diff --git a/core/net/mac/xmac.c b/core/net/mac/xmac.c
index 40c44be1e..102df223d 100644
--- a/core/net/mac/xmac.c
+++ b/core/net/mac/xmac.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: xmac.c,v 1.49 2010/01/25 11:43:32 adamdunkels Exp $
+ * $Id: xmac.c,v 1.50 2010/01/28 13:40:47 adamdunkels Exp $
  */
 
 /**
@@ -114,7 +114,7 @@ struct xmac_hdr {
 #ifdef XMAC_CONF_OFF_TIME
 #define DEFAULT_OFF_TIME (XMAC_CONF_OFF_TIME)
 #else
-#define DEFAULT_OFF_TIME (RTIMER_ARCH_SECOND / 2 - DEFAULT_ON_TIME)
+#define DEFAULT_OFF_TIME (RTIMER_ARCH_SECOND / 4 - DEFAULT_ON_TIME)
 #endif
 
 #define DEFAULT_PERIOD (DEFAULT_OFF_TIME + DEFAULT_ON_TIME)