[TowerTalk] Basic Antenna Modeling tutorial - W4RNL

[Larry Banks]

Hi Bill,

Glad that my response was useful and sorry for the delayed additional 
response.

Your first Q:  If I remember, and I was going through LB's tutorial a few 
years ago, I redid his tutorial models into the EZNEC version I had at the 
time.  I honestly can't remember if this was because his tutorial models 
didn't work, or I decided to redo them as "extra practice" with EZNEC.  At 
any rate, they all worked as I expected and I did gain experience in 
modeling his examples when I redid them into EZNEC.

Your second Q:  I quickly discovered that I needed EZNEC+ for the additional 
segments.  Modeling real-world antenna, even wire ones, need a lot of 
segments.  (See my unpublished analysis of a "real" fan dipole at the bottom 
of my web page: http://www.qsl.net/w1dyj/.  Because this complex dipole 
"wound around" my house, it has many wires.)  It also allows you to check 
the accuracy of the model, as increasing the segments by a factor of two or 
three and running the model again will tell you if you have enough segment 
granularity in your model.  I am currently designing a "simple" 40M vertical 
with radials at 10' and am up to 1109 segments to prove to myself that I 
know what I am doing...  (Modeling the source is the difficult part, and 
keeping all segments the same size is challenging.)

I also started modeling antennas many years ago with YO.  And I probably 
won't sell my programs -- I still have my college texts from 45+ years 
ago...

73 -- Larry -- W1DYJ





----- Original Message ----- 
From: "Bill Cotter" <n4lg at qx.net>
To: "Larry Banks" <larryb.w1dyj at verizon.net>
Sent: Saturday, January 25, 2014 8:25 AM
Subject: Basic Antenna Modeling tutorial - W4RNL


> Larry,
>
> Thanks for the thoughtful answers to my question about the tuutorial. I 
> have been wondering if the materials were somewhat dated since W4RNL 
> becoming a SK and the price is high for a ten year old product. It seems 
> that the use of EZnec was an afterthought with NEC being the primary focus 
> (typical in academia). I had been told that the course was dropped from 
> ARRL for these reasons.
>
> Q: How does your EZnec work with the W4RNL antenna files?
> Q: Do you see an advantage of EXnec+ over the entry level EZnec?
>
> What attracted me to the W4RNL course was the articles that LB had written 
> for QST over the years. They contained good explanations of the process, 
> and since I wasn't using NEC, miniNEC or EZnec, the code wasn't important. 
> Before considering the W4RNL series, I ordered the new book from ARRL 
> "Antenna Modeling for Beginners" and will compare the contents to the 
> W4RNL course table of contents.
>
> I have actually done antenna modeling for the past 20yrs using the K6STI 
> AO, TA and YO programs from Brian Beezley. He was one of the original 
> Naval scientists (mathematician) to work with the predecessors to NEC. His 
> modeling applications were an incredible leap forward for the average ham 
> trying to construct the best monobanders for DX'ing. Unfortunately, Brian 
> lost interest in the marketing of his tools, and stopped supporting them. 
> And, they have to run in DOS emulation mode <groan>.
>
> If you take a notion to sell your copy of the modeling courses, drop me a 
> line. I would be interested in a used copy.
>
> 73 es tnx Bill N4LG
>
>
>
>
>
> At 03:01 PM 1/24/2014, you wrote:
>>Hi Bill,
>>
>>I have both tutorials.  I bought them to "enhance" my use of EZNEC, which 
>>I have been using for quite a while.  (I now use EZNEC5+.)
>>
>>I got through about half of the first tutorial and found that, although I 
>>was learning some new and subtle stuff, it wasn't really extending my 
>>knowledge in a great way.  I still intend to finish it and the second 
>>tutorial "someday," probably when I get to the point where I need more 
>>advanced knowledge for whatever I am modeling.
>>
>>They are good - up to LB's (SK) typical level and well worth it.
>>
>>73 -- Larry -- W1DYJ
>>
>>
>>
>>
>>----- Original Message ----- From: "Bill Cotter" <n4lg at qx.net>
>>To: <towertalk at contesting.com>
>>Sent: Friday, January 24, 2014 12:07 PM
>>Subject: [TowerTalk] Basic Antenna Modeling tutorial - W4RNL
>>
>>
>>>Hi,
>>>
>>>I am interested in the L.B Cebik, W4RNL (SK) "Basic Antenna Modeling: A 
>>>Hands-On Tutorial" and the "Intermediate Antenna Modeling: A Hands-On 
>>>Tutorial". I recall seeing it carried by ARRL, but it is no longer on 
>>>their shelves.
>>>
>>>Before I make a decision to purchase, I would like to hear your thoughts 
>>>and/or experiences with this tutorial. Or, possibly alternatives. I have 
>>>purchased EZnec 5.0 and plan to use it with a tutorial.
>>>
>>>If you want to keep your comments private, please reply off-list to 
>>>n4lg at qx.net
>>>
>>>Thanks es 73 Bill N4LG
>>>