diff --git a/simulations/airshower_beacon_simulation/aa_generate_beacon.py b/simulations/airshower_beacon_simulation/aa_generate_beacon.py
index 8fb41a6..3551e51 100755
--- a/simulations/airshower_beacon_simulation/aa_generate_beacon.py
+++ b/simulations/airshower_beacon_simulation/aa_generate_beacon.py
@@ -18,6 +18,7 @@ import lib
 # {{{ vim marker
 tx_fname = 'tx.json'
 antennas_fname = 'antennas.hdf5'
+snr_fname = 'snr.json'
 c_light = lib.c_light
 
 def read_antenna_clock_repair_offsets(antennas, mode='all', freq_name=None):
@@ -49,6 +50,17 @@ def read_antenna_clock_repair_offsets(antennas, mode='all', freq_name=None):
 
     return time_offsets
 
+def write_snr_file(fname, snrs):
+    with open(fname, 'w') as fp:
+        return json.dump(
+                {'mean': np.mean(snrs), 'std': np.std(snrs), 'values': snrs},
+                fp
+                )
+
+def read_snr_file(fname):
+    with open(fname, 'r') as fp:
+        return json.load(fp)
+
 def write_tx_file(fname, tx, f_beacon, **kwargs):
     with open(fname, 'w') as fp:
         return json.dump(
diff --git a/simulations/airshower_beacon_simulation/ac_show_signal_to_noise.py b/simulations/airshower_beacon_simulation/ac_show_signal_to_noise.py
index d945bb5..d813a9d 100755
--- a/simulations/airshower_beacon_simulation/ac_show_signal_to_noise.py
+++ b/simulations/airshower_beacon_simulation/ac_show_signal_to_noise.py
@@ -42,6 +42,7 @@ if __name__ == "__main__":
     fname_dir = args.data_dir
     antennas_fname = path.join(fname_dir, beacon.antennas_fname)
     tx_fname = path.join(fname_dir, beacon.tx_fname)
+    snr_fname = path.join(fname_dir, beacon.snr_fname)
 
     # create fig_dir
     if fig_dir:
@@ -92,9 +93,8 @@ if __name__ == "__main__":
         N_samples = len(antennas[0].beacon)
         beacon_snrs = [ lib.signal_to_noise(myfilter(beacon_amp*ant.beacon), myfilter(ant.noise), samplerate=1/dt, signal_band=beacon_pb, noise_band=noise_pb) for i, ant in enumerate(antennas) ]
 
-        with open(path.join(fname_dir, 'snr.txt'), 'w') as f:
-            f.write('mean='+str(np.mean(beacon_snrs))+'\n')
-            f.write('std='+str(np.std(beacon_snrs))+'\n')
+        # write mean and std to file
+        beacon.write_snr_file(snr_fname, beacon_snrs)
 
         fig, ax = plt.subplots(figsize=figsize)
         ax.set_title(f"Maximum Beacon/Noise SNR (N_samples:{N_samples:.1e})")