diff --git a/simulations/airshower_beacon_simulation/ca_period_from_shower.py b/simulations/airshower_beacon_simulation/ca_period_from_shower.py
index 497dc61..008bda0 100755
--- a/simulations/airshower_beacon_simulation/ca_period_from_shower.py
+++ b/simulations/airshower_beacon_simulation/ca_period_from_shower.py
@@ -151,6 +151,7 @@ if __name__ == "__main__":
 
     from scriptlib import MyArgumentParser
     parser = MyArgumentParser(default_fig_dir="./figures/periods_from_shower_figures/")
+    parser.add_argument('--max-k', type=float, default=2, help='Maximum abs(k) allowed to be shifted. (Default: %(default)d)')
     args = parser.parse_args()
 
     fname = "ZH_airshower/mysim.sry"
@@ -159,7 +160,8 @@ if __name__ == "__main__":
     fig_subdir = path.join(fig_dir, 'shifts/')
     show_plots = args.show_plots
 
-    allowed_ks = [ -2, -1, 0, 1, 2]
+    max_k = int(args.max_k)
+    allowed_ks = np.arange(-max_k, max_k+1, dtype=int)
     Xref = 400
 
     N_runs = 3
@@ -465,7 +467,7 @@ if __name__ == "__main__":
             h5attrs = h5beacon_info[freq_name].attrs
 
             h5attrs['best_k'] = old_ks_per_loc[i]
-            h5attrs['best_k_time'] = old_ks_per_loc[i]*dt/f_beacon
+            h5attrs['best_k_time'] = old_ks_per_loc[i]/f_beacon
 
     if show_plots:
         plt.show()