diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6c38ac422..b36ac2226 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -865,7 +865,7 @@ if (Fortran_COMPILER_NAME MATCHES "gfortran.*")
     set (CMAKE_Fortran_FLAGS "${CMAKE_Fortran_FLAGS} -isysroot ${CMAKE_OSX_SYSROOT}")
   endif (CMAKE_OSX_SYSROOT)
 
-  set (CMAKE_Fortran_FLAGS_RELEASE "${CMAKE_Fortran_FLAGS_RELEASE} -funroll-all-loops -fno-f2c ${General_FFLAGS}")
+  set (CMAKE_Fortran_FLAGS_RELEASE "${CMAKE_Fortran_FLAGS_RELEASE} -fbounds-check -funroll-all-loops -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)
diff --git a/lib/fsk4hf/genwsprlf.f90 b/lib/fsk4hf/genwsprlf.f90
index bd9e2472e..0364c5bc3 100644
--- a/lib/fsk4hf/genwsprlf.f90
+++ b/lib/fsk4hf/genwsprlf.f90
@@ -1,4 +1,4 @@
-subroutine genwsprlf(msgbits,id,icw,cbb,csync)
+subroutine genwsprlf(msgbits,id,icw,cbb,csync,itone)
 
 !Encode a WSPR-LF message, produce baseband waveform and sync vector.
 
@@ -6,7 +6,7 @@ subroutine genwsprlf(msgbits,id,icw,cbb,csync)
   parameter (ND=300)                    !Data symbols: LDPC (300,60), r=1/5
   parameter (NS=109)                    !Sync symbols (2 x 48 + Barker 13)
   parameter (NR=3)                      !Ramp up/down (2 x half-length symbols)
-  parameter (NN=NR+NS+ND)               !Total symbols (410)
+  parameter (NN=NR+NS+ND)               !Total symbols (412)
   parameter (NSPS=16)                   !Samples per MSK symbol (16)
   parameter (N2=2*NSPS)                 !Samples per OQPSK symbol (32)
   parameter (N13=13*N2)                 !Samples in central sync vector (416)
@@ -22,8 +22,10 @@ subroutine genwsprlf(msgbits,id,icw,cbb,csync)
   integer*1 msgbits(KK),codeword(ND)
   integer icw(ND)
   integer id(NS+ND)
+  integer jd(NS+ND)
   integer isync(48)                          !Long sync vector
   integer ib13(13)                           !Barker 13 code
+  integer itone(NN)
   integer*8 n8
   data ib13/1,1,1,1,1,-1,-1,1,1,-1,1,-1,1/
   data first/.true./
@@ -125,5 +127,21 @@ subroutine genwsprlf(msgbits,id,icw,cbb,csync)
   enddo
   csync=x
 
+! Map I and Q to tones.
+  n=0
+  do i=1,204
+     n=n+1
+     jd(n)=id(i)/abs(id(i))
+     n=n+1
+     jd(n)=id(i+205)/abs(id(i+205))
+  enddo
+  jd(409)=id(205)/abs(id(205))
+  itone=0 
+  do i=1,204
+     itone(2*i-1)=(jd(2*i)*jd(2*i-1)+1)/2;
+     itone(2*i)=-(jd(2*i)*jd(2*i+1)-1)/2;
+  enddo
+  itone(409)=jd(409)                       !### Is this correct ??? ###
+
   return
 end subroutine genwsprlf
diff --git a/lib/fsk4hf/wsprlfsim.f90 b/lib/fsk4hf/wsprlfsim.f90
index b27b9f9ba..87a8b3728 100644
--- a/lib/fsk4hf/wsprlfsim.f90
+++ b/lib/fsk4hf/wsprlfsim.f90
@@ -31,10 +31,12 @@ program wsprlfsim
   complex cb13(0:N13-1)                 !Barker 13 waveform
   complex c(0:NZ-1)                     !Complex waveform
   complex c0(0:NZ-1)                    !Complex waveform
+  complex c1(0:NZ-1)                    !Complex waveform
   complex zz(NS+ND)                     !Complex symbol values (intermediate)
   complex z
   real xnoise(0:NZ-1)                   !Generated random noise
   real ynoise(0:NZ-1)                   !Generated random noise
+  real s(0:NZ-1)
   real rxdata(ND),llr(ND)               !Soft symbols
   real pp(2*NSPS)                       !Shaped pulse for OQPSK
   real a(5)                             !For twkfreq1
@@ -42,6 +44,7 @@ program wsprlfsim
   integer id(NS+ND)                     !NRZ values (+/-1) for Sync and Data
   integer ierror(NS+ND)
   integer icw(NN)
+  integer itone(NN)
   integer*1 msgbits(KK),decoded(KK),apmask(ND),cw(ND)
 !  integer*1 codeword(ND)
   data msgbits/0,0,1,0,0,1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,1,1,0,0,0,1, &
@@ -84,15 +87,12 @@ program wsprlfsim
      pp(i)=sin(0.5*(i-1)*twopi/(2*NSPS))
   enddo
 
-  call genwsprlf(msgbits,id,icw,cbb,csync)!Generate baseband waveform and csync
+  call genwsprlf(msgbits,id,icw,cbb,csync,itone)!Generate baseband waveform
   cb13=csync(3088:3503)                  !Copy the Barker 13 waveform
   a=0.
   a(1)=f0
-  call twkfreq1(cbb,NZ,fs,a,cbb)         !Mix to specified frequency
-
-!  write(*,3101) id
-!3101 format(20i3)
-
+  call twkfreq1(cbb,NZ,fs,a,c0)          !Mix baseband to specified frequency
+  
   isna=-20
   isnb=-40
   if(snrdb.ne.0.0) then
@@ -109,7 +109,7 @@ program wsprlfsim
      sqf=0.
      sqt=0.
      do iter=1,iters                     !Loop over requested iterations
-        c=cbb 
+        c=c0 
         if(delay.ne.0.0 .or. fspread.ne.0.0) then
            call watterson(c,NZ,fs,delay,fspread)
         endif
@@ -167,7 +167,7 @@ program wsprlfsim
 !-----------------------------------------------------------------        
 
         nterms=maxn
-        c0=c
+        c1=c
         do itry=1,20
            idf=itry/2
            if(mod(itry,2).eq.0) idf=-idf
@@ -176,7 +176,7 @@ program wsprlfsim
            ifer=1
            a(1)=idf*0.00085
            a(2:5)=0.
-           call twkfreq1(c0,NZ,fs,a,c)       !Mix c0 into c
+           call twkfreq1(c1,NZ,fs,a,c)       !Mix c1 into c
            call cpolyfitw(c,pp,id,maxn,aa,bb,zz,nhs)
            call msksoftsymw(zz,aa,bb,id,nterms,ierror,rxdata,nhard0,nhardsync0)
            if(nhardsync0.gt.35) cycle