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Re: nanoVNA - Measuring Inductors and Capacitors (Vers. 3)
#measurement
#tutorials
#video
Thank you for these videos.
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On Wed, Feb 17, 2021, 10:24 PM Gregg Messenger <techgreg@...> wrote:
For those of you who didn¡¯t like my first two attempts at this video.. I |
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Re: nanoVNA - Measuring Inductors and Capacitors (Vers. 3)
#measurement
#tutorials
#video
For those of you who didn¡¯t like my first two attempts at this video.. I think I¡¯ve done a much better job on this one of explaining why I take my readings at 90 degrees phase angle on the smith chart
:-) -- VE6WGM |
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nanoVNA - Measuring Inductors and Capacitors (Vers. 3)
#measurement
#tutorials
#video
Version 3
-- VE6WGM |
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nanoVNA - Measuring the resonant frequency of a crystal
#measurement
#tutorials
#video
A video I did up last summer on how to use the nanoVNA to measure the resonant frequency of crystals.
The intended audience is those who are not wanting a complete and exhaustive characterization of crystals, rather, a quick and simple method to take a handful of random crystals and to determine the resonant frequency so as to be able to sort and label said crystals. Also includes a simple explanation of parallel and series resonant modes of crystals. -- VE6WGM |
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Re: NanoVNA Testboard kit VNA Test Demo Board
#applications
On Wed, Feb 17, 2021 at 10:33 AM, Mark Adler wrote:
The boards are very similar. I have not seen any documentation online for the six-connector board. What is different is that two additional sections have been added so that you can build attenuators, filters and test jigs with a 50 ohm microstrip. The documentation link above is a good guide to assembling the middle section. The 50ohm resistors are provided in case you need some for the microstrip section. Roger |
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Re: nanoVNA - Measuring the resonant frequency of crystals
#tutorials
#video
#measurement
Raoul,
If you are interested in more info on measuring crystals with your NanoVNA I suggest the video by W2AEW on this subject. He carefully explains the terms and definitions and compares various testing methods. He has an extensive collection of videos and is well respected for the clarity and technical accuracy of what he presents. Quite a few recent ones deal with NanoVNA subjects. Roger |
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Re: NanoVNA Testboard kit VNA Test Demo Board
#applications
I received this same six-connector "NanoVNA Testboard Kit" with my VNA. Where can I find documentation for this kit? The documentation link in this thread is for a different two-connector test board.
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Re: Hardware deficiencies when measuring high impedance with S21
This just became a bit more interesting.
It seems that there is a discrepancy in how SimSmith calculates the angle depending on the circuit block used. For an S block it shows the same curve as in NanoVNA Saver and also in Rogers graph (green trace). But for a impedance block angle is different (red trace) and much closer to the modeled resistor (blue trace). [image: image.png] On Wed, 17 Feb 2021 at 03:52, Dragan Milivojevic via groups.io <d.milivojevic@...> wrote: I guess that depends on what you consider as minimal |
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Re: Hardware deficiencies when measuring high impedance with S21
I guess that depends on what you consider as minimal
and if you are modeling an ideal resistor or a more realistic one. For example: on the first image is the plot of voltage angle at the load (port 2 in this case), calculated from the S21 file if the load is an ideal 50¦¸. The black trace is for a model of a 10K resistor with 50fF of capacitance (reasonable value, according to Vishay for a 0805 capacitor) also into an ideal 50¦¸. [image: image.png] The second image shows the same plot but this time instead of an ideal 50¦¸ termination at port2, I used the measured values for port2. Not much of a change. [image: image.png] Last image is the port2 as measured, on a Smith chart (zoomed in quite a bit). [image: image.png] Keep in mind that the calibration was done with DIY "standards" and jig all made from cheap SMA connectors from AliExpress, where the center pin moves if you tighten the connectors enough. DYT also from China with unknown properties. Quite a sloopy setup. On Tue, 16 Feb 2021 at 20:47, Roger Need via groups.io <sailtamarack= [email protected]> wrote: Dragan, |
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Measurement of common mode attenuation - balun
#measurement
#tutorials
#video
Here¡¯s what I did to measure the common mode attenuation of a current balun that I recently constructed. -- VE6WGM |
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Re: Hardware deficiencies when measuring high impedance with S21
Dragan,
Thank you for clarifying what you did on your tests. I took a look at the .s2p file that you posted and see that you get the same large S21 phase shift that I got in my tests. I posted my plot of your S21 data below. For a tiny SMD resistor like the one you used the phase shift should be minimal (at least on the lower frequencies.). The S21 magnitude loss is very close to what it should be for a 10K resistor but that phase shift will give a lower R value and indicate reactance that isn't there if I understand this correctly. Do you agree? I also did a conversion from serial to parallel impedance and your S11 measurement was surprising close to 10K ohms. For a VNA designed for 50 ohm system impedance this was very good. Plot attached. Roger |
Martin Glazer
Gregg Messenger VE6WGM
Roger Need
Mark Adler
