RE: LF: Re: Loop Conductors and proximity effect Rdc Rac

["john sexton" <computernetworks@excite.com>]

Hi Cesare,
Funny thing, I too wasted a lot of time yesterday messing about with Excel trying to find a fit and the best I came up with was that it was approx. k/log(D/d). Polynomial fits didn't seem to work too well.

Thanks for the formula. It doesn't quite work though for values of D/d from 2 to 4, but perhaps the data were only approximations?

The data alone are pretty useful. Looks like that time at College wasn't entirely wasted, hi!
BTW Bill pointed out that the minimum separation can be small as you like if you use Litz wire and can get Rrf down or close to Rdc, because
Reff/Rrf = 1 + (q - 1) * SQRT (1-Rdc/Rrf)
reduces to 1 when Rdc = Rrf as an alternative to q = 1.
 
Thanks again.
73, John, G4CNN


--- On Mon 03/18, cesare tagliabue

wrote:
> Hello John
> I have found the Mesny's _expression_ on an old university stenciled
> book where only the data were given, but some time ago, for purpose of
> include it in a program, I have elaborated an empiric _expression_ that
> approximates sufficiently these data. That is:
> q = ( 1 + .95 d / D )^2 -
> .22
> Best 73 to all Cesare
>
> Cesare Tagliabue I 5 TGC
> WW-Loc JN53PS
> e-mail: cestag@dada.it
> url: http://www.dadacasa.com/i5tgc
>
> -----Messaggio originale-----
> Da: john sexton
> A: rsgb_lf_group@blacksheep.org
> Data: lunedì 18 marzo 2002 17.46
> Oggetto: LF: Loop Conductors and proximity effect Rdc Rac
>
>
> Hi Paul,
> From the interesting formula given by Cesare, the short answer to your
> question appears to be 1/2 inch.
> I tried to find out more about Mesny's _expression_ from the Internet,
> but it looks like you have to buy the book.
> I wonder whether Cesare can be persuaded to tell us the formula that
> relates q to D/d? At a guess it appears to be logarithmic.
> The second formula can be simplified to
> Reff/Rrf = 1 + (q-1)*sqrt(1-Rdc/Rrf)
> When D/d = 9, q = 1 so the second term disappears and Reff = Rrf.
> 73, John, G4CNN
>
>
>
> ----------------------------------------------------------------------------
>
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