NOTES:  For the simplified receiver, delete R20A, R20B, R21, and R55. Solder a jumper between X100 and S3 to
                connect the loop input directly to U0.

                Actual board size is 3.5" x 2.0"

                All 4 corners of the board must be grounded to the minibox thru metal standoffs.

                Solder 1/2" high shields along the long red pads bisecting U0 to help isolate the input.

                Use small coax such as RG-178 for the loop input and Sig Out lines.