diff --git a/LCU/checkhardware/rtsm.py b/LCU/checkhardware/rtsm.py
index e2cf89e5377e70e31606c36dff655fbbda7dc4f8..56f70d87ff3157b000454dccbb8af4df1387b41f 100755
--- a/LCU/checkhardware/rtsm.py
+++ b/LCU/checkhardware/rtsm.py
@@ -171,12 +171,14 @@ class CSV:
                         rcu, self.rcumode, self.obsid, check, freq[0], freq[1], self.record_timestamp)
         mean_spectra = "MEAN-SPECTRA=["
         for i in data.median_all_spectras(freq_band=mode_to_band(self.rcumode), polarity=data.polarity(rcu), masked=True):
+            if np.ma.is_masked(i): i = 0 ## FIX numpy >= 1.13
             mean_spectra += "%3.1f " % np.nan_to_num(i)
         mean_spectra += "]\n"
 
         bad_spectra = "BAD-SPECTRA=["
         for i in data.rcu_mean_spectra(rcu=rcu, masked=True):
             #logger.debug("BAD-SPECTRA=%s" % str(i))
+            if np.ma.is_masked(i): i = 0 ## FIX numpy >= 1.13
             bad_spectra += "%3.1f " % np.nan_to_num(i)
         bad_spectra += "]\n\n"