Return-Path: Received: (qmail 22538 invoked from network); 28 Nov 2002 13:17:34 -0000 Received: from marstons.services.quay.plus.net (212.159.14.223) by mailstore with SMTP; 28 Nov 2002 13:17:34 -0000 Received: (qmail 9068 invoked by uid 10001); 28 Nov 2002 13:17:24 -0000 X-MSMail-Priority: High Received: from post.thorcom.com (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 28 Nov 2002 13:17:24 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 18HOXC-0007qG-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 28 Nov 2002 13:16:50 +0000 Received: from [212.1.130.1] (helo=smtp-1.visp.telinco.net) by post.thorcom.com with esmtp (Exim 4.10) id 18HOXB-0007q7-00 for rsgb_lf_group@blacksheep.org; Thu, 28 Nov 2002 13:16:49 +0000 Received: from [212.1.156.161] (helo=standalone) by smtp-1.visp.telinco.net with smtp (Exim 3.32 #1) id 18HOOm-0004li-00 for rsgb_lf_group@blacksheep.org; Thu, 28 Nov 2002 13:08:08 +0000 Received: by localhost with Microsoft MAPI; Thu, 28 Nov 2002 13:16:42 -0000 Message-ID: <01C296E0.64AE4B20.g4jnt@thersgb.net> From: "Andy talbot" To: rsgb_lf_group@blacksheep.org Date: Thu, 28 Nov 2002 13:16:41 -0000 Importance: high X-Priority: 1 X-Mailer: Microsoft Internet E-mail/MAPI - 8.0.0.4211 MIME-Version: 1.0 Subject: RE: LF: loop antenna Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=1.0 required=5.0tests=DEAR_SOMEBODY,SPAM_PHRASE_01_02,X_PRIORITY_HIGHversion=2.42 X-Spam-Level: * Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group There is an awful lot of controversy over the G3LHZ theories on loops...................... Andy G4JNT -----Original Message----- From: James Moritz [SMTP:j.r.moritz@herts.ac.uk] Sent: 2002/11/28 11:50 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: loop antenna Dear Dave, Rik, LF Group, At 06:36 28/11/2002 +0000, you wrote: >I have just done a couple of calculations on Rik's loop using >formulae from Mike Underhill G3LHZ (which are quoted on my web site). >Mike says that the maximum Q is in fact limited by the size of the >loop and has a limiting value of Q=500/D, where D is the diameter of >the loop (or for a rectangular loop the circumference divided by pi). >Feeding Rik's dimensions into this gives a maximum Q of 20, and it >will in practice be lower than this due to resistive losses This calculation seems to be wildly divergent from the actual results of less than 1 ohm , amounting to a Q of a few hundred, quoted for "Lowfer" loops a little while back. Cheers, Jim Moritz 73 de M0BMU