diff --git a/rfio.c b/rfio.c
index d9955d6..3b75583 100644
--- a/rfio.c
+++ b/rfio.c
@@ -36,7 +36,7 @@ struct spectrogram read_spectrogram(char *prefix,int isub,int nsub,double f0,dou
   if (strstr(header,"NBITS         8")==NULL) {
     status=sscanf(header,"HEADER\nUTC_START    %s\nFREQ         %lf Hz\nBW           %lf Hz\nLENGTH       %f s\nNCHAN        %d\nNSUB         %d\n",s.nfd0,&s.freq,&s.samp_rate,&length,&nch,&msub);
   } else {
-    status=sscanf(header,"HEADER\nUTC_START    %s\nFREQ         %lf Hz\nBW           %lf Hz\nLENGTH       %f s\nNCHAN        %d\nNSUB         %d\nNBITS         8\nMEAN         %f\nRMS          %f",s.nfd0,&s.freq,&s.samp_rate,&length,&nch,&dummy,&zavg,&zstd);
+    status=sscanf(header,"HEADER\nUTC_START    %s\nFREQ         %lf Hz\nBW           %lf Hz\nLENGTH       %f s\nNCHAN        %d\nNSUB         %d\nNBITS         8\nMEAN         %f\nRMS          %f",s.nfd0,&s.freq,&s.samp_rate,&length,&nch,&msub,&zavg,&zstd);
     nbits=8;
   }
   s.freq+=foff;
@@ -69,7 +69,9 @@ struct spectrogram read_spectrogram(char *prefix,int isub,int nsub,double f0,dou
 
   // Number of subints
   s.nsub=nsub/nbin;
-
+  s.msub=msub;
+  s.isub=isub;
+  
   printf("Allocating %.2f MB of memory\n",(4* (float) s.nchan * (float) s.nsub)/(1024 * 1024));
   
   // Allocate
@@ -202,7 +204,7 @@ struct spectrogram read_spectrogram(char *prefix,int isub,int nsub,double f0,dou
   free(z);
   free(cz);
 
- return s;
+  return s;
 }
 
 void write_spectrogram(struct spectrogram s,char *prefix)
diff --git a/rfio.h b/rfio.h
index 8cf2451..15630b0 100644
--- a/rfio.h
+++ b/rfio.h
@@ -1,7 +1,7 @@
 #ifndef RFIO_H
 #define RFIO_H
 struct spectrogram {
-  int nsub,nchan;
+  int nsub,nchan,msub,isub;
   double *mjd;
   double freq,samp_rate;
   float *length;
diff --git a/rfplot.c b/rfplot.c
index aff1d1c..a808d04 100644
--- a/rfplot.c
+++ b/rfplot.c
@@ -24,6 +24,7 @@ struct data {
 
 void dec2sex(double x,char *s,int f,int len);
 void time_axis(double *mjd,int n,float xmin,float xmax,float ymin,float ymax);
+void bin_axis(int isub,int msub,float xmin,float xmax,float ymin,float ymax);
 void usage(void);
 void plot_traces(struct trace *t,int nsat,float fcen,float xmin,float xmax, int show_names);
 struct trace fit_trace(struct spectrogram s,struct select sel,int site_id,int graves);
@@ -56,7 +57,7 @@ int main(int argc,char *argv[])
   float heat_b[] = {0.0, 0.0, 0.0, 0.3, 1.0};
   float xmin,xmax,ymin,ymax,zmin,zmax=1.0;
   int i,j,k,flag=0,sn,maxflag=0;
-  int redraw=1,mode=0,posn=0,click=0,graves=0,grid=0;
+  int redraw=1,mode=0,posn=0,click=0,graves=0,grid=0,binaxis=0;
   float dt,zzmax,s1,s2,z,za,sigma,zs,zm;
   int ix,iy,isub=0,nx,ny,jx=-1,jy=-1;
   int i0,j0,i1,j1,jmax;
@@ -255,8 +256,14 @@ int main(int argc,char *argv[])
       }
 
       // Pixel axis
-      cpgbox("CTSM1",0.,0,"CTSM1",0.,0);
-
+      //cpgbox("CTSM1",0.,0,"CTSM1",0.,0);
+      if (binaxis==0) {
+	cpgbox("CTSM1",0.,0,"CTSM1",0.,0);
+      } else { 
+	cpgbox("C",0.,0,"CTSM1",0.,0);
+	bin_axis(s.isub,s.msub,xmin,xmax,ymin,ymax);
+      }
+      
       // Time axis
       cpgbox("B",0.,0,"",0.,0);
       time_axis(s.mjd,s.nsub,xmin,xmax,ymin,ymax);
@@ -367,6 +374,7 @@ int main(int argc,char *argv[])
       printf("c        Center view\n");
       printf("C        Toggle through color maps\n");
       printf("p/right  Toggle overlays\n");
+      printf("a        Toggle subint/bin file horizontal axis\n");
       printf("n        Toggle display of satellite names in overlay\n");
       printf("+        Zoom\n");
       printf("-/x      Unzoom\n");
@@ -387,6 +395,14 @@ int main(int argc,char *argv[])
     if (c=='q')
       break;
 
+    // Toggle bin axis
+    if (c=='a') {
+      if (binaxis==0)
+	binaxis=1;
+      else
+	binaxis=0;
+      redraw=1;
+    }
     
     // Toggle grid
     if (c=='k') {
@@ -1601,3 +1617,28 @@ float fit_gaussian_point(struct spectrogram s,float x,float y,struct select sel,
       
   return a[0];
 }
+
+// Plot horizontal axis in bin file steps
+void bin_axis(int isub,int msub,float xmin,float xmax,float ymin,float ymax)
+{
+  int i,imin,imax,di,istep;
+  float x;
+  char s[16];
+
+  // Get tickmark settings
+  imin=(int) floor(xmin/msub);
+  imax=(int) floor(xmax/msub);
+  di=imax-imin;
+  istep=(int) floor(di/6);
+  if (istep==0)
+    istep=1;
+
+  // Add ticks
+  for (i=imin;i<imax;i+=istep) {
+    x=i*msub;
+    sprintf(s,"%d",isub+i);
+    cpgtick(xmin,ymax,xmax,ymax,(x-xmin)/(xmax-xmin),0.5,0.5,-0.6,0.0,s);
+  }
+ 
+  return;
+}