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Excellent use of the NANO's. I have gone to including one of the NANOVNA's
in our standard (electronic) camping equipment. They are invaluable in any
portable setup.

Dave - W?LEV

On Sat, Oct 15, 2022 at 3:20 AM Connie Stillinger via groups.io <stillinger=
[email protected]> wrote:

On Fri, Oct 14, 2022 at 09:53 AM, W0LEV wrote:

At HF (1.8 through 30 MHz) the influence of adaptors is pretty minimal.
Above that, yes, you need to cal. with the adaptors and the appropriate
cal. kit(s). This should not be considered a 1 or 0 hard wall, but

rather

"fuzzy".

Dave - W?LEV

This is an enormously useful insight for my use case. With this
information, along with some of the other tips here, I spent several hours
this afternoon with my NanoVNA and my portable adjustable coil vertical HF
antenna in the back yard. (Wolf River coils Silver Bullet if anyone is
interested.) It makes sense that adapters are pretty small compared to
wavelength for HF so for road-trip ham radio use cases their effect can be
ignored.

With an adaptor and the knowledge that I could relax about it, I was able
to pretty easily and quickly adjust my antenna to be tuned pretty well on
10m, 20m, 40m. In all cases I was able to get ~0j and a low SWR.
Good enough to get a bunch of QSOs from California across the country on
20 watts, including my first NJ contact.

My radio does have a built-in SWR meter and antenna tuner but I don't
like the way it sweeps the frequencies with a couple of watts, which is
basically a transmission. Also SWR is not a great measure of what I
really want from my antenna -- which is resonance, namely no reactance at
the frequency of interest, as several people pointed out. By adjusting my
antenna with the NanoVNA I can get great results for portable ham operation
without using the tuner in my radio.

--
*Dave - W?LEV*
*Just Let Darwin Work*


--
Dave - W?LEV

Mike,

Version 5 of NanoVNA Saver has a lot of code changes and is buggy. I suggest you try version 4.

Also consider using NanoVNA app instead. Much better graphics scaling and sweep comparison features. Calibration works well and is reliable.

Roger

Just from a physics-based opinion, things that require calibration do tend to drift over time. Component aging, thermal/environmental cycling, physical impact (dropping on the ground), and overvoltage can all cause calibration errors. That's why my company has a calibration lab, and all test equipment is on a calibration/recalibration cycle. How often for the Nano is how confident you are in the saved cal vs the actual cal when it is done again.

Except to tell a stupidity, I prefer, to make the calibration on all the range of frequency which I will use, with many points (therefore many segments). Like: 20 segments for 1-30 MHz with smoothing 25-6 (2020 points with my -F). It takes time but only once. Then I use this calibration file for the current sub-bands.

Why :
You will see that the calibration file contains errors which will show up as straight lines in the graphs (like "parasites"). As these errors are in the calibration file they are found, in fact, by the calculations in nanovna-saver, on all the measurements (at the same frequency) and it has a very bad effect.

So, I correct in this single configuration file the faults by interpolation (by hand).
--
Fran?ois

I've been using the same calibrations over the HF range for over a year, and when I check the SOLT loads, they're still on the money.
I've done one 401 point calibration from 3.5 to 30 MHz and can use it anywhere between at any resolution due to the firmware's interpolation.

New user here so apologies if this has been covered already but I couldn't see it.

I have installed NanoVNA-Saver v0.5.3 on a Windows 10 laptop and I'm using it with a NanoVNA H4 with DisLord firmware v1.2.0.

When I start the program and just before the GUI appears the CMD window displays this:

NanoVNASaver.Hardware.Hardware - ERROR - No VNA detected. Hardware responded to CR with:
too many arguments, max 4
ch>

The program then runs OK and I can calibrate it with Segments = 1, points = 101 and bandwidth =4000.

However if I increase points to 401 the calibration fails and the CMD window shows this:

NanoVNASaver.SweepWorker - ERROR - list index out of range
Traceback (most recent call last):
File "NanoVNASaver\SweepWorker.py", line 79, in run
File "NanoVNASaver\SweepWorker.py", line 118, in _run
File "NanoVNASaver\SweepWorker.py", line 234, in readAveragedSegment
File "NanoVNASaver\SweepWorker.py", line 266, in readSegment
File "NanoVNASaver\SweepWorker.py", line 281, in readData
File "NanoVNASaver\Hardware\NanoVNA.py", line 144, in readValues
IndexError: list index out of range

Am I doing anything wrong?

Thanks,

Mike

(Hi, I didn't see this covered in the wiki or other topics. Apologies if it has been)

I'd like to save three calibrations (corresponding to 3 different frequency ranges) for repeated recall.

How often does the calibration need to be redone for a given set of parameters? Ie, does the NanoVNA drift over time or usage (or temperature)?

Thanks again,

Connie

On Fri, Oct 14, 2022 at 09:53 AM, W0LEV wrote:

At HF (1.8 through 30 MHz) the influence of adaptors is pretty minimal.
Above that, yes, you need to cal. with the adaptors and the appropriate
cal. kit(s). This should not be considered a 1 or 0 hard wall, but rather
"fuzzy".

Dave - W?LEV

This is an enormously useful insight for my use case. With this information, along with some of the other tips here, I spent several hours this afternoon with my NanoVNA and my portable adjustable coil vertical HF antenna in the back yard. (Wolf River coils Silver Bullet if anyone is interested.) It makes sense that adapters are pretty small compared to wavelength for HF so for road-trip ham radio use cases their effect can be ignored.

With an adaptor and the knowledge that I could relax about it, I was able to pretty easily and quickly adjust my antenna to be tuned pretty well on 10m, 20m, 40m. In all cases I was able to get ~0j and a low SWR. Good enough to get a bunch of QSOs from California across the country on 20 watts, including my first NJ contact.

My radio does have a built-in SWR meter and antenna tuner but I don't like the way it sweeps the frequencies with a couple of watts, which is basically a transmission. Also SWR is not a great measure of what I really want from my antenna -- which is resonance, namely no reactance at the frequency of interest, as several people pointed out. By adjusting my antenna with the NanoVNA I can get great results for portable ham operation without using the tuner in my radio.

On 10/14/22 1:50 PM, W0LEV wrote:

Jim, I've not experienced that problem when the model is properly set up.
I've designed and constructed many antennas from HF through L-band and the
1.42 GHz deep space neutral hydrogen emission using 4NEC2 which uses the
basic NEC2 engine. All have worked fine for me when finally implemented.

my experience likewise.

However, all the NEC engines have trouble handling "ground". Once the feed
impedance of a modeled antenna is determined with the NEC engines (EZNEC or
4NEC2 and some others), I then transition to SimSmith for the matching
solution.

It sort of depends on what "ground" is and how close you are. NEC4 does much better with antennas that are close to or touch the soil.

But NEC2 does pretty good, if you're aware of the limitations. A low dipole that's lambda/10 is modeled pretty much the same as NEC4 and with analytical results and actual test data.

I've done a lot of modeling of wires a short distance off the surface of the Moon. The analytical and NEC and other codes all agree.

Sometime ago, George Hagn and others at SRI compared measurements of actual antennas over actual measured soil properties with models and had good agreement.

The usual challenge is that soil isn't uniform and NEC has no way to model that.

Dave - W?LEV
On Fri, Oct 14, 2022 at 5:56 PM Jim Lux <jimlux@...> wrote:

On 10/14/22 10:28 AM, Michael Black via groups.io wrote:

Be aware that EZNec with the built-in NEC engine doesn't work well on

higher frequencies like 50MHz. The resonant point is off by a couple
hundred kilohertz. The latest LLNL engine gets it right.
Can you provide more information? NEC *defaults* to 300 MHz (1 meter
lambda), it's basically just geometry. I've done a *lot* of NEC
modeling and never seen errors like that.

I *have* seen errors due to unwise segmentation, and with single
precision, and situations where the assumption of uniform current
distribution on the surface of a wire is broken. But that's not
frequency related.

Mike W9MDB



On Friday, October 14, 2022 at 12:22:13 PM CDT, F1AMM <

18471@...> wrote:

I only start to know EZNEC well. If you install EZNEC, it files the

manual (in English) in the form of a Word file. It is huge because the
author explains a lot about good and bad modeling as well as ways to
identify bad modeling. It is this notice that I translated into French and
completed.

As far as I know NEC motors, other than EZNEC built-in NEC-2D, are

unaffordable for an OM (QSJ).

Back in 2011, I used something called FEKO Lite to model a PCB bowtie antenna with a tapered matching feedline that had to function both as an antenna and a rudder for an autonomous submarine. Periodically the sub would stick its rudder in the air to get a GPS fix and exchange satellite data. I sure wish I had a VNA for that project! Now I have the nanoVNA but FEKO may be beyond my budget.

OPENEMS.DE

Open EMS is to HFSS as
Linux? is to? Windows

Produced by a community of EE and software geeks.
Be sure to download the tutorials.
Like HFSS, it has quite the vertical learning curve.? ?Kent

Sonnet USA supplies a far-field radiation pattern program as an option on
all versions except the free SonnetLite. It probably costs an arm and a leg
to get it, though. I've been using SonnetLite for a long time to analyze
and design pc patterns like microstrip printed filters, microstrip matching
networks, etc.

73, Zack W9SZ

Thank hou for correcting me.

DaveD

Jim, I've not experienced that problem when the model is properly set up.
I've designed and constructed many antennas from HF through L-band and the
1.42 GHz deep space neutral hydrogen emission using 4NEC2 which uses the
basic NEC2 engine. All have worked fine for me when finally implemented.

However, all the NEC engines have trouble handling "ground". Once the feed
impedance of a modeled antenna is determined with the NEC engines (EZNEC or
4NEC2 and some others), I then transition to SimSmith for the matching
solution.

Dave - W?LEV

--
Dave - W?LEV

On 10/14/22 1:26 PM, Dave Daniel wrote:

I believe that NEC derivative modeling software only goes into the 300 MHz range.

NEC is not frequency limited - you can model wire antennas at 30 GHz if you like.

The problem is that nobody builds wire antennas at 10 GHz - the losses get high. Then you're doing microstrip patches, and while NEC models patches or gridded equivalents, it doesn't do things like account for a substrate and ground plane.

You need a different code.

On 10/14/22 12:21 PM, Douglas Butler wrote:

I am considering learning to use one of these programs to model 2.4 GHz PCB antennas. Are there some that are better at that frequency range?

In general Method of Moments (MMANA, NEC and programs that use NEC) is not a great way to model surfaces like patches.


If you're making simple patches, then the equations in textbooks like Pozar or Kraus will get you close enough to where you're more likely to have problems from manufacturing and material tolerances.

PUFF (which is ancient) will model patches.

I don't think there's a "student version" of HFSS or other similar codes.

I believe that NEC derivative modeling software only goes into the 300 MHz range.

The two higher-frequency software packages of which I am aware are CST Studio and Comsol Multiphysics. CST offers a partially-functional free version. I don’t know if Comsol offers something similar.

Others will probably have more ideas.

DaveD

None!
They do wire type antennas only.

I am considering learning to use one of these programs to model 2.4 GHz PCB antennas. Are there some that are better at that frequency range?

On 10/14/22 10:28 AM, Michael Black via groups.io wrote:

Be aware that EZNec with the built-in NEC engine doesn't work well on higher frequencies like 50MHz.? The resonant point is off by a couple hundred kilohertz.? The latest LLNL engine gets it right.

Can you provide more information? NEC *defaults* to 300 MHz (1 meter lambda), it's basically just geometry. I've done a *lot* of NEC modeling and never seen errors like that.

I *have* seen errors due to unwise segmentation, and with single precision, and situations where the assumption of uniform current distribution on the surface of a wire is broken. But that's not frequency related.

Mike W9MDB
On Friday, October 14, 2022 at 12:22:13 PM CDT, F1AMM <18471@...> wrote:
I only start to know EZNEC well. If you install EZNEC, it files the manual (in English) in the form of a Word file. It is huge because the author explains a lot about good and bad modeling as well as ways to identify bad modeling. It is this notice that I translated into French and completed.
As far as I know NEC motors, other than EZNEC built-in NEC-2D, are unaffordable for an OM (QSJ).