diff --git a/lib/src/phy/rf/rf_uhd_imp.cc b/lib/src/phy/rf/rf_uhd_imp.cc
index 9f13d22e4..83ca4fbc8 100644
--- a/lib/src/phy/rf/rf_uhd_imp.cc
+++ b/lib/src/phy/rf/rf_uhd_imp.cc
@@ -1342,7 +1342,12 @@ int rf_uhd_send_timed_multi(void*  h,
 
     // Set start of burst. Time spec only for the first packet in the burst
     md.start_of_burst = is_start_of_burst;
-    md.has_time_spec  = is_start_of_burst and has_time_spec;
+    // X300 devices work better if Timespec is sent at the start of the burst only
+    if (!handler->devname.compare(DEVNAME_X300)) {
+      md.has_time_spec = is_start_of_burst and has_time_spec;
+    } else {
+      md.has_time_spec = is_start_of_burst or has_time_spec;
+    }
 
     // middle packets are never end of burst, last one as defined
     if (nsamples - n > (int)tx_samples) {