diff --git a/application/controllers/Calltester.php b/application/controllers/Calltester.php
index d1ddad509..f922c2ce0 100644
--- a/application/controllers/Calltester.php
+++ b/application/controllers/Calltester.php
@@ -53,6 +53,7 @@ class Calltester extends CI_Controller {
 
 	/* Uses DXCC Class. Much faster */
 	function doClassCheck($de) {
+		ini_set('memory_limit', '-1');
 		$i = 0;
 		$result = array();
 
@@ -185,6 +186,7 @@ class Calltester extends CI_Controller {
 	}
 
 	function getQsos($station_id) {
+		ini_set('memory_limit', '-1');
 		$sql = 'select distinct col_country, col_call, col_dxcc, date(col_time_on) date, station_profile.station_profile_name, col_primary_key
 			from ' . $this->config->item('table_name') . '
 			join station_profile on ' . $this->config->item('table_name') . '.station_id = station_profile.station_id
@@ -368,273 +370,434 @@ class Calltester extends CI_Controller {
             'Callsign'  => 'WJ7R/C6A',
             'Country'   => 'Bahamas',
             'Adif'      => 60,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
 		$testarray[] = array(
             'Callsign'  => 'WJ7R/KH6',
             'Country'   => 'Hawaii',
             'Adif'      => 110,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
 		$testarray[] = array(
             'Callsign'  => 'WJ7R/C6',
             'Country'   => 'Bahamas',
             'Adif'      => 60,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'VE3EY/VP9',
             'Country'   => 'Bermuda',
             'Adif'      => 64,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'VP2MDG',
             'Country'   => 'Montserrat',
             'Adif'      => 96,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'VP2EY',
             'Country'   => 'Anguilla',
             'Adif'      => 12,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'VP2VI',
             'Country'   => 'British Virgin Islands.',
             'Adif'      => 65,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'VP2V/AA7V',
             'Country'   => 'British Virgin Islands',
             'Adif'      => 65,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'W8LR/R',
             'Country'   => 'United States Of America',
             'Adif'      => 291,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'SO1FH',
             'Country'   => 'Poland',
             'Adif'      => 269,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'KZ1H/PP',
             'Country'   => 'Brazil',
             'Adif'      => 108,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'K1KW/AM',
             'Country'   => 'None',
             'Adif'      => 0,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'K1KW/MM',
             'Country'   => 'None',
             'Adif'      => 0,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'TF/DL2NWK/P',
             'Country'   => 'Iceland',
             'Adif'      => 242,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'OZ1ALS/A',
             'Country'   => 'Denmark',
             'Adif'      => 221,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'LA1K',
             'Country'   => 'Norway',
             'Adif'      => 266,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'K1KW/M',
             'Country'   => 'United States Of America',
             'Adif'      => 291,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'TF/DL2NWK/M',
             'Country'   => 'Iceland',
             'Adif'      => 242,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'TF/DL2NWK/MM',
             'Country'   => 'None',
             'Adif'      => 0,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'TF/DL2NWK/P',
             'Country'   => 'Iceland',
             'Adif'      => 242,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => '2M0SQL/P',
             'Country'   => 'Scotland',
             'Adif'      => 279,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'FT8WW',
             'Country'   => 'Crozet Island',
             'Adif'      => 41,
-            'Date'      => 20230314
+            'Date'      => '2023-03-14'
         );
 
         $testarray[] = array(
             'Callsign'  => 'RV0AL/0/P',
             'Country'   => 'Asiatic Russia',
             'Adif'      => 15,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'OH/DJ1YFK',
             'Country'   => 'Finland',
             'Adif'      => 224,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'N6TR/7',
             'Country'   => 'United States Of America',
             'Adif'      => 291,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'KH0CW',
             'Country'   => 'United States Of America',
             'Adif'      => 291,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'R2FM/P',
             'Country'   => 'kaliningrad',
             'Adif'      => 126,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'R2FM',
             'Country'   => 'kaliningrad',
             'Adif'      => 126,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'FT5XO',
             'Country'   => 'Kerguelen Island',
             'Adif'      => 131,
-            'Date'      => 20050320
+            'Date'      => '2005-03-20'
         );
 
         $testarray[] = array(
             'Callsign'  => 'VP8CTR',
             'Country'   => 'Antarctica',
             'Adif'      => 13,
-            'Date'      => 19970207
+            'Date'      => '1997-02-07'
         );
 
         $testarray[] = array(
             'Callsign'  => 'FO0AAA',
             'Country'   => 'Clipperton',
             'Adif'      => 36,
-            'Date'      => '20000302'
+            'Date'      => '2000-03-02'
         );
 
         $testarray[] = array(
             'Callsign'  => 'CX/PR8KW',
             'Country'   => 'Uruguay',
             'Adif'      => 144,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'IQ3MV/LH',
             'Country'   => 'Italy',
             'Adif'      => 248,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'LA1K/QRP',
             'Country'   => 'Norway',
             'Adif'      => 266,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'LA1K/LGT',
             'Country'   => 'Norway',
             'Adif'      => 266,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         $testarray[] = array(
             'Callsign'  => 'SM1K/LH',
             'Country'   => 'Sweden',
             'Adif'      => 284,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
 		$testarray[] = array(
             'Callsign'  => 'KG4W',
             'Country'   => 'United States Of America',
             'Adif'      => 291,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
 		$testarray[] = array(
             'Callsign'  => 'KG4WW',
             'Country'   => 'Guantanamo Bay',
             'Adif'      => 105,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
         );
 
 		$testarray[] = array(
             'Callsign'  => 'KG4WWW',
             'Country'   => 'United States Of America',
             'Adif'      => 291,
-            'Date'      => $date = date('Ymd', time())
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'JA0JHQ/VK9X',
+            'Country'   => 'Christmas Island',
+            'Adif'      => 35,
+            'Date'      => '2015-05-08'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'D5M',
+            'Country'   => 'Liberia',
+            'Adif'      => 434,
+            'Date'      => '2025-12-14'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'AT44I',
+            'Country'   => 'Antarctica',
+            'Adif'      => 13,
+            'Date'      => '2025-12-16'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'PT7BZ/PY0F',
+            'Country'   => 'Fernando De Noronha',
+            'Adif'      => 56,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'VP6A',
+            'Country'   => 'Ducie Island',
+            'Adif'      => 513,
+            'Date'      => '2023-06-21'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => '9M1Z',
+            'Country'   => 'East Malaysia',
+            'Adif'      => 46,
+            'Date'      => '2024-06-24'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'VK2/W7BRS',
+            'Country'   => 'Lord Howe Island',
+            'Adif'      => 147,
+            'Date'      => '2024-07-18'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'G4SGX/6Y',
+            'Country'   => 'Jamaica',
+            'Adif'      => 82,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'DX0JP',
+            'Country'   => 'Spratly Islands',
+            'Adif'      => 247,
+            'Date'      => '2007-02-08'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'AU7JCB',
+            'Country'   => 'India',
+            'Adif'      => 324,
+            'Date'      => '2007-02-08'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'N2JBY/4X',
+            'Country'   => 'Israel',
+            'Adif'      => 336,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'KH5K',
+            'Country'   => 'Invalid',
+            'Adif'      => 0,
+            'Date'      => '1993-03-13'
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'HB/DK9TA',
+            'Country'   => 'Switzerland',
+            'Adif'      => 287,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'OE5DI/500',
+            'Country'   => 'Austria',
+            'Adif'      => 206,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'YI6SUL',
+            'Country'   => 'Invalid',
+            'Adif'      => 0,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => '3DA8/DF8LY/P',
+            'Country'   => 'Kingdom Of Eswatini',
+            'Adif'      => 468,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => '3X/DL5DAB',
+            'Country'   => 'Invalid',
+            'Adif'      => 0,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => '3X/DL5DA',
+            'Country'   => 'Guinea',
+            'Adif'      => 107,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'KN5H/6YA',
+            'Country'   => 'Jamaica',
+            'Adif'      => 82,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'DL2AAZ/6Y5',
+            'Country'   => 'Jamaica',
+            'Adif'      => 82,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => '6Y5WJ',
+            'Country'   => 'Jamaica',
+            'Adif'      => 82,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'R20RRC/0',
+            'Country'   => 'Asiatic Russia',
+            'Adif'      => 15,
+            'Date'      => $date = date('Y-m-d', time())
+        );
+
+		$testarray[] = array(
+            'Callsign'  => 'G4KJV/2K/P',
+            'Country'   => 'England',
+            'Adif'      => 223,
+            'Date'      => $date = date('Y-m-d', time())
         );
 
         set_time_limit(3600);
@@ -648,22 +811,24 @@ class Calltester extends CI_Controller {
 
         $i = 0;
 
+		$dxccobj = new Dxcc(null);
+
         foreach ($testarray as $call) {
             $i++;
-            $dxcc = $this->logbook_model->dxcc_lookup($call['Callsign'], $call['Date']);
+			$dxcc = $dxccobj->dxcc_lookup($call['Callsign'], $call['Date']);
 
-            $dxcc['adif'] = (isset($dxcc['adif'])) ? $dxcc['adif'] : 0;
-            $dxcc['entity'] = (isset($dxcc['entity'])) ? $dxcc['entity'] : 0;
+			$dxcc['adif'] = (isset($dxcc['adif'])) ? $dxcc['adif'] : 0;
+			$dxcc['entity'] = (isset($dxcc['entity'])) ? $dxcc['entity'] : 'None';
 
-            if ($call['Adif'] != $dxcc['adif']) {
-                $result[] = array(
-                                'Callsign'          => $call['Callsign'],
-                                'Expected country'  => $call['Country'],
-                                'Expected adif'     => $call['Adif'],
-                                'Result country'    => ucwords(strtolower($dxcc['entity']), "- (/"),
-                                'Result adif'       => $dxcc['adif'],
-                            );
-            }
+			$result[] = array(
+							'Callsign'          => $call['Callsign'],
+							'Date'              => $call['Date'],
+							'Expected country'  => $call['Country'],
+							'Expected adif'     => $call['Adif'],
+							'Result country'    => ucwords(strtolower($dxcc['entity']), "- (/"),
+							'Result adif'       => $dxcc['adif'],
+							'Passed'            => ($call['Adif'] == $dxcc['adif']) ? 'Yes' : 'No',
+						);
         }
 
         // End clock time in seconds
@@ -672,12 +837,13 @@ class Calltester extends CI_Controller {
         // Calculate script execution time
         $execution_time = ($end_time - $start_time);
 
-        echo " Execution time of script = ".$execution_time." sec <br/>";
-        echo $i . " calls tested. <br/>";
-        $count = 0;
+		$data['result'] = $result;
+		$data['execution_time'] = $execution_time;
+		$data['calls_tested'] = $i;
 
-        if ($result) {
-            $this->array_to_table($result);
-        }
+		$data['page_title'] = __("Callsign Tester");
+		$this->load->view('interface_assets/header', $data);
+		$this->load->view('calltester/call');
+		$this->load->view('interface_assets/footer');
     }
 }
diff --git a/application/views/calltester/call.php b/application/views/calltester/call.php
new file mode 100644
index 000000000..08b33b248
--- /dev/null
+++ b/application/views/calltester/call.php
@@ -0,0 +1,44 @@
+<div class="container">
+<?php
+
+echo $calls_tested . " calls tested.<br/>";
+
+if ($result) {
+	array_to_table($result);
+} ?>
+
+</div>
+
+<?php
+
+function array_to_table($table) {
+	// Sort table by Passed column (no first, then yes)
+	usort($table, function($a, $b) {
+		$aPassed = strtolower($a['Passed'] ?? '');
+		$bPassed = strtolower($b['Passed'] ?? '');
+
+		// no comes before yes
+		if ($aPassed !== 'yes' && $bPassed === 'yes') return -1;
+		if ($aPassed === 'yes' && $bPassed !== 'yes') return 1;
+		return 0;
+	});
+
+	echo '<table style="width:100%" class="table-sm table table-hover table-bordered text-center">';
+
+	// Table header
+	foreach ($table[0] as $key=>$value) {
+		echo "<th>".$key."</th>";
+	}
+
+	// Table body
+	foreach ($table as $value) {
+		$passed = strtolower($value['Passed'] ?? '');
+		$rowClass = ($passed === 'yes') ? 'table-success' : 'table-danger';
+		echo "<tr class='".$rowClass."'>";
+		foreach ($value as $key=>$val) {
+			echo "<td>".$val."</td>";
+		}
+		echo "</tr>";
+	}
+	echo "</table>";
+}
diff --git a/src/Dxcc/Dxcc.php b/src/Dxcc/Dxcc.php
index 779b49f4d..7dff41096 100644
--- a/src/Dxcc/Dxcc.php
+++ b/src/Dxcc/Dxcc.php
@@ -7,7 +7,7 @@ class Dxcc {
 	protected $dxccexceptions = array();
 
 	protected $csadditions = '/^X$|^D$|^T$|^P$|^R$|^B$|^A$|^M$|^LH$|^L$|^J$|^SK$/';
-	protected $lidadditions = '/^QRP$|^LGT$/';
+	protected $lidadditions = '/^QRP$|^LGT$|^2K$/';
 	protected $noneadditions = '/^MM$|^AM$/';
 
 	function __construct($date)	{
@@ -45,6 +45,8 @@ class Dxcc {
 			$call = "K";
 		} elseif (preg_match('/(^OH\/)|(\/OH[1-9]?$)/', $call)) {   # non-Aland prefix!
 			$call = "OH";                                             # make callsign OH = finland
+		} elseif (preg_match('/(^HB\/)|(\/HB[1-9]?$)/', $call)) {   # non-Liechtenstein prefix!
+			$call = "HB";                                             # make callsign HB = Switzerland
 		} elseif (preg_match('/(^CX\/)|(\/CX[1-9]?$)/', $call)) {   # non-Antarctica prefix!
 			$call = "CX";                                             # make callsign CX = Uruguay
 		} elseif (preg_match('/(^3D2R)|(^3D2.+\/R)/', $call)) {     # seems to be from Rotuma
@@ -170,7 +172,15 @@ class Dxcc {
 				if (preg_match($this->lidadditions, $b) || preg_match('/^[0-9]+$/', $b)) {        # check if $b is a lid-addition
 					$b = $a;
 					$a = null;                              # $a goes to $b, delete lid-add
-				} elseif ((preg_match('/\d[A-Z]+$/', $a)) && (preg_match('/\d$/', $b) || preg_match('/^[A-Z]\d[A-Z]$/', $b))) {   # check for call in $a
+				} elseif ((preg_match('/\d[A-Z]+$/', $a)) && (preg_match('/\d$/', $b) || preg_match('/^[A-Z]\d[A-Z]$/', $b) || preg_match('/^\d[A-Z]+$/', $b))) {
+					$temp = $b;
+					$b = $a;
+					$a = $temp;
+				}
+				# Additional check: if $a looks like a full callsign (longer than typical prefix)
+				# and $b looks like a country prefix (short, with digit), swap them
+				# This handles cases like JA0JHQ/VK9X where VK9X should be the prefix
+				elseif (strlen($a) >= 5 && preg_match('/^\d?[A-Z]+\d[A-Z]+$/', $a) && strlen($b) <= 5 && preg_match('/^[A-Z]+\d[A-Z]*$/', $b)) {
 					$temp = $b;
 					$b = $a;
 					$a = $temp;
@@ -210,38 +220,53 @@ class Dxcc {
 				} else {                                            # Case 1.2, no number
 					$prefix = substr($b, 0, 2) . "0";               # first two + 0
 				}
-			} elseif (($a == null) && (isset($c))) {                # Case 2, CALL/X
-				if (preg_match('/^(\d)/', $c)) {                    # Case 2.1, number
-					preg_match('/(.+\d)[A-Z]*/', $b, $matches);     # regular Prefix in $1
-					# Here we need to find out how many digits there are in the
-					# prefix, because for example A45XR/0 is A40. If there are 2
-					# numbers, the first is not deleted. If course in exotic cases
-					# like N66A/7 -> N7 this brings the wrong result of N67, but I
-					# think that's rather irrelevant cos such calls rarely appear
-					# and if they do, it's very unlikely for them to have a number
-					# attached.   You can still edit it by hand anyway..
-					if (!isset($matches[1]) || $matches[1] === null) {
-						$this->logError('preg_match failed to capture prefix in $b', [
-							'testcall' => $testcall,
-							'b' => $b,
-							'c' => $c,
-							'matches' => $matches
-						]);
-						return '';
-					}
-					if (preg_match('/^([A-Z]\d)\d$/', $matches[1])) {        # e.g. A45   $c = 0
-						$prefix = $matches[1] . $c;  # ->   A40
-					} else {                         # Otherwise cut all numbers
-						if (!preg_match('/(.*[A-Z])\d+/', $matches[1], $match)) {
-							$this->logError('preg_match failed to extract prefix without number', [
+			} elseif (($a == null) && ($c != null && $c != '')) {    # Case 2, CALL/X
+				if (preg_match($this->lidadditions, $c)) {        # check if $b is a lid-addition
+					$prefix = $b;
+				} else if (preg_match('/^(\d)/', $c)) {                    # Case 2.1, starts with digit
+					# Check if $c is a full country prefix (like 6YA, 6Y, etc.) not just a number
+					# A country prefix has the pattern: digit + letters (like 6YA, 6Y)
+					# NOT just a single digit
+					if (strlen($c) > 1 && preg_match('/^\d[A-Z]+$/', $c)) {
+						# This is a country prefix starting with a digit (like 6YA, 6Y)
+						# Use it directly - it's already a valid prefix
+						$prefix = $c;
+					} elseif (strlen($c) > 1 && preg_match('/^[A-Z]+\d[A-Z]*$/', $c)) {
+						# Country prefix starting with letters (like W1, K2, etc.)
+						$prefix = $c;
+					} else {
+						# Single digit, replace the digit in the base call                # Case 2.1, starts with digit
+						preg_match('/(.+\d)[A-Z]*/', $b, $matches);     # regular Prefix in $1
+						# Here we need to find out how many digits there are in the
+						# prefix, because for example A45XR/0 is A40. If there are 2
+						# numbers, the first is not deleted. If course in exotic cases
+						# like N66A/7 -> N7 this brings the wrong result of N67, but I
+						# think that's rather irrelevant cos such calls rarely appear
+						# and if they do, it's very unlikely for them to have a number
+						# attached.   You can still edit it by hand anyway..
+						if (!isset($matches[1]) || $matches[1] === null) {
+							$this->logError('preg_match failed to capture prefix in $b', [
 								'testcall' => $testcall,
-								'matches1' => $matches[1],
 								'b' => $b,
-								'c' => $c
+								'c' => $c,
+								'matches' => $matches
 							]);
 							return '';
 						}
-						$prefix = $match[1] . $c; # Add attached number
+						if (preg_match('/^([A-Z]\d)\d$/', $matches[1])) {        # e.g. A45   $c = 0
+							$prefix = $matches[1] . $c;  # ->   A40
+						} else {                         # Otherwise cut all numbers
+							if (!preg_match('/(.*[A-Z])\d+/', $matches[1], $match)) {
+								$this->logError('preg_match failed to extract prefix without number', [
+									'testcall' => $testcall,
+									'matches1' => $matches[1],
+									'b' => $b,
+									'c' => $c
+								]);
+								return '';
+							}
+							$prefix = $match[1] . $c; # Add attached number
+						}
 					}
 				} elseif (preg_match($this->csadditions, $c)) {
 					if (!preg_match('/(.+\d)[A-Z]*/', $b, $matches)) {
@@ -266,9 +291,15 @@ class Dxcc {
 					}
 					$prefix = $matches[1][0];
 				} else {                                            # Must be a Prefix!
-					if (preg_match('/\d$/', $c)) {                  # ends in number -> good prefix
+					# Check if $c looks like a country prefix
+					# Pattern: starts with digit followed by letters (6YA, 6Y) OR has digit in it
+					if (preg_match('/^\d[A-Z]+$/', $c)) {           # Starts with digit, has letters after (6YA, 6Y, etc.)
+						$prefix = $c;                               # Already a valid prefix
+					} elseif (preg_match('/\d$/', $c)) {            # ends in number -> good prefix
 						$prefix = $c;
-					} else {                                        # Add Zero at the end
+					} elseif (preg_match('/\d/', $c)) {             # contains digit but doesn't end with one
+						$prefix = $c . "0";                         # Add zero at end
+					} else {                                        # No digit, add zero
 						$prefix = $c . "0";
 					}
 				}
@@ -278,7 +309,7 @@ class Dxcc {
 				# $a contains the prefix we want
 				if (preg_match('/\d$/', $a)) {                      # ends in number -> good prefix
 					$prefix = $a;
-				} else {                                            # add zero if no number
+				} else {
 					$prefix = $a . "0";
 				}
 			}