Return-Path: Received: (qmail 3647 invoked from network); 15 Nov 2002 16:16:49 -0000 Received: from mx.last.plus.net (212.159.3.230) by mailstore with SMTP; 15 Nov 2002 16:16:49 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 5982 invoked from network); 15 Nov 2002 14:45:18 -0000 X-Priority: 3 Received: from post.thorcom.com (193.82.116.70) by mx.last.plus.net with SMTP; 15 Nov 2002 14:45:18 -0000 X-MSMail-Priority: Normal X-SQ: A X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18ChuM-0006iN-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 15 Nov 2002 14:57:22 +0000 Received: from [212.125.75.12] (helo=mail4.messagelabs.com) by post.thorcom.com with smtp (Exim 4.10) id 18ChuL-0006iD-00 for rsgb_lf_group@blacksheep.org; Fri, 15 Nov 2002 14:57:21 +0000 X-VirusChecked: Checked X-Env-Sender: William.Ashlock@edwards.boc.com X-Msg-Ref: server-24.tower-4.messagelabs.com!1037372236!39487 Received: (qmail 5735 invoked from network); 15 Nov 2002 14:57:17 -0000 Received: from unknown (HELO ukfw1.ge.boc.com) (193.131.2.157) by server-24.tower-4.messagelabs.com with SMTP; 15 Nov 2002 14:57:17 -0000 Received: from z-160-100-160-136.est.ibm.com ([160.100.160.136]) by ukfw1.ge.boc.com; Fri, 15 Nov 2002 14:57:17 +0000 (GMT) Received: from exc_wil04.edwards.boc.com ([162.118.144.226]) by exc_cra03.edwards.boc.com with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2653.13) id TP3FP095; Fri, 15 Nov 2002 15:00:47 -0000 Received: by EXC_WIL04 with Internet Mail Service (5.5.2653.19) id ; Fri, 15 Nov 2002 09:57:17 -0500 Message-ID: From: "Ashlock,William" To: rsgb_lf_group@blacksheep.org Date: Fri, 15 Nov 2002 09:57:16 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Subject: RE: LF: RE: Re: RE: Loop vs Marconi Content-Type: text/plain; charset=iso-8859-1; format=flowed X-Spam-Status: No, hits=0.2 required=5.0tests=EXCHANGE_SERVER,INVALID_MSGID,QUOTED_EMAIL_TEXT, SPAM_PHRASE_03_05version=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Hi Alex, >> My present loop is constructed from .63" OD copper pipe. The figure of merit >> for 50/50 loop antennas is the total AC resistance (Rac), including ground >> losses, and this one measures under 0.4 ohms. An RG-8 loop of the same >> dimensions will have a dry Rac of 0.60 ohms and is one that has more appeal >> to the average Lowfer. Signal is down just 1.7db from the pipe loop. >The loop perimeter is 60 meters. >Wire resistance: >R1 [Ohm/m] = ( 0.084 / d[mm] )*sqrt(F[MHz]) = ( 0.084 / 16 )*sqrt(0.185) = 0.0023 Ohm/m >Rac (copper) = 60*0.0023 = 0.14 Ohm. >You get Rac = 0.4 Ohm . So enviroment loss resistance should be >0.4 - 0.14 =0.26 Ohm. >Someone wrong? No - You're Lookin good! >You get 0.6 Ohm if RG-8 used. Enviroment loss should be the same, >0.26 Ohm. So 0.60 - 0.26 = 0.34 Ohm is copper resistance of RG-8. >Then diameter should be 16*(0.14/0.34)= 6.6 mm. I am not familar with >RG-8. Is it diameter about 7 mm? More like 9.2mm, but I put in a -16% factor for the Rac of copper braid Vs solid copper shell. >If TX power is about 1 kW it seems posible to get about 1 W ERP. Not >very bad... I don't disagree! How does that old proverb go? ..... Try it, you'll like it. Bill A _____________________________________________________________________ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com