Return-Path: Received: from rly-dc08.mx.aol.com (rly-dc08.mail.aol.com [172.19.136.37]) by air-dc08.mail.aol.com (v121.4) with ESMTP id MAILINDC081-b3a482eac8b31d; Sat, 17 May 2008 05:59:54 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dc08.mx.aol.com (v121.5) with ESMTP id MAILRELAYINDC086-b3a482eac8b31d; Sat, 17 May 2008 05:59:42 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1JxJAU-00027W-SQ for rs_out_1@blacksheep.org; Sat, 17 May 2008 10:57:34 +0100 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1JxJAR-00027N-NF for rsgb_lf_group@blacksheep.org; Sat, 17 May 2008 10:57:32 +0100 Received: from web87007.mail.ird.yahoo.com ([87.248.114.59]) by relay2.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1JxJAL-0004TU-KS for rsgb_lf_group@blacksheep.org; Sat, 17 May 2008 10:57:29 +0100 Received: (qmail 51204 invoked by uid 60001); 17 May 2008 09:56:55 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btinternet.com; h=X-YMail-OSG:Received:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID; b=0c6SvFhiCYs6KdgR7flnYmeNxdlMCDKE/lQ+mquNENcb1p8pDvhNHxGJDoaYNW8c/2+qiz8aL/Qs1pWC08z9T5rzNi41w9h5FyQWuxxnIHgI5khNJqC/WG3N4OodpPpx4CIhTC+ms4x5UKUrKJ9leRrWJrYEBbkAj4pCfs4/yAQ=; X-YMail-OSG: BVxDY1wVM1kwLXpAKpYLmZ2pT7rnR8cDfl_N89mneFydLml3bYMcypPe4HgbsIEF_wQ4lRNvBCLzhpis01WAwm4ne3TX7J58APQqn.JOyrNjVeBT11_cI8Qqpwrzld4.PNX3xDsBjTR4BmVyv1ZUew-- Received: from [217.42.208.63] by web87007.mail.ird.yahoo.com via HTTP; Sat, 17 May 2008 10:56:54 BST Date: Sat, 17 May 2008 10:56:54 +0100 (BST) From: KEN WRIGHT To: rsgb_lf_group@blacksheep.org In-Reply-To: <482E02DF.5010800@ukonline.co.uk> MIME-Version: 1.0 Message-ID: <44370.51189.qm@web87007.mail.ird.yahoo.com> DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: RE: Antenna wire Content-Type: multipart/alternative; boundary="0-1855953625-1211018214=:51189" Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-AOL-IP: 193.82.116.20 X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_helo : n X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_822_from : n X-Mailer: Unknown (No Version) --0-1855953625-1211018214=:51189 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Hi Peter. I did not think we used cad/copper for drop wire, 40lb open wire yes , I was with GPO/BT 1963 - 2002, and the early drop wire was stranded, rubberised insulation, later we went to solid and i thought we had stoped using cadmium by then. currnt drop wire is now 2 pair . Regards. Ken M0KHW IO91TV Peter Dodd wrote: many thanks to those who replied to my email regarding telephone drop wire. The material I have is not copper coated steel wire - it looks like copper material all through. The conductors are 1mm diameter and the black insulation is about 1.25mm thick. The pair of wires are 2.5mm apart. I have used it as twin feeder to an OCFD for the HF band to good effect. G3JMG, in an article in RadCom March 1970 noted that BT had their own recipe for the conductors of drop wire: an addition of one per cent cadmium to the basic copper mix. This increased the tensile strength of hard drawn copper by 50% from 30 tons psi to 30 tons psi. This also increased the DC resistance by about 20%. regards Peter, G3LDO > On 16 May 2008 at 7:08, Laurence KL1X wrote: > > >> ..........I never had to deal >> with open wire spans by the time of my apprecticeship but I think >> that was very similar physically. >> > > There was some open wire around when I was a BT (Post Office) > apprentice. It was solid copper wire. As I recall, dropwire (steel > with a thin copper coating) had a limit to its usable length because > it had a higher DC resistance than open wire. This resistance may not > be high in relation to other losses on an LF Marconi, but it would > rule out its use in a transmitting loop antenna. > > Mike, G3XDV > ========== > > > > > --0-1855953625-1211018214=:51189 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Hi Peter.
I did not think we used cad/copper for drop wire, 40lb  open wire yes ,  I was with  GPO/BT  1963  - 2002,  and the  early  drop wire  was  stranded, rubberised insulation, later we went to solid and i thought we had stoped using cadmium by then. currnt drop wire is now 2 pair .

Regards.
Ken
M0KHW

IO91TV
 

Peter Dodd <g3ldo@ukonline.co.uk> wrote:
many thanks to those who replied to my email regarding telephone drop wire.

The material I have is not copper coated steel wire - it looks like
copper material all through.
The conductors are 1mm diameter and the black insulation is about 1.25mm
thick. The pair of wires are 2.5mm apart. I have used it as twin feeder
to an OCFD for the HF band to good effect.
G3JMG, in an article in RadCom March 1970 noted that BT had their own
recipe for the conductors of drop wire: an addition of one per cent
cadmium to the basic copper mix. This increased the tensile strength of
hard drawn copper by 50% from 30 tons psi to 30 tons psi. This also
increased the DC resistance by about 20%.

regards

Peter, G3LDO
> On 16 May 2008 at 7:08, Laurence KL1X wrote:
>
>
>> ..........I never had to deal
>> with open wire spans by the time of my apprecticeship but I think
>> that was very similar physically.
>>
>
> There was some open wire around when I was a BT (Post Office)
> apprentice. It was solid copper wire. As I recall, dropwire (steel
> with a thin copper coating) had a limit to its usable length because
> it had a higher DC resistance than open wire. This resistance may not
> be high in relation to other losses on an LF Marconi, but it would
> rule out its use in a transmitting loop antenna.
>
> Mike, G3XDV
> ==========
>
>
>
>
>



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