diff --git a/core/Callsign.cpp b/core/Callsign.cpp
index 28ea5132..a31486e2 100644
--- a/core/Callsign.cpp
+++ b/core/Callsign.cpp
@@ -34,13 +34,13 @@ Callsign::Callsign(const QString &callsign,
     }
 }
 
-QRegularExpression Callsign::callsignRegEx()
+const QRegularExpression Callsign::callsignRegEx()
 {
     FCT_IDENTIFICATION;
     return QRegularExpression(callsignRegExString(), QRegularExpression::CaseInsensitiveOption);
 }
 
-QString Callsign::callsignRegExString()
+const QString Callsign::callsignRegExString()
 {
     FCT_IDENTIFICATION;
     return QString("^(([A-Z0-9]+)[\\/])?(([A-Z][0-9]|[A-Z]{1,2}|[0-9][A-Z])([0-9]|[0-9]+)([A-Z]+))([\\/]([A-Z0-9]+))?");
@@ -102,3 +102,16 @@ bool Callsign::isValid() const
     return valid;
 }
 
+// Based on wiki information
+// https://en.wikipedia.org/wiki/Amateur_radio_call_signs
+const QStringList Callsign::secondarySpecialSuffixes =
+{
+    "A",   // operator at a secondary location registered with the licensing authorities
+    "AM",  // aeronautical mobile
+    "M",   // mobile operation
+    "MM",  // marine mobile
+    "P",   // portable operation
+    "QRP",  // QRP - unofficial
+    "R",    // repeaters
+    "B"     // beacon
+};
diff --git a/core/Callsign.h b/core/Callsign.h
index 8b1c100b..3a87f0a3 100644
--- a/core/Callsign.h
+++ b/core/Callsign.h
@@ -10,8 +10,9 @@ class Callsign : public QObject
 public:
     explicit Callsign(const QString &callsign,
                       QObject *parent = nullptr);
-    static QRegularExpression callsignRegEx();
-    static QString callsignRegExString();
+    static const QRegularExpression callsignRegEx();
+    static const QString callsignRegExString();
+    static const QStringList secondarySpecialSuffixes;
 
     QString getCallsign() const;
     QString getHostPrefix() const;
diff --git a/data/Data.cpp b/data/Data.cpp
index 07f9dab1..c1a35800 100644
--- a/data/Data.cpp
+++ b/data/Data.cpp
@@ -991,18 +991,23 @@ DxccEntity Data::lookupDxcc(const QString &callsign)
         }
 
         QString lookupPrefix = callsign; // use the callsign with optional prefix as default to find the dxcc
-        QStringList specialSuffixes = { "AM", "MM", "QRP" }; // a list of suffixes that have a special meaning
-
         Callsign parsedCallsign(callsign); // use Callsign to split the callsign into its parts
-        if ( parsedCallsign.isValid() ) {
+
+        if ( parsedCallsign.isValid() )
+        {
             QString suffix = parsedCallsign.getSuffix();
-            if ( suffix.length() == 1 ) { // some countries add single numbers as suffix to designate a call area, e.g. /4
+            if ( suffix.length() == 1 ) // some countries add single numbers as suffix to designate a call area, e.g. /4
+            {
                 bool isNumber = false;
-                int number = suffix.toInt(&isNumber);
-                if ( isNumber ) {
+                (void)suffix.toInt(&isNumber);
+                if ( isNumber )
+                {
                     lookupPrefix = parsedCallsign.getBasePrefix() + suffix; // use the call prefix and the number from the suffix to find the dxcc
                 }
-            } else if ( suffix.length() > 1 && !specialSuffixes.contains(suffix) ) { // if there is more than one character and it is not one of the special suffixes, we definitely have a call prefix as suffix
+            }
+            else if ( suffix.length() > 1
+                      && !parsedCallsign.secondarySpecialSuffixes.contains(suffix) ) // if there is more than one character and it is not one of the special suffixes, we definitely have a call prefix as suffix
+            {
                 lookupPrefix = suffix;
             }
         }