Fig. 1. Schematic of TDR probe design: (1) F660 BEF Commscope 75 ohm RG6 coaxial cable; (2) female F-connector; (3) male F-Connector to plug; (4) polyethylene terminal block; (5) 3.2-mm diam. 316 stainless steel rod; (6) 3.2-mm diameter 316 stainless steel rod, optionally coated with 0.4-mm thick polyolefin heat shrink; (7) On Semiconductor MPN3404 PIN diode; and (8) terminal block sealed with a silicon sealant.