HF Current Meter

Since I experience trouble with HF interference in my shack, I needed to have a HF Current Meter to detect where the cause of the problem comes from. I came across a simple schematic of DJ4UF and decided to build that one. However, the challenge was to construct the clamp-on EMC ferrite for the current transformer. When I was abroad and doing some shopping in a department store, my eye catched an over sized clothespins and I immediately saw the alternative use for it.

The trick is to split the ferrite ring without damaging it completely, but that turned out not too difficult. There are several examples on the internet that you can use. You might even try to use a “snap it round cable split toroid” that you normally use to clamp on coax cables. Below you see the result of the clamp-on EMC ferrite and the uA meter. Simple and effective measurement tool for the shack.