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First put an adapter on the SMA connector and set up the calibration.? Go to Smith Chart.? Select your frequency range.? Short the test leads and see how much residual inductance there is.? Then

Dave: That choke also serves another very important function; it will short the plate supply to ground if the anode coupling capacitor should suffer from leakage current or fail short, keeping you

I have a NanoVNA-H4. Using this, what is the best accurate way to measure the inductance of a coil? Joe WB9SBD

It does. *Clyde K. Spencer*

This is just a test to see if this group passes images. Thank You Joe WB9SBD

When you do your calibration, the device includes the cable length as part of the device. It doesn’t matter if you do the calibrations at the vna or at the end of a 20 foot cable, that distance is

Hello, Measuring coax length has been discussed in several topics. However I have a query. I have calibrated at the end of the short coaxes delivered with the Nano (in my case NanoVNA H4) about 18 cm

The coax need not be any specific length, just long enough to make a "good" measurement (low enough in frequency). Z = SQRT (L/C) applies to any length, so long as the L and C are measured over the

Maybe you are assuming that the characteristics of your RG58A/U are as published. There is no guarantee that coax from lesser vendors actually meets the published specification defined for RG58A/U. I

Dave - I'd first like to explain why the Smith Chart method is showing 51.067 ohms for the RG-58A/U in the SimSmith simulation. As you can see in the attachments of my previous post, no adapters are

Why not measure the capacitance of the adaptors, alone, without the cable. You may have to borrow or buy those connectors identical to those on your cabled adaptors. Yes, a longer cable would also

Dave (W?LEV) - I looked at the method you described to determine the characteristic impedance of coax cable. See the attached plots from SimSmith using RG-58A/U.

Jim Lux and I have both written 1 MegOhm (if Jim had such a resistor). Not that this an optimum value by any means. It's just what we had. The sole purpose of the resistor is to keep voltage from

You could calibrate, with the 10 dB pad in place.? The SNR of the measurement is worse, but it's still valid. The other thing is that the output Z of the NanoVNA is probably pretty close to 50 ohms.

Also low inductance, low capacitance. Kent, AC1HJ

Over and above the NANOVNA issue: I presume you are dealing with a BJT amplifier? Even with a FET PA, the following should be considered. The input and output impedances of a power amplifier (PA)

This firmware conatain measure cable option (MARKER->MEASURE->CABLE): Use 1/4 wavelength (on image this marker 1 point) For detect cable impedance used 1/8 wavelength (on image this marker 2 point)

You can also iterate the VF. Measure the cable length exactly. Use Transform and set VF to a guessed value for the cable. Set the marker at the cable end on the curve (the top) and see what length the

I need to measure S11 going into an RF power amplifier (1-15 MHz range of interest.) While the amplifier has proven stable (so far) when driven through a 10 dB attenuator (from RF source), I am

Fred: You would need a resistor which would handle the power AND the voltage it would see; for legal limit transmit power, many otherwise-suitable resistors have insufficient voltage rating. Phil AD5X