diff --git a/package.nw/lib/gt.js b/package.nw/lib/gt.js
index af94ddc2..0f125182 100644
--- a/package.nw/lib/gt.js
+++ b/package.nw/lib/gt.js
@@ -12174,6 +12174,9 @@ function callsignToDxcc(insign)
     var end = parts.length - 1;
     if (ancPrefixes.includes(parts[end]))
     {
+      if (parts[end].toUpperCase() == "MM") {
+        return -1;
+      }
       parts.pop();
       end = parts.length - 1;
     }