diff --git a/libm65/ccf65.f90 b/libm65/ccf65.f90
index fc9fb94d8..a2a77b444 100644
--- a/libm65/ccf65.f90
+++ b/libm65/ccf65.f90
@@ -108,7 +108,6 @@ subroutine ccf65(ss,nhsym,nfast,ssmax,sync1,ipol1,jpz,dt1,flipk,      &
   enddo
   rms=sqrt(sq/49.0)
   sync1=ccfbest/rms - 4.0
-!  dt1=(2.5 + lagpk*(2048.0/11025.0))/nfast
   dt1=lagpk*(2048.0/11025.0)/nfast - 2.5
 
 ! Find base level for normalizing snr2.
diff --git a/libm65/decode1a.f b/libm65/decode1a.f
index c773bc784..4f2f69153 100644
--- a/libm65/decode1a.f
+++ b/libm65/decode1a.f
@@ -103,6 +103,7 @@
       nfft=512/nfast
       j=(dt00+dtbest+2.685)*1378.125 + joff
       if(nfast.eq.2) j=j-1506
+!      print*,'B',dt00,dtbest,j
       if(j.lt.0) j=0
 
       call timer('sh_ffts ',0)
@@ -141,7 +142,8 @@
       call timer('dec65b  ',0)
       call decode65b(s2,flip,mycall,hiscall,hisgrid,mode65,neme,ndepth,
      +    nqd,nkv,nhist,qual,decoded,s3,sy)
-      dt=dt00 + dtbest
+      dt=dt00 + dtbest + 1.7
+      if(nfast.eq.2) dt=dt00 + dtbest + 0.6
       call timer('dec65b  ',1)
 
       if(nqd.eq.1 .and. nkv.eq.0) then
@@ -152,7 +154,6 @@
             nsave=nsave+1
             nsave=mod(nsave-1,64)+1
             npol=nint(57.296*pol)
-            xdt=dt+0.8
 
             call s3avg(nsave,mode65,nutc,nhz,xdt,npol,ntol,s3,nsum,
      +                 nkv,decoded)
diff --git a/libm65/map65a.f90 b/libm65/map65a.f90
index 85a08f79b..5d9e30150 100644
--- a/libm65/map65a.f90
+++ b/libm65/map65a.f90
@@ -212,7 +212,6 @@ subroutine map65a(dd,ss,savg,newdat,nutc,fcenter,ntol,idphi,nfa,nfb,        &
                       xpol,mycall,hiscall,hisgrid,neme,ndepth,nqd,dphi,   &
                       ndphi,iloop,nutc,ikHz,idf,ipol,ntol,sync2,a,dt,     &
                       pol,nkv,nhist,nsum,nsave,qual,decoded)
-                 dt=dt+0.8                           !### empirical tweak
                  call timer('decode1a',1)
 
                  if(km.lt.MAXMSG) km=km+1
diff --git a/libm65/mapsim.f90 b/libm65/mapsim.f90
index f01a8a3af..8b791f16f 100644
--- a/libm65/mapsim.f90
+++ b/libm65/mapsim.f90
@@ -13,8 +13,8 @@ program mapsim
 
   nargs=iargc()
   if(nargs.ne.9) then
-     print*,'Usage: mapsim level "message"    mode f1 f2 nsigs pol SNR nfiles'
-     print*,'Example:        25 "CQ K1ABC FN42" B -22 33  20    45 -20    1'
+     print*,'Usage: mapsim  DT "message"     mode f1 f2 nsigs pol SNR nfiles'
+     print*,'Example:      2.5 "CQ K1ABC FN42" B -22 33  20    45 -20    1'
      print*,' '
      print*,'Enter message = "" to use entries in msgs.txt.'
      print*,'Enter pol = -1 to generate a range of polarization angles.'
@@ -23,8 +23,7 @@ program mapsim
   endif
 
   call getarg(1,arg)
-  read(arg,*) rmsdb                  !Average noise level in dB
-  rms=10.0**(0.05*rmsdb)
+  read(arg,*) dt0                    !Time delay
   call getarg(2,msg0)
   message=msg0                       !Transmitted message
   call getarg(3,mode)                !JT65 sub-mode (A B C B2 C2)
@@ -42,6 +41,8 @@ program mapsim
   call getarg(9,arg)
   read(arg,*) nfiles                 !Number of files
 
+  rmsdb=25.
+  rms=10.0**(0.05*rmsdb)
   fcenter=144.125d0                  !Center frequency (MHz)
   fsample=96000.d0                   !Sample rate (Hz)
   dt=1.d0/fsample                    !Sample interval (s)
@@ -98,7 +99,8 @@ program mapsim
 1020    format(i3,i4,f8.3,f7.1,i5,2x,a22)
 
         phi=0.
-        i0=fsample*(3.5d0+0.05d0*(isig-1))
+!        i0=fsample*(3.5d0+0.05d0*(isig-1))
+        i0=fsample*(1.d0 + dt0)
         do i=1,nwave
            phi=phi + dphi
            if(phi.lt.-twopi) phi=phi+twopi
diff --git a/mainwindow.cpp b/mainwindow.cpp
index c9dff6150..3a3c274f5 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -1,4 +1,4 @@
-//-------------------------------------------------------------- MainWindow
+//--------------------------------------------------------------- MainWindow
 #include "mainwindow.h"
 #include "ui_mainwindow.h"
 #include "devsetup.h"