With this NanoVNA Current Choke Test Rig, you can quickly design and test all sorts of common mode chokes in your home lab.

I would like to tell you about the NanoVNA Current Choke Test Rig made by my friend Mark Smith, N6MTS. In my last article, I talked about the challenges of figuring out design of common mode chokes using ferrites.

It turns out that in most cases, you need to experiment to find the right ferrite mix, number of turns or number of snap-on chokes needed to reduce RFI on cables. Common mode chokes work by “choking” unbalanced currents using an impedance much higher than your cable itself. These can work very well, but how do you know that you are getting the best performance.

It turns out that the cheap NanoVNA, properly calibrated, can do a great job of measuring choke performance. But only if you can set things up to measure common mode signals flowing down your cable. And, this is exactly what Mark’s NanoVNA Current Mode Choke Test Rig does for you.

As shown above, this test rig contains multiple types of connectors for the two ports, including N, VHF, SMA and BNC connectors. Plus, there is a switch to set up NanoVNA calibration before testing. So, for $59, you can turn your NanoVNA into a perfect tester for designing your chokes.

Watch Mark's video. He does a great job of explaining the common mode challenges and how to use his test rig.

NanoVNA Current Choke Test Rig – Give It a Try

Now, this test rig comes as a kit. You need to assemble it yourself, but that’s not hard. Check out the User Guide and Assembly Manual.

I could say a lot more, but Mark’s video pretty much covers everything in the right amount of understandable detail. Halibut Electronics is a small business devoted to novel tools that are very useful.