diff --git a/cpu/msp430/rtimer-arch.h b/cpu/msp430/rtimer-arch.h
index 446ef99e1..6063292b1 100644
--- a/cpu/msp430/rtimer-arch.h
+++ b/cpu/msp430/rtimer-arch.h
@@ -48,6 +48,20 @@
 #define RTIMER_ARCH_SECOND (4096U*8)
 #endif
 
+/* Do the math in 32bits to save precision.
+ * Round to nearest integer rather than truncate. */
+#define US_TO_RTIMERTICKS(US)  ((US) >= 0 ?                        \
+                               (((int32_t)(US) * (RTIMER_ARCH_SECOND) + 500000) / 1000000L) :      \
+                               ((int32_t)(US) * (RTIMER_ARCH_SECOND) - 500000) / 1000000L)
+
+#define RTIMERTICKS_TO_US(T)   ((T) >= 0 ?                     \
+                               (((int32_t)(T) * 1000000L + ((RTIMER_ARCH_SECOND) / 2)) / (RTIMER_ARCH_SECOND)) : \
+                               ((int32_t)(T) * 1000000L - ((RTIMER_ARCH_SECOND) / 2)) / (RTIMER_ARCH_SECOND))
+
+/* A 64-bit version because the 32-bit one cannot handle T >= 4295 ticks.
+   Intended only for positive values of T. */
+#define RTIMERTICKS_TO_US_64(T)  ((uint32_t)(((uint64_t)(T) * 1000000 + ((RTIMER_ARCH_SECOND) / 2)) / (RTIMER_ARCH_SECOND)))
+
 rtimer_clock_t rtimer_arch_now(void);
 
 #endif /* RTIMER_ARCH_H_ */
diff --git a/platform/sky/contiki-conf.h b/platform/sky/contiki-conf.h
index 53f22f87f..ff4ad8578 100644
--- a/platform/sky/contiki-conf.h
+++ b/platform/sky/contiki-conf.h
@@ -37,6 +37,10 @@
 #define CC2420_CONF_AUTOACK              1
 #endif /* CC2420_CONF_AUTOACK */
 
+/* The TSCH default slot length of 10ms is a bit too short for this platform,
+ * use 15ms instead. */
+#define TSCH_CONF_DEFAULT_TIMESLOT_LENGTH 15000
+
 /* Specify whether the RDC layer should enable
    per-packet power profiling. */
 #define CONTIKIMAC_CONF_COMPOWER         1
diff --git a/platform/sky/platform-conf.h b/platform/sky/platform-conf.h
index f5530f3aa..4d5bd9094 100644
--- a/platform/sky/platform-conf.h
+++ b/platform/sky/platform-conf.h
@@ -46,6 +46,13 @@
 /* Platform TMOTE_SKY */
 #define TMOTE_SKY 1
 
+/* Delay between GO signal and SFD: radio fixed delay + 4Bytes preample + 1B SFD -- 1Byte time is 32us
+ * ~327us + 129preample = 456 us */
+#define RADIO_DELAY_BEFORE_TX ((unsigned)US_TO_RTIMERTICKS(456))
+/* Delay between GO signal and start listening
+ * ~50us delay + 129preample + ?? = 183 us */
+#define RADIO_DELAY_BEFORE_RX ((unsigned)US_TO_RTIMERTICKS(183))
+
 #define PLATFORM_HAS_LEDS    1
 #define PLATFORM_HAS_BUTTON  1
 #define PLATFORM_HAS_LIGHT   1
diff --git a/platform/z1/contiki-conf.h b/platform/z1/contiki-conf.h
index 783b3ec8c..44d74efdb 100644
--- a/platform/z1/contiki-conf.h
+++ b/platform/z1/contiki-conf.h
@@ -103,6 +103,10 @@
 
 #define IEEE802154_CONF_PANID       0xABCD
 
+/* The TSCH default slot length of 10ms is a bit too short for this platform,
+ * use 15ms instead. */
+#define TSCH_CONF_DEFAULT_TIMESLOT_LENGTH 15000
+
 #define SHELL_VARS_CONF_RAM_BEGIN 0x1100
 #define SHELL_VARS_CONF_RAM_END 0x2000
 
diff --git a/platform/z1/platform-conf.h b/platform/z1/platform-conf.h
index 2d05c96b0..d17c463b6 100644
--- a/platform/z1/platform-conf.h
+++ b/platform/z1/platform-conf.h
@@ -43,6 +43,13 @@
  */
 #define ZOLERTIA_Z1 1  /* Enric */
 
+/* Delay between GO signal and SFD: radio fixed delay + 4Bytes preample + 1B SFD -- 1Byte time is 32us
+ * ~327us + 129preample = 456 us */
+#define RADIO_DELAY_BEFORE_TX ((unsigned)US_TO_RTIMERTICKS(456))
+/* Delay between GO signal and start listening
+ * ~50us delay + 129preample + ?? = 183 us */
+#define RADIO_DELAY_BEFORE_RX ((unsigned)US_TO_RTIMERTICKS(183))
+
 #define PLATFORM_HAS_LEDS    1
 #define PLATFORM_HAS_BUTTON  1
 #define PLATFORM_HAS_RADIO   1