Current across the antenna loading coil - from scratch
 

Oh, dear, Reg. We've driven you to drink, eh?

Can you continue to talk (reasonably coherently) after you've been
drinking to excess??

;-/
one of the Toms
may break out some Merlot shortly...

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:
On Mon, 10 Apr 2006 16:04:56 -0400, Michael Coslo
wrote:


Not that I could fan the flames any more anyhow, but just what was the
original discussion about anyhow?


Hmmm, Mike, I bet you didn't find a pony in that pile of "responses"
did you?

I learned something. Not exactly what I was asking about tho'

- 73 de Mike KB3EIA -

Current across the antenna loading coil - from scratch
 

Tom Donaly wrote:
Reg Edwards wrote:

"K7ITM" wrote


W8JI-Tom, Tom
Donaly, Ian White, Roy Lewallen, Gene Fuller, Reg Edwards, I, and
others I can think of are NOT, repeat NOT, absolutely NOT, most
definitely NOT, talking about a lumped-circuit model.


==========================================

I do wish you would't take my name in vain about what I might have
said or not said. I have in fact said little or nothing about lumped
circuits or anything else in this stupid, ridiculous argument. Please
don't drag me down to your level.
----
Reg Edwards.



If the argument is that ridiculous, why do you continue
to read it?


Morbid curiosity is what keeps me reading it!

This thread reminds me of the time at lunch in school, I put $5 in the
jukebox in the lunchroom. I continually pushed the buttons to play "On
the Cover of the Rolling Stone", the goofy song by Dr. Hook and the
Medicine show. After the 5th repeat, the kids would alternately groan
and laugh with each successive play. But most of them stuck around to
see just how many times the idiot would play the same song. (turns out
50 - at a dime a pop)

Some of us are now the students, listening to other people sing a
different version of "On the Cover of the Rolling Stone".

- 73 de Mike KB3EIA -

Current across the antenna loading coil - from scratch
 

On Fri, 14 Apr 2006 00:59:37 +0100, "Reg Edwards"
wrote:

Wot's seder?

Can one drink wine to excess?

At least four times. Get to act and sing too.

If so, can I join the club?

I was asked. Weren't you?

Current across the antenna loading coil - from scratch
 

K7ITM wrote:

(Continuing the basenote drift, since the basenote thread is pretty
much a mess anyway...)

So it's not clear to me who might be calling whom an unbeliever. Both
Christians and Jews celebrate seder. Maybe it would be those of some
other faith? It's interesting to me--and sad--that so many whose
religion teaches that God is all-powerful and too great to be known
fully by any person are intolerant of others whose religions teach just
the same thing. The intolerance seems as common between sects of
nominally the same religion as between religions. If you can't ever
fully know your god, who are you to say it's not the same god as the
one someone else worships differently, or as someone else worships as a
set of gods?

Hey, we might as well be discussing religion as loading coils...

Ducking,
Tom

No, it's just that certain groups of Xians, not a majority but getting
too populous for my taste, seem to think they are the be all end all,
and everyone else is going to HELL, even other Xians, especially
Catholics. And those that aren't Xian, fuggetaboutit, they are all
damned even if they are Good Samaritans and kinder than Mother Theresa,
because they don't belive in the RIGHT THINGS.

tom
K0TAR

Current across the antenna loading coil - from scratch
 

Richard Clark wrote:
On Thu, 13 Apr 2006 09:42:35 -0400, "Yuri Blanarovich"
wrote:


Happy Easter to everyone, even unbelievers!


Hi Yuri,

I was at Seder last night. Are you calling me an unbeliever?

73's
Richard Clark, KB7QHC

I would hope not!!

Here in NH the Jewish community invites the Christian, including
Catholic, Community to share the SEDER with them. The SEDER is served in
the meeting room at the local synagogue. About 200 non Jewish people,
meaning Christian, from the City of Manchester attend. It is an annual
event.

The Jewish Community is REFORMED. I do not imagine such an invitation
would occur from an Orthodox or Conservative Community. I respect their
practice.

In the recent past I have been invited to pray in the congregation with
a Conservative Community in Massachusetts. I am humbled. The Rabbi is a
holy man.

/S/ W1MCE, AKA Deacon Dave [Reverend Mr.]

Current across the antenna loading coil - from scratch
 

wrote:


Roy Lewallen wrote:

That this concept
is wrong can and has been shown by theory, modeling, and measurement. I
made and posted measurements on this newsgroup in November 2003 which
demonstrated clearly that the presumption is false.


Mike Coslo wrote:

Okay. It looks like we have at least some measurements that differ. Any
idea why that would be?


Yes, because the physical construction of the coil and the antenna
changes the capacitance from the inductor to the outside world and the
impedance loading the coil. It is the ratio of capaciatnce of the coil
to the outside world to the load impedance presented by the whip above
the coil that causes or allows any phase difference in current or
current level at each end of the coil.

It isn't standing waves, it is missing electrical degrees.

I can take a resonant mobile antenna of basically the same height and
construction, change only the coil while maintaining resonance, and
have difference of current and phase of current change all over the
place.

Try reading:

http://www.w8ji.com/mobile_and_loaded_antenna.htm

there is a link to actual measurements in that text.



The loading coil isn't making the antenna act like a physically longer
antenna. In the extreme case of a physically short inductor at the
feedpoint, it's simply modifying the feedpoint impedance and has no
effect whatever on the antenna's radiation.

Would the inductor then be best right past the feedpoint? Certainly
having the inductor at the far end, or in the middle seems like a bad
place for it. (not talking about trap antennas)


No. The current in the antenna below the loading coil (or a top hat of
sufficent capacitance)is essentially uniform. This increases radiation
resistance. Increased radiation resistance can increase efficiency.

See:

http://www.w8ji.com/radiation_resistance.htm

Wow, good pages, Tom.

Okay now. Your results are pretty compelling, and thanks for the
understandable treatment too. I note differing measurements, and a
reason for those measurements I'm still reading the pages, but wanted to
respond before you thought I was ignoring you.

For the next question, which is directed toward Yuri and/or Cecil, is
are your measurements at all related to what Tom reports? Do the numbers
correlate?


- 73 de Mike KB3EIA -

Current across the antenna loading coil - from scratch
 

Roy Lewallen wrote:
The amount the magnitude of the current drops across an inductor is
determined primarily by the amount of inductance and the capacitance
from the inductor to ground or the other half of the antenna. This is
easily explained by simple lumped constant circuit theory.

How does lumped constand circuit theory handle the phase shift through
the inductance? It is certainly NOT zero as your measured.
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Gene Fuller wrote:
I gave you a very specific reference to demonstrate your supposition was
incorrect. You came back with nothing but, "Because I say so." You have
not offered one shred of backing for your constant Vf argument.

Good Grief, Gene, can't I have a 6 day motorcycle in piece without
you saying something that is not true?
--
73, Cecil http://www.qsl.net/w5dxp

Current across the antenna loading coil - from scratch
 

Gene Fuller wrote:
Do you suppose that maybe the displacement current can actually work in
either direction?

I guess magical thinking works in any directions.
--
73, Cecil http://www.qsl.net/w5dxp