If you are thinking phased verticals, yes this is doable in a variety of
ways. I hope you are not thinking two element Yagi. A two element 80
meter Yagi is a very large undertaking mechanically. Take a look at the
Optibeam OB2-80+ for an example.
http://www.optibeam.de/
Unless you have a lot of time on your hands and are very good at
mechanical design, you will probably be better off just buying this.
Don't forget about the 100 ft plus tower you will need to effectively
use this. 150 ft would work much better.
I don't want to discourage you from learning the NEC programs. They are
very useful, and yes they can model this antenna. There are two free
programs and a demo available. These programs run NEC2, except
MMANA-GAL runs a modified version of MININEC.
You can get the free demo version of EZNEC which is fully functional
except for limiting you to 20 segments, which will be good only for
simple antennas. Download the EZNEC 4.0 Demo program.
http://www.eznec.com/
Be sure and consult the EZNEC help file for answers to your questions.
Another option is MMANA-GAL. It is also free.
http://mmhamsoft.amateur-radio.ca/
A full blown version of NEC2 including an optimizer. 4NEC2 (free)
http://home.ict.nl/%7Earivoors/Home.htm
Another site with reference info on the same program:
http://www.ok1rr.com/view.php?cisloclanku=2006022401
A disadvantage of this program is that there is no English version
manual, there is a German version. If you are just starting to learn
NEC then this one would not be the best choice because of that.
I use EZNEC version 4 mostly. It does a few things that you can't do
with the other programs, although it does not have an optimizer like
4NEC2. EZNEC has several ground choices and is easier to use for
vertical antennas because it allows the use of a Mininec ground,
although you have to manually insert the losses.
Jerry, K4SAV
StellarCAT wrote:
>I know there is an antenna group as well - I will post there
>also but I believe some here are able to respond to my
>questions...
>
>I was wondering - is there anything that prevents one from
>designing an antenna for 80 with hi-Q coils such that the
>resonant frequency is around 3.52 - 4% (to be used as a
>reflector at the low end)... and then have a shunt capacitor (if
>needed vacuum variable) at the feed point to "tune" it up the
>band to as high as 3.9 + 4% (to be used as a director at the top
>end)? Obviously the Q of the cap is very high and it should (?)
>be able to handle the high currents I would think...
>
>thoughts?
>
>The idea is to have 2 elements with motor driven caps -
>basically a "steppir" for 80 that would follow one around AND
>allow "instant" direction change.
>
>Will EZNEC model this very well (the lower cost $80 version)? It
>would consist of both lumped inductance as well capacitance.
>
>gary
>K9RX
>
>
>
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