Return-Path: Received: from rly-md08.mx.aol.com (rly-md08.mail.aol.com [172.20.29.146]) by air-md04.mail.aol.com (v121.4) with ESMTP id MAILINMD043-91a482e040c2de; Fri, 16 May 2008 18:01:01 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-md08.mx.aol.com (v121.5) with ESMTP id MAILRELAYINMD082-91a482e040c2de; Fri, 16 May 2008 18:00:47 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Jx7yc-0000qy-RD for rs_out_1@blacksheep.org; Fri, 16 May 2008 23:00:34 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Jx7yc-0000qp-CB for rsgb_lf_group@blacksheep.org; Fri, 16 May 2008 23:00:34 +0100 Received: from smarthost3.mail.uk.easynet.net ([212.135.6.13]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Jx7yZ-0001t0-RN for rsgb_lf_group@blacksheep.org; Fri, 16 May 2008 23:00:34 +0100 Received: from bb-87-82-9-228.ukonline.co.uk ([87.82.9.228] helo=[192.168.0.3]) by smarthost3.mail.uk.easynet.net with esmtp (Exim 4.10) id 1Jx7yU-000HdB-00 for rsgb_lf_group@blacksheep.org; Fri, 16 May 2008 23:00:26 +0100 Message-ID: <482E0477.3070508@ukonline.co.uk> Date: Fri, 16 May 2008 23:02:31 +0100 From: Peter Dodd User-Agent: Thunderbird 2.0.0.14 (Windows/20080421) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <482CBF61.3010505@ukonline.co.uk>, <002701c8b734$9cefe910$6401a8c0@asus>, <482DC54A.4041.18CD6C2@mike.dennison.ntlworld.com> <482E02DF.5010800@ukonline.co.uk> In-Reply-To: <482E02DF.5010800@ukonline.co.uk> X-Karma: 0: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: RE: Antenna wire Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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=none 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) Sorry, the sentence should have read "This increased the tensile strength of hard drawn copper by 50% from 20 tons psi to 30 tons psi" > 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 >> ========== >> >> >> >> >> > > > >