diff --git a/application/controllers/Adif.php b/application/controllers/Adif.php
index b1bb25194..00cc48a6c 100644
--- a/application/controllers/Adif.php
+++ b/application/controllers/Adif.php
@@ -85,17 +85,46 @@ class adif extends CI_Controller {
 
 	}
 
-	// Export all QSO Data in ASC Order of Date.
+	// Export all QSO Data in ASC Order of Date - use chunks to avoid memory exhaustion
 	public function exportall() {
-		// Set memory limit to unlimited to allow heavy usage
 		$this->require_tab_access('export');
+
 		ini_set('memory_limit', '-1');
+		set_time_limit(300);
 
 		$this->load->model('adif_data');
+		$this->load->library('AdifHelper');
 
-		$data['qsos'] = $this->adif_data->export_all(null, $this->input->post('from', true), $this->input->post('to', true));
+		$from = $this->input->post('from', true);
+		$to = $this->input->post('to', true);
 
-		$this->load->view('adif/data/exportall', $data);
+		$filename = $this->session->userdata('user_callsign').'-'.date('Ymd-Hi').'.adi';
+		header('Content-Type: text/plain; charset=utf-8');
+		header('Content-Disposition: attachment; filename="'.$filename.'"');
+
+		// Output ADIF header // No chance to use exportall-view any longer, because of chunking logic
+		echo $this->adifhelper->getAdifHeader($this->config->item('app_name'),$this->optionslib->get_option('version'));
+
+		// Stream QSOs in 5K chunks
+		$offset = 0;
+		$chunk_size = 5000;
+
+		do {
+			$qsos = $this->adif_data->export_all_chunked(null, $from, $to, false, null, $offset, $chunk_size);
+
+			if ($qsos->num_rows() > 0) {
+				foreach ($qsos->result() as $qso) {
+					echo $this->adifhelper->getAdifLine($qso);
+				}
+
+				// Free memory
+				$qsos->free_result();
+			}
+
+			$offset += $chunk_size;
+		} while ($qsos->num_rows() > 0);
+
+		exit;
 	}
 
 
@@ -143,10 +172,15 @@ class adif extends CI_Controller {
 
 		// Set memory limit to unlimited to allow heavy usage
 		ini_set('memory_limit', '-1');
+		set_time_limit(300);
 
 		$this->load->model('adif_data');
+		$this->load->library('AdifHelper');
 
+		// Get parameters
 		$station_id = $this->security->xss_clean($this->input->post('station_profile'));
+		$from = $this->input->post('from');
+		$to = $this->input->post('to');
 
 		// Used for exporting QSOs not previously exported to LoTW
 		if ($this->input->post('exportLotw') == 1) {
@@ -161,16 +195,45 @@ class adif extends CI_Controller {
 			$onlyop=null;
 		}
 
-		$data['qsos'] = $this->adif_data->export_custom($this->input->post('from'), $this->input->post('to'), $station_id, $exportLotw, $onlyop);
+		// Set headers for direct download
+		$filename = $this->session->userdata('user_callsign').'-'.date('Ymd-Hi').'.adi';
+		header('Content-Type: text/plain; charset=utf-8');
+		header('Content-Disposition: attachment; filename="'.$filename.'"');
 
-		$this->load->view('adif/data/exportall', $data);
+		echo $this->adifhelper->getAdifHeader($this->config->item('app_name'),$this->optionslib->get_option('version'));
 
+		// Collect QSO IDs for LoTW marking (since we can't access all at once)
+		$qso_ids_for_lotw = [];
 
-		if ((clubaccess_check(9)) && ($this->input->post('markLotw') == 1)) {	// Only allow marking if clubofficer or regular user!
-			foreach ($data['qsos']->result() as $qso) {
-				$this->adif_data->mark_lotw_sent($qso->COL_PRIMARY_KEY);
+		// Stream QSOs in 5K chunks
+		$offset = 0;
+		$chunk_size = 5000;
+
+		do {
+			$qsos = $this->adif_data->export_custom_chunked($from, $to, $station_id, $exportLotw, $onlyop, $offset, $chunk_size);
+
+			if ($qsos && $qsos->num_rows() > 0) {
+				foreach ($qsos->result() as $qso) {
+					echo $this->adifhelper->getAdifLine($qso);
+					// Collect IDs for LoTW marking
+					$qso_ids_for_lotw[] = $qso->COL_PRIMARY_KEY;
+				}
+				// Free memory
+				$qsos->free_result();
+			}
+
+			$offset += $chunk_size;
+		} while ($qsos && $qsos->num_rows() > 0);
+
+		// Handle LoTW marking after export
+		if ((clubaccess_check(9)) && ($this->input->post('markLotw') == 1) && !empty($qso_ids_for_lotw)) {
+			foreach ($qso_ids_for_lotw as $qso_id) {
+				$this->adif_data->mark_lotw_sent($qso_id);
 			}
 		}
+
+		// Stop execution
+		exit;
 	}
 
 	public function mark_lotw() {
diff --git a/application/controllers/Api.php b/application/controllers/Api.php
index 035e6fcd8..c07cb6e01 100644
--- a/application/controllers/Api.php
+++ b/application/controllers/Api.php
@@ -440,33 +440,64 @@ class API extends CI_Controller {
 
 		//load adif data module
 		$this->load->model('adif_data');
+		$this->load->library('AdifHelper');
 
-		//get qso data
-		$data['qsos'] = $this->adif_data->export_past_id($station_id, $fetchfromid, $limit);
+		// Initialize tracking variables
+		$total_fetched = 0;
+		$all_qso_ids = [];
+		$lastfetchedid = $fetchfromid;
 
-		//set internalonly attribute for adif creation
-		$data['internalrender'] = true;
+		// Process in chunks to avoid memory issues
+		$chunk_size = 5000;
+		$remaining_limit = $limit;
+		$offset = 0;
 
-		//if no new QSOs are ready, return that
-		$qso_count = count($data['qsos']->result());
-		if($qso_count <= 0) {
+		// Start building ADIF content
+		$adif_content = $this->adifhelper->getAdifHeader($this->config->item('app_name'),$this->optionslib->get_option('version'));
+
+		do {
+			// Calculate chunk size for this iteration
+			$current_chunk_size = min($chunk_size, $remaining_limit);
+
+			// Fetch chunk
+			$qsos = $this->adif_data->export_past_id_chunked($station_id, $fetchfromid, $current_chunk_size, null, $offset, $current_chunk_size);
+
+			if ($qsos && $qsos->num_rows() > 0) {
+				// Process chunk
+				foreach ($qsos->result() as $row) {
+					// Build ADIF content directly
+					$adif_content .= $this->adifhelper->getAdifLine($row);
+
+					// Track data for response
+					$all_qso_ids[] = $row->COL_PRIMARY_KEY;
+					$lastfetchedid = max($lastfetchedid, $row->COL_PRIMARY_KEY);
+					$total_fetched++;
+				}
+
+				// Free memory
+				$qsos->free_result();
+
+				// Update tracking
+				$remaining_limit -= $qsos->num_rows();
+				$offset += $qsos->num_rows();
+
+				// Stop if we've hit the requested limit
+				if ($total_fetched >= $limit) {
+					break;
+				}
+			}
+
+			// Continue if we got a full chunk and haven't hit the limit
+		} while ($qsos && $qsos->num_rows() > 0 && $total_fetched < $limit);
+
+		// Return response (same format as original)
+		if($total_fetched <= 0) {
 			http_response_code(200);
 			echo json_encode(['status' => 'successfull', 'message' => 'No new QSOs available.', 'lastfetchedid' => $fetchfromid, 'exported_qsos' => 0, 'adif' => null]);
-			return;
+		} else {
+			http_response_code(200);
+			echo json_encode(['status' => 'successfull', 'message' => 'Export successfull', 'lastfetchedid' => $lastfetchedid, 'exported_qsos' => $total_fetched, 'adif' => $adif_content]);
 		}
-
-		//convert data to ADIF
-		$adif_content = $this->load->view('adif/data/exportall', $data, TRUE);
-
-		//get new goalpost
-		$lastfetchedid = 0;
-		foreach ($data['qsos']->result() as $row) {
-			$lastfetchedid = max($lastfetchedid, $row->COL_PRIMARY_KEY);
-		}
-
-		//return API result
-		http_response_code(200);
-		echo json_encode(['status' => 'successfull', 'message' => 'Export successfull', 'lastfetchedid' => $lastfetchedid, 'exported_qsos' => $qso_count, 'adif' => $adif_content]);
 	}
 
 
diff --git a/application/controllers/Backup.php b/application/controllers/Backup.php
index 5c65e2028..945892e2e 100644
--- a/application/controllers/Backup.php
+++ b/application/controllers/Backup.php
@@ -29,31 +29,39 @@ class Backup extends CI_Controller {
 		$clean_key = $this->security->xss_clean($key);
 
 		$this->load->helper('file');
+		$this->load->library('AdifHelper');
 		// Set memory limit to unlimited to allow heavy usage
 		ini_set('memory_limit', '-1');
 		
 		$this->load->model('adif_data');
+		$filename = 'backup/logbook'. date('_Y_m_d_H_i_s') .'.adi';
 
-		$data['qsos'] = $this->adif_data->export_all($clean_key);
+		header('Content-Type: text/plain; charset=utf-8');
+		header('Content-Disposition: attachment; filename="'.$filename.'"');
 
-		$data['filename'] = 'backup/logbook'. date('_Y_m_d_H_i_s') .'.adi';
-		
-		if ( ! write_file($data['filename'], $this->load->view('backup/exportall', $data, true)))
-		{
-			$data['status'] = false;
-		}
-		else
-		{
-			$data['status'] = true;
-		}
+		// Output ADIF header // No chance to use exportall-view any longer, because of chunking logic
+		echo $this->adifhelper->getAdifHeader($this->config->item('app_name'),$this->optionslib->get_option('version'));
 
-		$data['page_title'] = __("ADIF - Backup");
-		
+		// Stream QSOs in 5K chunks
+		$offset = 0;
+		$chunk_size = 5000;
 
-		$this->load->view('interface_assets/header', $data);
-		$this->load->view('backup/adif_view');
-		$this->load->view('interface_assets/footer');
+		do {
+			$qsos = $this->adif_data->export_all_chunked($clean_key, null, null, false, null, $offset, $chunk_size);
 
+			if ($qsos->num_rows() > 0) {
+				foreach ($qsos->result() as $qso) {
+					echo $this->adifhelper->getAdifLine($qso);
+				}
+
+				// Free memory
+				$qsos->free_result();
+			}
+
+			$offset += $chunk_size;
+		} while ($qsos->num_rows() > 0);
+
+		exit;
 	}
 
 	/* Export the notes to XML */
diff --git a/application/libraries/AdifHelper.php b/application/libraries/AdifHelper.php
index 40adf9895..c317fd210 100644
--- a/application/libraries/AdifHelper.php
+++ b/application/libraries/AdifHelper.php
@@ -262,6 +262,15 @@ class AdifHelper {
 		return $line;
 	}
 
+	function getAdifHeader($app_name,$version) {
+		$adif_header = "Wavelog ADIF export\n";
+		$adif_header .= "<ADIF_VER:5>3.1.6\n";
+		$adif_header .= "<PROGRAMID:".strlen($app_name).">".$app_name."\r\n";
+		$adif_header .= "<PROGRAMVERSION:".strlen($version).">".$version."\r\n";
+		$adif_header .= "<EOH>\n\n";
+		return $adif_header;
+	}
+
     function getAdifFieldLine($adifcolumn, $dbvalue) {
         if ($dbvalue !== "" && $dbvalue !== null && $dbvalue !== 0) {
             return "<" . $adifcolumn . ":" . mb_strlen($dbvalue, "UTF-8") . ">" . $dbvalue . "\r\n";
diff --git a/application/models/Adif_data.php b/application/models/Adif_data.php
index e34845546..9dda46fce 100644
--- a/application/models/Adif_data.php
+++ b/application/models/Adif_data.php
@@ -2,6 +2,48 @@
 
 class adif_data extends CI_Model {
 
+	function export_all_chunked($api_key = null, $from = null, $to = null, $exportLotw = false, $onlyop = null, $offset = 0, $limit = 5000) {
+		$this->load->model('logbooks_model');
+		if ($api_key != null) {
+			$this->load->model('api_model');
+			if (strpos($this->api_model->access($api_key), 'r') !== false) {
+				$this->api_model->update_last_used($api_key);
+				$user_id = $this->api_model->key_userid($api_key);
+				$logbooks_locations_array = $this->list_station_locations($user_id);
+			}
+		} else {
+			$this->load->model('stations');
+			$logbooks_locations_array = $this->list_station_locations($this->session->userdata('user_id'));
+		}
+
+		$this->db->select($this->config->item('table_name').'.*, station_profile.*, dxcc_entities.name as station_country');
+		$this->db->order_by("COL_TIME_ON", "ASC");
+		$this->db->join('station_profile', 'station_profile.station_id = '.$this->config->item('table_name').'.station_id');
+		if ($from) {
+			$this->db->where("date(".$this->config->item('table_name').".COL_TIME_ON) >= ", $from);
+		}
+		if ($to) {
+			$this->db->where("date(".$this->config->item('table_name').".COL_TIME_ON) <= ",$to);
+		}
+		if ($onlyop) {
+			$this->db->where("upper(".$this->config->item('table_name').".col_operator)",$onlyop);
+		}
+		if ($exportLotw) {
+			$this->db->group_start();
+			$this->db->where($this->config->item('table_name').".COL_LOTW_QSL_SENT != 'Y'");
+			$this->db->or_where($this->config->item('table_name').".COL_LOTW_QSL_SENT", NULL);
+			$this->db->group_end();
+		}
+		$this->db->where_in('station_profile.station_id', $logbooks_locations_array);
+		$this->db->join('dxcc_entities', 'station_profile.station_dxcc = dxcc_entities.adif');
+
+		// Add chunking
+		$this->db->limit($limit, $offset);
+
+		$query = $this->db->get($this->config->item('table_name'));
+		return $query;
+	}	
+
 	function export_all($api_key = null,$from = null, $to = null, $exportLotw = false, $onlyop = null) {
 		$this->load->model('logbooks_model');
 		if ($api_key != null) {
@@ -125,6 +167,52 @@ class adif_data extends CI_Model {
 		return $this->db->get();
 	}
 
+	function export_custom_chunked($from, $to, $station_id, $exportLotw = false, $onlyop = null, $offset = 0, $limit = 5000) {
+		// Copy export_custom logic but add chunking for station_id > 0
+		$this->load->model('Stations');
+		if ($station_id == 0) {
+			// Use existing chunked export_all for all stations
+			return $this->export_all_chunked(null, $from, $to, $exportLotw, $onlyop, $offset, $limit);
+		}
+
+		// Check station access
+		if (!$this->Stations->check_station_is_accessible($station_id)) {
+			return;
+		}
+
+		// Build query identical to export_custom but add LIMIT/OFFSET
+		$this->db->select(''.$this->config->item('table_name').'.*, station_profile.*, dxcc_entities.name as station_country');
+		$this->db->from($this->config->item('table_name'));
+		$this->db->where($this->config->item('table_name').'.station_id', $station_id);
+
+		// Apply same filters as export_custom
+		if ($from) {
+			$this->db->where("date(".$this->config->item('table_name').".COL_TIME_ON) >= ", $from);
+		}
+		if ($to) {
+			$this->db->where("date(".$this->config->item('table_name').".COL_TIME_ON) <= ",$to);
+		}
+		if ($onlyop) {
+			$this->db->where("upper(".$this->config->item('table_name').".col_operator)",$onlyop);
+		}
+		if ($exportLotw) {
+			$this->db->group_start();
+			$this->db->where($this->config->item('table_name').".COL_LOTW_QSL_SENT != 'Y'");
+			$this->db->or_where($this->config->item('table_name').".COL_LOTW_QSL_SENT", NULL);
+			$this->db->group_end();
+		}
+
+		$this->db->order_by($this->config->item('table_name').".COL_TIME_ON", "ASC");
+		$this->db->join('station_profile', 'station_profile.station_id = '.$this->config->item('table_name').'.station_id');
+		$this->db->join('dxcc_entities', 'station_profile.station_dxcc = dxcc_entities.adif', 'left outer');
+
+		// Add chunking
+		$this->db->limit($limit, $offset);
+
+		return $this->db->get();
+	}
+
+
 	function export_custom($from, $to, $station_id, $exportLotw = false, $onlyop = null) {
 		// be sure that station belongs to user
 		$this->load->model('Stations');
@@ -165,25 +253,24 @@ class adif_data extends CI_Model {
 		}
 	}
 
-	function export_past_id($station_id, $fetchfromid, $limit, $onlyop = null) {
-		//create query
+	function export_past_id_chunked($station_id, $fetchfromid, $limit, $onlyop = null, $offset = 0, $chunk_size = 5000) {
+		// Copy export_past_id logic but add chunking support
 		$this->db->select(''.$this->config->item('table_name').'.*, station_profile.*, dxcc_entities.name as station_country');
 		$this->db->from($this->config->item('table_name'));
 		$this->db->where($this->config->item('table_name').'.station_id', $station_id);
-		$this->db->where($this->config->item('table_name').".COL_PRIMARY_KEY > " , $fetchfromid); //only get values past the fetchfromid value
-		$this->db->order_by($this->config->item('table_name').".COL_TIME_ON", "ASC");
-		$this->db->join('station_profile', 'station_profile.station_id = '.$this->config->item('table_name').'.station_id');
-		$this->db->join('dxcc_entities', 'station_profile.station_dxcc = dxcc_entities.adif', 'left outer');
+		$this->db->where($this->config->item('table_name').".COL_PRIMARY_KEY > ", $fetchfromid);
+
 		if ($onlyop) {
 			$this->db->where("upper(".$this->config->item('table_name').".col_operator)",$onlyop);
 		}
+
+		// Add chunking
+		$this->db->limit($chunk_size, $offset);
+
 		$this->db->order_by("COL_PRIMARY_KEY", "ASC");
+		$this->db->join('station_profile', 'station_profile.station_id = '.$this->config->item('table_name').'.station_id');
+		$this->db->join('dxcc_entities', 'station_profile.station_dxcc = dxcc_entities.adif', 'left outer');
 
-		if ($limit > -1) {
-			$this->db->limit($limit);
-		}
-
-		//return result
 		return $this->db->get();
 	}
 
diff --git a/application/views/adif/data/exportall.php b/application/views/adif/data/exportall.php
index 9f2b6b603..035eeb298 100644
--- a/application/views/adif/data/exportall.php
+++ b/application/views/adif/data/exportall.php
@@ -5,19 +5,14 @@
 		header('Content-Type: text/plain; charset=utf-8');
 		header('Content-Disposition: attachment; filename="'.$this->session->userdata('user_callsign').'-'.date('Ymd-Hi').'.adi"');
 	}
-?>
-Wavelog ADIF export
-<ADIF_VER:5>3.1.6
-<PROGRAMID:<?php echo strlen($this->config->item('app_name')); ?>><?php echo $this->config->item('app_name')."\r\n"; ?>
-<PROGRAMVERSION:<?php echo strlen($this->optionslib->get_option('version')); ?>><?php echo $this->optionslib->get_option('version')."\r\n"; ?>
-<EOH>
-
-<?php
 $CI =& get_instance();
 if (!$CI->load->is_loaded('AdifHelper')) {
 	$CI->load->library('AdifHelper');
 }
 
+echo $CI->adifhelper->getAdifHeader($CI->config->item('app_name'),$CI->optionslib->get_option('version'));
+
 foreach ($qsos->result() as $qso) {
     echo $CI->adifhelper->getAdifLine($qso);
 }
+?>