diff --git a/plugins/channeltx/modatv/atvmod.cpp b/plugins/channeltx/modatv/atvmod.cpp
index b54cfae99..088ae8b6f 100644
--- a/plugins/channeltx/modatv/atvmod.cpp
+++ b/plugins/channeltx/modatv/atvmod.cpp
@@ -145,7 +145,7 @@ void ATVMod::modulateSample()
 
 void ATVMod::pullVideo(Real& sample)
 {
-    if ((m_lineCount < 21) || (m_lineCount > 621) || ((m_lineCount > 309) && (m_lineCount < 333)))
+    if ((m_lineCount < 5 + m_nbBlankLines) || (m_lineCount > 621) || ((m_lineCount > 309) && (m_lineCount < 317 + m_nbBlankLines)))
     {
         pullVSyncLine(sample);
     }
@@ -318,16 +318,17 @@ void ATVMod::applyStandard()
         m_pointsPerFSync   = (uint32_t) roundf(2.3f * m_pointsPerTU); // equalizing pulse  (2.3/1.008 us)
         // what is left in a 64/1.008 us line for the image
         m_pointsPerImgLine = 64 * m_pointsPerTU - m_pointsPerSync - m_pointsPerBP - m_pointsPerFP;
-        m_pointsPerHBar    = 10 * m_pointsPerTU; // set a bar length to 10/1.008 us (~5 bars per line)
-        m_linesPerVBar     = 30;
         m_nbLines          = 525;
         m_nbLines2         = 262;
         m_nbImageLines     = 510;
         m_nbImageLines2    = 205;
         m_interlaced       = true;
         m_nbHorizPoints    = 64 * m_pointsPerTU; // full line
-        m_hBarIncrement    = m_spanLevel / 5.0f;
-        m_vBarIncrement    = m_spanLevel / 10.0f;
+        m_nbBlankLines     = 16;
+        m_pointsPerHBar    = m_pointsPerImgLine / 6;
+        m_linesPerVBar     = m_nbImageLines2  / 6;
+        m_hBarIncrement    = m_spanLevel / 6.0f;
+        m_vBarIncrement    = m_spanLevel / 6.0f;
         break;
     case ATVStdPAL625:
     default:
@@ -337,15 +338,16 @@ void ATVMod::applyStandard()
         m_pointsPerFSync   = (uint32_t) roundf(2.3f * m_pointsPerTU); // equalizing pulse  (2.3 us)
         // what is left in a 64 us line for the image
         m_pointsPerImgLine = 64 * m_pointsPerTU - m_pointsPerSync - m_pointsPerBP - m_pointsPerFP;
-        m_pointsPerHBar    = 10 * m_pointsPerTU; // set a bar length to 10 us (~5 bars per line)
-        m_linesPerVBar     = 30;
         m_nbLines          = 625;
         m_nbLines2         = 312;
         m_nbImageLines     = 610;
         m_nbImageLines2    = 305;
         m_interlaced       = true;
         m_nbHorizPoints    = 64 * m_pointsPerTU; // full line
-        m_hBarIncrement    = m_spanLevel / 5.0f;
-        m_vBarIncrement    = m_spanLevel / 10.0f;
+        m_nbBlankLines     = 16;
+        m_pointsPerHBar    = m_pointsPerImgLine / 6;
+        m_linesPerVBar     = m_nbImageLines2 / 6;
+        m_hBarIncrement    = m_spanLevel / 6.0f;
+        m_vBarIncrement    = m_spanLevel / 6.0f;
     }
 }
diff --git a/plugins/channeltx/modatv/atvmod.h b/plugins/channeltx/modatv/atvmod.h
index 4ad46865a..b7b8c8e99 100644
--- a/plugins/channeltx/modatv/atvmod.h
+++ b/plugins/channeltx/modatv/atvmod.h
@@ -43,6 +43,7 @@ public:
         ATVModInputUniform,
         ATVModInputHBars,
         ATVModInputVBars,
+        ATVModInputCheckbox,
         ATVModInputHGradient,
         ATVModInputVGradient
     } ATVModInput;
@@ -171,6 +172,7 @@ private:
     uint32_t m_nbImageLines;
     uint32_t m_nbImageLines2;
     uint32_t m_nbHorizPoints;    //!< number of line points per horizontal line
+    uint32_t m_nbBlankLines;
     float    m_hBarIncrement;
     float    m_vBarIncrement;
     bool     m_interlaced;       //!< true if image is interlaced (2 half frames per frame)
@@ -218,6 +220,10 @@ private:
             case ATVModInputVBars:
                 sample = (iLine / m_linesPerVBar) * m_vBarIncrement + m_blackLevel;
                 break;
+            case ATVModInputCheckbox:
+
+                sample = (((iLine / m_linesPerVBar)*5 + (pointIndex / m_pointsPerHBar)) % 2) * m_spanLevel * m_running.m_uniformLevel + m_blackLevel;
+                break;
             case ATVModInputHGradient:
                 sample = (pointIndex / (float) m_pointsPerImgLine) * m_spanLevel + m_blackLevel;
                 break;
diff --git a/plugins/channeltx/modatv/atvmodgui.ui b/plugins/channeltx/modatv/atvmodgui.ui
index 296ea7389..b595d9e01 100644
--- a/plugins/channeltx/modatv/atvmodgui.ui
+++ b/plugins/channeltx/modatv/atvmodgui.ui
@@ -370,6 +370,11 @@
           <string>V Bars</string>
          </property>
         </item>
+        <item>
+         <property name="text">
+          <string>Chekbox</string>
+         </property>
+        </item>
         <item>
          <property name="text">
           <string>H Grad</string>