diff --git a/lib/qra/q65/q65sim.f90 b/lib/qra/q65/q65sim.f90
index b2b119e56..61b36b0d8 100644
--- a/lib/qra/q65/q65sim.f90
+++ b/lib/qra/q65/q65sim.f90
@@ -9,11 +9,13 @@ program q65sim
   integer*2 iwave(NMAX)                  !Generated waveform
   integer itone(85)                      !Channel symbols (values 0-65)
   integer y(63)                          !Codeword
-  integer ifilenum(1)                    !new period lenth adjusted filenumber to work with averaging
+  integer istart                         !averaging compatible start seconds
+  integer imins                          !minutes for 15s period timestamp
+  integer isecs                          !seconds for 15s period timestamp
   real*4 xnoise(NMAX)                    !Generated random noise
   real*4 dat(NMAX)                       !Generated real data
   complex cdat(NMAX)                     !Generated complex waveform
-  complex cspread(0:NMAX-1)              !Complex amplitude for Rayleigh fading
+  complex cspread(0:NMAX-1)              !Complex amplitude for Rayleigh fading 
   complex z
   real*8 f0,dt,twopi,phi,dphi,baud,fsample,freq
   character msg*37,fname*17,csubmode*1,arg*12
@@ -27,7 +29,7 @@ program q65sim
      print*,'         f1   = Drift or Doppler rate (Hz/min)'
      print*,'         Stp  = Step size (Hz)'
      print*,'         Stp  = 0 implies no Doppler tracking'
-	 print*,'         Modified version for timestamp incrementing for 30-300s periods'
+     print*,'         Creates filenames which increment to permit averaging in first period'
      go to 999
   endif
   call getarg(1,msg)
@@ -96,15 +98,17 @@ program q65sim
   h=default_header(12000,npts)
 
   write(*,1004) 
-1004 format('File    TR   Freq Mode  S/N   Dop    DT   f1  Stp  Message'/70('-'))
+1004 format('File    TR   Freq Mode  S/N   Dop     DT   f1  Stp  Message'/70('-'))
 
   do ifile=1,nfiles  !Loop over requested number of files
-	 ifilenum = (ifile*ntrperiod/30) - (ntrperiod/30)
-     if(ntrperiod.lt.30) then          !wdg was 60
-        write(fname,1005) ifile        !Output filename
-1005    format('000000_',i6.6,'.wav')
+     istart = (ifile*ntrperiod*2) - (ntrperiod*2)
+     if(ntrperiod.lt.30) then !wdg was 60
+        imins=istart/60
+        isecs=istart-(60*imins)
+        write(fname,1005) imins,isecs        !Construction of output  filename for 15s periods with averaging
+1005    format('000000_',i4.4, i2.2,'.wav')
      else
-        write(fname,1106) ifilenum     !Output filename to be compatible with averaging
+        write(fname,1106) istart/60     !Output filename to be compatible with averaging 30-300s periods
 1106    format('000000_',i4.4,'.wav')
      endif
 
@@ -121,7 +125,7 @@ program q65sim
      sig=sqrt(2*bandwidth_ratio)*10.0**(0.05*snrdb)
      if(snrdb.gt.90.0) sig=1.0
      write(*,1020) ifile,ntrperiod,f0,csubmode,snrdb,fspread,xdt,f1,nstp,trim(msgsent)
-1020    format(i4,i6,f7.1,2x,a1,2x,f5.1,f6.2,2f6.1,i4,2x,a)
+1020    format(i4,i6,f7.1,2x,a1,2x,f5.1,1x,f6.2,2f6.1,i4,2x,a)
      phi=0.d0
      dphi=0.d0
      k=(xdt+0.5)*12000                   !Start audio at t=xdt+0.5 s (TR=15 and 30 s)