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On Tue, Mar 23, 2021 at 07:24 PM, jmr wrote: > I've not actually looked inside my nanovna but a quick glance at the online > schematic shows a classic resistive bridge. When you connect a test circuit

I've not actually looked inside my nanovna but a quick glance at the online schematic shows a classic resistive bridge. When you connect a test circuit to the CH0 input the bridge in the nanoVNA

If anyone does read the paper linked to by Roger the test setup for s11 in that paper is shown in figure 4 and it is awful with bits of wobbly copper tape and a metal bar making up the short and the

An interesting paper "Measuring Capacitor Parameters Using Vector Network Analyzers" by Stepins, Asmanis, and Asmanis might be of interest to members of this group. The three common methods of

Jim,, I did some research today on how the NanoVNA calculates the reflection coefficient, Gamma, from the digitized bridge signals. There is very little information on this available and the firmware

Jeff I have been using the ancient bridges for years and still use them for the high Z's. Yes! All of these ancient bridges had to go thru an initial balance for each freq. Not to mention you needed

Sorry, I made a slight goof with the last plot as the trace for the poly 470pF cap was from the wrong S1p file. To make the traces overlay correctly I have to make sure that both VNAs have the same

To make things harder for the nanoVNA I pulled a couple of 220pF ceramic disk caps from an old Cobra 148GTL-DX CB radio that was probably made in 1981. I put them in parallel to make up 440pF. These

Isee, it is complex but can be accurate. But as I understand it you really have to relate the thermal losses to the real power loss, reactive power does not produce heath. Regards, Ignacio EB4APL

Thank you Manfred, larry

Well, there is always the thermal method: Put the capacitor under test in a resonant circuit, thermally disconnected from the coil, excite it to a high amplitude, and measure the temperature rise of

I did not, but it is designed to measure the Q of resonant circuits, where the Q is normally defined by the L. So trying to measure the capacitor's Q using this principle leads to get the Q of the L

Yes, that should be a good test. The question is whether the ESR in a cap stays constant over frequency. Surely not! So even if I could measure its Q at 200MHz, that says alittle about its Q at 7MHz,

It's here: /g/nanovna-users/topic/79953788#20080>

Speaking of Q measurements has anyone tried this EDN design: <https://www.edn.com/novel-q-meter/> Mike N2MS

On 3/22/21 7:58 PM, Roger Need via groups.io wrote: > I spent the afternoon building a spreadsheet to calculate the reflection coefficient and phase angle required for different values of reactance

On 3/22/21 8:52 AM, Manfred Mornhinweg wrote: >> Manfred's plots of the 2000pF 'Hi Q' capacitor (on the EFHW transformer >> thread) obviously had a problem somewhere with the test setup or maybe his

Here's a Q plot of an ancient Philips 470pF poly capacitor from about 1MHz to 20MHz. I measured it on a regular Agilent VNA and then on the little nanovna. Both VNAs use a basic SMA mechanical

I spent the afternoon building a spreadsheet to calculate the reflection coefficient and phase angle required for different values of reactance and capacitance. It was quite interesting to test

Another fairly crude form of verification would be to place a large resistor in parallel with the cap and see if the Q curve changes as expected. Also, it would be worthwhile extending the frequency