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Old November 29th 07, 11:50 PM posted to rec.radio.amateur.antenna
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Gene Fuller wrote:
It appears you missed the primary message of the Corum article.


I'm afraid you missed the point. As long as the frequency
is kept constant, the VF and Z0 of coil stock will be
relatively constant - why wouldn't it be? W8JI missed
the 4 MHz delay through that coil by at least a magnitude.
It is impossible for that delay to be 3 nS. The measured
delay through my 75m bugcatcher coil is 25 nS.
--
73, Cecil http://www.w5dxp.com
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Old November 30th 07, 02:36 AM posted to rec.radio.amateur.antenna
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Cecil Moore wrote:
Gene Fuller wrote:
It appears you missed the primary message of the Corum article.


I'm afraid you missed the point. As long as the frequency
is kept constant, the VF and Z0 of coil stock will be
relatively constant - why wouldn't it be? W8JI missed
the 4 MHz delay through that coil by at least a magnitude.
It is impossible for that delay to be 3 nS. The measured
delay through my 75m bugcatcher coil is 25 nS.


Yup, I guess I don't understand the "point". You continue to use the
equations and charts derived in the Corum article, but you don't agree
with his conditions and caveats. There would have been no purpose for
his article if your paragraph above was correct. Have you expanded the
applicability range for his results? Where can we find your IEEE white
paper?

So, the "point" is ??????

73,
Gene
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Old November 30th 07, 05:26 AM posted to rec.radio.amateur.antenna
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Gene Fuller wrote:
So, the "point" is ??????


Given a 100 foot long helical transmission line at
4 MHz terminated in its characteristic impedance.
The VF is easily measured. This is a slow-wave
configuration.

Change the length to 50 feet terminated in its
characteristic impedance. Why would the characteristic
impedance change? Why would the VF change?

The coil diameter is 0.5 feet. The coil diameter ratio
to wavelength is 0.002. The turns per foot is 48.
The turns per wavelength is about 11800. Reading from
Fig.1 in the Corum article gives a VF of about 0.02.
Why would that change appreciably with frequency?
--
73, Cecil http://www.w5dxp.com
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Old November 30th 07, 06:35 AM posted to rec.radio.amateur.antenna
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On Thu, 29 Nov 2007 17:44:39 -0600, Cecil Moore
wrote:
Jim's point is that it can be done!

In that particular coil at 4 MHz - no, it cannot be done.


On Thu, 29 Nov 2007 17:50:36 -0600, Cecil Moore
wrote:
The measured delay through my 75m bugcatcher coil is 25 nS.


In one case, the measurement "cannot be done," and in another case 6
minutes later it can be done; and the difference all because of one
"particular" coil?

That is
1. the first coil is one mighty particular coil; or
2. no measurement was done for the second, not so particular coil.

Of course, for those who readily admit that English is not their best
language of communication (and their writing tends to support that
excuse); then we could be encountering:
1. another meaning, generally unknown or archaic, for particular; or
2. another meaning, generally unknown or archaic, for measurement; or
3. both.

My bet is the answer will not hinge on blaming poor spelling, failing
eyesight, a slip in thought, or the wrong meter setting (rubber
crutches of the past), but ultimately a novel definition of the word
"measurement" which will reveal a visit to the bench is superfluous to
the conceptual clarity of it all = intellectual mooching.

Of course, a novel definition of particular would amuse us all....
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Old November 30th 07, 05:09 PM posted to rec.radio.amateur.antenna
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Richard Clark wrote:
In one case, the measurement "cannot be done," and in another case 6
minutes later it can be done; and the difference all because of one
"particular" coil?


Good Grief! I cannot do the measurement on the W8JI coil
because I don't have the coil. Upon the coil that I do
have, a 75m bugcatcher coil, the measurement was easy.
--
73, Cecil http://www.w5dxp.com


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Old November 30th 07, 05:38 PM posted to rec.radio.amateur.antenna
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On Fri, 30 Nov 2007 17:09:42 GMT, Cecil Moore
wrote:

Richard Clark wrote:
In one case, the measurement "cannot be done," and in another case 6
minutes later it can be done; and the difference all because of one
"particular" coil?


Good Grief! I cannot do the measurement on the W8JI coil
because I don't have the coil. Upon the coil that I do
have, a 75m bugcatcher coil, the measurement was easy.


My goodness, it has been a long time since I've heard "Hearts and
Flowers" attempted through posting on this newsgroup. How sad! It
must be a titanic struggle to find the W8JI coil's description and
build one.

All the more strange for this shortfall given:
On Wed, 28 Nov 2007 13:25:34 -0600, Cecil Moore
wrote:
http://www.w8ji.com/inductor_current_time_delay.htm


No doubt your eyes are failing, or memory has lapsed momentarily, or
perhaps a recent personal crisis diverted your attention - or more
likely (and here we can all agree) the topic is utterly boring except
for these charming flirtations you offer (otherwise considered to be
intellectual pan-handling).

Anyway, the "suggestion" of measurement of a time delay in the quote
above is nothing more than that - a suggestion. If we were to press
for more details (always absent in these proclamations passing as
technical content), then we would find that, no, the measurement was
one of resonance (and likely not even that) which then through a weak
chain of rusty links of logic once again summons up the corrupted
reading of Corum(s) to INFER not measure.

I think the group was short-changed on the lack of a definition for
the amusing application of "particular." At least we would have
gotten some value added to drape the coffin of this thread.
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