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On Nov 10, 11:16 pm, "Jerry Martes" wrote:
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hello;

until now I have used 4nec2 to model cubical quad type antennas. Now,
I have been asked to design an end-fire helical antenna with a
groundplane. I've figured out how to model a ground plane using 'fast
ground' and radials and stuff, but I'm having trouble with the
excitation. I guess I don't really know the particulars of it. When
I was designing cubical quads, I'd just slap it on the loop and be
done with it; I assumed that nec was sort of making an open circuit in
the loop and connecting a transmission line to it--that type of
thing. How do I tell nec that I want one end of the conductors
connected to the ground plane, and the other to the helix? Does it
know somehow?

Any more tips on modeling helical antennas with ground planes in
4nec2?

Thanks alot for your help;
Sean.

Hi Sean

If you are willing to let me learn along with you, I'd like to try
modeling
your helix using EZNEC. I think I can model a helix over an infinite
ground plane using EZNEC.
I am interested in learning to use 4nec2but am a real poor learner,
especially when I dont bother to read the instructions.

Jerry KD6JDJ

this sounds good.

you said you can model a helix over an infinite ground plane in
eznec? What are you powering it with? a coax? if so, you have one
conductor connected to the helix, and the other is where? this is the
source of my confusion, i guess.

sean.


Hi Sean

I can make a helix with EZNEC very easily. I located the ground end of
the helix slightly away from ground. A short wire from the ground end of
the helix to ground becomes the feed.
Contact me at my E-mail and we can try your dimensions.
I'd sure like to learn to maneuver in 4nec2. This may be a motivator so
I can get more familiar with 4nec2