Re: NEC-LIST:Loading parasitic elements

Tom:

There are several books and many papers and articles that cover modeling
Yagi antennas. If you haven't read any, it's a good way to start and make
your NEC experience more productive.

One book by L.B. Cebik on antenna modeling looks especially good. You can
actually download the chapter on Yagis from the website.

Go to www.nittany-scientific.com and click on Books. Then, at the bottom of
the page, you'll see a way to view Chapter 18 or download it. Cebik's four
articles on antenna modeling in QST magazine are highly recommended. (QST
for Nov. 2000 through February 2001). They are on the ARRL website at
www.arrl.org but you may have to be an ARRL member to download them.

By the way, you don't want to stick a load in the parasitic elements - just
model them the way they really are. When you say that the NEC results don't
agree with your measurements, you really ought to be more detailed - what
did you measure and how - what did you model and how (sample of your NEC
deck and output results).

Regards,

Jacob Z. Schanker, P.E.
65 Crandon Way
Rochester, NY 14618
Phone: 585 442 3909
Fax: 585 442 2182
j.schanker_at_ieee.org
----- Original Message -----
From: "Tim Brown" <t.brown_at_eim.surrey.ac.uk>
To: <nec-list_at_gweep.ca>
Sent: Friday, July 05, 2002 2:38 PM
Subject: NEC-LIST:Loading parasitic elements

| Dear NEC List,
|
| Hi I'm a newcomer so apologies if something like this has already been
| covered in the past. I've been doing NEC simulations with parasitic
| elements, for example a half wavelength dipole with a parasitic one close
| to it (say 0.1 lambda). I apply a voltage source to the driven antenna as
| one would do and leave the other as it is, although I could apply a 50 ohm
| load but I can't see this working since it absorbs much of the current,
| which it shouldn't do. The results NEC gives are very much in
| contradiction with measurements I have done so was wondering if anyone has
| been able to find ways of overcoming the loading of parasitic
| elements. Or, on the other hand is it at all possible? Thanks,
| Tim.
| --
| The NEC-List mailing list <nec-list_at_gweep.ca>
| http://www.gweep.ca/mailman/listinfo.cgi/nec-list
|

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