diff --git a/examples/leo-delay-tracing-example.cc b/examples/leo-delay-tracing-example.cc
index 7969fcc..0fa17e6 100644
--- a/examples/leo-delay-tracing-example.cc
+++ b/examples/leo-delay-tracing-example.cc
@@ -74,17 +74,18 @@ int main (int argc, char *argv[])
 
   // Install internet stack on nodes
   AodvHelper aodv;
-  aodv.Set ("HelloInterval", TimeValue (Seconds (1)));
-  aodv.Set ("TtlStart", UintegerValue (10));
-  aodv.Set ("TtlIncrement", UintegerValue (10));
-  aodv.Set ("TtlThreshold", UintegerValue (100));
-  aodv.Set ("RreqRetries", UintegerValue (100));
-  aodv.Set ("RreqRateLimit", UintegerValue (10));
-  aodv.Set ("RerrRateLimit", UintegerValue (10));
-  aodv.Set ("ActiveRouteTimeout", TimeValue (Minutes (1)));
-  aodv.Set ("NextHopWait", TimeValue (MilliSeconds (200)));
-  aodv.Set ("NetDiameter", UintegerValue (1000));
-  aodv.Set ("PathDiscoveryTime", TimeValue (Seconds (1)));
+  //aodv.Set ("HelloInterval", TimeValue (Minutes (1)));
+  aodv.Set ("TtlStart", UintegerValue (5));
+  aodv.Set ("TtlIncrement", UintegerValue (5));
+  aodv.Set ("TtlThreshold", UintegerValue (200));
+  aodv.Set ("RreqRetries", UintegerValue (1000));
+  aodv.Set ("RreqRateLimit", UintegerValue (100));
+  //aodv.Set ("RerrRateLimit", UintegerValue (1));
+  //aodv.Set ("ActiveRouteTimeout", TimeValue (Minutes (1)));
+  //aodv.Set ("NextHopWait", TimeValue (MilliSeconds (200)));
+  aodv.Set ("NetDiameter", UintegerValue (100));
+  //aodv.Set ("AllowedHelloLoss", UintegerValue (10000));
+  //aodv.Set ("PathDiscoveryTime", TimeValue (Seconds (1)));
 
   InternetStackHelper stack;
   stack.SetRoutingHelper (aodv);
@@ -107,8 +108,8 @@ int main (int argc, char *argv[])
   Address remote = stations.Get (1)->GetObject<Ipv4> ()->GetAddress (1, 0).GetLocal ();//utIp.GetAddress (1, 0);
   std::cout << "REMOTE=" << Ipv4Address::ConvertFrom (remote);
   UdpClientHelper echoClient (remote, 9);
-  echoClient.SetAttribute ("MaxPackets", UintegerValue (360));
-  echoClient.SetAttribute ("Interval", TimeValue (Seconds (10.0)));
+  echoClient.SetAttribute ("MaxPackets", UintegerValue (60));
+  echoClient.SetAttribute ("Interval", TimeValue (Seconds (1)));
   echoClient.SetAttribute ("PacketSize", UintegerValue (1024));
   clientApps.Add (echoClient.Install (stations.Get (3)));
 
@@ -118,9 +119,11 @@ int main (int argc, char *argv[])
   std::cout << "Context,Sequence Number,Timestamp,Delay" << std::endl;
 
   serverApps.Start (Seconds (1));
-  clientApps.Start (Seconds (2));
+  clientApps.Start (Seconds (1));
+  serverApps.Stop (Minutes (1));
+  clientApps.Stop (Minutes (1));
 
-  Simulator::Stop (Minutes (60));
+  Simulator::Stop (Minutes (1));
   Simulator::Run ();
   Simulator::Destroy ();
 
diff --git a/model/isl-propagation-loss-model.cc b/model/isl-propagation-loss-model.cc
index bc2813f..b0d9f4e 100644
--- a/model/isl-propagation-loss-model.cc
+++ b/model/isl-propagation-loss-model.cc
@@ -1,29 +1,8 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2005,2006,2007 INRIA
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation;
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
- * Contributions: Timo Bingmann <timo.bingmann@student.kit.edu>
- * Contributions: Gary Pei <guangyu.pei@boeing.com> for fixed RSS
- * Contributions: Tom Hewer <tomhewer@mac.com> for two ray ground model
- *                Pavel Boyko <boyko@iitp.ru> for matrix
- */
 
 #include "ns3/log.h"
 #include "ns3/mobility-model.h"
+#include "ns3/double.h"
 #include "math.h"
 
 #include "isl-propagation-loss-model.h"
@@ -41,6 +20,12 @@ IslPropagationLossModel::GetTypeId (void)
     .SetParent<PropagationLossModel> ()
     .SetGroupName ("Leo")
     .AddConstructor<IslPropagationLossModel> ()
+    .AddAttribute ("MaxDistance",
+                   "Cut-off distance for signal propagation",
+                   DoubleValue (1000.0),
+                   MakeDoubleAccessor (&IslPropagationLossModel::SetCutoffDistance,
+				       &IslPropagationLossModel::GetCutoffDistance),
+                   MakeDoubleChecker<double> ())
   ;
   return tid;
 }
@@ -53,33 +38,30 @@ IslPropagationLossModel::~IslPropagationLossModel ()
 {
 }
 
-
-const double
-IslPropagationLossModel::EARTH_RAD_E6 = 6.371;
-
 bool
-IslPropagationLossModel::GetLos (Ptr<MobilityModel> a, Ptr<MobilityModel> b)
+IslPropagationLossModel::GetLos (Ptr<MobilityModel> moda, Ptr<MobilityModel> modb)
 {
   // origin of LOS
-  Vector3D o = a->GetPosition ();
-  o = Vector3D (o.x / 1e6, o.y / 1e6, o.z / 1e6);
-  double ol = o.GetLength ();
+  Vector3D oc = moda->GetPosition ();
+  Vector3D bp = modb->GetPosition ();
 
-  // second point of LOS
-  Vector3D bp = b->GetPosition ();
-  bp = Vector3D (bp.x / 1e6, bp.y / 1e6, bp.z / 1e6);
-
-  // unit vector
-  Vector3D u = Vector3D (o.x-bp.x, o.y-bp.y, o.z-bp.z);
+  // direction unit vector
+  Vector3D u = Vector3D (bp.x - oc.x, bp.y - oc.y, bp.z - oc.z);
   u = Vector3D (u.x / u.GetLength (), u.y / u.GetLength (), u.z / u.GetLength ());
 
-  // center point of sphere is 0
-  double uo = (u.x*o.x) + (u.y*o.y) + (u.z*o.z);
-  double delta = (uo*uo) - (ol*ol - (EARTH_RAD_E6*EARTH_RAD_E6));
+  double a = u.x*u.x + u.y*u.y + u.z*u.z;
+  double b = 2.0 * (oc.x*u.x + oc.y*u.y + oc.z*u.z);
+  double c = (oc.x*oc.x + oc.y*oc.y + oc.z*oc.z) - (LEO_EARTH_RAD*LEO_EARTH_RAD);
+  double discriminant = b*b - 4*a*c;
 
-  //NS_LOG_DEBUG ("a_pos="<<o<<";b_pos"<<bp<<";delta="<<delta);
+  NS_LOG_DEBUG ("a_pos="<<moda->GetPosition ()<<";b_pos"<<modb->GetPosition ()
+  		<<";u="<<u
+  		<<";a="<<a
+  		<<";b="<<b
+  		<<";c="<<c
+  		<<";disc="<<discriminant);
 
-  return delta < 0;
+  return discriminant < 0;
 }
 
 double
@@ -87,12 +69,13 @@ IslPropagationLossModel::DoCalcRxPower (double txPowerDbm,
                                         Ptr<MobilityModel> a,
                                         Ptr<MobilityModel> b) const
 {
-  if (!GetLos (a, b))
+  if (a->GetDistanceFrom (b) > m_cutoffDistance || !GetLos (a, b))
     {
+      NS_LOG_DEBUG ("DROP;"<<a->GetPosition ()<<";"<<b->GetPosition ());
       return -1000.0;
     }
 
-  NS_LOG_INFO ("LOS;"<<a->GetPosition ()<<";"<<b->GetPosition ());
+  NS_LOG_DEBUG ("LOS;"<<a->GetPosition ()<<";"<<b->GetPosition ());
 
   return txPowerDbm;
 }
@@ -103,4 +86,15 @@ IslPropagationLossModel::DoAssignStreams (int64_t stream)
   return 0;
 }
 
+void
+IslPropagationLossModel::SetCutoffDistance (double d)
+{
+  m_cutoffDistance = d * 1000.0;
+}
+
+double
+IslPropagationLossModel::GetCutoffDistance () const
+{
+  return m_cutoffDistance / 1000.0;
+}
 };
diff --git a/model/isl-propagation-loss-model.h b/model/isl-propagation-loss-model.h
index 49b841f..2bf0e19 100644
--- a/model/isl-propagation-loss-model.h
+++ b/model/isl-propagation-loss-model.h
@@ -1,26 +1,4 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/*
- * Copyright (c) 2005,2006,2007 INRIA
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation;
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
- * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
- * Contributions: Timo Bingmann <timo.bingmann@student.kit.edu>
- * Contributions: Gary Pei <guangyu.pei@boeing.com> for fixed RSS
- * Contributions: Tom Hewer <tomhewer@mac.com> for two ray ground model
- *                Pavel Boyko <boyko@iitp.ru> for matrix
- */
 
 #ifndef ISL_PROPAGATION_LOSS_MODEL_H
 #define ISL_PROPAGATION_LOSS_MODEL_H
@@ -28,13 +6,13 @@
 #include <ns3/object.h>
 #include <ns3/propagation-loss-model.h>
 
+#define LEO_EARTH_RAD 6.371009e6
+
 namespace ns3 {
 
 class IslPropagationLossModel : public PropagationLossModel
 {
 public:
-  static const double EARTH_RAD_E6;
-
   static TypeId GetTypeId (void);
   IslPropagationLossModel ();
   virtual ~IslPropagationLossModel ();
@@ -50,6 +28,14 @@ public:
    */
   static bool GetLos (Ptr<MobilityModel> a, Ptr<MobilityModel> b);
 private:
+  /**
+   * Cutoff distance for signal
+   */
+  double m_cutoffDistance;
+
+  void SetCutoffDistance (double d);
+  double GetCutoffDistance () const;
+
   /**
    * Returns the Rx Power taking into account only the particular
    * PropagationLossModel.
diff --git a/model/leo-propagation-loss-model.cc b/model/leo-propagation-loss-model.cc
index 29761fe..b820be9 100644
--- a/model/leo-propagation-loss-model.cc
+++ b/model/leo-propagation-loss-model.cc
@@ -103,26 +103,26 @@ LeoPropagationLossModel::DoCalcRxPower (double txPowerDbm,
                                         Ptr<MobilityModel> b) const
 {
   double distance = a->GetDistanceFrom (b);
-  double angle = GetAngle (a, b);
-  double rxc = txPowerDbm - m_atmosphericLoss - m_freeSpacePathLoss - m_linkMargin;
-
-  NS_LOG_DEBUG ("LEO propagation: a=" << a->GetPosition () << " b=" << b->GetPosition () << " m_cutOff="<<m_cutoffDistance<<" m_angle="<<m_elevationAngle<<" dist=" << distance << "angle=" << angle << "rxc=" << rxc);
 
   if (distance > m_cutoffDistance)
     {
-      NS_LOG_DEBUG ("LEO DROP DISTANCE: " << distance);
+      NS_LOG_DEBUG ("LEO DROP distance: a=" << a->GetPosition () << " b=" << b->GetPosition () << " m_cutOff="<<m_cutoffDistance<<" dist=" << distance);
+
       return -1000.0;
     }
 
+  double angle = GetAngle (a, b);
   if (angle > m_elevationAngle / 2.0)
     {
-      NS_LOG_DEBUG ("LEO DROP ANGLE: " << angle <<"; " << distance);
+      NS_LOG_DEBUG ("LEO DROP angle: a=" << a->GetPosition () << " b=" << b->GetPosition () << " m_cutOff="<<m_cutoffDistance<<" m_angle="<<m_elevationAngle<<" dist=" << distance << "angle=" << angle);
       return -1000.0;
     }
 
   // txPowerDbm includes tx antenna gain and losses
   // receiver loss and gain added at net device
   // P_{RX} = P_{TX} + G_{TX} - L_{TX} - L_{FS} - L_M + G_{RX} - L_{RX}
+  double rxc = txPowerDbm - m_atmosphericLoss - m_freeSpacePathLoss - m_linkMargin;
+  NS_LOG_INFO ("LEO TRANSMIT: angle=" << angle <<";distance=" << distance << ";rxc=" << rxc);
 
   return rxc;
 }