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.

Step 1: Scheme

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.

Step 2: Enclosure Box

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.

Step 3: Ferrite Clamp

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

Step 4: Assembling

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

Comments

[shanvks]

Can this be used to check the signal strength of a RF transmitter?

[kavea]

To check no, since the scale is just an indication, but if you connect two different transmitters to the same radiating cable or a radiating wire (antenna) you can say wich one inject more power.

[shanvks]

Thanks.