diff --git a/lib/fsk4hf/ft8b.f90 b/lib/fsk4hf/ft8b.f90
index bdbb187e9..75cf4d83d 100644
--- a/lib/fsk4hf/ft8b.f90
+++ b/lib/fsk4hf/ft8b.f90
@@ -236,9 +236,10 @@ subroutine ft8b(dd0,newdat,nfqso,ndepth,lsubtract,iaptype,icand,sync0,f1,xdt,
         message='                      '
         xsnr=-99.0
         if(count(cw.eq.0).eq.174) cycle           !Reject the all-zero codeword
-!    if( nharderrors.ge.0 .and. dmin.le.30.0 .and. nharderrors .lt. 30) then
-!***  These thresholds should probably be dependent on nap
-        if( nharderrors.ge.0 .and. dmin.le.50.0 .and. nharderrors .lt. 50) then
+        if(nharderrors.ge.0 .and. nharderrors+dmin.lt.60.0 .and. &        
+           .not.(sync.lt.2.0 .and. nharderrors.gt.35)      .and. &
+           .not.( iap .gt. 0 .and. nharderrors.gt.39)            &   
+          ) then
            call chkcrc12a(decoded,nbadcrc)
         else
            nharderrors=-1
diff --git a/lib/fsk4hf/sync8.f90 b/lib/fsk4hf/sync8.f90
index d52765871..cd0c1db81 100644
--- a/lib/fsk4hf/sync8.f90
+++ b/lib/fsk4hf/sync8.f90
@@ -1,7 +1,8 @@
 subroutine sync8(dd,nfa,nfb,syncmin,nfqso,s,candidate,ncand)
 
   include 'ft8_params.f90'
-  parameter (JZ=62)                            !DT up to +/- 1.25 s
+! Search over +/- 2.5s relative to start of interval. 
+  parameter (JZ=62)                        
   complex cx(0:NH1)
   real s(NH1,NHSYM)
   real savg(NH1)
@@ -133,7 +134,7 @@ subroutine sync8(dd,nfa,nfb,syncmin,nfqso,s,candidate,ncand)
 !  do i=ncand,1,-1
   do i=1,ncand
      j=indx(i)
-     if( candidate0(3,j) .ge. syncmin ) then
+     if( candidate0(3,j) .ge. syncmin .and. candidate0(2,j).ge.-1.5 ) then
        candidate(1,k)=abs(candidate0(1,j))
        candidate(2,k)=candidate0(2,j)
        candidate(3,k)=candidate0(3,j)
diff --git a/lib/ft8_decode.f90 b/lib/ft8_decode.f90
index de9bc4fbd..689575642 100644
--- a/lib/ft8_decode.f90
+++ b/lib/ft8_decode.f90
@@ -61,10 +61,10 @@ contains
       if(ipass.eq.1) then
         lsubtract=.true.
         if(ndepth.eq.1) lsubtract=.false.
-        syncmin=1.3
+        syncmin=1.5
       else
         lsubtract=.false.
-        syncmin=1.3
+        syncmin=1.5
       endif 
       call timer('sync8   ',0)
       call sync8(dd,nfa,nfb,syncmin,nfqso,s,candidate,ncand)