Return-Path: Received: from rly-dd08.mx.aol.com (rly-dd08.mail.aol.com [172.19.141.155]) by air-dd05.mail.aol.com (v121.4) with ESMTP id MAILINDD054-b93482e026d254; Fri, 16 May 2008 17:54:07 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dd08.mx.aol.com (v121.5) with ESMTP id MAILRELAYINDD085-b93482e026d254; Fri, 16 May 2008 17:53:52 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Jx7s1-0000jE-3m for rs_out_1@blacksheep.org; Fri, 16 May 2008 22:53:45 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Jx7s0-0000j5-Oj for rsgb_lf_group@blacksheep.org; Fri, 16 May 2008 22:53:44 +0100 Received: from smarthost2.mail.uk.easynet.net ([212.135.6.12]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Jx7rx-0001p7-6Y for rsgb_lf_group@blacksheep.org; Fri, 16 May 2008 22:53:44 +0100 Received: from bb-87-82-9-228.ukonline.co.uk ([87.82.9.228] helo=[192.168.0.3]) by smarthost2.mail.uk.easynet.net with esmtp (Exim 4.66) (envelope-from ) id 1Jx7ru-000MCc-Qz for rsgb_lf_group@blacksheep.org; Fri, 16 May 2008 22:53:38 +0100 Message-ID: <482E02DF.5010800@ukonline.co.uk> Date: Fri, 16 May 2008 22:55:43 +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> In-Reply-To: <482DC54A.4041.18CD6C2@mike.dennison.ntlworld.com> 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) 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 > ========== > > > > >