diff --git a/examples/cc2538dk/sniffer/netstack.c b/examples/cc2538dk/sniffer/netstack.c
index 0945be888..3aeb6968e 100644
--- a/examples/cc2538dk/sniffer/netstack.c
+++ b/examples/cc2538dk/sniffer/netstack.c
@@ -41,5 +41,6 @@ void
 netstack_init(void)
 {
   NETSTACK_RADIO.init();
+  NETSTACK_RADIO.on();
 }
 /*---------------------------------------------------------------------------*/