Clamp-on RF Current Meter

Here i show a realization of a clamp-on RF ammeter which is very useful to detect a radiation from RF cables or power supply cables due to standing waves.

The scheme is taken from http://www.qsl.net. In my case it's composed of an ammeter of 100uA, a PVC case and a ferrite clamp from Wurth Elektronik, 23.7 x 34 x 19mm, ref: 7427113. In case you are using another ferrite the value of the first resistor may change. For this ferrite, the resistor value can be chosen from 5 to 25 ohms depending on the sensitivity you want to achieve.

Cut out the area for the ammeter in the PVC box and connect the PCB you have made following the scheme in the previous step.

Cut out the area shown on the photo in the case of the ferrite clamp and wound 10 turns of thin wire.

Solder the PCB wires to the secondary wounding like on photo and you're done. The ferrite clamp can be fixed to the PVC box with a hot glue.

F4HWK