diff --git a/src/keyer.cpp b/src/keyer.cpp
index 276b06b..9b7a564 100644
--- a/src/keyer.cpp
+++ b/src/keyer.cpp
@@ -66,7 +66,7 @@ void Keyer::sendCharacter(const char ch)
         return;
     }
 
-    for (unsigned int i = 0; i < strlen(morseSymbols); i++) {
+    for (size_t i = 0; i < strlen(morseSymbols); i++) {
         m_messageQueue.push(morseSymbols[i]);
     }