Re: NEC-LIST: Coil-loading.

Doug, et al:

I believe that it was Michael Pupin of Columbia University who validated
Heaviside's theory of the transmission line. Pupin was an immigrant to
this country, and his biography is titled `From Immigrant to Inventor,' as
I recall.

Heaviside's connection with the transmission line and other aspects of
electric circuit theory is amazing. He was self-taught, and developed an
operational calculus that relied on his brilliant intuition, which
made it difficult for others to learn. His suggestion, based upon his
solution to the transmission-line equation, that adding inductance
would solve the problem was met with great skepticism, because it was well
known that inductance slowed everything down, not speeded it up.

Because of his reliance on intuition when applying his calculus, and
because he was not trained as an orthodox mathematician, he was ridiculed
by the `Cambridge Mathematicians' (as he referred to them), who said that
since he could not prove his results, he couldn't possibly understand
them, and, therefore, they were of no use. He responded,
`Because I do not understand my digestive processes, should I forego my
dinner?' At another time he stated, when doing some original work on
asymptotic expansions (which do not usually converge in the usual sense),
`The Cambridge Mathematicians tell me that this series does not converge.
Good! Maybe then we can use it.'

We usually think of Heaviside only as the developer of his operational
calculus (which was replaced by the Laplace transform, because every step
of IT could be proved mathematically by Bromwich, a geophysicist as I
recall, at the end of the 19th century), but his greatest lasting
contribution was to our much beloved Maxwell's equations. He first
formulated Maxwell's equations in the modern format, in which the electric
and magnetic fields were paramount, not various potentials. Together with
J. W. Gibbs, one of the great American thinkers, he helped promote the
expression of Maxwell's equations in vector notation--Gibbs developed the
concept of the vector operators divergence and curl. For that reason, we
sometimes hear the equations referred to as the Maxwell-Heaviside
equations.

The IEEE Press released an interesting biography of Heaviside several
years ago, titled `Oliver Heaviside: Sage in Solitude.' It's fascinating
reading.

Best,

Harold A. Sabbagh
Victor Technologies, LLC
PO Box 7706
Bloomington, IN 47407-7706
(812)339-8273
(812)338-8292 FAX
has_at_sabbagh.com

On Sat, 5 Feb 2005, D. B. Miron wrote:

> Thanks Roland,
>
> The purpose of a loading coil partway up an
> electrically-short whip is to pull up the average current in
> the lower section, which raises the radiation resistance and
> possibly the efficiency. The telegraph transmission line
> coils suggested by Heaviside were to raise the L/C of the
> line to match its R/G (resistance per unit
> length/conductance per unit length) to produce a real
> characteristic inpedance and a phase shift proportional to
> frequency, which reduces the pulse smearing that otherwise
> occurred on long lines. My recollection of the prototype
> story is that the head of the British Post Office said
> something like "engineers don't do math" and ignored
> Heaviside. It was a professor at one of thos small New York
> colleges, like Hunter College or Cooper Union, who built the
> first prototype and sold the idea to AT&T, so the Americans
> did the first successful trans-Atlantic cable.
>
> Regards,
> Doug Miron
>
> --
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> NEC-List_at_robomod.net
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>

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