diff --git a/src/radio.c b/src/radio.c
index f1c2277..8ab09b6 100644
--- a/src/radio.c
+++ b/src/radio.c
@@ -712,7 +712,7 @@ bool radio_handle_time_sync()
         return false;
     }
 
-    uint32_t time_millis = gps.time_of_week_millis + (GPS_TIME_LEAP_SECONDS * 1000);
+    uint32_t time_millis = gps.time_of_week_millis - (GPS_TIME_LEAP_SECONDS * 1000);
 
     if (time_millis == radio_previous_time_sync_scheduled) {
         // The GPS chip has not provided an updated time yet for some reason