My dear friend Cecil,

It's a waste of time mentioning things like DIP.TL.EZ and EZNEC4.
Hardly anybody has ever heard of whatever they are. I certainly
havn't. And the chances of obtaining them, even if legal, within the
next 12 months is so remote, by then, everybody will have forgotten
what it's all about and will have lost interest in the subject. So
nobody ever takes any notice of references and switches to another
more-interesting thread on the newsgroup.

If you have any facts to say then say them. It's up to you to be
convincing. If you think you need the support of Terman or Kraus then
you lack self-confidence. Bibles are usually misquoted, or taken out
of context anyway. Second-hand, plagiarised, information adds nothing
to reliability.

As usual, you gave only half of the information needed to make sense.

In addition to a thick neoprene layer of 0.1 inches, with a high
permittivity of 6.7, what was the antenna wire diameter and the
approximate height above ground?

Without such details your information is old-wives' waffle.

As things are, your velocity factor reduction of 7.8% does not go out
of the ball park value predicted by my formula.

My formula takes a few milliseconds to calculate. Whereas your method
requires a 4-weeks training course and several hours making the model.
----
Reg,G4FGQ

Reg Edwards wrote:
It's a waste of time mentioning things like DIP.TL.EZ and EZNEC4.
Hardly anybody has ever heard of whatever they are. I certainly
havn't. And the chances of obtaining them, even if legal, within the
next 12 months is so remote, by then, everybody will have forgotten
what it's all about and will have lost interest in the subject.

EZNEC is available in a free demo version from www.eznec.com
You can enter dielectric constant and thickness of insulation.

If you have any facts to say then say them. It's up to you to be
convincing.

I once replaced an uninsulated loop with insulated wire to
try to reduce wind static/noise in AZ. The resonant frequency
went down by about 200 kc on 40m.

As things are, your velocity factor reduction of 7.8% does not go out
of the ball park value predicted by my formula.

Maybe I misunderstood. I thought you were saying insulation
has no effect.

My formula takes a few milliseconds to calculate. Whereas your method
requires a 4-weeks training course and several hours making the model.

Some training is worth it. My training using ELNEC and later
EZNEC has been very valuable. I certainly wouldn't spend "several
hours" on a model only to report the results in one thread on
this newsgroup. That's not enough return on investment. It took
me about seven minutes for that last report.
--
73, Cecil http://www.qsl.net/w5dxp


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Oh my. It is time for a story. My students use superb oscilloscopes that
are actually computers with a D-to-A converter used to display waveforms.
When measuring things such as the peak-to-peak size of a periodic waveform,
students (being students) initially writedown the number exported by the
oscilloscope. Whereupon, I ask the student if they wrote the computer code
that exported the number and, if not, why did they believe the result. The
student is sent back to note the max. and min. value, and to perform the
reliable calculation of subtraction.

NEC source code exists, is understandable, and has been verified many
times by independent persons. I teach my students to avoid using tools that
can not be verified at a fundamental level. Of course, rules-of-thumb are
an important part of error checking, and somethings are only amiable of
being approximated with a heuristic equation.

Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:

"Reg Edwards"
snip

My formula takes a few milliseconds to calculate. Whereas your method
requires a 4-weeks training course and several hours making the model.
----
Reg,G4FGQ