diff --git a/application/controllers/Logbookadvanced.php b/application/controllers/Logbookadvanced.php
index d0f5f5836..870eb0dcd 100644
--- a/application/controllers/Logbookadvanced.php
+++ b/application/controllers/Logbookadvanced.php
@@ -149,15 +149,8 @@ class Logbookadvanced extends CI_Controller {
 
 		$qsos = [];
 
-		if ($this->session->userdata('user_measurement_base') == NULL) {
-			$measurement_base = $this->config->item('measurement_base');
-		}
-		else {
-			$measurement_base = $this->session->userdata('user_measurement_base');
-		}
-
 		foreach ($this->logbookadvanced_model->searchQsos($searchCriteria) as $qso) {
-			$qsos[] = $qso->toArray($measurement_base);
+			$qsos[] = $qso->toArray();
 		}
 
 		header("Content-Type: application/json");
@@ -183,17 +176,10 @@ class Logbookadvanced extends CI_Controller {
 			$qso = $this->logbook_model->qso_info($qsoID)->row_array();
 		}
 
-		if ($this->session->userdata('user_measurement_base') == NULL) {
-			$measurement_base = $this->config->item('measurement_base');
-		}
-		else {
-			$measurement_base = $this->session->userdata('user_measurement_base');
-		}
-
 		$qsoObj = new QSO($qso);
 
 		header("Content-Type: application/json");
-		echo json_encode($qsoObj->toArray($measurement_base));
+		echo json_encode($qsoObj->toArray());
 	}
 
 	function export_to_adif() {
@@ -243,16 +229,9 @@ class Logbookadvanced extends CI_Controller {
             $qsos[] = new QSO($data);
         }
 
-		if ($this->session->userdata('user_measurement_base') == NULL) {
-			$measurement_base = $this->config->item('measurement_base');
-		}
-		else {
-			$measurement_base = $this->session->userdata('user_measurement_base');
-		}
-
 		$q = [];
 		foreach ($qsos as $qso) {
-			$q[] = $qso->toArray($measurement_base);
+			$q[] = $qso->toArray();
 		}
 
 		header("Content-Type: application/json");
@@ -278,16 +257,9 @@ class Logbookadvanced extends CI_Controller {
             $qsos[] = new QSO($data);
         }
 
-		if ($this->session->userdata('user_measurement_base') == NULL) {
-			$measurement_base = $this->config->item('measurement_base');
-		}
-		else {
-			$measurement_base = $this->session->userdata('user_measurement_base');
-		}
-
 		$q = [];
 		foreach ($qsos as $qso) {
-			$q[] = $qso->toArray($measurement_base);
+			$q[] = $qso->toArray();
 		}
 
 		header("Content-Type: application/json");
@@ -643,15 +615,8 @@ class Logbookadvanced extends CI_Controller {
 			$custom_date_format = $this->config->item('qso_date_format');
 		}
 
-		if ($this->session->userdata('user_measurement_base') == NULL) {
-			$measurement_base = $this->config->item('measurement_base');
-		}
-		else {
-			$measurement_base = $this->session->userdata('user_measurement_base');
-		}
-
 		foreach ($qsos as $qso) {
-			$q[] = $qso->toArray($measurement_base);
+			$q[] = $qso->toArray();
 		}
 
 		header("Content-Type: application/json");
diff --git a/src/QSLManager/QSO.php b/src/QSLManager/QSO.php
index 7352e3750..d4f6b4951 100644
--- a/src/QSLManager/QSO.php
+++ b/src/QSLManager/QSO.php
@@ -83,6 +83,8 @@ class QSO
 	private string $stationpower;
 	private float $distance;
 
+	private string $measurement_base;
+
 	/**
 	 * @param array $data Does no validation, it's assumed to be a row from the database in array format
 	 */
@@ -244,6 +246,15 @@ class QSO
 
 		$this->stationpower = $data['COL_TX_PWR'] ?? '';
 		$this->distance = (float)$data['COL_DISTANCE'] ?? 0;
+
+		if ($CI->session->userdata('user_measurement_base') == NULL) {
+			$measurement_base = $CI->config->item('measurement_base');
+		}
+		else {
+			$measurement_base = $CI->session->userdata('user_measurement_base');
+		}
+
+		$this->measurement_base = $measurement_base;
 	}
 
 	/**
@@ -1001,7 +1012,7 @@ class QSO
 		return '<span id="operator">' . $this->operator . '</span>';
 	}
 
-	public function toArray($measurement_base): array
+	public function toArray(): array
 	{
 		return [
 			'qsoID' => $this->qsoID,
@@ -1044,15 +1055,15 @@ class QSO
 			'continent' => $this->continent,
 			'profilename' => $this->profilename,
 			'stationpower' => $this->stationpower,
-			'distance' => $this->getFormattedDistance($measurement_base)
+			'distance' => $this->getFormattedDistance()
 		];
 	}
 
-	private function getFormattedDistance($measurement_base): string
+	private function getFormattedDistance(): string
 	{
 		if ($this->distance == 0) return '';
 
-		switch ($measurement_base) {
+		switch ($this->measurement_base) {
 			case 'M':
 				$unit = "mi";
 				break;