More tweaks to FST280 decoding. Suppress blank free text msgs.

lib/77bit/packjt77.f90

@@ -281,6 +281,10 @@ subroutine unpack77(c77,nrx,msg,unpk77_success)
      call unpacktext77(c77(1:71),msg(1:13))
      msg(14:)='                        '
      msg=adjustl(msg)
+     if(msg(1:1).eq.' ') then
+        unpk77_success=.false.
+        return
+     endif
 
   else if(i3.eq.0 .and. n3.eq.1) then
 ! 0.1  K1ABC RR73; W9XYZ <KH1/KH7Z> -11   28 28 10 5       71   DXpedition Mode

lib/fst280/get_fst280_bitmetrics.f90

@@ -72,10 +72,10 @@ subroutine get_fst280_bitmetrics(cd,nss,hmod,bitmetrics,badsync)
    nsync=is1+is2+is3   !Number of correct hard sync symbols, 0-24
 
    badsync=.false.
-!   if(nsync .lt. 8) then
-!      badsync=.true.
-!      return
-!   endif
+   if(nsync .lt. 8) then
+      badsync=.true.
+      return
+   endif
 
    bitmetrics=0.0
    do nseq=1,4            !Try coherent sequences of 1, 2, and 4 symbols

lib/fst280_decode.f90

@@ -232,6 +232,7 @@ contains
          cframe=c2(is0:is0+164*nss-1)
          s2=sum(cframe*conjg(cframe))
          cframe=cframe/sqrt(s2)
+         bitmetrics=0
          call get_fst280_bitmetrics(cframe,nss,hmod,bitmetrics,badsync)
 
          hbits=0
@@ -243,7 +244,7 @@ contains
          ns5=count(hbits(313:320).eq.(/0,0,0,1,1,0,1,1/))
          ns6=count(hbits(321:328).eq.(/0,1,0,0,1,1,1,0/))
          nsync_qual=ns1+ns2+ns3+ns4+ns5+ns6
-!          if(nsync_qual.lt. 20) cycle
+         if(nsync_qual.lt. 30) cycle                   !### Value ?? ###
 
          scalefac=2.83
          llra(  1:140)=bitmetrics( 17:156, 1)
@@ -442,9 +443,10 @@ contains
    call pctile(s2(ia:ib),ib-ia+1,30,base)
    s2=s2/base
    
-   thresh=1.25
+   thresh=1.4
  
    ncand=0
+   candidates=0
    if(ia.lt.3) ia=3
    if(ib.gt.18000-2) ib=18000-2
    do i=ia,ib
@@ -464,13 +466,14 @@ contains
    snr_cand=0.
    snr_cand(1:ncand)=candidates(1:ncand,2)
    call indexx(snr_cand,ncand,indx)
-   nmax=5
-   do i=1,min(ncand,nmax)
+   nmax=min(ncand,5)
+   do i=1,nmax
       j=indx(ncand+1-i)
       candidates0(i,1:4)=candidates(j,1:4)
    enddo
-   candidates(1:nmax,1:4)=candidates0(1:nmax,1:4)
-   candidates(nmax+1:,1:4)=0.
+   ncand=nmax
+   candidates(1:ncand,1:4)=candidates0(1:ncand,1:4)
+   candidates(ncand+1:,1:4)=0.
 
    return 
  end subroutine get_candidates_fst280