diff --git a/app/src/main/java/org/traccar/client/AutostartReceiver.java b/app/src/main/java/org/traccar/client/AutostartReceiver.java
index ed8a28a..b3308c7 100644
--- a/app/src/main/java/org/traccar/client/AutostartReceiver.java
+++ b/app/src/main/java/org/traccar/client/AutostartReceiver.java
@@ -23,8 +23,6 @@ import android.preference.PreferenceManager;
 
 public class AutostartReceiver extends BroadcastReceiver {
 	
-	public static final String LOG_TAG = "Traccar.AutostartReceiver";
- 
     @Override
     public void onReceive(Context context, Intent intent) {
     	SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
diff --git a/app/src/main/java/org/traccar/client/MainActivity.java b/app/src/main/java/org/traccar/client/MainActivity.java
index 0b554d7..7dc51bd 100644
--- a/app/src/main/java/org/traccar/client/MainActivity.java
+++ b/app/src/main/java/org/traccar/client/MainActivity.java
@@ -33,8 +33,6 @@ import android.view.MenuItem;
 @SuppressWarnings("deprecation")
 public class MainActivity extends PreferenceActivity implements OnSharedPreferenceChangeListener {
 
-    public static final String LOG_TAG = "traccar";
-
     public static final String KEY_DEVICE = "id";
     public static final String KEY_ADDRESS = "address";
     public static final String KEY_PORT = "port";
diff --git a/app/src/main/java/org/traccar/client/NetworkManager.java b/app/src/main/java/org/traccar/client/NetworkManager.java
index de259ab..6b93b70 100644
--- a/app/src/main/java/org/traccar/client/NetworkManager.java
+++ b/app/src/main/java/org/traccar/client/NetworkManager.java
@@ -21,15 +21,20 @@ import android.content.Intent;
 import android.content.IntentFilter;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
+import android.util.Log;
 
 public class NetworkManager extends BroadcastReceiver {
 
+    private static final String TAG = NetworkManager.class.getSimpleName();
+
     private Context context;
     private NetworkHandler handler;
+    private ConnectivityManager connectivityManager;
 
     public NetworkManager(Context context, NetworkHandler handler) {
         this.context = context;
         this.handler = handler;
+        connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
     }
 
     public interface NetworkHandler {
@@ -37,8 +42,7 @@ public class NetworkManager extends BroadcastReceiver {
     }
 
     public boolean isOnline() {
-        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
-        NetworkInfo activeNetwork = cm.getActiveNetworkInfo();
+        NetworkInfo activeNetwork = connectivityManager.getActiveNetworkInfo();
         return activeNetwork != null && activeNetwork.isConnectedOrConnecting();
     }
 
@@ -55,7 +59,9 @@ public class NetworkManager extends BroadcastReceiver {
     @Override
     public void onReceive(Context context, Intent intent) {
         if (intent.getAction().equals(ConnectivityManager.CONNECTIVITY_ACTION) && handler != null) {
-            handler.onNetworkUpdate(intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false));
+            boolean isOnline = isOnline();
+            Log.i(TAG, "network " + (isOnline ? "on" : "off"));
+            handler.onNetworkUpdate(isOnline);
         }
     }
 
diff --git a/app/src/main/java/org/traccar/client/PositionProvider.java b/app/src/main/java/org/traccar/client/PositionProvider.java
index 9328493..f5103cb 100644
--- a/app/src/main/java/org/traccar/client/PositionProvider.java
+++ b/app/src/main/java/org/traccar/client/PositionProvider.java
@@ -27,9 +27,12 @@ import android.os.BatteryManager;
 import android.os.Build;
 import android.os.Bundle;
 import android.os.Handler;
+import android.util.Log;
 
 public class PositionProvider {
 
+    private static final String TAG = PositionProvider.class.getSimpleName();
+
     public static final String PROVIDER_MIXED = "mixed";
     public static final long PROVIDER_RETRY_PERIOD = 60 * 1000;
 
@@ -104,10 +107,12 @@ public class PositionProvider {
             }*/
             
             if (location != null && location.getTime() != lastTime) {
+                Log.i(TAG, "location new");
                 lastTime = location.getTime();
                 listener.onPositionUpdate(new Position(deviceId, location, getBatteryLevel()));
                 return true;
             } else {
+                Log.i(TAG, location != null ? "location old" : "location nil");
                 return false;
             }
         }
diff --git a/app/src/main/java/org/traccar/client/StatusActivity.java b/app/src/main/java/org/traccar/client/StatusActivity.java
index 772e71a..3f20962 100644
--- a/app/src/main/java/org/traccar/client/StatusActivity.java
+++ b/app/src/main/java/org/traccar/client/StatusActivity.java
@@ -23,7 +23,6 @@ import java.util.Set;
 
 import android.app.ListActivity;
 import android.os.Bundle;
-import android.util.Log;
 import android.view.Menu;
 import android.view.MenuInflater;
 import android.view.MenuItem;
@@ -43,7 +42,6 @@ public class StatusActivity extends ListActivity {
     }
 
     public static void addMessage(String message) {
-        Log.i(MainActivity.LOG_TAG, message);
         DateFormat format = DateFormat.getTimeInstance(DateFormat.SHORT);
         message = format.format(new Date()) + " - " + message;
         messages.add(message);
diff --git a/app/src/main/java/org/traccar/client/TrackingController.java b/app/src/main/java/org/traccar/client/TrackingController.java
index fc9656e..d76d85f 100644
--- a/app/src/main/java/org/traccar/client/TrackingController.java
+++ b/app/src/main/java/org/traccar/client/TrackingController.java
@@ -19,9 +19,11 @@ import android.content.Context;
 import android.content.SharedPreferences;
 import android.os.Handler;
 import android.preference.PreferenceManager;
+import android.util.Log;
 
 public class TrackingController implements PositionProvider.PositionListener, NetworkManager.NetworkHandler {
 
+    private static final String TAG = TrackingController.class.getSimpleName();
     private static final int RETRY_DELAY = 30 * 1000;
 
     private boolean isOnline;
@@ -49,7 +51,9 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     }
 
     public void start() {
-        read();
+        if (isOnline) {
+            read();
+        }
         positionProvider.startUpdates();
         networkManager.start();
     }
@@ -84,7 +88,19 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     // read -> send -> retry -> read -> send
     //
 
+    private void log(String action, Position position) {
+        if (position != null) {
+            action += " (" +
+                    "id:" + position.getId() +
+                    " time:" + position.getTime().getTime() / 1000 +
+                    " lat:" + position.getLatitude() +
+                    " lon:" + position.getLongitude() + ")";
+        }
+        Log.d(TAG, action);
+    }
+
     private void write(Position position) {
+        log("write", position);
         databaseHelper.insertPositionAsync(position, new DatabaseHelper.DatabaseHandler<Void>() {
             @Override
             public void onSuccess(Void result) {
@@ -101,6 +117,7 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     }
 
     private void read() {
+        log("read", null);
         databaseHelper.selectPositionAsync(new DatabaseHelper.DatabaseHandler<Position>() {
             @Override
             public void onSuccess(Position result) {
@@ -119,6 +136,7 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     }
 
     private void delete(Position position) {
+        log("delete", position);
         databaseHelper.deletePositionAsync(position.getId(), new DatabaseHelper.DatabaseHandler<Void>() {
             @Override
             public void onSuccess(Void result) {
@@ -133,6 +151,7 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     }
 
     private void send(final Position position) {
+        log("send", position);
         String request = ProtocolFormatter.formatRequest(
                 preferences.getString(MainActivity.KEY_ADDRESS, null),
                 Integer.parseInt(preferences.getString(MainActivity.KEY_PORT, null)),
@@ -153,10 +172,13 @@ public class TrackingController implements PositionProvider.PositionListener, Ne
     }
 
     private void retry() {
+        log("retry", null);
         handler.postDelayed(new Runnable() {
             @Override
             public void run() {
-                read();
+                if (isOnline) {
+                    read();
+                }
             }
         }, RETRY_DELAY);
     }
diff --git a/app/src/main/java/org/traccar/client/TrackingService.java b/app/src/main/java/org/traccar/client/TrackingService.java
index 6b95143..46d56b9 100644
--- a/app/src/main/java/org/traccar/client/TrackingService.java
+++ b/app/src/main/java/org/traccar/client/TrackingService.java
@@ -23,15 +23,19 @@ import android.os.Build;
 import android.os.IBinder;
 import android.os.PowerManager;
 import android.os.PowerManager.WakeLock;
+import android.util.Log;
 
 public class TrackingService extends Service {
 
+    private static final String TAG = TrackingService.class.getSimpleName();
+
     private TrackingController trackingController;
 
     private WakeLock wakeLock;
 
     @Override
     public void onCreate() {
+        Log.i(TAG, "service create");
         StatusActivity.addMessage(getString(R.string.status_service_create));
 
         PowerManager powerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
@@ -55,6 +59,7 @@ public class TrackingService extends Service {
 
     @Override
     public void onDestroy() {
+        Log.i(TAG, "service destroy");
         StatusActivity.addMessage(getString(R.string.status_service_destroy));
 
         if (trackingController != null) {