A question for RFRY regarding NEC software

[radio8z]

Hi Rich, and all,

I was very impressed with the agreement of your simulated field strength measurements vs. those measured as posted by Keith Hamilton regarding his Rangemaster. I thought the numbers were close enough that it validated your calculations and his measurements.

I visited the NEC site and was presented with too many choices of software, to the point that I gave up.

Would you please give some guidance as to which NEC software I should download?

Thanks,

Neil

 

[pbolyn]

Neil,

You can get started by downloading the EZNEC 4.0 demo program from http://www.eznec.com/demoinfo.htm It has some limitations, but it will give you good results for a simple base-loaded part 15 vertical. If you like it you can pay and download the full version. Maybe Rich has some other sources.

Phil B

> Hi Rich, and all,
>
> I was very impressed with the agreement of your simulated
> field strength measurements vs. those measured as posted by
> Keith Hamilton regarding his Rangemaster. I thought the
> numbers were close enough that it validated your
> calculations and his measurements.
>
> I visited the NEC site and was presented with too many
> choices of software, to the point that I gave up.
>
> Would you please give some guidance as to which NEC software
> I should download?
>
> Thanks,
>
> Neil
>
<P ID="signature">______________
Phil B
</P>

 

[radio8z]

> Neil,
>
> You can get started by downloading the EZNEC 4.0 demo
> program from http://www.eznec.com/demoinfo.htm It has some
> limitations, but it will give you good results for a simple
> base-loaded part 15 vertical. If you like it you can pay and
> download the full version. Maybe Rich has some other
> sources.
>
> Phil B
Phil,

Thanks for the information. When I get a chance I will check this out.

Neil

 

[rfry]

> Would you please give some guidance as to which
> NEC software I should download?
____________

All versions of NEC software use some iteration of the same basic calculating engines, most of which are in the public domain. The differences are in their software interfaces, I/O formats, screen designs etc. EZNEC is maybe a good starting point, although others have more features and better graphics output.

Using NEC correctly needs some study, strict observance of its "rules," and a background in antenna theory. Incorrect setup of a NEC model produces nice looking output data that is completely wrong.

//

 

[radio8z]

Thanks

Rich,

Thanks for the guidance.

You wrote:

"> Using NEC correctly needs some study, strict observance of
> its "rules," and a background in antenna theory. Incorrect
> setup of a NEC model produces nice looking output data that
> is completely wrong.
>"

This is why it is good to have some physical measurements to check the simulations. I use Electronic Workbench frequently, but it took a while before I had confidence in the results. I also found its limitations. The simulations looked good, but the bench results did not agree, especially at RF.

Neil

 

[rfry]

Re: Thanks

> >Using NEC correctly needs some study, strict observance
> of
> > its "rules," and a background in antenna theory.
> Incorrect
> > setup of a NEC model produces nice looking output data
> that
> > is completely wrong.
> >"
>
> This is why it is good to have some physical measurements to
> check the simulations.
______________

NEC can give amazingly close results to measured data accumulated for decades in the broadcast industry. I have compared NEC models I did for 90, 180 and 195 degree MW verticals to FCC standard efficiencies for them, and to the gains shown for them in antenna engineering textbooks (Kraus, Terman et al). The NEC data matches them within less than a percentage point of field strength, and would be an exact match if I refined the models a bit more.

//