I once again find myself needing to measure the RF current in a coaxial cable.
The signal in question is a high power (100W-1kW range) signal which is a stepped waveform with a 5MHz fundemental with multiple harmonics (the 7th harmonic is highest of any interest). I have to hand an active oscilloscope current probe of the clamp-on style (specifically Keysight N2893A) which has sufficient bandwidth to do the job. The question is one of building some form of adapter to connect the probe and coax cable.
I did wonder whether the probe could simply be clamped around the coax cable directly, however I'm not sure this will work - AFAIK the magnetic fields of current flowing through the sheild and central conductor should cancel out (?).
In the past I have used an adapter we built which is nothing more than two BNC connectors attached to a metal box (connects the sheilds), and a length of single core wire connecting the signal lines which the clamp can then attach to (pictured below).
Unfortunately I don't currently have access to this adapter, so I am going to need to build a new one.
I can probably cobble together something similar to the previous adapter with bits to hand, but I was wondering if there is any standard or common approach to doing this, or whether the DIY adapter we made previously is the best way to go.