From 1615bb419a82d61bba1b05f5b2264604fc51c966 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20K=C3=A4berich?= <j.kaeberich@gmx.de>
Date: Wed, 11 Feb 2026 15:06:17 +0100
Subject: [PATCH] only load default calibration when connecting to device

---
 .../PC_Application/LibreVNA-GUI/VNA/vna.cpp   | 27 +++++++++++++------
 .../PC_Application/LibreVNA-GUI/VNA/vna.h     |  1 +
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/Software/PC_Application/LibreVNA-GUI/VNA/vna.cpp b/Software/PC_Application/LibreVNA-GUI/VNA/vna.cpp
index 8144dc0..909005b 100644
--- a/Software/PC_Application/LibreVNA-GUI/VNA/vna.cpp
+++ b/Software/PC_Application/LibreVNA-GUI/VNA/vna.cpp
@@ -804,17 +804,26 @@ void VNA::initializeDevice()
     QSettings s;
     auto key = "DefaultCalibration"+window->getDevice()->getSerial();
     if (s.contains(key)) {
-        auto filename = s.value(key).toString();
-        qDebug() << "Attempting to load default calibration file " << filename;
-        if(QFile::exists(filename)) {
-            if(cal.fromFile(filename)) {
-                qDebug() << "Calibration successful from " << filename;
+
+        // only load default calibration once per device. This allows the user to switch to a different calibration
+        // and have it persist across device initializations. Only when connecting to the device again should the
+        // default calibration be loaded
+        if(defaultCalSerial != window->getDevice()->getSerial()) {
+            // we have never loaded the default calibration for this device, do so now
+            auto filename = s.value(key).toString();
+            qDebug() << "Attempting to load default calibration file " << filename;
+            if(QFile::exists(filename)) {
+                if(cal.fromFile(filename)) {
+                    qDebug() << "Calibration successful from " << filename;
+                    defaultCalSerial = window->getDevice()->getSerial();
+                } else {
+                    qDebug() << "Calibration not successfull from: " << filename;
+                }
             } else {
-                qDebug() << "Calibration not successfull from: " << filename;
+                qDebug() << "Calibration file not found: " << filename;
             }
-        } else {
-            qDebug() << "Calibration file not found: " << filename;
         }
+
         removeDefaultCal->setEnabled(true);
     } else {
         qDebug() << "No default calibration file set for this device";
@@ -833,6 +842,8 @@ void VNA::initializeDevice()
 void VNA::deviceDisconnected()
 {
     defaultCalMenu->setEnabled(false);
+    qDebug() << "disconnected";
+    defaultCalSerial.clear();
     emit sweepStopped();
 }
 
diff --git a/Software/PC_Application/LibreVNA-GUI/VNA/vna.h b/Software/PC_Application/LibreVNA-GUI/VNA/vna.h
index f593e08..2d9cee1 100644
--- a/Software/PC_Application/LibreVNA-GUI/VNA/vna.h
+++ b/Software/PC_Application/LibreVNA-GUI/VNA/vna.h
@@ -180,6 +180,7 @@ private:
 
     QMenu *defaultCalMenu;
     QAction *assignDefaultCal, *removeDefaultCal;
+    QString defaultCalSerial;
     QAction *saveCal;
 
     Deembedding deembedding;