On Thu, 14 Oct 2004 15:33:23 -0700, Roy Lewallen
wrote:

|Chuck wrote:
| Roy Lewallen wrote in message
| ...
|
|...pirated copy of EZNEC.
|
|
| That is an absolute lie!
|
| My disk is an original - with a large, black,
| bold, italicized EZNEC at the top of its
| label - and the party from whom I acquired
| it, gave it to me with your full knowledge
| and approval. I can only assume this lie is
| an egregious and deliberate attempt on
| your part to defame. I will not discuss this
| further in public.
|
|I'll take your word for it, and apologize. You had claimed long ago that
|the program was given or sold to you, but for reasons of your own you
|would never tell me from whom. (Although I certainaly approve of such
|transfers, I never gained knowledge of whom the transfer was from.) In
|my posting of Sept. 26, 1997 on this newsgroup, I said:
|
| I don't generally give support to someone who's not a registered user,
| but in this case I guess it's necessary. (You still haven't sent me
| the name of the person who gave you the program, so I can transfer the
| ownership to you from him.)
|
|Because you never furnished that information, I assumed that you had
|acquired it illicitly.
|
|If you'll email me the name or call of the person from which you
|acquired it and the amount you paid, I'll promptly send you a full
|refund, in accordance with my guarantee. You're obviously not a
|satisfied user.
|
|
|
| I made Chuck an offer a while back, as follows: That if he has the
| Raibeam tested at a certified antenna range and the results show a
| free-space gain of at least 5.5 dBd (7.65 dBi) with simultaneous 25 dB
| or greater f/b ratio, I'll pay the test fee. This is performance less
| than he claims and less than he claims his model shows. But so far he
| hasn't taken me up on the offer.
|
|
|
| It's rather moot, now that I am no longer in
| business. However, If it's your desire to
| spend money to embarrass yourself, I
| won't argue.
|
| There were two reasons why I let your offer
| slide. First, I was unaware of any testing
| facilities in my area, and second, I was
| struggling to meet customer demand and
| could not justify spending the time to
| develop a unit for UHF, since it was my
| understanding that most testing facilities
| could not accommodate frequencies lower
| than 100 MHz or so.
|
| I've since learned that the US Army testing
| range at Fort Huachuca in Tucson, AZ is
| open to civilian testing, and they can
| accommodate frequencies as low as 50
| MHz.

Fort Huachuca is not located in Tucson, it is located at Sierra Vista,
AZ, approximately 90 miles SE of Tucson.

Some of the capabilities are listed he

http://www.epg.army.mil/Test_Beds/ATF.htm

As an aside, I have tested under the ARC range and have been to the
top of the "Red Tower" just to look around. Quite a view! I've seen
photos of an M1-A1 tank mounted on the positioner of the "Compact"
range.

Unfortunately, when I was there five years ago, a lot of the equipment
associated with the compact range appeared to be in disrepair.

I suspect that you will have a hard time getting testing done here as
security is a big issue. But I could be wrong.


|
| My wife will finish her chemotherapy and
| radiation treatments in March, and since
| she is quite ill, I cannot foresee my being
| available until after that time.
|
| Allowing say 30 days or so for me to
| prepare an antenna, I invite you to make
| the arrangements in Tucson - say April -
| May, 2005 or so - and I will be more
| than happy to join you there.
|
| Is this agreeable?
|
|No, you'll have to make the arrangements.
|
|Determine the cost of the test. I suggest that we find someone who is
|willing and we both can trust to whom I'll send the money the test will
|cost, as proof of my willingness and ability to pay the test fee if the
|antenna meets the criteria. Let me know when the test is to be done, and
|I'll come down and observe. The person who pays will have the legal
|right to make the results public. I agree in advance to do so if I pay;
|I expect you to do likewise.
|
|Roy Lewallen, W7EL

I get feedback from some of my professional customers who have the
capability to test the antennas they analyze with EZNEC. They report
very good agreement between analysis and measurement. Of course, most of
them are real pros in both modeling and measurement. Given the choice of
believing their results or Ken's and Chuck's, I go for theirs. Even
though you might not consider those folks to be "experts", I do.


Maybe there are cases when things don't play as figured? Maybe would be of
interest for software author to find out, and if there is a glichand to find
the way to accomodate it? Have you figured out how to model loading coil of
particular inductance and physical size to reflect the real current drop across
it?
Experts said one time that she's flat.

But by all means, let's look at the test results -- unless you believe
that "critical coupling" results in radiation that conventional test
ranges can't detect but hams can. . .

Roy Lewallen, W7EL


Here we go again, W8JI snotty style?
I just mentioned what K7GCO found, in hope that it might shine some light at
the subject and arouse some curiosity about disagreement. If it is
inconvenient, than I am sorry to butt in here. I have no intentions to get
engaged in ****ing contest. Right now I am too busy with new ocean front QTH
next to 170 acre Rhombic antenna farm, DR1 design and business that brings
livelihood. When I get more time, I will get back to work on antennas, setup
test range (across salt water bay) and get into paper models vs. real ones.

Peace!

Yuri, K3BU.us

Yuri Blanarovich wrote:

Maybe there are cases when things don't play as figured? Maybe would be of
interest for software author to find out, and if there is a glichand to find
the way to accomodate it? Have you figured out how to model loading coil of
particular inductance and physical size to reflect the real current drop across
it?
Experts said one time that she's flat.

EZNEC v. 4.0 has a convenient helix creation feature, which allows the
user to quickly make a wire model of an inductor. An inductor modeled in
this way will show a current distribution very close to that of a real
inductor. There are two cautions, however. One is that EZNEC programs
prior to v. 4.0.7 had a bug that would create incorrectly sized wire
(when creating a helix or loop) if wire diameter was specified as AWG
rather than numerical diameter. So be sure to update your program to the
latest version by downloading and installing the latest update from
http://eznec.com/ez40updates. (You've said you don't read the manual, so
you probably aren't aware of these free updates.) The second caution is
that turns should ideally be spaced at least several wire diameters
apart. I have, however, seen good results with spacings down to one wire
diameter. At that spacing, though, EZNEC will overestimate the Q
somewhat (that is, underestimate the loss) because it doesn't account
for proximity effect.

. . .

Roy Lewallen, W7EL

"Roy Lewallen" wrote in message
...
Yuri Blanarovich wrote:

Ken, K7GCO got bunch of RAIbeams and put them up, wrote glowing review
for 73
Mag. He was impressed with the performance and wanted to figure out why
is it
so. He very carefully inserted dimensions into EZNEC model and could not
get
agreement. He had to go down to 48. 5 MHz in EZNEC to obtain similar
pattern
and parameters as real antenna resonant at 51.25 MHz.

So, maybe modeling doesn't "see" the dual driven elements and critical
coupling
well? It is amusing to see the "experts" defending unmistakability of
software
(loading coil case etc.)

I'm sure you're glad, as I am, that Chuck has finally accepted my offer
and agreed to have a real, professional test done, after something like
8 years.

Where is this "acceptance" stated ?

Chuck made a suggestion and then you made
a counter suggestion the last time I read the newsgroup !
I think it is to early for you Roy to be "amused" at the technical ability
of
other hams or experimenters in the hobby. Could you start off being humble
regarding efforts of other amateurs ?
Art





The results of the test should put to rest any speculation
about this issue. I'm looking forward to the test and seeing the test
results.

I get feedback from some of my professional customers who have the
capability to test the antennas they analyze with EZNEC. They report
very good agreement between analysis and measurement. Of course, most of
them are real pros in both modeling and measurement. Given the choice of
believing their results or Ken's and Chuck's, I go for theirs. Even
though you might not consider those folks to be "experts", I do.

But by all means, let's look at the test results -- unless you believe
that "critical coupling" results in radiation that conventional test
ranges can't detect but hams can. . .

Roy Lewallen, W7EL

On Thu, 14 Oct 2004 14:56:15 -0700, "Chuck"
wrote:

the onus is on you
to provide something

Hi Chuck,

Like I said, this has been a hoot.

73's
Richard Clark, KB7QHC

On 15 Oct 2004 01:19:49 GMT, oUsama (Yuri Blanarovich)
wrote:

Have you figured out how to model loading coil of
particular inductance and physical size to reflect the real current drop across
it?

Hi Yuri,

From Roy's description, you published at your web site how to do this
nearly a year ago. Have you lost that page?

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On 15 Oct 2004 01:19:49 GMT, oUsama (Yuri Blanarovich)
wrote:


Have you figured out how to model loading coil of
particular inductance and physical size to reflect the real current drop across
it?


Hi Yuri,

From Roy's description, you published at your web site how to do this
nearly a year ago. Have you lost that page?

73's
Richard Clark, KB7QHC

What is a "current drop?"
73,
Tom Donaly, KA6RUH

Yuri Blanarovich, K3BU wrote:
"Have you figured out how to model loading coil of particular
inductance and physical size to reflect the real current drop across
it?"

Current drop across a coil is E/Z where Z is complex. If a reflection is
involved in the antenna, there are multiple Es involved, perhaps.

Growing or shrinking current through a coil, generates a voltage which
opposes current in the coil. Because of its opposing direction it is
called "counter emf". The change in current in the coil generates the
counter emf. A steady d-c current in a coil generates no emf.

A given length of wire has much greater counter emf when coiled than
when stretched out straight. We say it has more "inductance". It`s
because fields from close-wound turns intercouple. With 3 turns
closewound in a coil, 3 times the lines of force cut 3 turns, so 9 times
the counter emf is generated. As a first approximation, the inductance
varies as the square of the number of turns.

Opposition of counter emf in a coil delays the rise of current in a coil
from the phase of an a-c voltage. In a perfect coil with no resistance,
the delay is 90-degrees or 1/4-cycle. Resistance, useful or useless,
reducees the current delay. Due only to the L/R ratio, the phase delay
imposed by a coil can vary from 90-degrees down to zero.

I did a web search on "r.r.a.a" which produced 590 hits. One of these
was something posted by Roy Lewallen entitled "Inductor Operation". Roy
had measured phase delay in a loading coil. If I understood Roy, he
found no phase delay in an antenna loading coil.

In my opinion, he should find delay even in a coil feeding a dummy load,
especially if the coil is large as compared with the dummy load.

Best regards, Richard Harrison, KB5WZI

Richard Harrison wrote:

Yuri Blanarovich, K3BU wrote:
"Have you figured out how to model loading coil of particular
inductance and physical size to reflect the real current drop across
it?"

Current drop across a coil is E/Z where Z is complex. If a reflection is
involved in the antenna, there are multiple Es involved, perhaps.

Growing or shrinking current through a coil, generates a voltage which
opposes current in the coil. Because of its opposing direction it is
called "counter emf". The change in current in the coil generates the
counter emf. A steady d-c current in a coil generates no emf.

A given length of wire has much greater counter emf when coiled than
when stretched out straight. We say it has more "inductance". It`s
because fields from close-wound turns intercouple. With 3 turns
closewound in a coil, 3 times the lines of force cut 3 turns, so 9 times
the counter emf is generated. As a first approximation, the inductance
varies as the square of the number of turns.

Opposition of counter emf in a coil delays the rise of current in a coil
from the phase of an a-c voltage. In a perfect coil with no resistance,
the delay is 90-degrees or 1/4-cycle. Resistance, useful or useless,
reducees the current delay. Due only to the L/R ratio, the phase delay
imposed by a coil can vary from 90-degrees down to zero.

I did a web search on "r.r.a.a" which produced 590 hits. One of these
was something posted by Roy Lewallen entitled "Inductor Operation". Roy
had measured phase delay in a loading coil. If I understood Roy, he
found no phase delay in an antenna loading coil.

In my opinion, he should find delay even in a coil feeding a dummy load,
especially if the coil is large as compared with the dummy load.

Best regards, Richard Harrison, KB5WZI

It might be profitable for you to actually try the measurement. Like
Roy, I also find no delay *across* a physically small coil. The coil
does cause a delay between current and voltage, and as theory would
indicate, that delay (and V/I phase relationship) appears everywhere in
the series circuit, rather than locally across the coil. But, as I
believe Reg and others have suggested previously, as the coil begins to
take on dimensions that are a larger faction of a wavelength,
propagation delays begin to produce additional effects, manifested in
particular by the standing wave profile. In physically small,
inductively large coils, I can find no propagation delay. This is
consistent with the report on W8JI's web page. However I think it's
reasonable to say that as the coil starts to become physically large, it
begins to produce observable delays. These delays appear to be greater
than one would expect for a straight conductor of the same length.
Perhaps someone here can explain why that might be, but I am as yet
unable to. I suspect that it's because as the coupling between turns is
reduced, the coil begins to look less like an inductor, and more like a
compact length of transmission line arranged in the shape of a helix.

73,

Jim AC6XG

Jim Kelley wrote:
"The coil does cause a delay between current and voltage, and as theory
would indicate that delay (and V/I phase relationswhip) appears
everywhere in the series circuit."

As an example, place a perfect coil and a perfect resistor in a series
combination. The voltage drop across the resistor is exactly in-phase
with the current throuigh the resistor. It is independent of the phase
of the circuit current. The voltage drop across the coil precedes the
current through the coil by 90-degrees.

The phase of current in the series circuit with respect to the voltage
applied to the circuit is determined with vector math.

Best regards, Richard Harrison, KB5WZI