diff --git a/application/models/Logbook_model.php b/application/models/Logbook_model.php
index 4269993a..204b052f 100755
--- a/application/models/Logbook_model.php
+++ b/application/models/Logbook_model.php
@@ -465,8 +465,13 @@ class Logbook_model extends CI_Model {
       $adif .= '<cqz:' . strlen($data['COL_CQZ']) . '>' . $data['COL_CQZ'];
       //$adif .= '<ituz:' . strlen($data['COL_ITUZ']) . '>' . $data['COL_ITUZ']; -- not yet implemented
 
-      $adif .= '<lotw_qsl_sent:' . strlen($data['COL_LOTW_QSL_SENT']) . '>' . $data['COL_LOTW_QSL_SENT'];
-      $adif .= '<lotw_qsl_rcvd:' . strlen($data['COL_LOTW_QSL_RCVD']) . '>' . $data['COL_LOTW_QSL_RCVD'];
+      if($data['COL_LOTW_QSL_SENT']) {
+         $adif .= '<lotw_qsl_sent:' . strlen($data['COL_LOTW_QSL_SENT']) . '>' . $data['COL_LOTW_QSL_SENT'];
+      }
+	  
+      if($data['COL_LOTW_QSL_RCVD']) {
+         $adif .= '<lotw_qsl_rcvd:' . strlen($data['COL_LOTW_QSL_RCVD']) . '>' . $data['COL_LOTW_QSL_RCVD'];
+      }
 
       if($data['COL_IOTA']) {
         $adif .= '<iota:' . strlen($data['COL_IOTA']) . '>' . $data['COL_IOTA'];