diff --git a/application/models/Logbook_model.php b/application/models/Logbook_model.php
index 204b052f..a17d4000 100755
--- a/application/models/Logbook_model.php
+++ b/application/models/Logbook_model.php
@@ -465,11 +465,11 @@ 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
 
-      if($data['COL_LOTW_QSL_SENT']) {
+      if(isset($data['COL_LOTW_QSL_SENT'])) {
          $adif .= '<lotw_qsl_sent:' . strlen($data['COL_LOTW_QSL_SENT']) . '>' . $data['COL_LOTW_QSL_SENT'];
       }
 	  
-      if($data['COL_LOTW_QSL_RCVD']) {
+      if(isset($data['COL_LOTW_QSL_RCVD'])) {
          $adif .= '<lotw_qsl_rcvd:' . strlen($data['COL_LOTW_QSL_RCVD']) . '>' . $data['COL_LOTW_QSL_RCVD'];
       }