Interesting test fixture. Didn't know it existed.
I did it a different way..... and used a clamp on RF ammeter around the coax to measure CM current. Of course the CM current being measured will change, depending on where on the coax, it is clamped.
Still, the measurements can be taken in several different places on the coax. ( marked with painters green tape)....using CM choke #1. Then repeat, using CM choke #2. This also assumes the same power from the XCVR of linear amplifier is being applied. You will know asap, on the freqs being measured, whether CM choke #1 is better / worse then CM choke #2...( or CM choke #3/4/5 etc.
