diff --git a/lib/jt65_decode.f90 b/lib/jt65_decode.f90
index f47d37bbf..2d9dd7af0 100644
--- a/lib/jt65_decode.f90
+++ b/lib/jt65_decode.f90
@@ -143,14 +143,16 @@ contains
        ncand=0
        if(.not.robust) then
           call timer('sync65  ',0)
-          call sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,0)
+          call sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,0,    &
+               single_decode)
           call timer('sync65  ',1)
        endif
        if(ncand.gt.50) robust=.true.
        if(robust) then
           ncand=0
           call timer('sync65  ',0)
-          call sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,1)
+          call sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,1,   &
+               single_decode)
           call timer('sync65  ',1)
        endif
 
@@ -201,10 +203,10 @@ contains
 
           nfreq=nint(freq+a(1))
           ndrift=nint(2.0*a(2))
-!          s2db=10.0*log10(sync2) - 35             !### empirical ###
-!          if(width.gt.3) s2db=s2db + 2.1*sqrt(width-3.0) + 1.5 +     &
-!               0.11*(width-7.0)                   !### empirical^2 ###
-          s2db=sync1 - 30.0 + db(width/3.3)
+!###
+!          s2db=10.0*log10(sync2) - 35             !### empirical (HF) 
+          s2db=sync1 - 30.0 + db(width/3.3)        !### VHF/UHF/microwave
+!###
           nsnr=nint(s2db)
           if(nsnr.lt.-30) nsnr=-30
           if(nsnr.gt.-1) nsnr=-1
diff --git a/lib/sync65.f90 b/lib/sync65.f90
index 9b08066da..f6a5c033c 100644
--- a/lib/sync65.f90
+++ b/lib/sync65.f90
@@ -1,10 +1,12 @@
-subroutine sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,nrobust)
+subroutine sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,nrobust,   &
+     single_decode)
 
   parameter (NSZ=3413,NFFT=8192,MAXCAND=300)
   real ss(322,NSZ)
   real ccfblue(-11:540)             !CCF with pseudorandom sequence
-  real ccfred(NSZ)                 !Peak of ccfblue, as function of freq
-  
+  real ccfred(NSZ)                  !Peak of ccfblue, as function of freq
+  logical single_decode
+
   type candidate
      real freq
      real dt
@@ -31,7 +33,8 @@ subroutine sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,nrobust)
   do i=ia,ib
      call xcor(ss,i,nhsym,nsym,lag1,lag2,ccfblue,ccf0,lagpk0,flip,fdot,nrobust)
 ! Remove best-fit slope from ccfblue and normalize so baseline rms=1.0
-!     call slope(ccfblue(lag1),lag2-lag1+1,lagpk0-lag1+1.0)
+     if(.not.single_decode) call slope(ccfblue(lag1),lag2-lag1+1,      &
+          lagpk0-lag1+1.0)
      ccfred(i)=ccfblue(lagpk0)
      if(ccfred(i).gt.ccfmax) then
         ccfmax=ccfred(i)
@@ -43,12 +46,6 @@ subroutine sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,nrobust)
   ccfred(ia-1)=ccfred(ia)
   ccfred(ib+1)=ccfred(ib)
 
-!  do i=1,NSZ
-!     ssum=sum(ss(1:322,i))/322.0
-!     write(61,3001) i*df,ccfred(i),ssum
-!  enddo
-
-
   do i=ia,ib
      freq=i*df
      itry=0
@@ -64,8 +61,10 @@ subroutine sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,nrobust)
         endif
      endif
      if(itry.ne.0) then
-        call xcor(ss,i,nhsym,nsym,lag1,lag2,ccfblue,ccf0,lagpk,flip,fdot,nrobust)
-!        call slope(ccfblue(lag1),lag2-lag1+1,lagpk-lag1+1.0)
+        call xcor(ss,i,nhsym,nsym,lag1,lag2,ccfblue,ccf0,lagpk,flip,fdot,  &
+             nrobust)
+        if(.not.single_decode) call slope(ccfblue(lag1),lag2-lag1+1,       &
+             lagpk-lag1+1.0)
         xlag=lagpk
         if(lagpk.gt.lag1 .and. lagpk.lt.lag2) then
            call peakup(ccfblue(lagpk-1),ccfmax,ccfblue(lagpk+1),dx2)
@@ -76,20 +75,14 @@ subroutine sync65(ss,nfa,nfb,naggressive,ntol,nhsym,ca,ncand,nrobust)
         ccfblue(lag2)=0.
         ca(ncand)%freq=freq
         ca(ncand)%dt=dtx
-!        ca(ncand)%sync=ccfred(i)
-        ca(ncand)%sync=db(ccfred(i)) - 16.0
+        if(single_decode) then
+           ca(ncand)%sync=db(ccfred(i)) - 16.0
+        else
+           ca(ncand)%sync=ccfred(i)
+        endif
      endif
      if(ncand.eq.MAXCAND) return
   enddo
 
-!  do i=1,NSZ
-!     write(52,3001) i*df,ccfred(i)
-!3001 format(3f12.3)
-!  enddo
-!  do i=-10,58
-!     write(53,3002) i,i*2048.0/11025.0,ccfblue(i)
-!3002 format(i6,2f12.3)
-!  enddo
-
   return
 end subroutine sync65