diff --git a/Detector.cpp b/Detector.cpp
index 822d8d4..e3f291f 100644
--- a/Detector.cpp
+++ b/Detector.cpp
@@ -49,9 +49,9 @@ void Detector::clear ()
   unsigned msInPeriod ((now % 86400000LL) % (m_period * 1000));
   int prevKin = dec_data.params.kin;
   dec_data.params.kin = qMin ((msInPeriod * m_frameRate) / 1000, static_cast<unsigned> (sizeof (dec_data.d2) / sizeof (dec_data.d2[0])));
-  m_bufferPos = m_samplesPerFFT;
+  m_bufferPos = 0;
   m_ns=secondInPeriod();
-  memset(dec_data.d2, 0, sizeof(dec_data.d2) - (sizeof(dec_data.d2[0])));
+  memset(dec_data.d2, 0, sizeof(dec_data.d2));
   qDebug() << "advancing detector buffer from" << prevKin << "to" << dec_data.params.kin << "delta" << dec_data.params.kin - prevKin;
 #else
   dec_data.params.kin = 0;