diff --git a/lib/ft4/ft4_decode.f90 b/lib/ft4/ft4_decode.f90
index d8f1a6d8f..f62569343 100644
--- a/lib/ft4/ft4_decode.f90
+++ b/lib/ft4/ft4_decode.f90
@@ -34,7 +34,7 @@ subroutine ft4_decode(cdatetime0,tbuf,nfa,nfb,nQSOProgress,ncontest,nfqso, &
    integer apbits(2*ND)
    integer apmy_ru(28),aphis_fd(28)
    integer icos4a(0:3),icos4b(0:3),icos4c(0:3),icos4d(0:3)
-   integer*2 iwave(NMAX)                 !Generated full-length waveform
+   integer*2 iwave(NMAX)                 !Raw received data
    integer*1 message77(77),rvec(77),apmask(2*ND),cw(2*ND)
    integer*1 hbits(2*NN)
    integer graymap(0:3)
diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 2298635b9..1194a0942 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -8671,18 +8671,17 @@ void MainWindow::ft4_rx(int k)
   static bool wrapped=false;
   short id[60000];
   const int istep=3456;
+  const int k_enough=55296;  //4.608 s
 
   if(k<m_kin0) m_kin0=0;
   int nhsec=k/istep;
   if(nhsec0>nhsec) nhsec0=-1;
   if(nhsec==nhsec0) return;
+  if(k<k_enough and !wrapped) return;
 
-//  if(k<60000 and !wrapped) return;
-  if(k<52800 and !wrapped) return;
-
-//Process FT4 data at intervals of istep/12000.0 seconds
+//Process FT4 data at intervals of istep/12000.0 = 0.288 seconds
   int j=k/istep;
-  j=istep*j-52800;
+  j=istep*j-k_enough;
   if(j<0) j+=NRING;
   float tbuf=j/12000.0;
   for(int i=0; i<60000; i++) {