4nec2 hidden variables.
 

On Sun, 14 Aug 2011 23:27:33 +0200, Helmut Wabnig [email protected] ---
-.dotat wrote:

Want one?

Not really, since I can't do anything to fix the alleged problem.

4nec2 from time to time destroys it's saved antenna files.
Just lost another 2 hours of work.

Nobody does backups until after they have lost data. I've been using
4NEC2 for at least 7 years and have never lost a file. Well, I have
accidentally overwritten a file, but that was my fault. When I tinker
with antennas, I save multiple versions of the same design with the
version number appended as in file001.nec. This way, if I make a
horrible mistake, I can go back to a previous version and try again.

Now I understand why it's free.
Can't charge money for bugs.

Well, that why we have alternatives to 4NEC2 and why I don't charge
for my free advice:
http://www.smeter.net/antennas/mmana.php
http://www.eznec.com
http://www.nittany-scientific.com
http://www.hamradiosecrets.com/antenna-design-software.html
http://www.si-list.net/swindex.html (old but still useful)


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

4nec2 hidden variables.
 

On Sun, 14 Aug 2011 19:46:34 -0700, Jeff Liebermann
wrote:

On Sun, 14 Aug 2011 23:27:33 +0200, Helmut Wabnig [email protected] ---
-.dotat wrote:

Want one?

Not really, since I can't do anything to fix the alleged problem.

4nec2 from time to time destroys it's saved antenna files.
Just lost another 2 hours of work.

Nobody does backups until after they have lost data. I've been using
4NEC2 for at least 7 years and have never lost a file. Well, I have
accidentally overwritten a file, but that was my fault. When I tinker
with antennas, I save multiple versions of the same design with the
version number appended as in file001.nec. This way, if I make a
horrible mistake, I can go back to a previous version and try again.

Now I understand why it's free.
Can't charge money for bugs.

Well, that why we have alternatives to 4NEC2 and why I don't charge
for my free advice:
http://www.smeter.net/antennas/mmana.php
http://www.eznec.com
http://www.nittany-scientific.com
http://www.hamradiosecrets.com/antenna-design-software.html
http://www.si-list.net/swindex.html (old but still useful)


###########"Backup, you say it". ###########

When optimizing for F/B also 4nec2 results in a too short driven
element, same as YAGICAD, they obviously use the same formula,
(a long two-liner) from literature.
I actually built antennas following that prescription,
and they do not work without additional corrections,
e.g. a very long hair-pin match.



Imagine a 3 element 2 meter yagi,

|
| |
| | |
| | |
| | |
| | |
| | |
| |
|

Something is wrong here with the capacitive driven element.
Now I am having a hard time, because I want to find out in
what differs a gain optimized vs a F/B optimized antenna
and it is questionable whether that can be done with software.
Have not tried other programs yet.

http://imageshack.us/photo/my-images/837/snc14096a.jpg/

The Front to Back ratio is very frequency dependent
http://imageshack.us/photo/my-images/220/fbratio.jpg/
(Without the hair pin match)
http://img5.imageshack.us/img5/3479/snc14112hairpin.jpg

Therefore I put the driver on a slider
http://img841.imageshack.us/img841/8...14097small.jpg
which allows to adjust the working frequency of the antenna
over a 10 MHz range on 2 meters. Adjust for minimum reception
from the back and the antenna is optimized for that frequency.

Now I want to collect a list of recipes which allow to build the
antenna without having to tweak it on the antenna analyzer.

A similar design once was offered by DIAMOND MAY1000
http://www.rfparts.com/diamond/MAY1000.html
Look at the frequency chart
http://www.rfparts.com/diamond/pdfdo...dj%20Chart.pdf
With that antenna one could adjust the element lengths *and*
the distance between the elements, which is crucial for the F/B ratio.

A Yagi with fixed element positions can only be used for 1 frequency
(within a very small range) and therefore may be impractical
in many situations. The CEBIK tape measure antenna with their
water-pipe construction could be easily modified with a moveable
center element.
http://www.g6hoq.com/documents/2m%20...structions.pdf
Above line as shortlink: http://tinyurl.com/3m5p5nq


w.

4nec2 hidden variables.
 

Helmut,

your ranting and raving about 4Nec2 seem entirely unfair, the 'bugs'
that you complain do not seem to be bugs at all, just the way the
program works; which is not to your liking.

Placing sources requires that you click whilst away from the wire and
then drag the source onto the wire. This is not a bug, just the way that
the author chose to do it.

In many years of using 4Nec2 I have never had it loose a file, so I can
only assume that there is some sort of problem at your end.

Yes, it would be nice to have a 'New' button, but again not a bug, just
the way that the program works. If this minor inconvenience pains you
that much ask the author to add one.

Regarding optimization the phrase 'garbage in garbage out' springs to
mind. Optimizers are just that, optimizers, they WILL NOT take a rubbish
design and turn it into the perfect antenna.

Optimizers rely on finding minima (or maxima) in the set of parameters
that you supply, so unless you are close to a good design it is very
likely that they will 'get stuck' in a local minima and then home in on
something other than an optimum design. So you have to have a good
design to start with and also not try to optimize to a set of
unrealistic goals. This applies TO ALL optimizers not just 4Nec2.

Regards
Jeff

4nec2 hidden variables.
 

So, the software is not perfect... but some of your complaints are are
result of your own ignorance of modelling, NEC and 4NEC2.

Helmut, your vitrolic rant doesn't strike a chord with me.

Right now, Arie has some personal issues that we would all rather not have
in our lives, and yet he is finding time for some problem resolution.

Arie, I dips me lid (that means "hats off" in Oz).

Owen

4nec2 hidden variables.
 

On Mon, 15 Aug 2011 09:59:00 +0100, Jeff wrote:


Placing sources requires that you click whilst away from the wire and
then drag the source onto the wire. This is not a bug, just the way that
the author chose to do it.


Show me the place in the manual or help where that is described.
Normally we do drag and drop, but here we must drag, drop & move.
Made me crazy, but no longer now since I know it,
and I will keep it a secret and not tell anyone.


In many years of using 4Nec2 I have never had it loose a file, so I can
only assume that there is some sort of problem at your end.

Of course, it's free, so it must be my fault.
From the little programming I did, I know it's 99% user interface
and 1% programming the more interesting part.


Yes, it would be nice to have a 'New' button, but again not a bug, just
the way that the program works. If this minor inconvenience pains you
that much ask the author to add one.


No, no, it's free.

Regarding optimization the phrase 'garbage in garbage out' springs to
mind. Optimizers are just that, optimizers, they WILL NOT take a rubbish
design and turn it into the perfect antenna.

Optimizers rely on finding minima (or maxima) in the set of parameters
that you supply, so unless you are close to a good design it is very
likely that they will 'get stuck' in a local minima and then home in on
something other than an optimum design. So you have to have a good
design to start with and also not try to optimize to a set of
unrealistic goals. This applies TO ALL optimizers not just 4Nec2.

Regards
Jeff

You are right, that's how it is.

w.

4nec2 hidden variables.
 

On 15/08/2011 13:50, Helmut Wabnig wrote:
On Mon, 15 Aug 2011 09:59:00 +0100, wrote:


Placing sources requires that you click whilst away from the wire and
then drag the source onto the wire. This is not a bug, just the way that
the author chose to do it.


Show me the place in the manual or help where that is described.
Normally we do drag and drop, but here we must .
Made me crazy, but no longer now since I know it,
and I will keep it a secret and not tell anyone.


Firstly it is not 'drag, drop& move'; it is click, drag & drop! Try
reading the Help a little more closely, you will find that it says:

"The next thing to do is add a voltage-source. While still in Add-mode,
click the 'Source button' (right of the 'Wire button'). Next click and
hold down your left mouse-button somewhere in the picture-box. At the
current mouse-pointer position a new source-object is displayed. Drag
the source-object to the middle of the second wire, just between the two
lower wires-ends of the feedline and release the mouse-button. When
properly positioned a new source is now added."




In many years of using 4Nec2 I have never had it loose a file, so I can
only assume that there is some sort of problem at your end.

Of course, it's free, so it must be my fault.
From the little programming I did, I know it's 99% user interface
and 1% programming the more interesting part.

No one else reports this problem so draw your own conclusions!!! The
fact that it is free has no bearing on it.



Yes, it would be nice to have a 'New' button, but again not a bug, just
the way that the program works. If this minor inconvenience pains you
that much ask the author to add one.


No, no, it's free.

Have you contacted the author and asked for this feature? No? I thought
not. Again the fact that it is free has no bearing.




Regarding optimization the phrase 'garbage in garbage out' springs to
mind. Optimizers are just that, optimizers, they WILL NOT take a rubbish
design and turn it into the perfect antenna.

Optimizers rely on finding minima (or maxima) in the set of parameters
that you supply, so unless you are close to a good design it is very
likely that they will 'get stuck' in a local minima and then home in on
something other than an optimum design. So you have to have a good
design to start with and also not try to optimize to a set of
unrealistic goals. This applies TO ALL optimizers not just 4Nec2.

Regards
Jeff

You are right, that's how it is.

Yes that is the way it is with ALL optimizers, not just 4nec2; gigo.

No one is forcing you to use 4nec2, however, no one else seems to be
having the problems that you claim are 'bugs', perhaps you should have
more patience, read the help more closely, and not be so quick to criticize.

Jeff

4nec2 hidden variables.
 

On Mon, 15 Aug 2011 14:20:28 +0100, Jeff wrote:

On 15/08/2011 13:50, Helmut Wabnig wrote:
On Mon, 15 Aug 2011 09:59:00 +0100, wrote:


Placing sources requires that you click whilst away from the wire and
then drag the source onto the wire. This is not a bug, just the way that
the author chose to do it.


Show me the place in the manual or help where that is described.
Normally we do drag and drop, but here we must .
Made me crazy, but no longer now since I know it,
and I will keep it a secret and not tell anyone.


Firstly it is not 'drag, drop& move'; it is click, drag & drop! Try
reading the Help a little more closely, you will find that it says:

"The next thing to do is add a voltage-source. While still in Add-mode,
click the 'Source button' (right of the 'Wire button'). Next click and
hold down your left mouse-button somewhere in the picture-box. At the
current mouse-pointer position a new source-object is displayed. Drag
the source-object to the middle of the second wire, just between the two
lower wires-ends of the feedline and release the mouse-button. When
properly positioned a new source is now added."

It does not work as described, period.

w.

4nec2 hidden variables.
 

On Mon, 15 Aug 2011 14:20:28 +0100, Jeff wrote:

On 15/08/2011 13:50, Helmut Wabnig wrote:
On Mon, 15 Aug 2011 09:59:00 +0100, wrote:


Placing sources requires that you click whilst away from the wire and
then drag the source onto the wire. This is not a bug, just the way that
the author chose to do it.


Show me the place in the manual or help where that is described.
Normally we do drag and drop, but here we must .
Made me crazy, but no longer now since I know it,
and I will keep it a secret and not tell anyone.


Firstly it is not 'drag, drop& move'; it is click, drag & drop! Try
reading the Help a little more closely, you will find that it says:

"The next thing to do is add a voltage-source. While still in Add-mode,
click the 'Source button' (right of the 'Wire button'). Next click and
hold down your left mouse-button somewhere in the picture-box. At the
current mouse-pointer position a new source-object is displayed. Drag
the source-object to the middle of the second wire, just between the two
lower wires-ends of the feedline and release the mouse-button. When
properly positioned a new source is now added."

It does not work as described, when inserting a source on a dipole
wire in the center segment, one of the first things to do in Example1.


w.

4nec2 hidden variables.
 

Firstly it is not 'drag, drop& move'; it is click, drag& drop! Try
reading the Help a little more closely, you will find that it says:

"The next thing to do is add a voltage-source. While still in Add-mode,
click the 'Source button' (right of the 'Wire button'). Next click and
hold down your left mouse-button somewhere in the picture-box. At the
current mouse-pointer position a new source-object is displayed. Drag
the source-object to the middle of the second wire, just between the two
lower wires-ends of the feedline and release the mouse-button. When
properly positioned a new source is now added."

It does not work as described, when inserting a source on a dipole
wire in the center segment, one of the first things to do in Example1.


w.


Utter Rubbish!!! It works EXACTLY as described!!!

Hold down the left mouse button, drag the source to the segment where
you wish it to be, release the button - exactly as described!!!

Jeff

4nec2 hidden variables.
 

On 8/13/2011 12:07 PM, Helmut Wabnig wrote:
Am trying to run an optimization on my 3 element yagi which I finally
got into the editor, which was difficult enough.
The optimizer says: no variables selected
but there are none to select.
Empty list field.

Oh, how I hate this.
Praise Bill Gates for his user-friendly WINDOWS
and to hell with all amateur softwares.

Nowhere in the helps and getting started they explain that.
I do not want to learn from examples, I rather work from the
basics upwards. Would anyone learn math from a calculus
formula without knowing the arabic numbers first?

Am in a baad mood tooday.


w.

Does your model have symbols defined (using the 4nec2 specific SY card?)
That's what it uses to populate the list.

Which editor are you using? If you already have a NEC input deck, it's
easiest to use the non-graphical editor.

What are you optimizing for.

Sure, you can whine about wanting better help files, but face it, Arie
is providing the product for free. If you are already proficient in
NEC, the help provided is fairly useful. If you are learning if from
scratch, yep, it's a pain.