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The rectangular plot of the one port S data is insufficient to determine Q. You will need the differential phase shift of the reflection coefficient as well. Taken together with the appropriate

Thanks for reminding me, Jim. I've been meaning to look into log scales, both x and y. Right now everything is linear only. Brian

OK, I see you calculated Q from the marker frequency values. Interpolation would be easy and would improve accuracy. Maybe I could add interpolated Q calculation to the marker. Looks like I would need

There's lots of different ways to plot the same data, and people develop their approaches based on the ones they're familiar with. I guess, too, in the "bad old days" when plots were done by hand (or

Thanks for the illustration. How did you get Q = 145.8? Why does the rectangular plot needs phase slope added to discern? Is the dip it too broad and shallow? A rectangular phase plot is available.

Here is an illustration... attached.

This is true for some measurements but not all... Consider a one port measurement, only S11, for a shunt series resonator.

The jig is made using one section of the commercially available NanoVNA test board. Available on eBay, Amazon and from Chinese sellers. You can find discussions about this board on several posts in

Alan, I don't understand what you're suggesting. If I wanted to find center frequency and Q, I'd just look at the rectangular plot, which is available. Brian

Thank you.

A useful addition to your bag is a constant Q contour. The Q = 1 contour permits resonator unloaded Q to be determined from S11 or S21 data overlaid on the chart. Three dB bandwidth and center

Hi Roger Apologies for resurrecting an old post I was just wondering if you could provide any details on the S11 / S21 test jig, it looks pretty much ideal for the matching tests I would like to try.

Nizar, The renormalization makes some assumptions that may not apply to your balun, in particular that S11=S22. This is often close to true for things like ceramic filters, but is probably not close

More Smith chart tricks: https://k6sti.neocities.org/splot.htm Brian

Hi Dave as asked here below the attached new measurements with renormalized Z0 coax 78.5 Ohm and 50 Ohm ( first balun Zc= 62 Ohm) , cursor at the same frequency 14.125Mhz . 73's Nizar .

Hi Dave Thanks I do not use any external artifact to take S21 Losses measurements with equivalent 78.5 Ohm coax Z0 , i just use the DiSlord Z0 renormalisation option on Display menu, this option take

According to the Github page it is the latest "Official" release, Feb 24 2025 . I just d/l it last week. Don't know about older units. I have a Deepelec V3 and seems to be fine

Instead of reading where the plot intersects, read the numbers at the top of the screen which is where your cursor is placed. You have: -0.774 dB loss at 54.6 + j 35.2 ohms equivalent of 64 ohms for

Hi All i tryed to change the balun designe with the same FT140-43 but with 1X12 turns this time , I measure the charateristic impedance of the balun is around 142 Ohm ( see Smith shart focused on the

Hi Dave Thanks Pse take a look to the graphic curve , the losses difference is huge over all the band from 50Khz to 30Mhz , marker value not so important here . 73's Nizar