Re: Off topic nanoVNA: EZNEC
On 10/14/22 10:21 AM, F1AMM 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). NEC2 is free, as is 4nec2, as is MMANA. NEC4 (or NEC5) require a one time license fee to Lawrence Livermore. Yes, one of the huge advantages of EZNEC is the modeling assistance in the manual, which is actually generally applicable to all method of moments codes (e.g. NEC). Antenna modeling is one of those idiosyncratic things that you learn by doing, especially the subtle points and tricks. For instance, gridding for solids (or boxes) is a whole art in itself. Attached are a couple of screen shots from 4nec2, for a model built with some custom built software. In one, I'm gridding a 6U cubesat that has 4 2.5m long booms. In the other, I'm gridding the ground plane under an antenna for an array radio telescope. To keep this remotely NanoVNA related, one test of the gridding is whether the modeled feedpoint Z matches the measured feedpoint Z, and that's a lot easier with a NanoVNA. It's small enough to put inside a mockup satellite, so you don't have to worry about cables.
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Re: Off topic nanoVNA: EZNEC
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.
Mike W9MDB
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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).
--
F1AMM (Fran?ois)
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Re: Off topic nanoVNA: EZNEC
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).
--
F1AMM (Fran?ois)
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Re: Antenna tuning in field, calibration with SMA cal set followed by BNC and UHF adaptors
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 On Thu, Oct 13, 2022 at 7:10 PM Connie Stillinger via groups.io <stillinger= [email protected]> wrote: Hi -- I would like to use the NanoVNA for measuring and adjusting antennas
in the field for relatively casual POTA and other portable ham radio
activities (e.g. tuning the loading coil on a vertical; or tuning wire
lengths on a dipole or EFHW; etc).
My antennas' feed points as well as my feed lines are all either UHF or
BNC, and my radio has a UHF connector.
The problem is that the NanoVNA has SMA connectors and only an SMA
calibration set. In order to measure my antennas and cables I need to
use adapters.
Do I need to acquire or make BNC and UHF calibration sets for this kind of
field antenna measurement? Or is calibration using the SMA cal set at
all useful for this kind of amateur radio activity? I know it's not ideal
but since I'm not looking for a high degree of precision I wonder how bad
the error will be.
How can I measure the error due to the use of adaptors?
Thanks,
Connie
-- *Dave - W?LEV* *Just Let Darwin Work* -- Dave - W?LEV
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Re: Off topic nanoVNA: EZNEC
I've never really progressed past creating an input deck using the text editor and viewing the results in the geometry screen. One of the members at digitalhome.ca wrote a python optimization script for HDTV antennas that would produce some excellent optimizations if you let the program chug on long enough.
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On Fri, Oct 14, 2022 at 10:55 AM, Jim Lux wrote: and keeping track of endpoints, matching segment lengths in
parallel conductors, etc. by hand is a pain.
These days, most of my model building is done with python to generate
NEC input decks and to process the output, but I use 4nec2 for quick
visualizations.
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Re: Off topic nanoVNA: EZNEC
On 10/14/22 7:44 AM, Zack Widup wrote: How do the results of the two compare?
They're basically the same NEC engine underneath - So if you have EZNEC or 4nec2, you have a UI that builds a model and hands it off to the NEC2 engine, which does the computation, then the program displays the results (graphically) Both have useful features to do things like tapers and insulated members, often by turning one model element YOU enter into multiple elements in the model passed to NEC, or by changing some parameter in a model element. For example 4nec2 has had a "current source" since the beginning, but NEC2 doesn't. 4nec2 simulates that by using a NT (network) card to turn a current source into a voltage source (which NEC2 does support). And both can use the NEC4 engine, which has better modeling, and some additional features. The real issue with NEC isn't the performance (these days, it's blindingly fast on almost any PC) it's that it describes the structure and analysis in terms of various card types (yes, originally punched cards), and keeping track of endpoints, matching segment lengths in parallel conductors, etc. by hand is a pain. These days, most of my model building is done with python to generate NEC input decks and to process the output, but I use 4nec2 for quick visualizations. Zack W9SZ
On Fri, Oct 14, 2022 at 8:44 AM Jim Lux <jimlux@...> wrote:
On 10/14/22 2:25 AM, F1AMM wrote:
4nec2 is much less efficient than EZNEC. EZNEC offers, in particular, a very good antenna geometry editor. EZNEC "opens" .NEC files but
unfortunately they are only rarely compatible because 4nec2 authorizes
variables in GW cards (lines) which EZNEC does not support.
Now that EZNEC is "free", we must abandon 4nec2 as we abandoned
MMANA-GAL Basic for 4nec2.
I prefer 4nec2's interface and it works well with other engines (e.g.
NEC4.2)
It's probably more of a personal preference thing.
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Re: Off topic nanoVNA: EZNEC
How do the results of the two compare?
Zack W9SZ
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On Fri, Oct 14, 2022 at 8:44 AM Jim Lux <jimlux@...> wrote: On 10/14/22 2:25 AM, F1AMM wrote:
4nec2 is much less efficient than EZNEC. EZNEC offers, in particular, a very good antenna geometry editor. EZNEC "opens" .NEC files but
unfortunately they are only rarely compatible because 4nec2 authorizes
variables in GW cards (lines) which EZNEC does not support.
Now that EZNEC is "free", we must abandon 4nec2 as we abandoned
MMANA-GAL Basic for 4nec2.
I prefer 4nec2's interface and it works well with other engines (e.g.
NEC4.2)
It's probably more of a personal preference thing.
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Re: Off topic nanoVNA: EZNEC
Yes, although 113 members is over the 100 member limit for a basic group.
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On Oct 14, 2022, at 09:14, va3rr via groups.io <va3rr@...> wrote:
?I think this page explains the lack of membership. Spoiler $$
/static/pricing
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Windows - Yesterday it worked, today is doesn't.? Windows is like that.
W4CWZ
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On 10/13/2022 4:42 PM, Bill KD2RZW via groups.io wrote: I honestly do not have a clue what the hell I did but I figured it out? HAHA. I removed everything and started from the beginning again. I really don't like this result because I cant explain myself and this does no good to anyone who comes across this thread but I will not complain. Now I have to select the firmware to go with..
--
"The United States has become a place where entertainers and professional athletes are mistaken for
people of importance."
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Re: Off topic nanoVNA: EZNEC
On 10/14/22 2:25 AM, F1AMM wrote: 4nec2 is much less efficient than EZNEC. EZNEC offers, in particular, a very good antenna geometry editor. EZNEC "opens" .NEC files but unfortunately they are only rarely compatible because 4nec2 authorizes variables in GW cards (lines) which EZNEC does not support.
Now that EZNEC is "free", we must abandon 4nec2 as we abandoned MMANA-GAL Basic for 4nec2. I prefer 4nec2's interface and it works well with other engines (e.g. NEC4.2) It's probably more of a personal preference thing.
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Re: Off topic nanoVNA: EZNEC
I think this page explains the lack of membership. Spoiler $$ /static/pricing
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Re: Antenna tuning in field, calibration with SMA cal set followed by BNC and UHF adaptors
The S11 minimum return loss does not indicate resonance.? Common mode current can affect the value and thus the SWR and mislead you when you are not measuring at the antenna.Only J0=0 indicates resonance.??
Mike W9MDB
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On Friday, October 14, 2022 at 07:00:17 AM CDT, Donald S Brant Jr <dsbrantjr@...> wrote:
If you just need to tune an antenna "on frequency" you do not even need to calibrate your VNA; it will show the S11 return loss dip at the correct frequency; the magnitude will be wrong but it is not relevant in this case, you are only looking ofr a minimum.? I do this when tuning my loop antenna and it works fine.? At HF, the error intorduced by adding an adapter after calibration is small.?
73, Don N2VGU
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Re: Off topic nanoVNA: EZNEC
That's unfortunate. I am a subscribed member, and the general info page for this group indicates: " [email protected] (disabled because this group cannot add any more members)" and there's only 113 members... va3rr
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Re: Off topic nanoVNA: EZNEC
If has probably reached the membership limit for the group type. The only thing I can think of is to retry joining every so often in case someone drops out of the group.
DaveD
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On Oct 14, 2022, at 08:57, F1AMM <18471@...> wrote:
?
For that information, I would go to the 4NEC2 group.
** It begins badly
4NEC2 displays This Group Cannot Add Any Members
4nec2defguide is open but 2 messages in 2022 and 1 message in 2021
Your advice please
Sidenote.. I still prefer mmana ** MMna, I gave.
It does not know how to calculate an impedance on a real ground. MMna assumes a conductive ground.
--
F1AMM Fran?ois
-----Message d'origine----- De la part de Dave Daniel et de Siegfried Jackstien
14 octobre 2022 14:37
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Re: Off topic nanoVNA: EZNEC
For that information, I would go to the 4NEC2 group. ** It begins badly 4NEC2 displays This Group Cannot Add Any Members 4nec2defguide is open but 2 messages in 2022 and 1 message in 2021 Your advice please Sidenote.. I still prefer mmana ** MMna, I gave. It does not know how to calculate an impedance on a real ground. MMna assumes a conductive ground. -- F1AMM Fran?ois -----Message d'origine----- De la part de Dave Daniel et de Siegfried Jackstien 14 octobre 2022 14:37
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Re: Off topic nanoVNA: EZNEC
Sidenote.. I still prefer mmana
Easy graphical editor
Lots of functions
Free
Dg9bfc sigi
Am 14.10.2022 14:36 schrieb Dave Daniel <kc0wjn@...>:
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As I wrote earlier, I haved used EZNEC but not (yet) 4NEC2, so I can¡¯t
advise you about versions and documentation for 4NEC2. For that
information, I would go to the 4NEC2 group.
DaveD
On Oct 14, 2022, at 08:17, F1AMM <18471@...> wrote:
?
That is a superficial comparison of the two simulators. Now that you
are a member of the
ham-antennas group, you should find and read the posts in that group
from W0LEV comparing
the two simulators. Thanks for your advice.
I had started using 4nec2. I switched to EZNEC because there was a
notice that I translated into French.
The version of 4nec2 that I have is 5.9.3 Is this the correct one?
I have the documentation
NEC-2 Manual, Part III: User's Guide (nec2.doc)
It is marked WDBN 0.92
Is there any other documentation besides 4nec2.chm?
I will watch 4nec2 again. At the time I thought I was going crazy with
the cards but I got used to it.
73
--
F1AMM Fran?ois
-----Message d'origine----- De la part de Dave Daniel
vendredi 14 octobre 2022 12:26
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Re: Off topic nanoVNA: EZNEC
As I wrote earlier, I haved used EZNEC but not (yet) 4NEC2, so I can¡¯t advise you about versions and documentation for 4NEC2. For that information, I would go to the 4NEC2 group.
DaveD
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On Oct 14, 2022, at 08:17, F1AMM <18471@...> wrote:
?
That is a superficial comparison of the two simulators. Now that you are a member of the
ham-antennas group, you should find and read the posts in that group from W0LEV comparing
the two simulators.
Thanks for your advice.
I had started using 4nec2. I switched to EZNEC because there was a notice that I translated into French.
The version of 4nec2 that I have is 5.9.3 Is this the correct one?
I have the documentation
NEC-2 Manual, Part III: User's Guide (nec2.doc)
It is marked WDBN 0.92
Is there any other documentation besides 4nec2.chm?
I will watch 4nec2 again. At the time I thought I was going crazy with the cards but I got used to it.
73
--
F1AMM Fran?ois
-----Message d'origine----- De la part de Dave Daniel
vendredi 14 octobre 2022 12:26
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Re: Off topic nanoVNA: EZNEC
That is a superficial comparison of the two simulators. Now that you are a member of the
ham-antennas group, you should find and read the posts in that group from W0LEV comparing
the two simulators. Thanks for your advice. I had started using 4nec2. I switched to EZNEC because there was a notice that I translated into French. The version of 4nec2 that I have is 5.9.3 Is this the correct one? I have the documentation NEC-2 Manual, Part III: User's Guide (nec2.doc) It is marked WDBN 0.92 Is there any other documentation besides 4nec2.chm? I will watch 4nec2 again. At the time I thought I was going crazy with the cards but I got used to it. 73 -- F1AMM Fran?ois -----Message d'origine----- De la part de Dave Daniel vendredi 14 octobre 2022 12:26
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Re: Antenna tuning in field, calibration with SMA cal set followed by BNC and UHF adaptors
If you just need to tune an antenna "on frequency" you do not even need to calibrate your VNA; it will show the S11 return loss dip at the correct frequency; the magnitude will be wrong but it is not relevant in this case, you are only looking ofr a minimum. I do this when tuning my loop antenna and it works fine. At HF, the error intorduced by adding an adapter after calibration is small.
73, Don N2VGU
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Re: Off topic nanoVNA: EZNEC
That is a superficial comparison of the two simulators. Now that you are a member of the ham-antennas group, you should find and read the posts in that group from W0LEV comparing the two simulators.
The bottom line is that 4NEC2 will give ¡°better¡± results, but is much more difficult to learn.
Caveat: I¡¯ve been using Roy¡¯s EZNEC for decades but have never used 4NEC2 (I have downloaded it and plan to start learning it at some point in the future when I am ready to erect antennas on my new property).
I know Dave Eckhardt, W0LEV, pretty well, having worked in the same location as he did at StorageTek in CO and having had many personal conversations with him over the years about antennas and propagation. One should read his posts carefully. He is very knowledgeable about antennas and antenna modeling.
DaveD
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On Oct 14, 2022, at 05:25, F1AMM <18471@...> wrote:
?4nec2 is much less efficient than EZNEC. EZNEC offers, in particular, a very good antenna geometry editor. EZNEC "opens" .NEC files but unfortunately they are only rarely compatible because 4nec2 authorizes variables in GW cards (lines) which EZNEC does not support.
Now that EZNEC is "free", we must abandon 4nec2 as we abandoned MMANA-GAL Basic for 4nec2.
--
F1AMM Fran?ois
-----Message d'origine----- De la part de Joseph DiVincenzo
14 octobre 2022 11:05
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va3rr
Donald S Brant Jr