diff --git a/sysmocom/defaults.conf b/sysmocom/defaults.conf
index b175cbb..ed0b575 100644
--- a/sysmocom/defaults.conf
+++ b/sysmocom/defaults.conf
@@ -154,6 +154,7 @@
   enable_pcap: false
   tx_gain: 89
   rx_gain: 60
+  rf_dev_sync: none
   log_options: all.level=error,all.max_size=0,nas.level=debug,nas.max_size=1,s1ap.level=debug,s1ap.max_size=1,x2ap.level=debug,x2ap.max_size=1,rrc.level=debug,rrc.max_size=1
 
 srsue: