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-   -   Current in antenna loading coils controversy (https://www.radiobanter.com/antenna/670-current-antenna-loading-coils-controversy.html)

Yuri Blanarovich November 12th 03 03:15 AM


A design which 'exceeds' specified performance is as poor as one which
'under exceeds'.

Significant deviations in either direction are sure indications of poor
engineering education and incompetence.

Both deviations are equally expensive and wasteful in terms of time,
materials and labour.



Now that is some "wisdom" coming out of FGQ think tank :-)
All the briliant engineers and inventors? Shame on you!
You come up with better and cheaper solution, you are incompetent!
(must be union mentality)

BUm

Roy Lewallen November 12th 03 03:26 AM

Ok,

For anyone who cares, the magnitude of the current out of the inductor
in the later test measured 5.4% less than the current in. No phase shift
was discernible. An analytical person could build on this information to
investigate the properties of longer inductors placed elsewhere in the
antenna.

Thank you for the comments, Cecil, Yuri, Richards, Art, and others. I've
learned a good lesson from this -- that this isn't an appropriate forum
or appropriate audience for the sort of quantitative analysis and
reasoning I'm familiar and comfortable with. And that the considerable
time and effort required to make careful measurements is really of very
little benefit -- certainly not anywhere near enough to justify it.

With a great sigh of relief from everyone, I'm sure, I'll now turn this
thread back over to Yuri, Cecil, et al.

My apologies to everyone for taking up so much bandwidth.

73,
Roy Lewallen, W7EL

Yuri Blanarovich wrote:
Would anyone care to comment before I post the measurement results? And,
Yuri, please correct me if I've misinterpreted your theory.

Roy Lewallen, W7EL




It is not my theory. My argument with W8JI and his followers: is the current in
typical loading coil in quarter wave radiator same at both ends or does it drop
with distance from the feedpoint. I have made temperature observations, W9UCW
measured the difference, W5DXP provided some explanation. Based on Cecils
analysis of data you provided, and on my understanding of the phenomena I
guestimated drop in current in your setup. No theory, no mathematical procedure
(yet) just attempt (using degrees replaced by coil in a radiator) at
explanation of what is happening. I will measure things myself, try to verify
previous measurements and then come up with conclusions and "theory". So far
Cecils (and ON4UN book) theory seems to be closest to the truth.

As far as your measurements, it appears that you are trying to use the worse
case extreme situation (feed point, toroid) to prove your case. Why don't you
use thermo ammeters or current probe without leads and normal coil and do it on
typical mobile whip antenna.
Here is the info on homebrew current probe:
http://www.isd.net/~lyle/currprob/currprob.htm

I am going to build one too, it is handy to check the current while sliding
along the radiator, which easier than inserting ammeter.

I posted my 7 points, so far not one argument against, had few agreements.

What's this guessing game anyway? Why don't you try to prove that W9UCW
measurements are off the rocker?

Yuri, K3BU



Cecil Moore November 12th 03 03:30 AM

Yuri Blanarovich wrote:
What's this guessing game anyway?


If you can talk an astronomer into predicting the day in 2004 when
the first level 3 solar storm will hit earth, you can discredit him
when his prediction falls through.
--
73, Cecil http://www.qsl.net/w5dxp



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Yuri Blanarovich November 12th 03 03:34 AM

Roy Lewallen wrote:
Now, that's quite an insult, based on a total lack of information about
my career and what I've accomplished.



Cecil wrote:
Why is it OK for you to insult my engineering capabilities but not
vice versa? How does it feel?


I wrote:
Ditto happened to me, started with W8JI (they can do that) but when I responded
in kind, they don't like it and the cultists join in choir, defending their
favorite "guru", ignoring the facts.
If it works on transmit, it should work on receive too :-)

I mentioned on the outset, if we can exchange arguments in a civil manner, I am
for it and will respond in kind, but when someone pulls out ridicule, snotty
remarks and insults, then the gloves are off.
As the famous King said: "Can we all get along?"

Yuri



Cecil Moore November 12th 03 03:37 AM

Roy Lewallen wrote:
For anyone who cares, the magnitude of the current out of the inductor
in the later test measured 5.4% less than the current in. No phase shift
was discernible.


A better way to measure phase shift is to measure the delay between
the zero-crossings of the two currents.
--
73, Cecil http://www.qsl.net/w5dxp



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w4jle November 12th 03 03:58 AM

or approximately 22 inches per division...at the speed of light.

"Cecil Moore" wrote in message
...
Roy Lewallen wrote:
If the small inductor
shows a measureable phase shift from input to output, I'll be just as
wrong as I'll be if it shows a magnitude change.


And if the small inductor shows a phase shift too small to be
measured, you will have invented faster than light transmission
because inches per nanosecond is easy to measure nowadays. Heck,
my old bench scope will display two nanoseconds per division.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore November 12th 03 04:36 AM

Yuri Blanarovich wrote:
I mentioned on the outset, if we can exchange arguments in a civil manner, I am
for it and will respond in kind, but when someone pulls out ridicule, snotty
remarks and insults, then the gloves are off.


It gets downright aggravating to hear over and over just how competent the
guru side is compared to the other (implied) ignorant side (as if gurus
cannot possibly be wrong).
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil Moore November 12th 03 04:37 AM

w4jle wrote:
or approximately 22 inches per division...at the speed of light.


Hard to believe RF can propagate through a coil faster than that, eh?
--
73, Cecil http://www.qsl.net/w5dxp



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w4jle November 12th 03 07:25 AM

If it is proved that the coil works differently than my assumptions, will my
radio stop working?

Why bother with an expensive loading coil if nothing changes through it? I
may as well take down my bug catcher and replace it with a hunk of pipe.
That way I can put an even bigger capacitance hat on it.

I am resuming the count of pirouetting angels...If only the darn pin would
quit sticking me!

"Cecil Moore" wrote in message
...
w4jle wrote:
or approximately 22 inches per division...at the speed of light.


Hard to believe RF can propagate through a coil faster than that, eh?
--
73, Cecil http://www.qsl.net/w5dxp



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Richard Harrison November 12th 03 02:28 PM

Roy, W7EL wrote:
"When all this is done, I hope that readers come away with some
assurance that circuit theory does work and can be applied to antenna
problems -- provided that the assumotions made for the components are
valid."

Yes. And, there is another proviso. The reflected energy must be
considered along with the incident energy. Antenna problems are
relatives of transmission line problems.

Terman wrote of impedance in a transmission line with a reflection:
"When a reflected wave is present, the impedance will be alternately
greater and lower than the characteristic impedance, as illustrated in
Fig. 4-10."

This is also true of standing-wave antennas but is complicated by r-f
radiation from the antenna.

Early in this thread, I gave the example of W5LIT`s mobile antenna which
was all coil. It was a bamboo pole wound end to end with wire. At the
feed end its impedance was low. Approximately 90-degrees away at the tip
end, impedance was very high as indicated by the corona often produced
by the high voltage.

The current at the tip end was much less than at the feed point. The
ARRL Antenna Book shows how this can happen in Fig 6 on page 16-4 of the
19th edition.

I admire and appreciate Roy`s experimental verification of antenna
speculations and predictions. Until demonstrated, theory is only theory
and all such explanations are not necessarily so.

Best regards, Richard Harrison, KB5WZI



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