Message-ID: <000401c1cddd$8fa4e720$15666ec3@cestag>
From: "cesare tagliabue" <cestag@dada.it>
To: rsgb_lf_group@blacksheep.org
Subject: LF: R: Loop Conductors and proximity effect  Rdc Rac
Date: Sun, 17 Mar 2002 18:58:12 +0100
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 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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