Hi Tony,
You can in fact measure the impedance (R and X) of a ferrite cored common mode choke with the AA-230 Zoom.
The AA-230 Zoom uses a 10 bit ADC, so that is a greater limitation on resolution that say the AA-600... so the range of impedances you can measure with moderate accuracy is reduced.
If you connect a ferrite cored inductor with VERY short wires to the AA-230 Zoom and sweep it, you will observe that at extreme impedances, the results become noisy... a consequence of the ADC resolution.
Does that make it worthless?
It depends on the question you wish to answer.
If you want to find the range of frequencies where Zcm is moderately high (say |Zcm>1000), then you don't need to measure Zcm to 1% accuracy, you merely want a plot of Zcm vs f.
Now I NEVER use Antscope2 because it cannot display such data. I use a backlevel version of Antscope (1).
Now you can see that it does get the jaggies at really high magnitudes, and the AA-230 will be more limited in range.
We can however reasonably say that |Zcm|>1000 from 1-30MHz, >2000 from 1.6-16MHz.
You might not be able to use the AA-230 Zoom with Antscope(1), but you can export the data as s1p and use it in another application to analyse it. A bit laborious, but it can be done.
When you start making measurements, you will find that the response is EXTREMELY sensitive to physical layout of the inductor and the connections... you will see the self resonant frequency vary widely with changes in layout. That sensitivity is not a defect of the measurement environment, the same thing will happen if you box the inductor up with connectors etc.
On the matter of reconciliation of measurement with calculators, most calculators are flawed conceptually and they are unlikely to reconcile. Tools that do not take account of the frequency dependence of permeability, and that it is a complex quantity are going to fail above 1MHz for most ferrites we use in ham radio.
Owen
