diff --git a/simulations/airshower_beacon_simulation/bd_antenna_phase_deltas.py b/simulations/airshower_beacon_simulation/bd_antenna_phase_deltas.py
index fc0fe6d..37bd41e 100755
--- a/simulations/airshower_beacon_simulation/bd_antenna_phase_deltas.py
+++ b/simulations/airshower_beacon_simulation/bd_antenna_phase_deltas.py
@@ -43,20 +43,20 @@ if __name__ == "__main__":
     N_base = len(basenames)
     N_ant = len(antennas)
 
-    # reshape time_diffs into N_ant x N_ant array
+    # reshape time_diffs into N_ant x N_ant matrix
     sigma_phase_matrix = np.full( (N_ant, N_ant), np.nan, dtype=float)
-    #sigma_phase_matrix = np.arange(0, N_ant**2, dtype=float).reshape( (N_ant,N_ant))
 
+    ## set i=i terms to 0
+    for i in range(N_ant):
+        sigma_phase_matrix[i,i] = 0
+
+    ## fill matrix
     name2idx = lambda name: int(name)-1
     for i, b in enumerate(basenames):
         idx = (name2idx(b[0]), name2idx(b[1]))
 
-        if idx[0] == idx[1]:
-            # hopefully 0
-            pass
-
         sigma_phase_matrix[(idx[0], idx[1])] = lib.phase_mod(true_phase_diffs[i])
-        sigma_phase_matrix[(idx[1], idx[0])] = lib.phase_mod(true_phase_diffs[i])
+        sigma_phase_matrix[(idx[1], idx[0])] = lib.phase_mod(-1*true_phase_diffs[i])
 
     mat_kwargs = dict(
         norm = Normalize(vmin=-np.pi, vmax=+np.pi),
@@ -82,7 +82,7 @@ if __name__ == "__main__":
     if True:
         # for each row j subtract the 0,j element from the whole row
         # and apply phase_mod
-        first_row = (sigma_phase_matrix[0,:] * np.ones_like(sigma_phase_matrix)).T
+        first_row = -1*(sigma_phase_matrix[0,:] * np.ones_like(sigma_phase_matrix)).T
 
         # Show subtraction Matrix as figure
         if True: