Vincent antenna
 

Yuri Blanarovich wrote:

...
To put it mildly:
The biggest crock of sheeeet yet!

bada BUm



Could you possibly lighten up on the intellectual content of your
posts--some of are "Yuri Challenged" yanno?

JS

Vincent antenna
 

Yuri Blanarovich wrote:

...
Yuri K3BU.us



Frankly, I DON'T think diversity is a good thing, any chance of
convincing you we are all idiots and you would be better off returning
to your country of birth? Well hell, just a thought ... :-D

JS

Loading Coils; was : Vincent antenna
 

Tom Donaly wrote:
In other words, you can't do it. Why don't you just say so?

In other words, I don't take stupid paths down the
primrose lane. Here's one for you: If electrons
were in the nucleus and protons orbited the nucleus,
would RF waves still propagate the same way?
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Looks like I didn't miss much by being out of town for a few days. The
same arguments and hand-waving are still raging. But I'll try to add one
constructive bit of information:

NEC calculates field interactions by means of very fundamental and very
well established electromagnetic principles. As a result, it does a very
good job of predicting currents in an inductor which is modeled as a
helix. There are some caveats as there always are with any modeling
process, particularly:

1. The spacing between the outsides of the wires in adjacent turns
should be at least one wire diameter, and ideally several. NEC does not
account for uneven distribution of current around a wire (proximity
effect). This mainly impacts effective resistance.

2. The whole model must do some radiating, although even very
inefficient radiating structures are analyzed with good accuracy. A
check of the average gain usually reveals if there's a problem with the
overall calculation. I've gotten quite good results with a model
consisting of a fairly small coil with a wire through the center
connecting the coil ends, and a source at the middle of the wire.

To the extent that the program is providing accurate results, it can be
used as a verification or refutation of measurements, and to test
whatever alternate theories one wants to propose. Cecil likes to split
currents into sets of traveling waves, which in itself is fine. However,
when all the waves are added together to produce the actual current, the
result should agree with measurement and with analysis by established
theory. This means that, again to the extent that the model calculations
are being done correctly, the solution using traveling waves should
agree with NEC modeling results.

One huge advantage of using NEC results is that they're not limited by
lumped constant, traveling wave, waveguide mode, or other approximations
which hold only over some range of conditions. Results should transition
from one to another smoothly since the same fundamental laws apply
regardless of the regime. (One additional caveat, though, when doing
analysis at extremely high frequencies: the wire circumference has to be
no more than a small fraction of a wavelength, because as mentioned
earlier the program does assume equal current distribution around the wire.)

Of course, comparison of rigorous numerical measurements or modeling
results with vague, hand-waving theories with no supporting equations or
other mathematical tools is a total waste of the reader's time, and
that's pretty much all that seems to be happening here. But if anyone is
actually seriously interested in investigating alternative theories or
analytical methods, NEC or derivative programs such as EZNEC can provide
powerful assistance in confirming or refuting them. Unless, of course,
the objective is an attempt to refute the validity of Maxwell's
equations, in which case disagreement with NEC should be expected.

Both NEC and EZNEC provide simple ways of generating a helical model.

Roy Lewallen, W7EL

Loading Coils; was : Vincent antenna
 

Gene Fuller wrote:
In that paper
he indicated various conditions for validity, such as the fact that the
coil must be near a quarter wave resonance for some of the mathematical
approximations to be valid.

What he *didn't* say is that if that same coil is cut
in half and used at the same frequency, the Z0 and VF
change.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Gene Fuller wrote:
Actually, the context has been the loading coil measured by W8JI.

Actually, W8JI himself says the coil he used is similar
to a 75m mobile loading coil.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

K7ITM wrote:
Others are welcome to ponder all that while Cecil tries to unstick
himself from his tarbaby.

It's your tarbaby, Tom, not mine. When you can tell me
what's the difference between a duck, I will tackle your
equally ridiculous questions.
--
73, Cecil http://www.w5dxp.com

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:

...
Roy Lewallen, W7EL

Oh gawd, the voice of recon' and ruin returns!

Don't question NEC/EZNEC, they are gods! Etc. ...

Why not tear 'em open, maybe if we see the equations which these
applications utilize we can make much better arguments? ... however, a
childish belief in "magic" is cute, huh?

As always,
JS

Loading Coils; was : Vincent antenna
 

Cecil Moore wrote:
Tom Donaly wrote:
In other words, you can't do it. Why don't you just say so?

In other words, I don't take stupid paths down the
primrose lane. Here's one for you: If electrons
were in the nucleus and protons orbited the nucleus,
would RF waves still propagate the same way?

Why can't I stick photographic film between the windings in a large coil
in HF range and get clouding of the film--apparently these photons are
"different" and don't react with the emulsion?

Sorry, I have a religious belief in EM radiation which does NOT involve
photons ... :-(

Now don't throw stones, I am just "reaching",
JS

Loading Coils; was : Vincent antenna
 

Roy Lewallen wrote:
But if anyone is
actually seriously interested in investigating alternative theories or
analytical methods, NEC or derivative programs such as EZNEC can provide
powerful assistance in confirming or refuting them.

Here is an email response from Roy, W7EL, when I used
EZNEC to disprove his invalid coil current measurements.
He apparently didn't like the EZNEC results from this file:

http://www.w5dxp.ez/coil512.EZ

Roy Lewallen wrote on May 12, 2007:
I resent your trying to use EZNEC support as a surreptitious
way to continue pushing your junk science on me. If you send
me one more non-support related email, I'll put you on my spam
list so your messages won't even make it to my ISP and I won't
have to waste any more of my time on you. That'll mean no more
EZNEC support, and I'll refund your EZNEC purchase price. So go
ahead, send me one more non-support email and make an easy $149.00.

Roy previously posted my private email without my permission
so turn about is fair play.
--
73, Cecil http://www.w5dxp.com