diff --git a/CMakeLists.txt b/CMakeLists.txt
index 12b41b1d4..b3fbfcbbd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -241,6 +241,7 @@ set (wsjt_FSRCS
   lib/dcoord.f90
   lib/decode65a.f90
   lib/decode65b.f90
+  lib/fftw3mod.f90
   lib/jt9fano.f90
   lib/decoder.f90
   lib/decjt9.f90
@@ -256,7 +257,6 @@ set (wsjt_FSRCS
   lib/fano232.f90
   lib/fchisq.f90
   lib/fchisq65.f90
-  lib/fftw3mod.f90
   lib/fil3.f90
   lib/fil4.f90
   lib/fil6521.f90
@@ -492,7 +492,7 @@ endif (APPLE)
 #
 # Fortran setup
 #
-set (General_FFLAGS "-fbounds-check -Wall -Wno-conversion -fno-second-underscore")
+set (General_FFLAGS "-Wall -Wno-conversion -fno-second-underscore")
 
 # FFLAGS depend on the compiler
 get_filename_component (Fortran_COMPILER_NAME ${CMAKE_Fortran_COMPILER} NAME)
@@ -509,7 +509,7 @@ if (Fortran_COMPILER_NAME MATCHES "gfortran.*")
   endif (CMAKE_OSX_SYSROOT)
 
   set (CMAKE_Fortran_FLAGS_RELEASE "${CMAKE_Fortran_FLAGS_RELEASE} -funroll-all-loops -fno-f2c ${General_FFLAGS}")
-  set (CMAKE_Fortran_FLAGS_DEBUG   "${CMAKE_Fortran_FLAGS_DEBUG} -fno-f2c ${General_FFLAGS}")
+  set (CMAKE_Fortran_FLAGS_DEBUG   "${CMAKE_Fortran_FLAGS_DEBUG} -fbounds-check -fno-f2c ${General_FFLAGS}")
 elseif (Fortran_COMPILER_NAME MATCHES "ifort.*")
   # ifort (untested)
   set (CMAKE_Fortran_FLAGS_RELEASE "${CMAKE_Fortran_FLAGS_RELEASE} -f77rtl ${General_FFLAGS}")
@@ -517,13 +517,13 @@ elseif (Fortran_COMPILER_NAME MATCHES "ifort.*")
 elseif (Fortran_COMPILER_NAME MATCHES "g77")
   # g77
   set (CMAKE_Fortran_FLAGS_RELEASE "${CMAKE_Fortran_FLAGS_RELEASE} -funroll-all-loops -fno-f2c -m32 ${General_FFLAGS}")
-  set (CMAKE_Fortran_FLAGS_DEBUG   "${CMAKE_Fortran_FLAGS_DEBUG} -fno-f2c -m32 ${General_FFLAGS}")
+  set (CMAKE_Fortran_FLAGS_DEBUG   "${CMAKE_Fortran_FLAGS_DEBUG} -fbounds-check -fno-f2c -m32 ${General_FFLAGS}")
 else (Fortran_COMPILER_NAME MATCHES "gfortran.*")
   message ("CMAKE_Fortran_COMPILER full path: " ${CMAKE_Fortran_COMPILER})
   message ("Fortran compiler: " ${Fortran_COMPILER_NAME})
   message ("No optimized Fortran compiler flags are known, we just try -O2...")
   set (CMAKE_Fortran_FLAGS_RELEASE "${CMAKE_Fortran_FLAGS_RELEASE} -O2 ${General_FFLAGS}")
-  set (CMAKE_Fortran_FLAGS_DEBUG   "${CMAKE_Fortran_FLAGS_DEBUG} ${General_FFLAGS}")
+  set (CMAKE_Fortran_FLAGS_DEBUG   "${CMAKE_Fortran_FLAGS_DEBUG} -fbounds-check ${General_FFLAGS}")
 endif (Fortran_COMPILER_NAME MATCHES "gfortran.*")
 
 
@@ -593,6 +593,12 @@ if (NOT "${QT_LIBRARY_DIR}" STREQUAL "/lib" AND NOT "${QT_LIBRARY_DIR}" STREQUAL
 endif ()
 
 
+#
+# OpenMP
+#
+find_package (OpenMP)
+
+
 #
 # fftw3 single precsion library
 #
@@ -698,8 +704,17 @@ endif (WIN32)
 # targets
 #
 
-# build a library of package functionality
+# build a library of package functionality (without and optionally with OpenMP support)
 add_library (wsjt STATIC ${wsjt_CSRCS} ${wsjt_CXXSRCS} ${wsjt_FSRCS})
+if (${OPENMP_FOUND})
+  add_library (wsjt_omp STATIC ${wsjt_CSRCS} ${wsjt_CXXSRCS} ${wsjt_FSRCS})
+  file (MAKE_DIRECTORY ${CMAKE_BINARY_DIR}/fortran_modules_omp)
+  set_target_properties (wsjt_omp
+    PROPERTIES
+    COMPILE_FLAGS ${OpenMP_C_FLAGS}
+    Fortran_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/fortran_modules_omp
+    )
+endif (${OPENMP_FOUND})
 
 # build a library of package Qt functionality
 add_library (wsjt_qt STATIC ${wsjt_qt_CXXSRCS} ${wsjt_qt_GENUISRCS} ${GENAXSRCS})
@@ -721,6 +736,18 @@ add_executable (jt9 lib/jt9.f90 lib/jt9a.f90 lib/jt9b.f90 lib/jt9c.f90 ${jt9_CXX
 target_link_libraries (jt9 wsjt ${FFTW3_LIBRARIES})
 qt5_use_modules (jt9 Core)
 
+if (${OPENMP_FOUND})
+  add_executable (jt9_omp lib/jt9.f90 lib/jt9a.f90 lib/jt9b.f90 lib/jt9c.f90 ${jt9_CXXSRCS} wsjtx.rc)
+  set_target_properties (jt9_omp
+    PROPERTIES
+    COMPILE_FLAGS ${OpenMP_C_FLAGS}
+    Fortran_MODULE_DIRECTORY ${CMAKE_BINARY_DIR}/fortran_modules_omp
+    LINK_FLAGS "${OpenMP_C_FLAGS} -Wl,--stack,8388608"
+    )
+  target_link_libraries (jt9_omp wsjt_omp ${FFTW3_LIBRARIES})
+  qt5_use_modules (jt9_omp Core)
+endif (${OPENMP_FOUND})
+
 # build configuration dialog and transceiver interface test application
 #add_executable (ConfigTest ${ConfigTest_CXXSRCS} ${ConfigTest_GENUISRCS} wsjtx.rc)
 #target_link_libraries (ConfigTest wsjt wsjt_qt ${hamlib_LIBRARIES})
@@ -790,7 +817,7 @@ install (TARGETS wsjtx
   BUNDLE DESTINATION . COMPONENT runtime
   )
 
-install (TARGETS jt9 jt65code jt9code
+install (TARGETS jt9 jt65code jt9code jt9_omp
   RUNTIME DESTINATION ${WSJT_BIN_DESTINATION} COMPONENT runtime
   BUNDLE DESTINATION ${WSJT_BIN_DESTINATION} COMPONENT runtime
   )
diff --git a/lib/decoder.f90 b/lib/decoder.f90
index d65a4e890..4d3013b1d 100644
--- a/lib/decoder.f90
+++ b/lib/decoder.f90
@@ -50,17 +50,16 @@ subroutine decoder(ss,id2)
   if(nmode.eq.65) go to 800
 
 !  print*,'A'
-!!$OMP PARALLEL PRIVATE(id)
-!!$OMP SECTIONS
+!$OMP PARALLEL SECTIONS PRIVATE(id)
 
-!!$OMP SECTION
+!$OMP SECTION
 !  print*,'B'
   call timer('decjt9  ',0)
   call decjt9(ss,id2,nutc,nfqso,newdat,npts8,nfa,nfsplit,nfb,ntol,nzhsym,  &
        nagain,ndepth,nmode)
   call timer('decjt9  ',1)
 
-!!$OMP SECTION
+!$OMP SECTION
   if(nmode.ge.65 .and. (.not.done65)) then
      if(newdat.ne.0) dd(1:npts65)=id2(1:npts65)
      nf1=nfa
@@ -71,8 +70,7 @@ subroutine decoder(ss,id2)
      call timer('jt65a   ',1)
   endif
 
-!!$OMP END SECTIONS NOWAIT
-!!$OMP END PARALLEL 
+!$OMP END PARALLEL SECTIONS
 !  print*,'D'
 
 ! JT65 is not yet producing info for nsynced, ndecoded.