diff --git a/application/controllers/Logbook.php b/application/controllers/Logbook.php
old mode 100755
new mode 100644
index 8a8b7372..0372f9cf
--- a/application/controllers/Logbook.php
+++ b/application/controllers/Logbook.php
@@ -711,6 +711,40 @@ class Logbook extends CI_Controller {
 		$this->db->where('station_profile.user_id', $this->session->userdata('user_id'));
 		$this->db->order_by(''.$this->config->item('table_name').'.COL_TIME_ON', 'desc');
 		return $this->db->get();
+  }
+
+	function search_duplicates($station_id) {
+		$station_id = $this->security->xss_clean($station_id);
+
+		$this->load->model('user_model');
+
+		if(!$this->user_model->authorize($this->config->item('auth_mode'))) { return; }
+		
+		$CI =& get_instance();
+		$CI->load->model('logbooks_model');
+		$logbooks_locations_array = $CI->logbooks_model->list_logbook_relationships($this->session->userdata('active_station_logbook'));
+		
+		if (!$logbooks_locations_array) {
+			return null;
+		}
+
+		$location_list = "'".implode("','",$logbooks_locations_array)."'";
+		
+		$sql = 'select count(*) as occurence, COL_CALL, COL_MODE, COL_SUBMODE, station_callsign, COL_SAT_NAME, COL_BAND,  min(col_time_on) Mintime, max(col_time_on) Maxtime from ' . $this->config->item('table_name') . 
+		' join station_profile on ' . $this->config->item('table_name') . '.station_id = station_profile.station_id where ' . $this->config->item('table_name') .'.station_id in ('. $location_list . ')'; 
+		
+		if ($station_id != 'All') {
+			$sql .= ' and station_profile.station_id = ' . $station_id;
+		}
+		
+		$sql .= ' group by col_call, col_mode, COL_SUBMODE, STATION_CALLSIGN, col_band, COL_SAT_NAME having count(*) > 1 and timediff(maxtime, mintime) < 3000';
+
+		$query = $this->db->query($sql);
+
+		$data['qsos'] = $query;
+
+		$this->load->view('search/duplicates_result.php', $data);
+
 	}
 
 	/*
diff --git a/application/controllers/Search.php b/application/controllers/Search.php
index b6e8dd65..024abba8 100644
--- a/application/controllers/Search.php
+++ b/application/controllers/Search.php
@@ -56,6 +56,18 @@ class Search extends CI_Controller {
         }
     }
 
+	// Searches for duplicate QSOs within 30m of time difference
+    public function duplicates() {
+		$this->load->model('stations');
+
+		$data['station_profile'] = $this->stations->all_of_user();
+        $data['page_title'] = "Duplicate QSOs within 30m time difference";
+
+		$this->load->view('interface_assets/header', $data);
+		$this->load->view('search/duplicates');
+		$this->load->view('interface_assets/footer');
+    }
+
     function json_result() {
           if(isset($_POST['search'])) {
 			  $result = $this->fetchQueryResult($_POST['search'], false);
diff --git a/application/controllers/Timeline.php b/application/controllers/Timeline.php
index 87321556..29ee5416 100644
--- a/application/controllers/Timeline.php
+++ b/application/controllers/Timeline.php
@@ -25,26 +25,47 @@ class Timeline extends CI_Controller {
             $band = 'All';
         }
 
-        if ($this->input->post('mode') != NULL) {   // Band is not set when page first loads.
+        if ($this->input->post('mode') != NULL) {
             $mode = $this->input->post('mode');
         }
         else {
             $mode = 'All';
         }
 
-        if ($this->input->post('awardradio') != NULL) {   // Band is not set when page first loads.
+        if ($this->input->post('awardradio') != NULL) {
             $award = $this->input->post('awardradio');
         }
         else {
             $award = 'dxcc';
         }
 
+        if ($this->input->post('qsl') != NULL) {
+            $qsl = $this->input->post('qsl');
+        }
+        else {
+            $qsl = '0';
+        }
+
+        if ($this->input->post('lotw') != NULL) {
+            $lotw = $this->input->post('lotw');
+        }
+        else {
+            $lotw = '0';
+        }
+
+        if ($this->input->post('eqsl') != NULL) {
+            $eqsl = $this->input->post('eqsl');
+        }
+        else {
+            $eqsl = '0';
+        }
+
         $this->load->model('modes');
         $this->load->model('bands');
 
         $data['modes'] = $this->modes->active();
 
-        $data['timeline_array'] = $this->Timeline_model->get_timeline($band, $mode, $award);
+        $data['timeline_array'] = $this->Timeline_model->get_timeline($band, $mode, $award, $qsl, $lotw, $eqsl);
         $data['worked_bands'] = $this->bands->get_worked_bands();
         $data['bandselect'] = $band;
         $data['modeselect'] = $mode;
diff --git a/application/models/Timeline_model.php b/application/models/Timeline_model.php
index 72203337..684bd732 100644
--- a/application/models/Timeline_model.php
+++ b/application/models/Timeline_model.php
@@ -3,7 +3,7 @@ if (!defined('BASEPATH')) exit('No direct script access allowed');
 
 class Timeline_model extends CI_Model
 {
-    function get_timeline($band, $mode, $award)  {
+    function get_timeline($band, $mode, $award, $qsl, $lotw, $eqsl)  {
 		$CI =& get_instance();
 		$CI->load->model('logbooks_model');
 		$logbooks_locations_array = $CI->logbooks_model->list_logbook_relationships($this->session->userdata('active_station_logbook'));
@@ -15,16 +15,16 @@ class Timeline_model extends CI_Model
 		$location_list = "'".implode("','",$logbooks_locations_array)."'";
 
         switch ($award) {
-            case 'dxcc': $result = $this->get_timeline_dxcc($band, $mode, $location_list); break;
-            case 'was':  $result = $this->get_timeline_was($band, $mode, $location_list);  break;
-            case 'iota': $result = $this->get_timeline_iota($band, $mode, $location_list); break;
-            case 'waz':  $result = $this->get_timeline_waz($band, $mode, $location_list);  break;
+            case 'dxcc': $result = $this->get_timeline_dxcc($band, $mode, $location_list, $qsl, $lotw, $eqsl); break;
+            case 'was':  $result = $this->get_timeline_was($band, $mode, $location_list, $qsl, $lotw, $eqsl);  break;
+            case 'iota': $result = $this->get_timeline_iota($band, $mode, $location_list, $qsl, $lotw, $eqsl); break;
+            case 'waz':  $result = $this->get_timeline_waz($band, $mode, $location_list, $qsl, $lotw, $eqsl);  break;
         }
 
         return $result;
     }
 
-    public function get_timeline_dxcc($band, $mode, $location_list) {
+    public function get_timeline_dxcc($band, $mode, $location_list, $qsl, $lotw, $eqsl) {
         $sql = "select min(date(COL_TIME_ON)) date, prefix, col_country, end, adif from "
             .$this->config->item('table_name'). " thcv
             join dxcc_entities on thcv.col_dxcc = dxcc_entities.adif
@@ -44,6 +44,8 @@ class Timeline_model extends CI_Model
             $sql .= " and col_mode ='" . $mode . "'";
         }
 
+        $sql .= $this->addQslToQuery($qsl, $lotw, $eqsl);
+
         $sql .= " group by col_dxcc, col_country
                 order by date desc";
 
@@ -52,7 +54,7 @@ class Timeline_model extends CI_Model
         return $query->result();
     }
 
-    public function get_timeline_was($band, $mode, $location_list) {
+    public function get_timeline_was($band, $mode, $location_list, $qsl, $lotw, $eqsl) {
         $sql = "select min(date(COL_TIME_ON)) date, col_state from "
             .$this->config->item('table_name'). " thcv
             where station_id in (" . $location_list . ")";
@@ -74,6 +76,8 @@ class Timeline_model extends CI_Model
         $sql .= " and COL_DXCC in ('291', '6', '110')";
         $sql .= " and COL_STATE in ('AK','AL','AR','AZ','CA','CO','CT','DE','FL','GA','HI','IA','ID','IL','IN','KS','KY','LA','MA','MD','ME','MI','MN','MO','MS','MT','NC','ND','NE','NH','NJ','NM','NV','NY','OH','OK','OR','PA','RI','SC','SD','TN','TX','UT','VA','VT','WA','WI','WV','WY')";
 
+        $sql .= $this->addQslToQuery($qsl, $lotw, $eqsl);
+
         $sql .= " group by col_state
                 order by date desc";
 
@@ -82,7 +86,7 @@ class Timeline_model extends CI_Model
         return $query->result();
     }
 
-    public function get_timeline_iota($band, $mode, $location_list) {
+    public function get_timeline_iota($band, $mode, $location_list, $qsl, $lotw, $eqsl) {
         $sql = "select min(date(COL_TIME_ON)) date,  col_iota, name, prefix from "
             .$this->config->item('table_name'). " thcv
             join iota on thcv.col_iota = iota.tag
@@ -102,6 +106,8 @@ class Timeline_model extends CI_Model
             $sql .= " and col_mode ='" . $mode . "'";
         }
 
+        $sql .= $this->addQslToQuery($qsl, $lotw, $eqsl);
+
         $sql .= " and col_iota <> '' group by col_iota, name, prefix
                 order by date desc";
 
@@ -110,7 +116,7 @@ class Timeline_model extends CI_Model
         return $query->result();
     }
 
-    public function get_timeline_waz($band, $mode, $location_list) {
+    public function get_timeline_waz($band, $mode, $location_list, $qsl, $lotw, $eqsl) {
         $sql = "select min(date(COL_TIME_ON)) date, col_cqz from "
             .$this->config->item('table_name'). " thcv
             where station_id in (" . $location_list . ")";
@@ -129,6 +135,8 @@ class Timeline_model extends CI_Model
             $sql .= " and col_mode ='" . $mode . "'";
         }
 
+        $sql .= $this->addQslToQuery($qsl, $lotw, $eqsl);
+
         $sql .= " and col_cqz <> '' group by col_cqz
                 order by date desc";
 
@@ -136,5 +144,39 @@ class Timeline_model extends CI_Model
 
         return $query->result();
     }
+
+    
+	// Adds confirmation to query
+	function addQslToQuery($qsl, $lotw, $eqsl) {
+		$sql = '';
+		if ($lotw == 1 and $qsl == 0 and $eqsl == 0) {
+			$sql .= " and col_lotw_qsl_rcvd = 'Y'";
+		}
+
+		if ($qsl == 1 and $lotw == 0 and $eqsl == 0) {
+			$sql .= " and col_qsl_rcvd = 'Y'";
+		}
+
+        if ($eqsl == 1 and $lotw == 0 and $qsl == 0) {
+			$sql .= " and col_eqsl_qsl_rcvd = 'Y'";
+		}
+
+        if ($lotw == 1 and $qsl == 1 and $eqsl == 0) {
+			$sql .= " and (col_lotw_qsl_rcvd = 'Y' or col_qsl_rcvd = 'Y')";
+		}
+
+		if ($qsl == 1 and $lotw == 0 and $eqsl == 1) {
+			$sql .= " and (col_qsl_rcvd = 'Y' or col_eqsl_qsl_rcvd = 'Y')";
+		}
+
+        if ($eqsl == 1 and $lotw == 1 and $qsl == 0) {
+			$sql .= " and (col_eqsl_qsl_rcvd = 'Y' or col_lotw_qsl_rcvd = 'Y')";
+		}
+
+		if ($qsl == 1 && $lotw == 1 && $eqsl == 1) {
+			$sql .= " and (col_qsl_rcvd = 'Y' or col_lotw_qsl_rcvd = 'Y' or col_eqsl_qsl_rcvd = 'Y')";
+		}
+		return $sql;
+	}
  
 }
diff --git a/application/views/interface_assets/footer.php b/application/views/interface_assets/footer.php
index 3e6ebe42..baed13ac 100644
--- a/application/views/interface_assets/footer.php
+++ b/application/views/interface_assets/footer.php
@@ -855,7 +855,7 @@ function getLookupResult() {
 <?php } ?>
 
 
-<?php if ($this->uri->segment(1) == "search") { ?>
+
 <script type="text/javascript">
   $(function () {
      $('[data-toggle="tooltip"]').tooltip()
@@ -892,9 +892,34 @@ function getLookupResult() {
     });
   });
 </script>
+
+<?php if ($this->uri->segment(1) == "search") { ?>
 <script type="text/javascript">
 i=0;
 
+function findduplicates(){
+    event.preventDefault();
+    $('#partial_view').load(base_url+"index.php/logbook/search_duplicates/"+$("#station_id").val(), function() {
+        $('.qsolist').DataTable({
+            "pageLength": 25,
+            responsive: false,
+            ordering: false,
+            "scrollY":        "500px",
+            "scrollCollapse": true,
+            "paging":         false,
+            "scrollX": true,
+            dom: 'Bfrtip',
+            buttons: [
+                'csv'
+            ]
+        });
+        // change color of csv-button if dark mode is chosen
+        if (isDarkModeTheme()) {
+            $(".buttons-csv").css("color", "white");
+        }
+    });
+}
+
 function searchButtonPress(){
     event.preventDefault()
     if ($('#callsign').val()) {
diff --git a/application/views/search/duplicates.php b/application/views/search/duplicates.php
new file mode 100644
index 00000000..5176def2
--- /dev/null
+++ b/application/views/search/duplicates.php
@@ -0,0 +1,43 @@
+<div class="container search">
+
+	<h1>
+		Search
+		<small class="text-muted">Ready to find a QSO?</small>
+	</h1>
+
+	<div class="card text-center">
+	  <div class="card-header">
+	    <ul class="nav nav-tabs card-header-tabs">
+	      <li class="nav-item">
+	        <a class="nav-link" href="<?php echo site_url('search'); ?>">Search</a>
+	      </li>
+	      <li class="nav-item">
+	        <a class="nav-link" href="<?php echo site_url('search/filter'); ?>">Advanced Search</a>
+	      </li>
+		  <li class="nav-item">
+	        <a class="nav-link active" href="<?php echo site_url('search/duplicates'); ?>">Duplicate QSOs</a>
+	      </li>
+	    </ul>
+	  </div>
+	  <div class="card-body">
+	  	<form method="post" action="" id="search_box" name="test">
+		  <div class="form-group row">
+		    <label for="callsign" class="col-sm-2 col-form-label">Station location:</label>
+		    <select id="station_id" name="station_profile" class="custom-select col-sm-3 mb-3 mr-sm-3">
+					<option value="All">All</option>
+                    <?php foreach ($station_profile->result() as $station) { ?>
+                    <option value="<?php echo $station->station_id; ?>">Callsign: <?php echo $station->station_callsign; ?> (<?php echo $station->station_profile_name; ?>)</option>
+                    <?php } ?>
+                    </select>
+		    <div class="col-sm-2">
+		    	<button onclick="findduplicates();" class="btn btn-outline-success my-2 my-sm-0" type="submit"><i class="fas fa-search"></i> Search</button>
+		    </div>
+		  </div>
+		</form>
+
+		<div id="partial_view"></div>
+
+	  </div>
+	</div>
+
+</div>
diff --git a/application/views/search/duplicates_result.php b/application/views/search/duplicates_result.php
new file mode 100644
index 00000000..f2900c46
--- /dev/null
+++ b/application/views/search/duplicates_result.php
@@ -0,0 +1,50 @@
+<?php
+if ($qsos->result() != NULL) {
+	Echo 'The following QSOs were found on the same band, mode, date and time difference 30 minutes:';
+	echo '<table style="width:100%" class="qsolist table-sm table-bordered table-hover table-striped table-condensed">
+	<thead>
+	<tr>
+	<th style=\'text-align: center\'>Occurrence</th>
+	<th style=\'text-align: center\'>'.$this->lang->line('gen_hamradio_callsign').'</th>
+	<th style=\'text-align: center\'>Min date</th>
+	<th style=\'text-align: center\'>Min time</th>
+	<th style=\'text-align: center\'>Max date</th>
+	<th style=\'text-align: center\'>Max time</th>
+	<th style=\'text-align: center\'>' . $this->lang->line('gen_hamradio_mode') . '</th>
+	<th style=\'text-align: center\'>' . $this->lang->line('gen_hamradio_band') . '</th>
+	<th style=\'text-align: center\'>' . $this->lang->line('gen_hamradio_station') . '</th>
+	</tr>
+	</thead><tbody>';
+
+	// Get Date format
+	if($this->session->userdata('user_date_format')) {
+		// If Logged in and session exists
+		$custom_date_format = $this->session->userdata('user_date_format');
+	} else {
+		// Get Default date format from /config/cloudlog.php
+		$custom_date_format = $this->config->item('qso_date_format');
+	}
+
+	$i = 0;
+	foreach ($qsos->result() as $qso) {
+		echo '<tr>';
+		echo '<td style=\'text-align: center\'>' . $qso->occurence . '</td>';
+		echo '<td style=\'text-align: center\'><form id="searchcall_'.$i.'" method="POST" action="'.site_url('search'). '"><input type="hidden" value="'. strtoupper($qso->COL_CALL) .'" name="callsign"><a href="javascript:$(\'#searchcall_'.$i++.'\').submit()">' . $qso->COL_CALL . '</a></form></td>';
+		echo '<td style=\'text-align: center\'>'; $timestamp = strtotime($qso->Mintime); echo date($custom_date_format, $timestamp); echo '</td>';
+		echo '<td style=\'text-align: center\'>'; $timestamp = strtotime($qso->Mintime); echo date('H:i', $timestamp); echo '</td>';
+		echo '<td style=\'text-align: center\'>'; $timestamp = strtotime($qso->Maxtime); echo date($custom_date_format, $timestamp); echo '</td>';
+		echo '<td style=\'text-align: center\'>'; $timestamp = strtotime($qso->Maxtime); echo date('H:i', $timestamp); echo '</td>';
+		echo '<td style=\'text-align: center\'>'; echo $qso->COL_SUBMODE==null?$qso->COL_MODE:$qso->COL_SUBMODE; echo '</td>';
+		echo '<td style=\'text-align: center\'>'; if($qso->COL_SAT_NAME != null) { echo $qso->COL_SAT_NAME; } else { echo strtolower($qso->COL_BAND); }; echo '</td>';
+		echo '<td style=\'text-align: center\'><span class="badge badge-light">' . $qso->station_callsign . '</span></td>';
+		echo '</tr>';
+	}
+
+	echo '</tbody></table>';
+	?>
+
+	<?php
+} else {
+	echo '<div class="alert alert-danger"><a href="#" class="close" data-dismiss="alert" aria-label="close">&times;</a>No duplicate QSO\'s were found.</div>';
+}
+?>
\ No newline at end of file
diff --git a/application/views/search/filter.php b/application/views/search/filter.php
index e4c632df..380717d8 100644
--- a/application/views/search/filter.php
+++ b/application/views/search/filter.php
@@ -21,6 +21,9 @@
 	      </li>
 	      <li class="nav-item">
 	        <a class="nav-link active" href="<?php echo site_url('search/filter'); ?>">Advanced Search</a>
+	      </li>
+		  <li class="nav-item">
+	        <a class="nav-link" href="<?php echo site_url('search/duplicates'); ?>">Duplicate QSOs</a>
 	      </li>
 	    </ul>
 	  </div>
diff --git a/application/views/search/main.php b/application/views/search/main.php
index da2c2892..df09c491 100644
--- a/application/views/search/main.php
+++ b/application/views/search/main.php
@@ -13,6 +13,9 @@
 	      </li>
 	      <li class="nav-item">
 	        <a class="nav-link" href="<?php echo site_url('search/filter'); ?>">Advanced Search</a>
+	      </li>
+		  <li class="nav-item">
+	        <a class="nav-link" href="<?php echo site_url('search/duplicates'); ?>">Duplicate QSOs</a>
 	      </li>
 	    </ul>
 	  </div>
diff --git a/application/views/timeline/index.php b/application/views/timeline/index.php
index b6a8506e..3d6049e4 100644
--- a/application/views/timeline/index.php
+++ b/application/views/timeline/index.php
@@ -68,6 +68,24 @@
             </div>
         </div>
 
+        <div class="form-group row">
+                <div class="col-md-1 control-label">Confirmation</div>
+                <div class="col-md-10">
+                    <div class="form-check-inline">
+                        <input class="form-check-input" type="checkbox" name="qsl" value="1" id="qsl" <?php if ($this->input->post('qsl'))  echo ' checked="checked"'; ?> >
+                        <label class="form-check-label" for="qsl">QSL</label>
+                    </div>
+                    <div class="form-check-inline">
+                        <input class="form-check-input" type="checkbox" name="lotw" value="1" id="lotw" <?php if ($this->input->post('lotw')) echo ' checked="checked"'; ?> >
+                        <label class="form-check-label" for="lotw">LoTW</label>
+                    </div>
+                    <div class="form-check-inline">
+                        <input class="form-check-input" type="checkbox" name="eqsl" value="1" id="eqsl" <?php if ($this->input->post('eqsl')) echo ' checked="checked"'; ?> >
+                        <label class="form-check-label" for="eqsl">eQSL</label>
+                    </div>
+                </div>
+            </div>
+
             <div class="form-group row">
                 <label class="col-md-1 control-label" for="button1id"></label>
                 <div class="col-md-10">
diff --git a/application/views/view_log/qso.php b/application/views/view_log/qso.php
index e334a63a..c8f7f1e0 100644
--- a/application/views/view_log/qso.php
+++ b/application/views/view_log/qso.php
@@ -298,7 +298,7 @@
                     <?php if(($this->config->item('use_auth') && ($this->session->userdata('user_type') >= 2)) || $this->config->item('use_auth') === FALSE) { ?>
                         <br>
                             <div style="display: inline-block;"><p class="editButton"><a class="btn btn-primary" href="<?php echo site_url('qso/edit'); ?>/<?php echo $row->COL_PRIMARY_KEY; ?>" href="javascript:;"><i class="fas fa-edit"></i><?php echo $this->lang->line('qso_btn_edit_qso'); ?></a></p></div>
-                            <div style="display: inline-block;"><form method="POST" action="<?php echo site_url('search'); ?>"><input type="hidden" value="<?php echo strtoupper($row->COL_CALL); ?>" name="callsign"><button class="btn btn-primary" type="submit"><i class="fas fa-eye"></i> More QSOs</button><form></div>
+                            <div style="display: inline-block;"><form method="POST" action="<?php echo site_url('search'); ?>"><input type="hidden" value="<?php echo strtoupper($row->COL_CALL); ?>" name="callsign"><button class="btn btn-primary" type="submit"><i class="fas fa-eye"></i> More QSOs</button></form></div>
                     <?php } ?>
 
                     <?php
diff --git a/assets/js/sections/contesting.js b/assets/js/sections/contesting.js
index 2b246e4d..0a0701a6 100644
--- a/assets/js/sections/contesting.js
+++ b/assets/js/sections/contesting.js
@@ -189,6 +189,8 @@ $("#callsign").keyup(function () {
 			highlight(call.toUpperCase());
 		});
 		checkIfWorkedBefore();
+		var qTable = $('.qsotable').DataTable();
+		qTable.search(call).draw();
 	}
 	else if (call.length <= 2) {
 		$('.callsign-suggestions').text("");
@@ -226,6 +228,9 @@ function reset_log_fields() {
 	$("#callsign").focus();
 	setRst($("#mode").val());
 	$('#callsign_info').text("");
+
+	var qTable = $('.qsotable').DataTable();
+	qTable.search('').draw();
 }
 
 RegExp.escape = function (text) {
@@ -396,6 +401,9 @@ function logQso() {
 				localStorage.setItem("gridsquarereceived", $("#exch_gridsquare_r").val());
 				localStorage.setItem("gridsquaresent", $("#exch_gridsquare_s").val());
 				localStorage.setItem("copytodok", $('#copyexchangetodok').is(":checked"));
+
+				var qTable = $('.qsotable').DataTable();
+				qTable.search('').draw();
 			}
 		});
 	}
diff --git a/assets/json/satellite_data.json b/assets/json/satellite_data.json
index 24288ef5..2f121561 100644
--- a/assets/json/satellite_data.json
+++ b/assets/json/satellite_data.json
@@ -566,5 +566,17 @@
             }
          ]
       }
+   },
+   "GREENCUBE":{
+      "Modes":{
+         "V":[
+            {
+               "Uplink_Mode":"PKT",
+               "Uplink_Freq":"435310000",
+               "Downlink_Mode":"PKT",
+               "Downlink_Freq":"435310000"
+            }
+         ]
+      }
    }
 }