diff --git a/src/comm/UDPLink.cc b/src/comm/UDPLink.cc
index 1e952fbbf5b394723fc488b98b97b31d2f3daccd..ad475ce57b6cac7f0daa27d1e2a6b75f26c71a2f 100644
--- a/src/comm/UDPLink.cc
+++ b/src/comm/UDPLink.cc
@@ -160,8 +160,12 @@ void UDPLink::_writeBytes(const QByteArray data)
         return;
     }
     emit bytesSent(this, data);
+
+    QMutexLocker locker(&_sessionTargetsMutex);
+
     // Send to all manually targeted systems
-    for(UDPCLient* target: _udpConfig->targetHosts()) {
+    for (int i=0; i<_udpConfig->targetHosts().count(); i++) {
+        UDPCLient* target = _udpConfig->targetHosts()[i];
         // Skip it if it's part of the session clients below
         if(!contains_target(_sessionTargets, target->address, target->port)) {
             _writeDataGram(data, target);
@@ -219,11 +223,13 @@ void UDPLink::readBytes()
         if(_isIpLocal(sender)) {
             asender = QHostAddress(QString("127.0.0.1"));
         }
-        if(!contains_target(_sessionTargets, asender, senderPort)) {
+        QMutexLocker locker(&_sessionTargetsMutex);
+        if (!contains_target(_sessionTargets, asender, senderPort)) {
             qDebug() << "Adding target" << asender << senderPort;
             UDPCLient* target = new UDPCLient(asender, senderPort);
             _sessionTargets.append(target);
         }
+        locker.unlock();
     }
     //-- Send whatever is left
     if (databuffer.size()) {
@@ -280,16 +286,13 @@ bool UDPLink::_hardwareConnect()
     if (_connectState) {
         _socket->joinMulticastGroup(QHostAddress("224.0.0.1"));
         //-- Make sure we have a large enough IO buffers
-
 #ifdef __mobile__
-        int bufferSizeMultiplier = 1;
+        _socket->setSocketOption(QAbstractSocket::SendBufferSizeSocketOption,     64 * 1024);
+        _socket->setSocketOption(QAbstractSocket::ReceiveBufferSizeSocketOption, 128 * 1024);
 #else
-        int bufferSizeMultiplier = 4;
+        _socket->setSocketOption(QAbstractSocket::SendBufferSizeSocketOption,    256 * 1024);
+        _socket->setSocketOption(QAbstractSocket::ReceiveBufferSizeSocketOption, 512 * 1024);
 #endif
-        int receiveBufferSize = _udpConfig->isTransmitOnly() ? 0 : 512 * 1024;
-        _socket->setSocketOption(QAbstractSocket::SendBufferSizeSocketOption,     bufferSizeMultiplier * 64 * 1024);
-        _socket->setSocketOption(QAbstractSocket::ReceiveBufferSizeSocketOption, bufferSizeMultiplier * receiveBufferSize);
-
         _registerZeroconf(_udpConfig->localPort(), kZeroconfRegistration);
         QObject::connect(_socket, &QUdpSocket::readyRead, this, &UDPLink::readBytes);
         emit connected();
@@ -361,9 +364,7 @@ void UDPLink::_deregisterZeroconf()
 //--------------------------------------------------------------------------
 //-- UDPConfiguration
 
-UDPConfiguration::UDPConfiguration(const QString& name)
-    : LinkConfiguration(name)
-    , _transmitOnly(false)
+UDPConfiguration::UDPConfiguration(const QString& name) : LinkConfiguration(name)
 {
     AutoConnectSettings* settings = qgcApp()->toolbox()->settingsManager()->autoConnectSettings();
     _localPort = settings->udpListenPort()->rawValue().toInt();
@@ -373,9 +374,7 @@ UDPConfiguration::UDPConfiguration(const QString& name)
     }
 }
 
-UDPConfiguration::UDPConfiguration(UDPConfiguration* source)
-    : LinkConfiguration(source)
-    , _transmitOnly(false)
+UDPConfiguration::UDPConfiguration(UDPConfiguration* source) : LinkConfiguration(source)
 {
     _copyFrom(source);
 }
diff --git a/src/comm/UDPLink.h b/src/comm/UDPLink.h
index caec844a594d09c149fb8f8c2e5bac2627129a82..83eb7b0e369ebe4fe0a8f584c6a3d8b2538500d1 100644
--- a/src/comm/UDPLink.h
+++ b/src/comm/UDPLink.h
@@ -7,14 +7,6 @@
  *
  ****************************************************************************/
 
-
-/*!
- * @file
- *   @brief UDP connection (server) for unmanned vehicles
- *   @author Lorenz Meier <mavteam@student.ethz.ch>
- *
- */
-
 #pragma once
 
 #include <QString>
@@ -22,7 +14,7 @@
 #include <QMap>
 #include <QMutex>
 #include <QUdpSocket>
-#include <QMutexLocker>
+#include <QMutex>
 #include <QQueue>
 #include <QByteArray>
 
@@ -111,14 +103,6 @@ public:
      */
     void setLocalPort   (quint16 port);
 
-    /*!
-     * @brief Set the UDP port to be transmit only. Receive buffer is set to zero.
-     *
-     */
-    void setTransmitOnly (bool state) { _transmitOnly = state; }
-
-    bool isTransmitOnly () { return _transmitOnly; }
-
     /*!
      * @brief QML Interface
      */
@@ -150,7 +134,6 @@ private:
     QList<UDPCLient*>   _targetHosts;
     QStringList         _hostList;      ///< Exposed to QML
     quint16             _localPort;
-    bool                _transmitOnly;
 };
 
 class UDPLink : public LinkInterface