diff --git a/test_holo_support.py b/test_holo_support.py
index 342708165451e5d3cd5038e755bae62478433ee0..803ecf4aae71b56c3fd154bb78ba57e842f40664 100644
--- a/test_holo_support.py
+++ b/test_holo_support.py
@@ -5,8 +5,8 @@ def test_apply_holo_support(npix, cell, epsilon):
     np.random.seed(420)
     # place uv-coverage at inner half of cell centers
     # the outer half will never be populated if sampling at the Nyquist rate
-    u = np.fft.fftshift(np.fft.fftfreq(2*npix, d=cell))[npix//2:-npix//2]
-    umax = u.max() 
+    u = np.fft.fftshift(np.fft.fftfreq(2*npix, d=cell))[npix//2:-npix//2+1]
+    umax = np.abs(u).max() 
     uu, vv = np.meshgrid(u, u)
     nrow = uu.size
     uvw = np.vstack((uu.flatten(), vv.flatten(), np.zeros(nrow))).T
@@ -19,7 +19,9 @@ def test_apply_holo_support(npix, cell, epsilon):
     bl = ng.Baselines(coord=uvw, freq=freq)
     flags = np.zeros((nrow, 1), dtype=np.bool)
     idx = ng.getIndices(bl, conf, flags)
-    print('Support of gridder = ', conf.W())
+    W = conf.W()
+    print('Support of gridder = ', W)
+    print('Theoretical maximum non-zero diagonals (2*W - 1)**2 = ', (2*W-1)**2)
 
     # get explicit holo
     Ntot = 4 * npix**2
@@ -32,6 +34,14 @@ def test_apply_holo_support(npix, cell, epsilon):
     
     # indicator
     holo_ind = np.where(holo > 0.0, 1.0, 0.0)
+    # check number of non-zero diagonals
+    num_diags = 0
+    for i in range(-(Ntot//2), Ntot//2+1):
+        tmp = np.trace(holo_ind, i)
+        if tmp:
+            num_diags += 1
+    print("Original holo has %i non-zero diagonals"%num_diags)
+
 
     import matplotlib.pyplot as plt
     plt.figure('H1')
@@ -54,9 +64,17 @@ def test_apply_holo_support(npix, cell, epsilon):
     # indicator
     holo_ind2 = np.where(holo2 > 0.0, 1.0, 0.0)
 
+    num_diags2 = 0
+    for i in range(-(Ntot//2), Ntot//2+1):
+        tmp = np.trace(holo_ind2, i)
+        if tmp:
+            num_diags2 += 1
+    print("Perturbed holo has %i non-zero diagonals"%num_diags2)
+
+
     import matplotlib.pyplot as plt
     plt.figure('H2')
     plt.imshow(np.fft.fftshift(holo_ind2))
     plt.show()
 
-test_apply_holo_support(16, 1e-2, 1e-3)
\ No newline at end of file
+test_apply_holo_support(8, 1e-2, 1e-3)
\ No newline at end of file