diff --git a/fastplot.cpp b/fastplot.cpp
index 02ad944e5..c9934f9f2 100644
--- a/fastplot.cpp
+++ b/fastplot.cpp
@@ -205,7 +205,7 @@ void FPlotter::draw()                                         //draw()
   update();                                             //trigger a new paintEvent
 }
 
-void FPlotter::mousePressEvent(QMouseEvent *event)             //mousePressEvent
+void FPlotter::mousePressEvent(QMouseEvent *event)      //mousePressEvent
 {
   int x=event->x();
   int y=event->y();
@@ -221,7 +221,7 @@ void FPlotter::mousePressEvent(QMouseEvent *event)             //mousePressEvent
   if(y >= 120) y0+=100;
   if(m_x0+m_x1 != 0) {
     painter.setPen(Qt::black);
-    painter.drawLine(m_x0,m_y0,m_x1,m_y0);                  //Erase previous yellow line
+    painter.drawLine(m_x0,m_y0,m_x1,m_y0);              //Erase previous yellow line
     painter.drawLine(m_x0,m_y0-3,m_x0,m_y0+3);
     painter.drawLine(m_x1,m_y0-3,m_x1,m_y0+3);
   }
@@ -229,7 +229,7 @@ void FPlotter::mousePressEvent(QMouseEvent *event)             //mousePressEvent
   painter.drawLine(x0,y0,x1,y0);                        //Draw yellow line
   painter.drawLine(x0,y0-3,x0,y0+3);
   painter.drawLine(x1,y0-3,x1,y0+3);
-  update();                                           //trigger a new paintEvent
+  update();                                             //trigger a new paintEvent
   m_x0=x0;
   m_x1=x1;
   m_y0=y0;
diff --git a/lib/fast_decode.f90 b/lib/fast_decode.f90
index f00d93000..3bdad537b 100644
--- a/lib/fast_decode.f90
+++ b/lib/fast_decode.f90
@@ -1,19 +1,29 @@
-subroutine fast_decode(id2,narg,bShMsgs,line,pchk_file,mycall_12,hiscall_12)
+subroutine fast_decode(id2,narg,ntrperiod,bShMsgs,line,pchk_file,     &
+     mycall_12,hiscall_12)
 
   parameter (NMAX=30*12000)
   integer*2 id2(NMAX)
+  integer*2 id2a(NMAX)
+  integer*2 id2b(NMAX)
   integer narg(0:14)
   logical*1 bShMsgs
   real dat(30*12000)
   complex cdat(262145),cdat2(262145)
   real psavg(450)
-  logical pick
+  logical pick,first
   character*6 cfile6
   character*80 line(100)
   character*512 pchk_file
   character*12 mycall_12,hiscall_12
   character*6 mycall,hiscall
-  save npts
+  data first/.true./
+  save npts,cdat,cdat2,id2a,id2b
+
+  if(first) then
+     id2a=0
+     id2b=0
+     first=.false.
+  endif
 
   mycall=mycall_12(1:6)
   hiscall=hiscall_12(1:6)
@@ -31,6 +41,9 @@ subroutine fast_decode(id2,narg,bShMsgs,line,pchk_file,mycall_12,hiscall_12)
   ntol=narg(11)
   nhashcalls=narg(12)
 
+  line(1:100)(1:1)=char(0)
+  if(t0.gt.float(ntrperiod)) go to 900
+
   if(nmode.eq.102) then
      call fast9(id2,narg,line)
      go to 900
@@ -38,11 +51,20 @@ subroutine fast_decode(id2,narg,bShMsgs,line,pchk_file,mycall_12,hiscall_12)
      call jtmsk_decode(id2,narg,line)
      go to 900
   else if(nmode.eq.104) then
+     if(newdat.eq.1) then
+        id2b=id2a
+        id2a=id2
+     endif
      ia=max(1,nint(t0*12000.0))
      ib=min(ndat0,nint(t1*12000.0))
      nz=ib-ia+1
-     call msk144_decode(id2(ia),nz,nutc,0,pchk_file,mycall,hiscall,bShMsgs,  &
-          ntol,t0,line)
+     if(newdat.eq.1 .or. npick.le.1) then
+        call msk144_decode(id2(ia),nz,nutc,0,pchk_file,mycall,hiscall,   &
+             bShMsgs,ntol,t0,line)
+     else
+        call msk144_decode(id2b(ia),nz,nutc,0,pchk_file,mycall,hiscall,   &
+             bShMsgs,ntol,t0,line)
+     endif
      go to 900
   endif
 
diff --git a/lib/msk144_decode.f90 b/lib/msk144_decode.f90
index fdb328338..d0ef4e843 100644
--- a/lib/msk144_decode.f90
+++ b/lib/msk144_decode.f90
@@ -15,6 +15,7 @@ subroutine msk144_decode(id2,npts,nutc,nprint,pchk_file,mycall,hiscall,   &
   logical*1 bShMsgs
 
   line(1:100)(1:1)=char(0)
+  if(maxval(id2(1:npts)).eq.0 .and. minval(id2(1:npts)).eq.0) go to 900
 
   hist=0
   do i=0,npts-1
@@ -56,5 +57,6 @@ subroutine msk144_decode(id2,npts,nutc,nprint,pchk_file,mycall,hiscall,   &
   endif
 
   if(line(1)(1:6).eq.'      ') line(1)(1:1)=char(0)
-  return
+
+900 return
 end subroutine msk144_decode
diff --git a/mainwindow.cpp b/mainwindow.cpp
index d69f0d767..7bbcc0370 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -107,8 +107,8 @@ extern "C" {
                 float* level, float* sigdb, float* snr, float* dfreq,
                 float* width);
 
-  void fast_decode_(short id2[], int narg[], bool* bShMsgs, char msg[],
-                    char pchkFile[], char mycall[], char hiscall[],
+  void fast_decode_(short id2[], int narg[], int* ntrperiod, bool* bShMsgs,
+                    char msg[], char pchkFile[], char mycall[], char hiscall[],
                     int len1, int len2, int len3, int len4);
   void hash_calls_(char calls[], int* ih9, int len);
   void degrade_snr_(short d2[], int* n, float* db, float* bandwidth);
@@ -2210,8 +2210,8 @@ void MainWindow::decode()                                       //decode()
     narg[14]=m_config.aggressive();
     memcpy(d2b,dec_data.d2,2*360000);
     watcher3.setFuture (QtConcurrent::run (std::bind (fast_decode_,&d2b[0],
-        &narg[0],&m_bShMsgs,&m_msg[0][0],&m_pchkFile[0],dec_data.params.mycall,
-        dec_data.params.hiscall,80,512,12,12)));
+        &narg[0],&m_TRperiod,&m_bShMsgs,&m_msg[0][0],&m_pchkFile[0],
+        dec_data.params.mycall,dec_data.params.hiscall,80,512,12,12)));
   } else {
     memcpy(to, from, qMin(mem_jt9->size(), size));
     QFile {m_config.temp_dir ().absoluteFilePath (".lock")}.remove (); // Allow jt9 to start