diff --git a/fpga/fpga_lf.bit b/fpga/fpga_lf.bit
index 51b0681cd..bd4d821bb 100644
Binary files a/fpga/fpga_lf.bit and b/fpga/fpga_lf.bit differ
diff --git a/fpga/lo_edge_detect.v b/fpga/lo_edge_detect.v
index dc97fc6f5..bb1301574 100644
--- a/fpga/lo_edge_detect.v
+++ b/fpga/lo_edge_detect.v
@@ -35,10 +35,12 @@ wire tag_modulation = ssp_dout & !lf_field;
 wire reader_modulation = !ssp_dout & lf_field & pck_divclk;
 
 // No logic, straight through.
-assign pwr_oe1 = 1'b0; // not used in LF mode
+assign pwr_oe1 = 1'b0; 						// not used in LF mode 
+assign pwr_oe3 = 1'b0; 						// base antenna load = 33 Ohms
+// when modulating, add another 33 Ohms and 10k Ohms in parallel:
 assign pwr_oe2 = tag_modulation;
-assign pwr_oe3 = tag_modulation;
-assign pwr_oe4 = tag_modulation;
+assign pwr_oe4 = tag_modulation; 
+
 assign ssp_clk = cross_lo;
 assign pwr_lo = reader_modulation;
 assign pwr_hi = 1'b0;