John Smith wrote:

Cecil:

Here is the crux of my fruitless attempts to use EZNEC...
With EZNEC, when I plug in the value of my gamma rod and -jxr, along with
all other elements, EZNEC spits out an error! (something about too short a
loop seems to bother EZNEC, but this short loop IS working!)
However, I am looking at a REAL and functional antenna which appears to be
well matched and receiving well.
So, I end up throwing up my hands and just using the antenna and going about
with the "cut-and-try" method! (probably just my inability to use the app)

Or maybe not. EZNEC apparently won't properly model
the Lattin antenna. www.g3ycc.karoo.net/lattin.htm

Somewhere I have a .ez file that shows 20 dBi omni-
directional gain from an inverted-L antenna. Now that's
what you need. :-)

And you taught me something today. I didn't know one
can attach .ez files to a newsgroup posting.
--
73, Cecil http://www.qsl.net/w5dxp

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Cecil Moore wrote:

Or maybe not. EZNEC apparently won't properly model
the Lattin antenna. www.g3ycc.karoo.net/lattin.htm
. . .

I took a look at it, and sure enough, it can't. The antenna is
constructed from tubular 300 ohm twinlead, and EZNEC has no way to
account for the dielectric between conductors. In that antenna, it looks
like the velocity factor of the differential mode field between
conductors would be important to its operation, and without the ability
to model the dielectric between conductors, EZNEC wouldn't get the
velocity factor right.

When I see a claim that EZNEC can't model a particular antenna, I often
find that the reason for the claim is that the antenna's inventor or
seller has dreamed up some magical property to explain the impossibly
good performance he's claiming for the antenna. EZNEC models the antenna
just fine, it just doesn't model the magical property and validate the
claims -- that is, it shows how the antenna really works, not how the
huckster claims it works. But there are, certainly, some kinds of
antennas which it really can't model properly for one reason or another.
The Lattin antenna is one of those.

Roy Lewallen, W7EL

On Thu, 07 Apr 2005 10:05:04 -0700, Roy Lewallen
wrote:

But there are, certainly, some kinds of
antennas which it really can't model properly for one reason or another.
The Lattin antenna is one of those.

Hi Roy,

Having model dozens of variations of this antenna, as well as what was
described in the patent - I cannot think of one reason why it should
work except through haphazard luck. Certainly the offered "theories"
are no more credible than those for other antennas that defy modeling
such as the single or double bazooka, the eh, the cfa.

This antenna has many reports of its confounding expectation and then
in the same breath those who are confounded expressing their sincere
belief it works. It's one of those situations where the builder can't
get it to sing, but has a brother-in-law who knows this fellow who
lives next door to one who can, but who took it down ten years ago
because it was so hard to tune.

Perhaps you could widen your customer base if you added a "belief
scale" to the available control settings for EZNEC. It could range
from "agnostic" to "I believe in miracles."

73's
Richard Clark, KB7QHC