diff --git a/python/packages/nisar/antenna/beamformer.py b/python/packages/nisar/antenna/beamformer.py
index 4acc7cf9b..bea3a5a05 100644
--- a/python/packages/nisar/antenna/beamformer.py
+++ b/python/packages/nisar/antenna/beamformer.py
@@ -815,6 +815,11 @@ def compute_transmit_pattern_weights(tx_trm_info, norm=False):
         if np.isclose(abs(tx_weights[bcal_lines_idx]).min(), 0):
             raise RuntimeError('Zero-value BCAL data is encountered!')
 
+        # handle case where first line isn't BCAL
+        bcal_rel = (tx_weights[bcal_lines_idx[0]] /
+                    tx_weights[bcal_lines_idx[0], 0])
+        tx_weights[:bcal_lines_idx[0]] /= bcal_rel
+
         for line_start, line_stop in zip(bcal_lines_idx[:-1],
                                          bcal_lines_idx[1:]):
             # normalize BCAL wrt to the first TX channel to get relative