diff --git a/lib/sync64.f90 b/lib/sync64.f90
index a3d0e53fa..d73943087 100644
--- a/lib/sync64.f90
+++ b/lib/sync64.f90
@@ -1,43 +1,45 @@
 subroutine sync64(dd,nf1,nf2,maxf1,dtx,f0,kpk,snrdb,s3a)
+
   parameter (NMAX=60*12000)                  !Max size of raw data at 12000 Hz
   parameter (NSPS=2304)                      !Samples per symbol at 4000 Hz
   parameter (NSPC=7*NSPS)                    !Samples per Costas array
   real dd(NMAX)                              !Raw data
   real x(672000)                             !Up to 56 s at 12000 Hz
-  real t(5)
-  real s3a(0:63,1:63)
-  real s0(0:NSPC-1)
-  real s1(0:NSPC-1)
-  real s2(0:NSPC-1)
-  real s3(0:NSPC-1)
-  real s0a(0:NSPC-1)
-
-  integer*8 count0,count1,clkfreq
-  integer icos7(0:6)
+  real s3a(0:63,1:63)                        !Synchronized symbol spectra
+  real s1(0:NSPC-1)                          !Power spectrum of Costas 1
+  real s2(0:NSPC-1)                          !Power spectrum of Costas 2
+  real s3(0:NSPC-1)                          !Power spectrum of Costas 3
+  real s0(0:NSPC-1)                          !Sum of s1+s2+s3
+  real s0a(0:NSPC-1)                         !Best synchromized spectrum
+  integer icos7(0:6)                         !Costas 7x7 tones
   integer ipk0(1)
-
-  complex cc(0:NSPC-1)
-  complex c0(0:336000)
-  complex c1(0:NSPC-1)
-  complex c2(0:NSPC-1)
-  complex c3(0:NSPC-1)
+  complex cc(0:NSPC-1)                       !Costas waveform
+  complex c0(0:336000)                       !Complex spectrum of dd()
+  complex c1(0:NSPC-1)                       !Complex spectrum of Costas 1
+  complex c2(0:NSPC-1)                       !Complex spectrum of Costas 2
+  complex c3(0:NSPC-1)                       !Complex spectrum of Costas 3
+  logical first
   equivalence (x,c0)
-  data icos7/2,5,6,0,4,1,3/                            !Costas 7x7 pattern
+  data icos7/2,5,6,0,4,1,3/                  !Costas 7x7 tone pattern
+  data first/.true./
   save
 
-  twopi=8.0*atan(1.0)
-  dfgen=12000.0/6912.0
-  k=-1
-  phi=0.
-  do j=0,6
-     dphi=twopi*icos7(j)*dfgen/4000.0
-     do i=1,2304
-        phi=phi + dphi
-        if(phi.gt.twopi) phi=phi-twopi
-        k=k+1
-        cc(k)=cmplx(cos(phi),sin(phi))
+  if(first) then
+     twopi=8.0*atan(1.0)
+     dfgen=12000.0/6912.0
+     k=-1
+     phi=0.
+     do j=0,6                               !Compute complex Costas waveform
+        dphi=twopi*icos7(j)*dfgen/4000.0
+        do i=1,2304
+           phi=phi + dphi
+           if(phi.gt.twopi) phi=phi-twopi
+           k=k+1
+           cc(k)=cmplx(cos(phi),sin(phi))
+        enddo
      enddo
-  enddo
+     first=.false.
+  endif
 
   npts0=54*12000
   nfft1=672000
@@ -45,11 +47,8 @@ subroutine sync64(dd,nf1,nf2,maxf1,dtx,f0,kpk,snrdb,s3a)
   df1=12000.0/nfft1
   fac=2.0/nfft1
   x=fac*dd(1:nfft1)
-  call system_clock(count0,clkfreq)
   call four2a(c0,nfft1,1,-1,0)             !Forward r2c FFT
   call four2a(c0,nfft2,1,1,1)              !Inverse c2c FFT; c0 is analytic sig
-  call system_clock(count1,clkfreq)
-  t(1)=float(count1-count0)/float(clkfreq)
   npts2=npts0/3                            !Downsampled complex data length
   nfft3=NSPC
   nh3=nfft3/2
@@ -66,7 +65,6 @@ subroutine sync64(dd,nf1,nf2,maxf1,dtx,f0,kpk,snrdb,s3a)
   kb=maxf1
   ipk=0
   kpk=0
-  call system_clock(count0,clkfreq)
   do iter=1,2
      do j1=ja,jb,jstep
         j2=j1 + 39*2304
@@ -101,8 +99,6 @@ subroutine sync64(dd,nf1,nf2,maxf1,dtx,f0,kpk,snrdb,s3a)
               ipk=ipk0(1)
               f0=(ipk+ia-1)*df3
               kpk=k
-!              write(16,3101) jpk,ipk,kpk,dtx,f0,snr
-!3101          format(3i5,f8.3,f8.2,f10.1)
            endif
         enddo
      enddo
@@ -112,9 +108,11 @@ subroutine sync64(dd,nf1,nf2,maxf1,dtx,f0,kpk,snrdb,s3a)
 !     ka=kpk
 !     kb=kpk
   enddo
-  call system_clock(count1,clkfreq)
-  t(2)=float(count1-count0)/float(clkfreq)
   snrdb=10.0*log10(snr)-39.0
 
+!###
+! Now use tweak on the c0() array, then do nfft4=NSPS FFTs to get s3a(), 
+! the properly synchronized symbol spectra.
+
   return
 end subroutine sync64