diff --git a/application/models/Logbook_model.php b/application/models/Logbook_model.php
index ccb4f9c05..8e4bb9b35 100755
--- a/application/models/Logbook_model.php
+++ b/application/models/Logbook_model.php
@@ -471,6 +471,19 @@ class Logbook_model extends CI_Model {
     } else {
       $txpower = null;
     }
+
+    if($this->input->post('stx')) {
+      $stx_string = $this->input->post('stx');
+    } else {
+      $stx_string = null;
+    }
+
+    if($this->input->post('srx')) {
+      $srx_string = $this->input->post('srx');
+    } else {
+      $srx_string = null;
+    }
+
     $data = array(
        'COL_TIME_ON' => $this->input->post('time_on'),
        'COL_TIME_OFF' => $this->input->post('time_off'),
@@ -513,9 +526,9 @@ class Logbook_model extends CI_Model {
        'COL_FREQ_RX' => $this->parse_frequency($this->input->post('freq_display_rx')),
        'COL_STX_STRING' => $this->input->post('stx_string'),
        'COL_SRX_STRING' => $this->input->post('srx_string'),
-		'COL_STX' => $this->input->post('stx'),
-		'COL_SRX' => $this->input->post('srx'),
-		'COL_CONTEST_ID' => $this->input->post('contest_name'),
+		   'COL_STX' => $stx_string,
+		   'COL_SRX' => $srx_string,
+		   'COL_CONTEST_ID' => $this->input->post('contest_name'),
        'COL_QSL_VIA' => $this->input->post('qsl_via_callsign'),
        'station_id' => $this->input->post('station_profile'),
        'COL_OPERATOR' => $this->input->post('operator_callsign'),