EZNEC

Are there any EZNEC users out there? Has anyone had any luck with the program?

[N3ATS]

Yeah, I play with it occasionally.

I've used MMANA-GAL also, but comparing the two, EZNEC is far more accurate. By accurate I mean what the program says vs. what I see in real life.

I had a guy model my 300 ohm LL fed 20-10 doublet for me then I tweaked it down the the way I have it built. EZNEC was spot on. It's much easier to learn once you have a basic antenna modeled and you can change aspects of it.

BTW, the antenna works excellent at 35'.

I am looking at a pair of 15 foot verticals with tophats to be placed on the roof for 40M and phased up close at 1/8 wave spacing. If I shift the phase 155 degrees, I get a pretty good radiation pattern. (As it is shown on the modeling.) The classical phased array of a pair of 1/4 wave verticals spaced 1/4 wavelength and phased at 1/4 wave shows a stronger lobe at 90 degrees from max radiation.

This array shows a stronger pattern in one direction than what I was expecting, but the broadside is lost in the squishiness of the radiation.

I love playing with that program. If you want to share files, I would love to see what you have done with your "tweaking" you are talking about. Ground definitions make a ton of difference in performance. So maybe this is what you are talking about fixing.

[N3ATS]

My soil is wet in the back 1/3 of my yard. This is due to a spring that runs underground but close to the surface. When it rains heavy a good portion of my yard is a swamp for a few days. About half of my doublet is over this wet earth.

I use medium soil for my models, though I am not learned enough to understand why different soils impact antenna performance. I figure it's a good middle of the road calculation. I understand height above ground, but not why the ground itself effects the antenna.

As far as tweaking, I meant that the guy who modeled my antenna did it just by the basic specs I gave him. I opened it up and changed length, height, feedline lengths, etc. exactly how they are here.

Here is a write-up on this antenna.

http://www.n3ats.com/?Homebrew_Stuff::3 ... ed_Doublet (http://www.n3ats.com/?Homebrew_Stuff::30-10_Meter_Ladder-Line_Fed_Doublet)

Here is the link to the EZNEC file...

http://www.n3ats.com/downloads/2010LLFD.EZ

Thank you for the file. I can email you one of mine if you like.

The doublet is a good antenna as you have it there. I have a tri band beam that covers 20-15-and 10. The lower bands become the real kick in the butt. That is where your marshy land can come in real handy.

Ground definitions mean hardly nothing to a horizontal antenna. You can change those values in the program all day and get no change in pattern or gain. (well, very little)

Vertical antennas highly rely on the ground definitions. You can get some livable gain at fairly low radiation angles with the verticals, especially if they are phased and on marshy land.

Basically, the earth is a distributed resistance that will actually eat up your signal. Horizontal antennas do better a wavelength above the ground or more. Vertical antennas need some space if they are above lossy dirt. If you happen to live on saltwater, your plant life dies, but your vertical antenna patterns thrive.

I emailed those files to you I developed. They are 40M verticals with top hats. The top hat allows us to greatly shorten the antenna height without using lossy coils. This allows the area where the maximum vertical RF currents to exist along the antenna rather than in the coil.

This phased vertical one is a 1/8 wave spacing for limited spaces. It could be placed on most home roofs. I am trying to work out the details of the phasing. If you look at the gain at 10 degrees, it is over 3 dBi.

I thought it was pretty good for forty.

[kc7jty]

EZNEC? Isn't that the term used to describe the heavy medicinal odor present after the use of the pungent smelling lubricant that's used to administer enemas?

[K1OU]

EZNEC? Isn't that the term used to describe the heavy medicinal odor present after the use of the pungent smelling lubricant that's used to administer enemas?


Bill, why do you hate antennas so much?

[rot]

EZNEC? Isn't that the term used to describe the heavy medicinal odor present after the use of the pungent smelling lubricant that's used to administer enemas?


Bill, why do you hate antennas so much?

Either that is way to funny or I am more retardeder..most retardeder..
WTF
rotFL.

[kc7jty]

EZNEC? Isn't that the term used to describe the heavy medicinal odor present after the use of the pungent smelling lubricant that's used to administer enemas?


Bill, why do you hate antennas so much?
It's not that I hate antennas, it's just that I'm obsessed with anal cavities

[kf0rt]

EZNEC? Isn't that the term used to describe the heavy medicinal odor present after the use of the pungent smelling lubricant that's used to administer enemas?


Bill, why do you hate antennas so much?
It's not that I hate antennas, it's just that I'm obsessed with anal cavities

You and KWW?

Sorry, mon... that was uncalled for. :roll:

[kc7jty]

EZNEC? Isn't that the term used to describe the heavy medicinal odor present after the use of the pungent smelling lubricant that's used to administer enemas?


Bill, why do you hate antennas so much?
It's not that I hate antennas, it's just that I'm obsessed with anal cavities

You and KWW?

Sorry, mon... that was uncalled for. :roll:
Actually it was moderator Tom I had in mind.