diff --git a/include/gui/glscope.h b/include/gui/glscope.h
index 66b71e74e..caa426545 100644
--- a/include/gui/glscope.h
+++ b/include/gui/glscope.h
@@ -82,7 +82,7 @@ public:
 	Mode getDataMode() const { return m_mode; }
 	void connectTimer(const QTimer& timer);
 
-	static const int m_memHistorySizeLog2 = 4;
+	static const int m_memHistorySizeLog2 = 5;
 
 signals:
 	void traceSizeChanged(int);
@@ -100,7 +100,7 @@ private:
 
 	// traces
 	std::vector<Complex> m_rawTrace[1<<m_memHistorySizeLog2];
-	int m_sampleRates[16];
+	int m_sampleRates[1<<m_memHistorySizeLog2];
 	BitfieldIndex<m_memHistorySizeLog2> m_memTraceIndex;   //!< current index of trace being written
 	BitfieldIndex<m_memHistorySizeLog2> m_memTraceHistory; //!< trace index shift into history
 	int m_memTraceIndexMax;
diff --git a/include/gui/glscopegui.h b/include/gui/glscopegui.h
index 85251ec6e..6e21fc295 100644
--- a/include/gui/glscopegui.h
+++ b/include/gui/glscopegui.h
@@ -96,7 +96,7 @@ private slots:
 	void on_traceIntensity_valueChanged(int index);
 	void on_trigPre_valueChanged(int value);
 	void on_trigDelay_valueChanged(int value);
-	void on_memHistory_valueChanged(int value);
+	void on_memIndex_valueChanged(int value);
 	void on_trigCount_valueChanged(int value);
 	void on_trigIndex_valueChanged(int value);
 
diff --git a/sdrbase/gui/glscopegui.cpp b/sdrbase/gui/glscopegui.cpp
index 4ca6adc71..c71044b1c 100644
--- a/sdrbase/gui/glscopegui.cpp
+++ b/sdrbase/gui/glscopegui.cpp
@@ -12,9 +12,9 @@ const qreal GLScopeGUI::amps[11] = { 0.2, 0.1, 0.05, 0.02, 0.01, 0.005, 0.002, 0
 GLScopeGUI::GLScopeGUI(QWidget* parent) :
 	QWidget(parent),
 	ui(new Ui::GLScopeGUI),
-	m_messageQueue(NULL),
-	m_scopeVis(NULL),
-	m_glScope(NULL),
+	m_messageQueue(0),
+	m_scopeVis(0),
+	m_glScope(0),
 	m_sampleRate(1),
 	m_displayData(GLScope::ModeIQ),
 	m_displayOrientation(Qt::Horizontal),
@@ -57,7 +57,7 @@ void GLScopeGUI::setBuddies(MessageQueue* messageQueue, ScopeVis* scopeVis, GLSc
 	m_messageQueue = messageQueue;
 	m_scopeVis = scopeVis;
 	m_glScope = glScope;
-	ui->memHistory->setMaximum((1<<GLScope::m_memHistorySizeLog2)-1);
+	ui->memIndex->setMaximum((1<<GLScope::m_memHistorySizeLog2)-1);
 	connect(m_glScope, SIGNAL(traceSizeChanged(int)), this, SLOT(on_scope_traceSizeChanged(int)));
 	connect(m_glScope, SIGNAL(sampleRateChanged(int)), this, SLOT(on_scope_sampleRateChanged(int)));
 	applySettings();
@@ -741,7 +741,7 @@ void GLScopeGUI::on_gridIntensity_valueChanged(int index)
 {
 	m_displayGridIntensity = index;
 	ui->gridIntensity->setToolTip(QString("Grid intensity: %1").arg(m_displayGridIntensity));
-	if(m_glScope != NULL)
+	if(m_glScope != 0)
 		m_glScope->setDisplayGridIntensity(m_displayGridIntensity);
 }
 
@@ -749,7 +749,7 @@ void GLScopeGUI::on_traceIntensity_valueChanged(int index)
 {
 	m_displayTraceIntensity = index;
 	ui->traceIntensity->setToolTip(QString("Trace intensity: %1").arg(m_displayTraceIntensity));
-	if(m_glScope != NULL)
+	if(m_glScope != 0)
 		m_glScope->setDisplayTraceIntensity(m_displayTraceIntensity);
 }
 
@@ -774,15 +774,15 @@ void GLScopeGUI::on_trigLevelFine_valueChanged(int value)
 	applyTriggerSettings();
 }
 
-void GLScopeGUI::on_memHistory_valueChanged(int value)
+void GLScopeGUI::on_memIndex_valueChanged(int value)
 {
 	QString text;
 	text.sprintf("%02d", value % (1<<GLScope::m_memHistorySizeLog2));
 	ui->memIndexText->setText(text);
 
-	if(m_glScope != NULL)
+	if(m_glScope != 0)
 	{
-		m_glScope->setMemHistoryShift(value % (1<<GLScope::m_memHistorySizeLog2));
+		m_glScope->setMemHistoryShift(value);
 	}
 }
 
diff --git a/sdrbase/gui/glscopegui.ui b/sdrbase/gui/glscopegui.ui
index e2aa4b519..8b5dfbf46 100644
--- a/sdrbase/gui/glscopegui.ui
+++ b/sdrbase/gui/glscopegui.ui
@@ -433,7 +433,7 @@
       </widget>
      </item>
      <item>
-      <widget class="QDial" name="memHistory">
+      <widget class="QDial" name="memIndex">
        <property name="maximumSize">
         <size>
          <width>24</width>