diff --git a/application/models/Logbook_model.php b/application/models/Logbook_model.php
index 5f7decf7..c2d5597e 100755
--- a/application/models/Logbook_model.php
+++ b/application/models/Logbook_model.php
@@ -212,7 +212,7 @@ class Logbook_model extends CI_Model {
       $data['COL_MY_IOTA'] = strtoupper(trim($station['station_iota']));
       $data['COL_MY_SOTA_REF'] = strtoupper(trim($station['station_sota']));
       $data['COL_MY_WWFF_REF'] = strtoupper(trim($station['station_wwff']));
-      $data['COL_MY_POTA_REF'] = strtoupper(trim($station['station_pota']));
+      $data['COL_MY_POTA_REF'] = $station['station_pota'] == null ? '' : strtoupper(trim($station['station_pota']));
 
       $data['COL_STATION_CALLSIGN'] = strtoupper(trim($station['station_callsign']));
       $data['COL_MY_DXCC'] = strtoupper(trim($station['station_dxcc']));