diff --git a/lib/fsk4hf/wspr_fsk8_sim.f90 b/lib/fsk4hf/wspr_fsk8_sim.f90
index e2c587c8d..b4003f8da 100644
--- a/lib/fsk4hf/wspr_fsk8_sim.f90
+++ b/lib/fsk4hf/wspr_fsk8_sim.f90
@@ -8,14 +8,17 @@ program wspr_fsk8_sim
   type(hdr) h                            !Header for .wav file
   character arg*12,fname*16
   character msg*22,msgsent*22
+  complex c0(0:NZ-1)
+  complex c(0:NZ-1)
+  real*8 fMHz
   integer itone(NN)
   integer*2 iwave(NMAX)                  !Generated full-length waveform  
 
 ! Get command-line argument(s)
   nargs=iargc()
-  if(nargs.ne.5) then
-     print*,'Usage:   wspr_fsk8_sim "message"        f0   DT nfiles snr'
-     print*,'Example: wspr_fsk8_sim "K1ABC FN42 30" 1640 0.0   10   -33'
+  if(nargs.ne.8) then
+     print*,'Usage:   wspr5sim "message"       f0  DT fsp del  nwav nfiles snr'
+     print*,'Example: wspr5sim "K1ABC FN42 30" 50 0.0 0.1 1.0  1      10   -33'
      go to 999
   endif
   call getarg(1,msg)                     !Message to be transmitted
@@ -24,8 +27,14 @@ program wspr_fsk8_sim
   call getarg(3,arg)
   read(arg,*) xdt                        !Time offset from nominal (s)
   call getarg(4,arg)
-  read(arg,*) nfiles                     !Number of files
+  read(arg,*) fspread                    !Watterson frequency spread (Hz)
   call getarg(5,arg)
+  read(arg,*) delay                      !Watterson delay (ms)
+  call getarg(6,arg)
+  read(arg,*) nwav                       !1 for *.wav file, 0 for *.c4 file
+  call getarg(7,arg)
+  read(arg,*) nfiles                     !Number of files
+  call getarg(8,arg)
   read(arg,*) snrdb                      !SNR_2500
 
   twopi=8.0*atan(1.0)
@@ -45,15 +54,53 @@ program wspr_fsk8_sim
 1000 format('f0:',f9.3,'   DT:',f6.2,'   TxT:',f6.1,'   SNR:',f6.1,    &
           '  BW:',f4.1,2x,a22)
 
+
+  phi=0.0
+  c0=0.
+  k=-1 + nint(xdt/dt)
+  do j=1,NN                              !Generate OQPSK waveform from itone
+     dphi=twopi*(f0+itone(j)*baud)*dt
+     if(k.eq.0) phi=-dphi
+     do i=1,NSPS
+        k=k+1
+        phi=phi+dphi
+        if(phi.gt.twopi) phi=phi-twopi
+        xphi=phi
+        if(k.ge.0 .and. k.lt.NZ) c0(k)=cmplx(cos(xphi),sin(xphi))
+     enddo
+  enddo
+
+  if( fspread .ne. 0.0 .or. delay .ne. 0.0 ) then
+    call watterson(c0,NZ,fs,delay,fspread)
+  endif
+
+  c0=sig*c0                              !Scale to requested sig level
+
   do ifile=1,nfiles
-     call wspr_fsk8_wav(baud,xdt,f0,itone,snrdb,iwave)
-     h=default_header(12000,NMAX)
-     write(fname,1102) ifile
-1102 format('000000_',i4.4,'.wav')
-     open(10,file=fname,status='unknown',access='stream')
-     write(10) h,iwave                !Save to *.wav file
-     close(10)
-     write(*,1110) ifile,xdt,f0,snrdb,fname
+    if(nwav.eq.0) then
+      if( snrdb.lt.90) then
+        do i=0,NZ-1
+          xnoise=gran()
+          ynoise=gran()
+          c(i)=c0(i)+cmplx(xnoise,ynoise)
+        enddo
+      endif
+      write(fname,1100) ifile
+1100  format('000000_',i4.4,'.c4')
+      open(10,file=fname,status='unknown',access='stream')
+      fMHz=1.866d0
+      nmin=4
+      write(10) fname,nmin,fMHz,c
+    else
+      call wspr_fsk8_wav(baud,xdt,f0,itone,snrdb,iwave)
+      h=default_header(12000,NMAX)
+      write(fname,1102) ifile
+1102  format('000000_',i4.4,'.wav')
+      open(10,file=fname,status='unknown',access='stream')
+      write(10) h,iwave                !Save to *.wav file
+      close(10)
+    endif
+    write(*,1110) ifile,xdt,f0,snrdb,fname
 1110 format(i4,f7.2,f8.2,f7.1,2x,a16)
   enddo
        
diff --git a/lib/fsk4hf/wspr_fsk8d.f90 b/lib/fsk4hf/wspr_fsk8d.f90
index 72fe3646a..c107f8481 100644
--- a/lib/fsk4hf/wspr_fsk8d.f90
+++ b/lib/fsk4hf/wspr_fsk8d.f90
@@ -15,7 +15,7 @@ program wspr_fsk8d
 ! Still to do: find and decode more than one signal in the specified passband.
 
   include 'wspr_fsk8_params.f90'
-  character arg*8,message*22,cbits*50,infile*80,datetime*11
+  character arg*8,message*22,cbits*50,infile*80,fname*16,datetime*11
   character*120 data_dir
   complex csync(0:N7-1)                 !Sync symbols for Costas 7x7 array
   complex c1(0:2*N7-1)
@@ -81,14 +81,23 @@ program wspr_fsk8d
   do ifile=7,nargs
      call getarg(ifile,infile)
      open(10,file=infile,status='old',access='stream')
-     read(10,end=999) ihdr,iwave
-     close(10)
+     j1=index(infile,'.c4')
      j2=index(infile,'.wav')
-     read(infile(j2-4:j2-1),*) nutc
-     datetime=infile(j2-11:j2-1)
-     if(degrade.gt.0.0) call degrade_snr(iwave,NMAX,degrade,rxbw)
-     call wspr_fsk8_downsample(iwave,c)
-
+     if(j1.gt.0) then
+       read(10,end=999) fname,ntrmin,fMHz,c(0:NZ-1)
+       read(fname(8:11),*) nutc
+       write(datetime,'(i11)') nutc
+     else if(j2.gt.0) then
+       read(10,end=999) ihdr,iwave
+       read(infile(j2-4:j2-1),*) nutc
+       datetime=infile(j2-11:j2-1)
+       if(degrade.gt.0.0) call degrade_snr(iwave,NMAX,degrade,rxbw)
+       call wspr_fsk8_downsample(iwave,c)
+     else
+       print*,'Wrong file format?'
+       go to 999
+     endif
+     close(10)
      pmax=0.
      df1=fs/(2*N7)
      ia=nint(100.0/df1)