LF: R: Loop Conductors and proximity effect Rdc Rac

["cesare tagliabue" <cestag@dada.it>]

Hello Paul

       Following the Mesny's expression for proximity effect we have:
D/d      q
1          3.5
1.5       2.48
2          2
3          1.5
4          1.28
5          1.19
6          1.12
7          1.07
8          1.03
=>9       1

Where D is the distance between centre of wires, d is the diameter of the
wire and q is a factor to be inserted in the following expression:

Reff / Rrf = 1 + (q - 1) * SQR (( p - 1 ) / p )

Where Rrf is the RF resistance of a single wire and p is = Rrf / Rdc
Reff is the effective resistance due to proximity effect and Rdc is the
d.c. resistance of the wire.

 Hope that will help you,  73  Cesare

Cesare Tagliabue   I 5 TGC
WW-Loc  JN53PS
e-mail: cestag@dada.it
url: http://www.dadacasa.com/i5tgc

-----Messaggio originale-----
Da: Paul A. Cianciolo <paulc@snet.net>
A: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>;
Lowfer@mailman.Qth.Net <lowfer@mailman.qth.net>
Data: domenica 17 marzo 2002 17.13
Oggetto: LF: Loop Conductors and proximity effect Rdc Rac


> Hello Folks
>
> After researching the construction of Litz wire (Thanks John Sexton, Bill A
> and many others) and speaking to a few wire manufactures, I feel I
> understand better the complex weaving that is needed to make Rac of this
> wire close to the Rdc.
>
> A loop using single turn of 100 pair telephone cable was in the planning
> stages.
>
> So now after opening up a few types of telephone, 100 pairs/#24 and 25
> pairs/24 cat 5 wire,
> none of these are designed with the same weaving as the litz wire. They are
> designed for low crosstalk between conductors and
> immunity to outside interference.
>
> So here is the question....  The proximity effect!
>
> Where can I acquire data about the distance needed between conductors to
> avoid this effect?
>
> For instance..  I have lots of Belden 9555 which is dual RG59 LAN cable.
> > From a 1000' roll
> I could acquire 10 200' runs that could be spaced at some distance and put
> in parallel.
>
> This would bring the Rdc of the loop down to .052 Ohm's.  I need to get an
> idea if the spacing of these 10 conductors
> would need to be 1", 5" 10" or more to disregard the proximity effect and
> have a very low Rac.
>
> anyone have any thoughts
>
>
>
>
> Paulc
> W1VLF
>
>
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