diff --git a/FDTD/operator.cpp b/FDTD/operator.cpp
index 9ca0926..77d333d 100644
--- a/FDTD/operator.cpp
+++ b/FDTD/operator.cpp
@@ -35,6 +35,7 @@ Operator::Operator()
 {
 	m_MeshType = ProcessFields::CARTESIAN_MESH;
 	Exc = 0;
+	dT = 0;
 }
 
 Operator::~Operator()
@@ -77,6 +78,7 @@ void Operator::Init()
 		m_BC[n]=0;
 
 	Exc = 0;
+	dT = 0;
 }
 
 void Operator::Reset()
@@ -531,7 +533,16 @@ int Operator::CalcECOperator()
 	if (Calc_EC()==0)
 		return -1;
 
-	CalcTimestep();
+	if (dT>0)
+	{
+		double save_dT = dT;
+		CalcTimestep();
+		if (dT<save_dT)
+			cerr << "Operator::CalcECOperator: Warning, forced timestep: " << save_dT << "s is larger than calculated timestep: " << dT << "s! It is not recommended using this timestep!! " << endl;
+		dT = save_dT;
+	}
+	else
+		CalcTimestep();
 
 	InitOperator();
 
diff --git a/FDTD/operator.h b/FDTD/operator.h
index 8ee5a0e..fd3e43a 100644
--- a/FDTD/operator.h
+++ b/FDTD/operator.h
@@ -54,6 +54,8 @@ public:
 	virtual void ApplyElectricBC(bool* dirs); //applied by default to all boundaries
 	virtual void ApplyMagneticBC(bool* dirs);
 
+	//! Set a forced timestep to use by the operator
+	virtual void SetTimestep(double ts) {dT = ts;}
 	double GetTimestep() const {return dT;};
 	double GetNumberCells() const;