On 8/16/2011 2:25 AM, Helmut Wabnig wrote:
On Tue, 16 Aug 2011 09:48:00 +0100, wrote:


Well if you don't actually follow the instructions on the Help then what
can you expect! Don't blame the program and then say the Help is wrong
or not there! RTFM.

"click and hold down your left mouse-button somewhere in the
picture-box" then "Drag the source-object to the middle of the second wire".

Jeff
Of course you are right,
but there are thousands of (unread) help pages left.
Should I read them all?

On YOUTUBE another (not me) user said, he falls asleep
after 4 pages of help text ( the getting started stuff).
I printed the "getting started" but fell asleep after page 3.

w.


Should you read them?

Depends on if you want to make use of the program or not. for ANY
modeling program (and any drafting program, as well) there's a fairly
big first step in the learning curve.

And, because 4nec2 isn't a "drafting" or "drawing" program, it's UI
doesn't follow the more common conventions. It's designed to make
entering antennas easy for some subset of people. 4nec2 started with
just using notepad to edit the NEC input deck and a formatted editor to
edit cards.

Folks who start with EZNEC often find using raw NEC decks difficult,
because they're used to the tabular model entry of EZNEC.

Folks who start with Visio, pre version 5, find modern versions of Visio
a pain, because the UI changed to conform to PowerPoint.

Autocad is certainly not "intuitive" unless you've been using it a while.


For what it's worth, the 4nec2 help files are a whole lot better than
the documentation for NEC itself.

Beyond the details of entering the geometry and simulation conditions
(which are idiosyncratic for ALL antenna modeling programs.. no two are
alike, nor are the input file formats directly compatible, for the most
part)

There's a fair amount of "art" in effectively using the programs and
understanding the limitations inherent in the modeling technique being
used (method of moments on wires for NEC). It's not just a matter of
creating a bazillion segments and letting your processor grind away,
because there's all sorts of subtle numerical precision issues.

4nec2 (and EZNEC) both provide some amount of help in keeping you away
from egregious model errors (segment lengths that are unreasonable
relative to wavelength and/or wire diameter).

There's also well known techniques for modeling flat surfaces with
meshes that provide results that match actual measurement, even if the
model doesn't "look" quite right if you render it.

NEC is very much a power tool like a chainsaw.. you can do things that
you couldn't do with hand tools, but you can also do things that you
don't really want. It takes some practice and background knowledge to
use it effectively.


The value of purpose built modeling tools like AO is that they have a
very constrained model space tuned to a particular application, so the
program can
a) have a simple model entry (e.g. you can only do Yagi-Uda)
b) have a sophisticated objective function for optimization

NEC is a lot harder: you can enter any geometry from a simple wire to an
entire battleship with 100s of antennas.