diff --git a/applications/apertif/commissioning/tests/start_wg_at_bsn.sh b/applications/apertif/commissioning/tests/start_wg_at_bsn.sh
index eff99e19f76ded42673caf424de6b1f35cb9f268..9b4b410ae667e2c35894e58840ff8b98e6bab27e 100644
--- a/applications/apertif/commissioning/tests/start_wg_at_bsn.sh
+++ b/applications/apertif/commissioning/tests/start_wg_at_bsn.sh
@@ -21,6 +21,11 @@
 
 # Author: Eric Kooistra
 # Purpose: Start WG synchronously at multiple dishes
+#
+#   For block diagram of the WG in the bn_filterbank FPGA see:
+#
+#    $RADIOHDL/applications/apertif/doc/schematics/apertif_fpga_firmware_unb1_fn_beamformer.pdf
+#
 # Usage:
 # 
 # At ccu-corr.