diff --git a/src/configuration.cpp b/src/configuration.cpp
index 9eba716..9c77f2c 100644
--- a/src/configuration.cpp
+++ b/src/configuration.cpp
@@ -48,6 +48,8 @@ bool Configuration::writeFile() {
         data["wifi"]["autoAP"]["password"]          = wifiAutoAP.password;
         data["wifi"]["autoAP"]["timeout"]           = wifiAutoAP.timeout;
 
+        callsign.trim();
+        callsign.toUpperCase();
         data["callsign"]                            = callsign;
 
         data["aprs_is"]["active"]                   = aprs_is.active;