diff --git a/grc/gsm_receiver_hier.xml b/grc/gsm_receiver_hier.xml
index 8a6bc5e..ca28972 100644
--- a/grc/gsm_receiver_hier.xml
+++ b/grc/gsm_receiver_hier.xml
@@ -35,4 +35,10 @@
     <type>message</type>
     <optional>1</optional>
   </source>
+  
+  <source>
+    <name>measurements</name>
+    <type>message</type>
+    <optional>1</optional>
+  </source>
 </block>