diff --git a/CMakeLists.txt b/CMakeLists.txt
index 81b620f68..f5908f7f4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -317,7 +317,6 @@ set (wsjt_FSRCS
   lib/grayline.f90
   lib/grid2deg.f90
   lib/hash.f90
-  lib/hopping.f90
   lib/image.f90
   lib/indexx.f90
   lib/interleave4.f90
@@ -629,7 +628,7 @@ include (FortranCInterface)
 FortranCInterface_VERIFY (CXX QUIET)
 FortranCInterface_HEADER (FC.h MACRO_NAMESPACE "FC_" SYMBOL_NAMESPACE "FC_"
   SYMBOLS
-  hopping
+  grayline
   )
 
 
diff --git a/WSPRBandHopping.cpp b/WSPRBandHopping.cpp
index 27f8e3316..b2a1f49d5 100644
--- a/WSPRBandHopping.cpp
+++ b/WSPRBandHopping.cpp
@@ -17,10 +17,10 @@
 extern "C"
 {
 #ifndef CMAKE_BUILD
-#define FC_hopping hopping_
+#define FC_grayline grayline_
 #else
 #include "FC.h"
-  void FC_hopping (int const * year, int const * month, int const * nday, float const * uth, char const * my_grid
+  void FC_grayline (int const * year, int const * month, int const * nday, float const * uth, char const * my_grid
                    , int const * nduration, int * isun
                    , int my_grid_len);
 #endif
@@ -312,10 +312,10 @@ auto WSPRBandHopping::next_hop () -> Hop
   my_grid = (my_grid + "      ").left (6); // hopping doesn't like
                                            // short grids
 
-  // look up band for this period
-  FC_hopping (&year, &month, &day, &uth, my_grid.toLatin1 ().constData ()
-           , &m_->gray_line_duration_, &period_index
-           , my_grid.size ());
+  // look up the period for this time
+  FC_grayline (&year, &month, &day, &uth, my_grid.toLatin1 ().constData ()
+               , &m_->gray_line_duration_, &period_index
+               , my_grid.size ());
 
   band_index = next_hopping_band();
 
diff --git a/lib/hopping.f90 b/lib/hopping.f90
deleted file mode 100644
index d27d8b96a..000000000
--- a/lib/hopping.f90
+++ /dev/null
@@ -1,8 +0,0 @@
-subroutine hopping(nyear,month,nday,uth,mygrid,nduration,isun)
-
-  character*6 mygrid
-
-  call grayline(nyear,month,nday,uth,mygrid,nduration,isun)
-
-  return
-end subroutine hopping