diff --git a/core/net/mac/contikimac.c b/core/net/mac/contikimac.c
index e3002ef6e..f1b162a44 100644
--- a/core/net/mac/contikimac.c
+++ b/core/net/mac/contikimac.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: contikimac.c,v 1.19 2010/03/30 23:01:32 adamdunkels Exp $
+ * $Id: contikimac.c,v 1.20 2010/03/31 11:54:38 adamdunkels Exp $
  */
 
 /**
@@ -99,7 +99,7 @@ struct announcement_msg {
 #define CYCLE_TIME (RTIMER_ARCH_SECOND / MAC_CHANNEL_CHECK_RATE)
 #endif
 
-#define MAX_PHASE_STROBES                  8
+#define MAX_PHASE_STROBES                  12
 
 #define CCA_COUNT_MAX 2
 #define CCA_CHECK_TIME                     RTIMER_ARCH_SECOND / 8192
@@ -108,7 +108,7 @@ struct announcement_msg {
 
 #define STREAM_CCA_COUNT                   (CYCLE_TIME / (CCA_SLEEP_TIME + CCA_CHECK_TIME) - CCA_COUNT_MAX)
 
-#define GUARD_TIME                         3 * CHECK_TIME
+#define GUARD_TIME                         7 * CHECK_TIME
 
 #define INTER_PACKET_INTERVAL              RTIMER_ARCH_SECOND / 5000
 #define AFTER_ACK_DETECTECT_WAIT_TIME      RTIMER_ARCH_SECOND / 1500
@@ -694,7 +694,8 @@ send_packet(mac_callback_t mac_callback, void *mac_callback_ptr)
         if(len == ACK_LEN) {
           leds_on(LEDS_BLUE);
           got_strobe_ack = 1;
-          encounter_time = last_transmission_time;
+          //          encounter_time = last_transmission_time;
+          encounter_time = now;
           break;
         } else {
           PRINTF("contikimac: collisions while sending\n");
diff --git a/core/net/mac/phase.c b/core/net/mac/phase.c
index 514a4ccf9..7368fcd5c 100644
--- a/core/net/mac/phase.c
+++ b/core/net/mac/phase.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * $Id: phase.c,v 1.5 2010/03/29 21:50:01 adamdunkels Exp $
+ * $Id: phase.c,v 1.6 2010/03/31 11:54:38 adamdunkels Exp $
  */
 
 /**
@@ -73,7 +73,7 @@ MEMB(phase_memb, struct phase_queueitem, PHASE_QUEUESIZE);
 /*---------------------------------------------------------------------------*/
 void
 phase_update(const struct phase_list *list,
-             const rimeaddr_t * neighbor, rtimer_clock_t time,
+             const rimeaddr_t *neighbor, rtimer_clock_t time,
              int mac_status)
 {
   struct phase *e;
@@ -89,7 +89,7 @@ phase_update(const struct phase_list *list,
          phase (rebooted). We try a number of transmissions to it
          before we drop it from the phase list. */
       if(mac_status == MAC_TX_NOACK) {
-        printf("phase noacks %d\n", e->noacks);
+        printf("phase noacks %d to %d.%d\n", e->noacks, neighbor->u8[0], neighbor->u8[1]);
         e->noacks++;
         if(e->noacks >= MAX_NOACKS) {
           list_remove(*list->list, e);
@@ -162,7 +162,8 @@ phase_wait(struct phase_list *list,
       /*      printf("neighbor phase 0x%02x (cycle 0x%02x)\n", e->time & (cycle_time - 1),
               cycle_time);*/
       now = RTIMER_NOW();
-      wait = (rtimer_clock_t)((e->time - now - e->noacks * cycle_time) & (cycle_time - 1));
+      wait = (rtimer_clock_t)((e->time - now - e->noacks * wait_before) &
+                              (cycle_time - 1));
       if(wait < wait_before) {
         wait += cycle_time;
       }