diff --git a/M17Control.cpp b/M17Control.cpp
index 2cd0279..aaf2d1b 100644
--- a/M17Control.cpp
+++ b/M17Control.cpp
@@ -279,7 +279,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 			m_rfFN = (frame[0U] << 8) + (frame[1U] << 0);
 		}
 
-		LogDebug("M17, audio: FN: %u, errs: %u/272 (%.1f%%)", m_rfFN & 0x7FU, errors, float(errors) / 2.72F);
+		LogDebug("M17, audio: FN: %u, errs: %u/272 (%.1f%%)", m_rfFN & 0x7FFFU, errors, float(errors) / 2.72F);
 
 		m_rfBits += 272U;
 		m_rfErrs += errors;