diff --git a/applications/apertif/designs/apertif_unb1_correlator/src/vhdl/apertif_unb1_correlator_nodes.vhd b/applications/apertif/designs/apertif_unb1_correlator/src/vhdl/apertif_unb1_correlator_nodes.vhd
index 1f0a49e7fa10c9c88a096f6120b16f6696c5fd27..876013eb266b0c66e2c6bc7ad6cae081162b1999 100644
--- a/applications/apertif/designs/apertif_unb1_correlator/src/vhdl/apertif_unb1_correlator_nodes.vhd
+++ b/applications/apertif/designs/apertif_unb1_correlator/src/vhdl/apertif_unb1_correlator_nodes.vhd
@@ -162,6 +162,8 @@ ARCHITECTURE str OF apertif_unb1_correlator_nodes IS
   CONSTANT c_nof_10GbE_streams      : NATURAL := c_revision_select.nof_10GbE_inputs;
   -- Normally we have 8 nodes * 3 10GbE inputs = 24 inputs = 300 visibilities. In 1x10GbE mode, we have 8 inputs = 36 visibilities.
   CONSTANT c_nof_visibilities       : NATURAL := sel_a_b(c_nof_10GbE_streams=1, 36, 300);
+  
+  CONSTANT c_usr_frame_len          : NATURAL := 176; -- 8-bit mode: 176 6-bit mode: 240 
 
   -- Enable block generators
   CONSTANT c_use_phy                : t_c_unb1_board_use_phy  := (1, sel_a_b(c_use_bg_input, 0, 1), 0, 0, 0, 0, 0, 1);
@@ -380,7 +382,7 @@ BEGIN
       g_use_repack         => c_use_repack,     
       g_usr_use_complex    => c_use_complex,    
       g_usr_data_w         => c_mesh_data_w,              
-      g_usr_frame_len      => 176,               
+      g_usr_frame_len      => c_usr_frame_len,               
       g_aux                => c_unb1_board_aux  
     )
     PORT MAP(