diff --git a/public_html/planeObject.js b/public_html/planeObject.js
index d1b7593..92ede4b 100644
--- a/public_html/planeObject.js
+++ b/public_html/planeObject.js
@@ -245,7 +245,7 @@ PlaneObject.prototype.updateData = function(receiver_timestamp, data) {
 		this.squawk	= data.squawk;
 };
 
-PlaneObject.prototype.updateTick = function(receiver_timestamp) {
+PlaneObject.prototype.updateTick = function(receiver_timestamp, last_timestamp) {
         // recompute seen and seen_pos
         this.seen = receiver_timestamp - this.last_message_time;
         this.seen_pos = (this.last_position_time === null ? null : receiver_timestamp - this.last_position_time);
@@ -262,7 +262,7 @@ PlaneObject.prototype.updateTick = function(receiver_timestamp) {
 	} else {
                 this.visible = true;
                 if (this.position !== null) {
-			if (this.updateTrack(5)) {
+			if (this.updateTrack(receiver_timestamp - last_timestamp + 5)) {
                                 this.updateLines();
                                 this.updateMarker(true);
                         } else { 
diff --git a/public_html/script.js b/public_html/script.js
index 5961087..7d6e160 100644
--- a/public_html/script.js
+++ b/public_html/script.js
@@ -29,7 +29,7 @@ var SitePosition = null;
 
 var ReceiverClock = null;
 
-var LastReceiverTimestamp = null;
+var LastReceiverTimestamp = 0;
 var StaleReceiverCount = 0;
 var FetchPending = null;
 
@@ -108,7 +108,7 @@ function fetchData() {
                 // update timestamps, visibility, history track for all planes - not only those updated
                 for (var i = 0; i < PlanesOrdered.length; ++i) {
                         var plane = PlanesOrdered[i];
-                        plane.updateTick(now);
+                        plane.updateTick(now, LastReceiverTimestamp);
                 }
                 
 		refreshTableInfo();
@@ -277,6 +277,8 @@ function end_load_history() {
                         var plane = PlanesOrdered[i];
                         plane.updateTick(now);
                 }
+
+                LastReceiverTimestamp = last;
         }
 
         PositionHistoryBuffer = null;