diff --git a/applications/lofar2/model/rtdsp/plotting.py b/applications/lofar2/model/rtdsp/plotting.py
index 964277b5d5c0adf308eb0c50122c60182ccf316f..83965c17648e3bcc915447f7b3708bea7703690e 100644
--- a/applications/lofar2/model/rtdsp/plotting.py
+++ b/applications/lofar2/model/rtdsp/plotting.py
@@ -215,7 +215,7 @@ def plot_power_spectrum(fn, HF, fmt='r', fs=1.0, fLim=None, dbLim=None):
     plt.grid(True)
 
 
-def plot_magnitude_spectrum(f, HF, fmt='r', fs=1.0, fLim=None, voltLim=None):
+def plot_magnitude_spectrum(fn, HF, fmt='r', fs=1.0, fLim=None, voltLim=None):
     """Plot magnitude (= voltage) spectrum
 
     Input:
@@ -227,7 +227,7 @@ def plot_magnitude_spectrum(f, HF, fmt='r', fs=1.0, fLim=None, voltLim=None):
     f = fn * fs  # scale fn by fs
     flabel = 'Frequency [fs = %f]' % fs
 
-    plt.plot(f * fs, np.abs(HF), fmt)
+    plt.plot(f, np.abs(HF), fmt)
     plt.title('Magnitude spectrum')
     plt.ylabel('Voltage')
     plt.xlabel(flabel)