80 mm H-probe

thingiverse

Here's a DIY H-probe for noise measurements on cables - specifically designed for use with RG58 cable. I recommend using a standard RG58 cable fitted with a BNC connector. First, insert the BNC connector into the lower recess of the handle and route the cable up through the handle before looping it around the square loop. Next, trim the cable so that its end just touches where it exits the handle (refer to the diagram). For optimal sensitivity, cut the shield of the cable exactly in the center of the probe - I've included a small indentation in the 3D model to help you locate this spot. It's crucial that the shield is completely severed and that you minimize the gap as much as possible. Finally, at the end of the cable, solder the inner conductor to the shield, and then strip away the insulation from the cable where it exits the handle before soldering its end onto the shield.