diff --git a/sdrbase/dsp/agc.cpp b/sdrbase/dsp/agc.cpp
index f87c5660f..ee4662593 100644
--- a/sdrbase/dsp/agc.cpp
+++ b/sdrbase/dsp/agc.cpp
@@ -5,6 +5,7 @@
  *      Author: f4exb
  */
 
+#include <algorithm>
 #include "dsp/agc.h"
 #include "util/smootherstep.h"
 
@@ -48,13 +49,21 @@ MagSquaredAGC::MagSquaredAGC(int historySize, double R, double threshold) :
 	m_magsq(0.0),
 	m_threshold(threshold),
 	m_gate(0),
-	m_stepCounter(0),
+	m_stepLength(std::min(2400, historySize/2)),
+	m_stepUpCounter(0),
+    m_stepDownCounter(0),
 	m_gateCounter(0)
 {}
 
 MagSquaredAGC::~MagSquaredAGC()
 {}
 
+void MagSquaredAGC::resize(int historySize, Real R)
+{
+    m_stepLength = std::min(2400, historySize/2);
+    AGC::resize(historySize, R);
+}
+
 void MagSquaredAGC::feed(Complex& ci)
 {
 	m_magsq = ci.real()*ci.real() + ci.imag()*ci.imag();
@@ -91,16 +100,23 @@ double MagSquaredAGC::feedAndGetValue(const Complex& ci)
 
     if (m_count <  m_moving_average.historySize())
     {
-        if (m_stepCounter < 2400) {
-            m_stepCounter++;
+        m_stepDownCounter = m_stepLength;
+
+        if (m_stepUpCounter < m_stepLength) {
+            m_stepUpCounter++;
         }
 
-        return m_u0 * StepFunctions::smootherstep(m_stepCounter/2400.0);
+        return m_u0 * StepFunctions::smootherstep(m_stepUpCounter/m_stepLength);
     }
     else
     {
-        m_stepCounter = 0;
-        return 0.0;
+        m_stepUpCounter = 0;
+
+        if (m_stepDownCounter > 0) {
+            m_stepDownCounter--;
+        }
+
+        return m_u0 * StepFunctions::smootherstep(m_stepDownCounter/m_stepLength);
     }
 
     //return (m_count <  m_moving_average.historySize()) ? m_u0 : 0.0;
@@ -116,13 +132,21 @@ MagAGC::MagAGC(int historySize, double R, double threshold) :
 	m_magsq(0.0),
 	m_threshold(threshold),
 	m_gate(0),
-	m_stepCounter(0),
+	m_stepLength(std::min(2400, historySize/2)),
+	m_stepUpCounter(0),
+    m_stepDownCounter(0),
 	m_gateCounter(0)
 {}
 
 MagAGC::~MagAGC()
 {}
 
+void MagAGC::resize(int historySize, Real R)
+{
+    m_stepLength = std::min(2400, historySize/2);
+    AGC::resize(historySize, R);
+}
+
 void MagAGC::feed(Complex& ci)
 {
 	m_magsq = ci.real()*ci.real() + ci.imag()*ci.imag();
@@ -159,16 +183,23 @@ double MagAGC::feedAndGetValue(const Complex& ci)
 
     if (m_count <  m_moving_average.historySize())
     {
-        if (m_stepCounter < 480) {
-            m_stepCounter++;
+        m_stepDownCounter = m_stepLength;
+
+        if (m_stepUpCounter < m_stepLength) {
+            m_stepUpCounter++;
         }
 
-        return m_u0 * StepFunctions::smootherstep(m_stepCounter/480.0);
+        return m_u0 * StepFunctions::smootherstep(m_stepUpCounter/m_stepLength);
     }
     else
     {
-        m_stepCounter = 0;
-        return 0.0;
+        m_stepUpCounter = 0;
+
+        if (m_stepDownCounter > 0) {
+            m_stepDownCounter--;
+        }
+
+        return m_u0 * StepFunctions::smootherstep(m_stepDownCounter/m_stepLength);
     }
 
     //return (m_count <  m_moving_average.historySize()) ? m_u0 : 0.0;
diff --git a/sdrbase/dsp/agc.h b/sdrbase/dsp/agc.h
index 61bb74c77..c07f2f487 100644
--- a/sdrbase/dsp/agc.h
+++ b/sdrbase/dsp/agc.h
@@ -34,6 +34,7 @@ class MagSquaredAGC : public AGC
 public:
 	MagSquaredAGC(int historySize, double R, double threshold);
 	virtual ~MagSquaredAGC();
+	void resize(int historySize, Real R);
 	virtual void feed(Complex& ci);
 	double feedAndGetValue(const Complex& ci);
 	double getMagSq() const { return m_magsq; }
@@ -41,10 +42,12 @@ public:
 	void setGate(int gate) { m_gate = gate; }
 private:
 	double m_magsq;
-	double m_threshold; //!< squelch on magsq average with transition from +3dB
-    int m_gate;
-    int m_stepCounter;
-    int m_gateCounter;
+	double m_threshold;    //!< squelch on magsq average
+    int m_gate;            //!< power threshold gate in number of samples
+    int m_stepLength;      //!< transition step length in number of samples
+    int m_stepUpCounter;   //!< step up transition samples counter
+    int m_stepDownCounter; //!< step down transition samples counter
+    int m_gateCounter;     //!< threshold gate samples counter
 };
 
 class MagAGC : public AGC
@@ -52,6 +55,7 @@ class MagAGC : public AGC
 public:
 	MagAGC(int historySize, double R, double threshold);
 	virtual ~MagAGC();
+	void resize(int historySize, Real R);
 	virtual void feed(Complex& ci);
     double feedAndGetValue(const Complex& ci);
 	Real getMagSq() const { return m_magsq; }
@@ -59,10 +63,12 @@ public:
     void setGate(int gate) { m_gate = gate; }
 private:
 	double m_magsq;
-    double m_threshold; //!< squelch on magsq average
-    int m_gate;
-    int m_stepCounter;
-    int m_gateCounter;
+    double m_threshold;    //!< squelch on magsq average
+    int m_gate;            //!< power threshold gate in number of samples
+    int m_stepLength;      //!< transition step length in number of samples
+    int m_stepUpCounter;   //!< step up transition samples counter
+    int m_stepDownCounter; //!< step down transition samples counter
+    int m_gateCounter;     //!< threshold gate samples counter
 };
 
 class AlphaAGC : public AGC