Just one comment. I'm not using EZNEC because I don't know if it'll run
on my computer without a lot of hassle.
On 12/2/20 11:19 AM, Rick Hiller via BVARC wrote:
Hey, Jonathan,
That is exactly how you are to do it. One point though, you do not
have to specify the exact segment to place it. Just give the LOAD
window a "percentage from the end" and it will place it close enough.
However, If you do have the 500 segment version you can place it
exactly where you wish by using many segments to define the element.
Definitions and How To's --- In EZNEC, go to Help/Contents and click
on LOADS / RLC and LOADING COILS and also TRAPS.
There are good explanations of each implementation and probably more
detail than you want if you follow all of the subsequent links.
GL and 73...rick
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On Wed, Dec 2, 2020 at 10:13 AM Jonathan Guthrie via BVARC
<[email protected] <mailto:[email protected]>> wrote:
I got a question about analyzing antennas with traps and loading.
If you're familiar with the book "The Short Vertical Antenna and
Ground Radial" by Sevick, I simulated one of the antennas he wrote
about in an NEC2 system and I think I got it right, but the way
that you put traps and loading coils and such into NEC is not well
described anywhere that I could find, nor are there many examples
with simple antennas that have any loading coils. If you're not
familiar with the book, or you're interested in which antenna,
Sevick describes a 40m antenna that's right at 6 feet tall with a
cap hat on the top and a loading coil in the middle. The way I
modeled this is by having a single wire from near the ground to
the top of the antenna and then one wire for each of the eight
spreaders in the cap hat and a wire between each of the ends of
the spreader. I arranged the elements such that the coil is near
the center of one of the segments in the vertical wire and I put a
lumped inductance on that segment. It seems to work, in that I
got SWR curves that are similar to what's in the book, but is that
how you're supposed to do it?
Similarly, with a trap dipole, I just have one wire and put an
appropriate capacitor and inductor in parallel at the center of
the desired segments.
On 12/1/2020 8:35 PM, Rick Hiller via BVARC wrote:
Comments on your suggestions: Sorry for the length.
*MiniNEC, EZNEC, 4NEC2, MMANA-GA*L are all based on the NEC
computation engine. What differs is the interface to you, the
user. I prefer EZNEC but then I have been using it for about 20
years.
Cost for the Ham Radio level versions: EZNEC DEMO is free but
with severe limitations for all but very simple antennas. $99
gets you to a quite useable version. 4NEC2 is totally free.
MiniNEC is $29. MMANA-GAL is 139 Euro's, There are PRO versions
and interface add-ons from various 3rd parties for most of the
modeling engines. Just like my comment about the Nano VNA, in
that it's gonna take some time to understand its' use and even
more time to study antenna systems to understand what you are
doing and why and how -- same goes for modeling software.
But....certainly all in good fun and ham education and well worth
the journey.
*Folded dipoles a*re simply a way to get a match to 300 ohm TL.
No advantage in gain , etc. Maybe slightly quieter on
receive...maybe. TTFD is a different fish.
*Books: *ARRL Antenna Handbook is certainly the antenna
builders/users bible. You can however buy the Kindle version of
each of the separated set books, so you don't have to spend the
$60. Most of the theory is the same in these new editions
versus going back to the 70's and before. The practical side of
antennas with new materials, etc. is what gets upgraded with each
new edition. Old versions of the ARRL antenna manual can be had
for $10 typically. You can't go wrong buying any older version.
If I had to steer you to books to read to get you up to speed
about your total antenna system -- ATU, TL, tools, and grounding,
I would tell you to get the following ARRL Joel Hallas and Ward
Silver books:
The Care and Feeding of Transmission Lines -- Hallas
Understanding your Antenna Analyzer -- Hallas
ARRL Guide to Antenna Tuners -- Hallas
Grounding and Bonding for the Radio Amateur -- Silver
I'd tell you to read and understand these before jumping into a
NanoVNA, of which there is also a small book on the use of the
NanoVNA. Kindle version available for $4 or thereabouts.
Sorry for the bandwidth, but I don't agree with just buying
something just because it is suggested. There is alot to learn
in Amateur Radio and it is certainly fun to have a continual
information influx throughout the life of your Ham Radio
journey. But watching the $'s helps you buy bigger toys later on.
GL ES 73....Rick -- W5RH
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On Tue, Dec 1, 2020 at 1:16 PM KJ Anderson via BVARC
<[email protected] <mailto:[email protected]>> wrote:
* MiniNEC pro analyzer
o
http://www.blackcatsystems.com/software/mininec-antenna-analysis-modeling-software.html
<http://www.blackcatsystems.com/software/mininec-antenna-analysis-modeling-software.html>
* DX Commander
o https://www.m0mcx.co.uk/ <https://www.m0mcx.co.uk/>
* Folded dipoles (couldn’t google a site reference other
than the actual antenna form)
* EZNEC
o https://www.eznec.com/ <https://www.eznec.com/>
o There’s a free version
* ARRL Antenna Physics
o
http://www.arrl.org/shop/Antenna-Physics-An-Introduction-2nd-Edition/
<http://www.arrl.org/shop/Antenna-Physics-An-Introduction-2nd-Edition/>
o http://www.arrl.org/shop/ARRL-Antenna-Book-Boxed-Set/
<http://www.arrl.org/shop/ARRL-Antenna-Book-Boxed-Set/>
*-------------------------------------------------*
*KJ Anderson*
253-380-2636
www.linkedin.com/in/scrumnerd
<http://www.linkedin.com/in/scrumnerd>
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--
Rick Hiller
*/e-mail: [email protected] <mailto:[email protected]>/*
*/Cell: 832-474-3713/*
*/Physical: 9031 Troulon Drive/*
*/ Houston, TX 77036/*
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*/e-mail: [email protected] <mailto:[email protected]>/*
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*/ Houston, TX 77036/*
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Jonathan Guthrie
ARS KA8KPN
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