diff --git a/transmit.py b/transmit.py
index 80dd034..b34bb99 100644
--- a/transmit.py
+++ b/transmit.py
@@ -2,8 +2,9 @@
 from rn2483 import Parameters, Radio
 import time
 
+CALLSIGN: str = "??????"
 TRANSMIT_DATA: str = (
-    "VA3INI - This is a test message to test the functionality of the RN2483 transceiver with a long packet containing plenty of data - VA3INI - Packet number follows"
+    f"{CALLSIGN} - This is a test message to test the functionality of the RN2483 transceiver with a long packet containing plenty of data - {CALLSIGN} - Packet number follows"
 )