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My study (amateur) concerns the cascading of 2 adapters in 'L' one high pass and the other low pass to carry out two adaptations of impedance at two different frequencies. To generalize the brought

I knew about the phone lines. My problem is that if we calculate the S11 with complex values, it leads, for example, to a ROS which can be negative. S11 is no longer in a circle of radius 1. Is this

Definitely so. When working w

Sure it is: S11 is just a representation of the reflection coefficient on port 1 of the UUT. Generally people use just the log magnitude in dB, but it has a phase, too. Nothing prevents the Z0 being

Hello In the attached formula (ROS.png), as long as Zo is real, even if Zl is complex, everything is fine and S11 remains in a circle of radius 1. and the ROS is between 1 and infinity. If Zo is

This is my test fixture, calibrated at the croc clips. It's not ideal but I'm limited by the length of the coil. Should be OK at my measurement frequency of 70kHz though! -- Mike

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Roger, the method I suggested requires inductance calculated this way. It yields an accurate coil model over a narrow frequency range. To my surprise, it seemed good enough over the whole 3.5-4 MHz

On Sun, Jun 25, 2023 at 11:04 PM, Roger Need wrote: > > On Sun, Jun 25, 2023 at 02:27 PM, Mike wrote: > > > > > Thank you Roger. The coil is 95 turns of 0.9mm enamelled copper wire close > > wound on

The VNA can only measure R + jX or R//jX (with later firmware versions). It calculates inductance by dividing X by 2*pi*frequency and this ONLY gives an estimate of the true coil L if the coil is air

Mike, Attached is an analysis of your coil using Coil64. The numbers are close to what you measured. For an air wound coil the actual L will not vary much in the frequency range of up to 12 MHz. Note

Thanks for the link Brian. -- Mike

Mike, measure the inductance and series resistance at the model frequency. I believe recent VNA firmware versions can provide these values directly. Otherwise calculate them from R and X. Then create

Thank you Jim. -- Mike

Thank you Roger. The coil is 95 turns of 0.9mm enamelled copper wire close wound on a 36mm PVC former. -- Mike

ESR is the ohmic resistance *at RF* which will be higher than the DC resistance (skin effect). What you should be able to do is measure the Z (both X and R) far away from self resonance, and get a

Yes it is more complicated than that. The inductance will vary with frequency and so will the ESR. In the case of an air wound coil the underlying inductance will slightly change as you increase

On rf the resistance is higher as dc resistance Dg9bfc sigi Am 25.06.2023 22:26 schrieb Mike <mail@...>:

I have wound a 110uH coil for an antenna system and I want to create a model of the inductor that I can use in a simulation program. In other words, I need to know the inductance, parasitic

Hi. Few questions: 1) I organized the name format of the .cal files stored in the microSD card of my NanoVNA-H4 as per the image in order to easily find them, as only capital letters can be used and