diff --git a/simulations/airshower_beacon_simulation/ab_modify_clocks.py b/simulations/airshower_beacon_simulation/ab_modify_clocks.py
index facb2d1..5de3b44 100755
--- a/simulations/airshower_beacon_simulation/ab_modify_clocks.py
+++ b/simulations/airshower_beacon_simulation/ab_modify_clocks.py
@@ -19,7 +19,7 @@ if __name__ == "__main__":
     from os import path
     import sys
 
-    max_clock_offset = 100# ns
+    max_clock_offset = 100 if len(sys.argv) < 1 else int(sys.argv[1]) # ns
     remake_clock_offsets = True
 
     seed = 12345
@@ -40,6 +40,8 @@ if __name__ == "__main__":
     if not path.isfile(antennas_fname):
         print("Antenna file cannot be found, did you try generating a beacon?")
         sys.exit(1)
+
+    print(f"Modifying clocks upto {max_clock_offset}ns.")
     
     # read in antennas
     with h5py.File(antennas_fname, 'a') as fp: