Return-Path: Received: from mtain-ma05.r1000.mx.aol.com (mtain-ma05.r1000.mx.aol.com [172.29.96.13]) by air-dc09.mail.aol.com (v129.4) with ESMTP id MAILINDC094-86a74c2497c438b; Fri, 25 Jun 2010 07:49:24 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-ma05.r1000.mx.aol.com (Internet Inbound) with ESMTP id BD05B380000A7; Fri, 25 Jun 2010 07:49:20 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OS7O2-0006zK-94 for rs_out_1@blacksheep.org; Fri, 25 Jun 2010 12:47:58 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OS7O1-0006zB-RS for rsgb_lf_group@blacksheep.org; Fri, 25 Jun 2010 12:47:57 +0100 Received: from smtp817.mail.ird.yahoo.com ([77.238.189.17]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1OS7O1-000821-0q for rsgb_lf_group@blacksheep.org; Fri, 25 Jun 2010 12:47:57 +0100 Received: (qmail 16080 invoked from network); 25 Jun 2010 11:47:49 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MIMEOLE; b=bSMJcCK4zaEj0iq2J4biFUQt8YDDw7SW9WXg0KgMKquqEnt+XEJkD4bkSdkgTovF0TWVZFh5zHYpau6EGe5Yo+3TPq2D5przgJCWLCyookpXFE1mXqir0LP9lgjjDpSNyYsbOxb687WJJa7R4pSoJBln4SsDznwQLIWT0dX2J4o= ; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btopenworld.com; s=s1024; t=1277466469; bh=rmpvxbUN+yuubTVVgbfnPcf4h7NkWQLWMiUZGx0YpM4=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MIMEOLE; b=1zAzsGkYGHPDHFrRy9tEcGduM/+fVgXCyAl57FOBxRyUT4TsZ4klwNkx/PpMwVIT0kdulwchlSmfYrNK5TXUC3XrEzrQQwILv6QwiMmxNJ2EYhM7tSIzygPxwNhhcprpk2L8oD5RqfMIHid33KAr1WouzDJR7m0FQ++Hq4Bvfi4= Received: from JimPC (james.moritz@86.181.92.22 with login) by smtp817.mail.ird.yahoo.com with SMTP; 25 Jun 2010 11:47:49 +0000 GMT X-Yahoo-SMTP: Cxhli3eswBD1ozmtAojhjrja86kWx0Qm9tycD5QR1DKWrOLgjJcXkw-- X-YMail-OSG: WhZUfowVM1lNnuZmECdKr0V9sPgcPyw3YoYb1mF8TCH_htxsZfSxNLCoFGJ.zjVPqd3GPbFW1ATFjvfs6WdhhFMT8bnStHN0vTq3ulyQhBBjQeTfSQNGfEBUV0I3Vr19VUGtOVfaDPUgeFh3Cn6K7Pa8Z.i2kcRDBXMnJsgDnd0fhXYceV4uspcElXqLLLDn4FkSLnoIuK87Ddq.HVsdqC7saMY06iclzvD9EsKM0JPETQxfDa6vlMyWW2JvtbnyJ.Gykutlds9bSjNBANrBn67yyn4- X-Yahoo-Newman-Property: ymail-3 Message-ID: <45C30B1620CA4C5CA65D6DB3D8A1E0F4@JimPC> From: "James Moritz" To: References: <6DEA7E8987244A48846E44813972D608@TonyLaptop> <1845591504.511262.1277453070420.JavaMail.fmail@mwmweb034> <75F6684803394030B28412B2B11384EC@TonyLaptop> In-Reply-To: <75F6684803394030B28412B2B11384EC@TonyLaptop> Date: Fri, 25 Jun 2010 12:47:48 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18197 X-MIMEOLE: Produced By Microsoft MimeOLE V6.0.6002.18197 DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,UNPARSEABLE_RELAY=0.001 Subject: Re: LF: Antenna wire Content-Type: text/plain; format=flowed; charset="UTF-8"; reply-type=original 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=0.1 required=5.0 tests=MISSING_OUTLOOK_NAME 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-global-disposition: G X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m249.2 ; domain : btopenworld.com DKIM : pass x-aol-sid: 3039ac1d600d4c2497c0218b X-AOL-IP: 193.82.116.20 Dear Tony, LF Group, The most important parameter of an LF vertical antenna is its height, more specifically the "effective height", which, for antennas that are a small fraction of a wavelength in overall length, is roughly speaking the average height of the conductors making up the antenna. Increasing the length has secondary benefits, but height has by far the strongest effect on overall efficiency. The resistance of the wire will contribute to overall losses, but at LF this is relatively low due to the reduced "skin effect" compared to higher frequencies. So even fairly thin wire will probably add no more than a few ohms to the overall loss resistance, and this will be reduced if you go for the parallel 2-wire configuration. So the main thing is to go for robust, reasonably light weight wire that can be put under enough tension to minimise sagging and so reduction of the height. I have used the tri-rated switchgear cable favoured by G7NKS for 10 years now without problems, but I guess any stranded, plastic sheathed cable would be about the same. One could split up mains cable to get this quite cheaply if specialist suppliers are not convenient. The solid-cored "twin and earth" mains cable is probably the cheapest and easiest to strip the outer sheathing off, and the inner cores are very robust although obviously less flexible. Probably the smallest 1mm^2 gauge would be fine. I have tried using copper coated MIG welder wire for antennas, but as G3YMC says, the coating is too thin and quickly rusts through. There is such a thing as "copperweld" wire with a thicker copper cladding, but this is quite a specialised thing. Electric fence wire looks tempting, but usually has stainless steel strands with a high RF resistance. A lot of the el Cheapo TV coax around has a copper-plated steel centre conductor with an outer consisting of a few strands of braid with an aluminium foil, and in my experience is well worth avoiding for any application! Cheers, Jim Moritz 73 de M0BMU ----- Original Message ----- From: "Tony Baldwin" To: Sent: Friday, June 25, 2010 10:35 AM Subject: Re: LF: Antenna wire Would welding wire do, the CO2 welding wire about 1mm copper coated steel wire ? That I already have a roll of and it's available in Lidl this week. Tony, EI8JK.