diff --git a/plugins/channeltx/modpacket/packetmod.cpp b/plugins/channeltx/modpacket/packetmod.cpp
index 7291774e1..141c1214e 100644
--- a/plugins/channeltx/modpacket/packetmod.cpp
+++ b/plugins/channeltx/modpacket/packetmod.cpp
@@ -575,16 +575,32 @@ int PacketMod::webapiActionsPost(
         if (channelActionsKeys.contains("tx"))
         {
             SWGSDRangel::SWGPacketModActions_tx* tx = swgPacketModActions->getTx();
-            QString callsign(*tx->getCallsign());
-            QString to(*tx->getTo());
-            QString via(*tx->getVia());
-            QString data(*tx->getData());
+            QString *callsignP = tx->getCallsign();
+            QString *toP = tx->getTo();
+            QString *viaP = tx->getVia();
+            QString *dataP = tx->getData();
+            if (callsignP && toP && viaP && dataP)
+            {
+                QString callsign(*callsignP);
+                QString to(*toP);
+                QString via(*viaP);
+                QString data(*dataP);
 
-            PacketMod::MsgTXPacketMod *msg = PacketMod::MsgTXPacketMod::create(callsign, to, via, data);
-            m_basebandSource->getInputMessageQueue()->push(msg);
+                PacketMod::MsgTXPacketMod *msg = PacketMod::MsgTXPacketMod::create(callsign, to, via, data);
+                m_basebandSource->getInputMessageQueue()->push(msg);
+                return 202;
+            }
+            else
+            {
+                errorMessage = "Packet must contain callsign, to, via and data";
+                return 400;
+            }
+        }
+        else
+        {
+            errorMessage = "Unknown action";
+            return 400;
         }
-
-        return 202;
     }
     else
     {
diff --git a/plugins/channeltx/modpacket/packetmodsource.cpp b/plugins/channeltx/modpacket/packetmodsource.cpp
index d849e4ec0..d0e352812 100644
--- a/plugins/channeltx/modpacket/packetmodsource.cpp
+++ b/plugins/channeltx/modpacket/packetmodsource.cpp
@@ -39,8 +39,9 @@ PacketModSource::PacketModSource() :
     m_bitIdx(0),
     m_last5Bits(0),
     m_state(idle),
-    m_scrambler(0x10800, 0x0)
-{
+    m_scrambler(0x10800, 0x0),
+    m_spectrumSink(nullptr)
+ {
     m_lowpass.create(301, m_channelSampleRate, 22000.0 / 2.0);
     qDebug() << "PacketModSource::PacketModSource creating BPF : " << m_channelSampleRate;
     m_bandpass.create(301, m_channelSampleRate, 800.0, 2600.0);
diff --git a/plugins/channeltx/modpacket/readme.md b/plugins/channeltx/modpacket/readme.md
index 3b4dcbdd1..8becdc427 100644
--- a/plugins/channeltx/modpacket/readme.md
+++ b/plugins/channeltx/modpacket/readme.md
@@ -48,7 +48,7 @@ Enter your amateur radio callsign and optionally a sub-station ID (SSID). E.g. M
 
 <h3>10: Preemphaisis Filter</h3>
 
-Check this button to enable a FM preemphasis filter, which amplifiers higher frequencies. Right click to open the dialog to adjust settings for the filter.
+Check this button to enable a FM preemphasis filter, which amplifies higher frequencies. Right click to open the dialog to adjust settings for the filter.
 
 <h3>11: Bandpass Filter</h3>
 
@@ -58,7 +58,7 @@ Check this button to enable a baseband bandpass filter. Right click to open the
 
 Check this button to repeated transmit a packet. Right click to open the dialog to adjust the delay between retransmission and number of times the packet should be repeated.
 
-<h3>13: Insertion position</h3>
+<h3>13: Insert position</h3>
 
 Inserts position as APRS formatted latitude and longitude in to the current cursor position within the data field. Lattitude and longitude can be specified under Preferences > My position.