diff -r f8f2a9d65576 src/devices/wifi/yans-wifi-phy.cc
--- a/src/devices/wifi/yans-wifi-phy.cc	Wed Mar 10 11:11:38 2010 +0100
+++ b/src/devices/wifi/yans-wifi-phy.cc	Mon Mar 15 13:19:52 2010 +1100
@@ -726,7 +726,7 @@
 {
   NS_ASSERT (m_txPowerBaseDbm <= m_txPowerEndDbm);
   NS_ASSERT (m_nTxPower > 0);
-  double dbm = m_txPowerBaseDbm + power * (m_txPowerEndDbm - m_txPowerBaseDbm) / m_nTxPower;
+  double dbm = m_txPowerBaseDbm + power * (m_txPowerEndDbm - m_txPowerBaseDbm) / (m_nTxPower == 1 ? 1 : m_nTxPower - 1);
   return dbm;
 }