8 @@ void MainWindow::startTx2()
     transmit (snr);
     signalMeter->setValue(0);
     if(m_mode.mid(0,4)=="WSPR" and !m_tune) {
-<<<<<<< variant A
-      t = " Transmitting " + m_mode + " ----------------------- " +
-        QString {m_config.bands ()->find (m_dialFreq)->name_};
->>>>>>> variant B
       t = " Transmiting " + m_mode + " ----------------------- " +
         m_config.bands ()->find (m_dialFreq);
-####### Ancestor
-      t = " Transmiting " + m_mode + " ----------------------- " +
-        QString {m_config.bands ()->find (m_dialFreq)->name_};
-======= end
       ui->decodedTextBrowser->append(t.rightJustified (71, '-'));
 
       QFile f {m_dataDir.absoluteFilePath ("ALL_WSPR.TXT")};
@@ -3821,14 +3804,15 @@ void MainWindow::pskSetLocal ()
 {
   // find the station row, if any, that matches the band we are on
   auto stations = m_config.stations ();
-  auto matches = stations->match (stations->index (0, 0)
+  auto matches = stations->match (stations->index (0, StationList::band_column)
                                   , Qt::DisplayRole
                                   , ui->bandComboBox->currentText ()
                                   , 1
                                   , Qt::MatchExactly);
   QString antenna_description;
   if (!matches.isEmpty ()) {
-    antenna_description = stations->index (matches.first ().row (), 2).data ().toString ();
+    antenna_description = stations->index (matches.first ().row ()
+                                           , StationList::description_column).data ().toString ();
   }
   psk_Reporter->setLocalStation(m_config.my_callsign (), m_config.my_grid (),
         antenna_description, QString {"WSJT-X v" + version() + " " +
@@ -4274,7 +4258,6 @@ void MainWindow::on_cbBandHop_toggled(bool b)
 
 void MainWindow::bandHopping()
 {
-  QString bandName[]={"160","80","60","40","30","20","17","15","12","10"};
   QDateTime t = QDateTime::currentDateTimeUtc();
   QString date = t.date().toString("yyyy MMM dd").trimmed();
   QString utc = t.time().toString().trimmed();
@@ -4286,9 +4269,8 @@ void MainWindow::bandHopping()
   float sec=t.time().second() + 0.001*t.time().msec();
   float uth=nhr + nmin/60.0 + sec/3600.0;
   int isun;
-  int iband0,iband;
+  int iband0;
   int ntxnext;
-  int i,j;
 
   static int icall=0;
   if(m_hopTest) uth+= 2.0*icall/60.0;
@@ -4296,7 +4278,7 @@ void MainWindow::bandHopping()
 
 // Find grayline status, isun: 0=Sunrise, 1=Day, 2=Sunset, 3=Night
   hopping_(&nyear, &month, &nday, &uth,
-           const_cast <char *> (m_config.my_grid ().toLatin1().constData()),
+           m_config.my_grid ().toLatin1().constData(),
            &m_grayDuration, &m_pctx, &isun, &iband0, &ntxnext, 6);
 
 
@@ -4306,97 +4288,72 @@ void MainWindow::bandHopping()
     m_nrx=1;
   }
 
-if( m_bandHopping ) {
-  QString bname;
-  QStringList s;
-  if(isun==0) s=m_sunriseBands;
-  if(isun==1) s=m_dayBands;
-  if(isun==2) s=m_sunsetBands;
-  if(isun==3) s=m_nightBands;
+  if( m_bandHopping ) {
+    QStringList s;
+    if(isun==0) s=m_sunriseBands;
+    if(isun==1) s=m_dayBands;
+    if(isun==2) s=m_sunsetBands;
+    if(isun==3) s=m_nightBands;
 
-  Frequency f0=0;
-  iband=-1;
-  for(i=0; i<s.length(); i++) {              //See if designated band is active
-    if(s.at(i)==bandName[iband0]) {
-      f0=(Frequency)1000000*m_fWSPR[bandName[iband0]]+0.5;
-      bname=s.at(i);
-      iband=iband0;
+    QString new_band;
+    if (s.contains (hopping_bands[iband0])) { //See if designated band is active
+      new_band = hopping_bands[iband0];
     }
-  }
-
-//If designated band is not active, choose one that is active
-  if(iband==-1) {
-    for(i=0; i<s.length(); i++) {
-      j=qrand() % s.length();
-      bname=s.at(j);
-      f0=(Frequency)1000000*m_fWSPR[bname]+0.5;
-      if(s.at(j)!=bandName[m_band00]) break;
-    }
-    for(i=0; i<10; i++) {
-      if(bname==bandName[i]) {
-        iband=i;
-        break;
+    else {
+      // If designated band is not active, choose one that is active
+      // and in the hopping list
+      for (auto i = 0; i < s.size (); ++i) { // arbitrary number of iterations
+        auto const& bname = s[qrand() % s.size ()]; // pick a random band
+        if (bname != m_band00 && hopping_bands.contains (bname)) {
+          new_band = bname;
+          break;
+        }
       }
     }
-  }
+    qDebug () << "bandHopping: m_band00:" << m_band00 << "new candidate band:" << new_band;
 
-  QThread::msleep(1500);
+    QThread::msleep(1500);
 
-//  qDebug() << nhr << nmin << int(sec) << bname << f0 << 0.000001*f0;
+    //  qDebug() << nhr << nmin << int(sec) << m_band00 << f0 << 0.000001*f0;
 
-  m_band00=iband;
-  auto frequencies = m_config.frequencies ();
-  // Iterate the filtered-by-mode FrequencyList model
-  for (int row = 0; row < frequencies->rowCount (); ++row) {
-    // Lookup the underlying source model index from the filtered model index
-    auto const& source_index = frequencies->mapToSource (frequencies->index (row, FrequencyList::frequency_column));
-    // and use it to directly access the list of frequencies that the
-    // FrequencyList model wraps (we could also use the model data()
-    // member using the EditRole of the frequency_column but this way
-    // avoids going via a QVariant item)
-    auto const& f = frequencies->frequency_list ()[source_index.row ()].frequency_;
-    if(f==f0) {
-      on_bandComboBox_activated(row); //Set new band
-//      qDebug() << nhr << nmin << int(sec) << "Band selected" << i << 0.000001*f0 << 0.000001*f;
-      break;
+    auto const& row = m_config.frequencies ()->best_working_frequency (new_band);
+    if (row >= 0) {             // band is configured
+      m_band00 = new_band;
+      ui->bandComboBox->setCurrentIndex (row);
+      on_bandComboBox_activated (row);
+
+      m_cmnd="";
+      QFile f1 {m_appDir + "/user_hardware.bat"};
+      if(f1.exists()) {
+        m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware.bat ") + m_band00;
+      }
+      QFile f2 {m_appDir + "/user_hardware.cmd"};
+      if(f2.exists()) {
+        m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware.cmd ") + m_band00;
+      }
+      QFile f3 {m_appDir + "/user_hardware.exe"};
+      if(f3.exists()) {
+        m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware.exe ") + m_band00;
+      }
+      QFile f4 {m_appDir + "/user_hardware"};
+      if(f4.exists()) {
+        m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware ") + m_band00;
+      }
+      if(m_cmnd!="") p3.start(m_cmnd);     // Execute user's hardware controller
+
+      // Produce a short tuneup signal
+      m_tuneup = false;
+      if (m_tuneBands.contains (m_band00)) {
+          m_tuneup = true;
+          on_tuneButton_clicked (true);
+          tuneATU_Timer->start (2500);
+      }
     }
-  }
 
-  m_cmnd="";
-  QFile f1 {m_appDir + "/user_hardware.bat"};
-  if(f1.exists()) {
-    m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware.bat ") + bname;
+    // Display grayline status
+    QString dailySequence[4]={"Sunrise grayline","Day","Sunset grayline","Night"};
+    auto_tx_label->setText(dailySequence[isun]);
   }
-  QFile f2 {m_appDir + "/user_hardware.cmd"};
-  if(f2.exists()) {
-    m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware.cmd ") + bname;
-  }
-  QFile f3 {m_appDir + "/user_hardware.exe"};
-  if(f3.exists()) {
-    m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware.exe ") + bname;
-  }
-  QFile f4 {m_appDir + "/user_hardware"};
-  if(f4.exists()) {
-    m_cmnd=QDir::toNativeSeparators (m_appDir + "/user_hardware ") + bname;
-  }
-  if(m_cmnd!="") p3.start(m_cmnd);     // Execute user's hardware controller
-
-// Displat grayline status
-  QString dailySequence[4]={"Sunrise grayline","Day","Sunset grayline","Night"};
-  auto_tx_label->setText(dailySequence[isun]);
-
-// Produce a short tuneup signal
-  s=m_tuneBands;
-  m_tuneup=false;
-  for(int i=0; i<s.length(); i++) {
-    if(s.at(i)==bname) m_tuneup=true;
-  }
-  if(m_tuneup) {
-    on_tuneButton_clicked(true);
-    tuneATU_Timer->start(2500);
-  }
-} //endif m_bandHopping
-
 }
 
 void MainWindow::on_pushButton_clicked()
diff --git a/mainwindow.h b/mainwindow.h
index c670a6283..74bf5d99b 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -328,7 +328,7 @@ private:
   qint32  m_pctx;
   qint32  m_nseq;
   qint32  m_grayDuration;
-  qint32  m_band00;
+  QString m_band00;
 
   bool    m_btxok;		//True if OK to transmit
   bool    m_diskData;
@@ -454,8 +454,6 @@ private:
   QStringList m_nightBands;
   QStringList m_tuneBands;
 
-  QMap<QString,double> m_fWSPR;
-
   QHash<QString,bool> m_pfx;
   QHash<QString,bool> m_sfx;
 
@@ -552,7 +550,7 @@ extern "C" {
   void wspr_downsample_(short int d2[], int* k);
   void savec2_(char* fname, int* m_TRseconds, double* m_dialFreq, int len1);
 
-  void hopping_(int* nyear, int* month, int* nday, float* uth, char* MyGrid,
+  void hopping_(int* nyear, int* month, int* nday, float* uth, char const * MyGrid,
                 int* nduration, int* npctx, int* isun, int* iband,
                 int* ntxnext, int len);
 }