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Sorry, heres the graph with numbers!

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Mike

I've been following this article on how to accurately measure the Q of a coil:



I measured a series LC circuit and converted the S11 file to R+jX. When I plotted R against frequency I observed a peak at the resonant frequency. Any idea what is causing this?

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Mike

Ok.

I understand. If you cant remove coil from its surrounding circuit, a GDO is usefull.

"(Why? Because oceans on Titan are likely liquid methane, ethane, etc)," interesting. Good luck with that probe. i follow Spacex to see when people get to the moon again.

Is there a good a GDO or schema somewhere. Mine is from Heathkit from stone age.

I also have a nanoVNA-F with which I am very satisfied: use f < 300 MHz). Thanks to this forum I was able to update the Firmware. It is not essential but we can thus recover the .sp1 and .sp2 files produced by the box directly.

In reality I use my nanoVNA-F always connected to the nanovna-saver software which extends, with the notion of segment, the use of the box. I do a large part of the calculations from the .sp1 and .sp2 files produced by nanaovna-saver. It is good to set nanaovna-saver to produce a lot of measurement points. 2010 measurements is a bit slow but generally optimum.

Using nanovna-saver is quite easy. Remember to reset the CALIBRATE / RESET box each time before using nanovna-saver. It "normalizes" calibrations and measurements on the same basis.

If you are on Windows 10 or above, the standard version installs without problem. I'm on Seven and you need either a specific version or an old version.
73
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F1AMM
Fran?ois

Michael. Here is a very good demo re the NanoVNA.



Doug

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On 7/1/23 1:07 PM, Diogenio via groups.io wrote:

Group: I have a Nano-F V. 3.1 but have never controlled it from my computer. I'd like to do that, as I need to generate and save an S1P file for some RF transformer work I'm doing.
Can someone please recommend the best public-domain software to use, something that is not buggy or full of spyware? Again, I want to generate and save an S1P file of a sweep.

I use NanoVNA-Saver (which is in Python, and runs on any platform). Others like NanoVNA-App, which is Windows only.

Those two seem to be popular.

If you're looking for something minimalist, there's nanovna.py - it's a command line utility that I use if I just want to command the nanovna from a script.

#!/usr/bin/env bash
time
./nanovna.py --start 50000 --stop 100000000 --points 201 -o testxyz --port 0
time

does a sweep from 50kHz to 100 MHz with 201 points and stores the output in a file called testxyz.s1p.

Group: I have a Nano-F V. 3.1 but have never controlled it from my computer. I'd like to do that, as I need to generate and save an S1P file for some RF transformer work I'm doing.

Can someone please recommend the best public-domain software to use, something that is not buggy or full of spyware? Again, I want to generate and save an S1P file of a sweep.

Many thanks,

I think this related to gcc speed optimisation, TinySA code critical to execute timings and can depend from how compiler optimise code
Most of warnings related to ChibiOS low level code

PS gcc v9.3 provide more compact (and possible little slow) code, more high versions can more faster code, and need fix sweep timings

This happens with tinySA as well with NanoVNA, see my github issues:
and

Try the Absolute Beginners Guide in the files section of this group

/g/nanovna-users/files/Absolute%20Beginner%20Guide%20to%20The%20NanoVNA

In its simplest form you will need an sma to uhf adapter that will connect your nanvna to the tuner in place of your transmitter.
Watch the smith chart along with the swr and or logmag curves while you tune to the frequency you want to work.

As Lester said, its very educational and you just tuned up without transmitting.

I can send you a pic if you need it. Hope this helps.
Bryan, n0luf

I have a VNA-H. I can't get it calibrated. I don't think it is the unit, I
think it's just me. I notice some instructions are for newer units. So what
would you recommend? Best instructions and maybe best video on calibration
of this model?

On Fri, Jun 30, 2023 at 01:28 PM, Bob AF9W wrote:

need to measure some inductors

The nano can measure inductance all by itself, too. Or, at least give you the impedance at the frequency you are measuring with.
And the recent -H firmware versions have a specific "find resonance" function/feature/menu choice as well. But, as mentioned above, the connections between nano and coil will limit the absolute accuracy of the reading. Some users build special connection jigs for particular measurements.
Connecting your trap directly to the nano may give you the info you need too. You can see the shape of the curve as well as get numerical values.
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Doug, K8RFT

Thank you very much for your explanations.

1/ We found in old spectrum analyzers for RADAR (1960) delay lines made of a coaxial cable with losses. Our teacher had told us that it allowed to have a lower speed of propagation. I guess we can say that it is a lossy coaxial therefore presenting a complex characteristic impedance (true or false?). If we use a nanaoVNA, what will be the consequences?

2/ More recently I have seen the use of radiating coaxial cable to retransmit radios in the tunnels. This is a cable where the outer conductor is split. This type of cable also has a complex characteristic impedance. Also, what would be the consequence with a nanoVNA?
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F1AMM
Fran?ois

De la part de Maynard Wright, P. E., W6PAP
Envoyé : vendredi 30 juin 2023 20:23

On 6/30/23 2:07 PM, Leif M wrote:

I hope this is not a silly question, but where do you need GDO, if you have a VNA? That is, you can measure coils and capacitors with VNA. Measuring resonance frequency is bit harder, because Q gets easily too low, and it depends on firmware how you can find the resonance.

It's hard to measure an assembled trap (or measure self resonance of a coil) with traditional 1 or 2 port fixtures, because the fixture is part of the system. I suppose you could develop some appropriate calibration loads (equiv to Short, Open, Load) to "dembed" the fixture.

But if what you're interested is resonant frequency, then a "loosely coupled" coil hooked to the VNA to measure S11 works pretty well. The loose coupling reduces the loading from the measurement system, and you can support the unit under test well away from other "stuff".

We've used a similar technique at JPL to measure the resonance and Q of a microwave cavity at cryogenic temperatures. You can fill the cavity with, say, liquid methane, or ethane, or mixtures of them, and measure the EM properties. The cavity has two loop probes and we make multiple measurements as the probe orientation changes, and from that can calculate the effect of the probe.

(Why? Because oceans on Titan are likely liquid methane, ethane, etc)

Thanks,, Mike.

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Bob AF9W

I am measuring traps in a bandpass filter in circuit for tuning the filter. I have created some pickup coils that "sort of" work but I am looking for an improved solution. I'm using the Nanovna to find the resonant frequency of the traps in a Cauer filter.

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Bob AF9W

Can you measure just the area where the spike is. I have had odd readings when the scale has been too coarse, and have missed some retails..

Equivalent circuit=Spice model is not same as impedance. VNA gives you impedance, Coil64 and give you equivalent circuit. Or an approximation of it.

.

I hope this is not a silly question, but where do you need GDO, if you have a VNA? That is, you can measure coils and capacitors with VNA. Measuring resonance frequency is bit harder, because Q gets easily too low, and it depends on firmware how you can find the resonance.