Return-Path: Received: (qmail 6706 invoked from network); 8 May 2003 17:42:47 -0000 Content-Transfer-Encoding: 8bit Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 8 May 2003 17:42:47 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 29013 invoked from network); 8 May 2003 17:42:52 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 8 May 2003 17:42:51 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.14) id 19DpOx-0002sA-U6 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 08 May 2003 18:41:51 +0100 Received: from [207.136.80.126] (helo=jandor.look.ca) by post.thorcom.com with esmtp (Exim 4.14) id 19DpOs-0002s0-RH for rsgb_lf_group@blacksheep.org; Thu, 08 May 2003 18:41:46 +0100 Received: from [216.66.146.130] (helo=bc-van-mut-a53-10-130.look.ca) by jandor.look.ca with smtp (Exim 4.05) id 19DpOo-0007nG-00 for rsgb_lf_group@blacksheep.org; Thu, 08 May 2003 17:41:43 +0000 X-Sender: eldridge@direct.ca X-Mailer: Windows Eudora Version 1.4.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org From: "Bob Eldridge " Message-ID: Date: Thu, 08 May 2003 17:41:43 +0000 Content-Type: text/plain; charset=us-ascii; format=flowed Subject: Re: LF: Mains Cable and other transmission lines X-Spam-Status: No, hits=0.0 required=5.0tests=noneversion=2.53 X-Spam-Checker-Version: SpamAssassin 2.53 (1.174.2.15-2003-03-30-exp) X-SA-Exim-Scanned: Yes Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false >At 13:55 04/05/2003 +0100, you wrote: >>After reading Jim's e-mail I searched through all my radio books >>(Terman, Kraus et al) for enlightenment and the reason for 50ohms as a >>standard is not discussed at all. >>Any references Jim? > I read somewhere that 77 ohms cable was determined to be the impedance giving lowest attenuation, and that when it was filled with polyethylene dielectric it created a 50 ohms cable. Bob VE7BS