diff --git a/commons.h b/commons.h
index e5071b9..20c2ec3 100644
--- a/commons.h
+++ b/commons.h
@@ -18,6 +18,14 @@
 #endif
 #endif
 
+#ifndef TEST_FOX_WAVE_GEN_OFFSET
+#if TEST_FOX_WAVE_GEN
+    #define TEST_FOX_WAVE_GEN_OFFSET 25
+#else
+    #define TEST_FOX_WAVE_GEN_OFFSET 0
+#endif
+#endif
+
 #ifdef __cplusplus
 #include <cstdbool>
 extern "C" {
diff --git a/lib/ft8/foxfilt.f90 b/lib/ft8/foxfilt.f90
index d97923a..15312e2 100644
--- a/lib/ft8/foxfilt.f90
+++ b/lib/ft8/foxfilt.f90
@@ -2,6 +2,7 @@ subroutine foxfilt(nslots,nfreq,width,wave)
 
   parameter (NN=79,ND=58,KK=87,NSPS=4*1920)
   parameter (NWAVE=NN*NSPS,NFFT=614400,NH=NFFT/2)
+  parameter (OFFSET=25)
   real wave(NWAVE)
   real x(NFFT)
   complex cx(0:NH)
@@ -12,7 +13,7 @@ subroutine foxfilt(nslots,nfreq,width,wave)
   call four2a(x,NFFT,1,-1,0)              !r2c
   df=48000.0/NFFT
   fa=nfreq - 0.5*6.25
-  fb=nfreq + 7.5*6.25 + (nslots-1)*60.0
+  fb=nfreq + 7.5*6.25 + (nslots-1)*(width+OFFSET)
   ia2=nint(fa/df)
   ib1=nint(fb/df)
   ia1=nint(ia2-width/df)
diff --git a/lib/ft8/foxgen.f90 b/lib/ft8/foxgen.f90
index 335dce5..330f0cd 100644
--- a/lib/ft8/foxgen.f90
+++ b/lib/ft8/foxgen.f90
@@ -17,6 +17,7 @@ subroutine foxgen()
   use crc
   parameter (NN=79,ND=58,KK=87,NSPS=4*1920)
   parameter (NWAVE=NN*NSPS,NFFT=614400,NH=NFFT/2)
+  parameter (OFFSET=25)
   character*40 cmsg
   character*22 msg,msgsent
   character*6 mygrid
@@ -36,8 +37,9 @@ subroutine foxgen()
   equivalence (x,cx),(y,cy)
   data icos7/4,2,5,6,1,3,0/                   !Costas 7x7 tone pattern
 
+  width=50.0
   bcontest=.false.
-  fstep=60.d0
+  fstep=width+OFFSET
   dfreq=6.25d0
   dt=1.d0/48000.d0
   twopi=8.d0*atan(1.d0)
@@ -127,7 +129,6 @@ subroutine foxgen()
   
 !  call plotspec(2,wave)          !Plot the spectrum
 
-  width=50.0
   call foxfilt(nslots,nfreq,width,wave)
   peak3=maxval(abs(wave))
   wave=wave/peak3
diff --git a/plotter.cpp b/plotter.cpp
index 4606769..e684b1a 100644
--- a/plotter.cpp
+++ b/plotter.cpp
@@ -457,7 +457,7 @@ void CPlotter::DrawOverlay()                   //DrawOverlay()
   if(m_mode=="FT8"){
       int fwidth=XfromFreq(m_rxFreq+bw)-XfromFreq(m_rxFreq);
 #if TEST_FOX_WAVE_GEN
-      int offset=XfromFreq(m_rxFreq+bw+10)-XfromFreq(m_rxFreq+bw);
+      int offset=XfromFreq(m_rxFreq+bw+TEST_FOX_WAVE_GEN_OFFSET)-XfromFreq(m_rxFreq+bw) + 4; // + 4 for the line padding
 #endif
       QPainter overPainter(&m_DialOverlayPixmap);
       overPainter.initFrom(this);
@@ -465,22 +465,26 @@ void CPlotter::DrawOverlay()                   //DrawOverlay()
       overPainter.fillRect(0, 0, m_Size.width(), m_h, Qt::transparent);
       QPen thinRed(Qt::red, 1);
       overPainter.setPen(thinRed);
-      overPainter.drawLine(0, 30, 0, m_h);
-      overPainter.drawLine(fwidth+1, 30, fwidth+1, m_h);
+      overPainter.drawLine(0, 30, 0, m_h); // first slot, left line
+      overPainter.drawLine(fwidth + 1, 30, fwidth + 1, m_h); // first slot, right line
 #if TEST_FOX_WAVE_GEN
       if(m_turbo){
-        overPainter.drawLine(offset+fwidth+1, 30, offset+fwidth+1, m_h);
-        overPainter.drawLine(offset+2*fwidth+1, 30, offset+2*fwidth+1, m_h);
+        for(int i = 1; i < TEST_FOX_WAVE_GEN_SLOTS; i++){
+            overPainter.drawLine(i*(fwidth + offset), 30, i*(fwidth + offset), m_h); // n slot, left line
+            overPainter.drawLine(i*(fwidth + offset) + fwidth + 2, 30, i*(fwidth + offset) + fwidth + 2, m_h); // n slot, right line
+        }
       }
 #endif
 
       overPainter.setPen(penRed);
-      overPainter.drawLine(0, 26, fwidth, 26);
-      overPainter.drawLine(0, 28, fwidth, 28);
+      overPainter.drawLine(0, 26, fwidth, 26); // first slot, top bar
+      overPainter.drawLine(0, 28, fwidth, 28); // first slot, top bar 2
 #if TEST_FOX_WAVE_GEN
       if(m_turbo){
-        overPainter.drawLine(offset+fwidth, 26, offset+2*fwidth, 26);
-        overPainter.drawLine(offset+fwidth, 28, offset+2*fwidth, 28);
+        for(int i = 1; i < TEST_FOX_WAVE_GEN_SLOTS; i++){
+            overPainter.drawLine(i*(fwidth + offset) + 1, 26, i*(fwidth + offset) + fwidth + 1, 26); // n slot, top bar
+            overPainter.drawLine(i*(fwidth + offset) + 1, 28, i*(fwidth + offset) + fwidth + 1, 28); // n slot, top bar 2
+        }
       }
 #endif
 
@@ -489,12 +493,14 @@ void CPlotter::DrawOverlay()                   //DrawOverlay()
       hoverPainter.setCompositionMode(QPainter::CompositionMode_Source);
       hoverPainter.fillRect(0, 0, m_Size.width(), m_h, Qt::transparent);
       hoverPainter.setPen(QPen(Qt::white));
-      hoverPainter.drawLine(0, 30, 0, m_h);
-      hoverPainter.drawLine(fwidth+1, 30, fwidth+1, m_h);
+      hoverPainter.drawLine(0, 30, 0, m_h); // first slot, left line hover
+      hoverPainter.drawLine(fwidth, 30, fwidth, m_h); // first slot, right line hover
 #if TEST_FOX_WAVE_GEN
       if(m_turbo){
-        hoverPainter.drawLine(offset+fwidth+1, 30, offset+fwidth+1, m_h);
-        hoverPainter.drawLine(offset+2*fwidth+1, 30, offset+2*fwidth+1, m_h);
+          for(int i = 1; i < TEST_FOX_WAVE_GEN_SLOTS; i++){
+              hoverPainter.drawLine(i*(fwidth + offset), 30, i*(fwidth + offset), m_h); // n slot, left line
+              hoverPainter.drawLine(i*(fwidth + offset) + fwidth + 2, 30, i*(fwidth + offset) + fwidth + 2, m_h); // n slot, right line
+          }
       }
 #endif