My Time Domain Reflectometer (TDR) circuit is now available in kit form. Far Circuits has made a TDR kit that consists of circuit board and components. The Far Circuits version is a slightly modified circuits, the modification is that the circuit board has a 5V regulator IC in it. With that regulator the circuit power supply can be in 8-15V DC range (maybe eve higher). I have received a sample kit but I have not yet built my kit.