Calculates the absolute load impedance, reflection coefficient, VSWR, return loss and mismatch loss of a load. This circuit can be simulated in a FLEXI-BOX, and a transmission line (50 Ohm track) PCB is available which easily adapts for this circuit with one simple trimming operation. There is a selection of 50 Ohm RF connectors available and a 75 Ohm BNC or TNC will also fit directly onto the box with no modifications.