Return-Path: <owner-rsgb_lf_group@blacksheep.org> Received: (qmail 85239 invoked from network); 6 Jan 2004 19:26:41 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore01.plus.net with SMTP; 6 Jan 2004 19:26:41 -0000 Received: (qmail 5671 invoked from network); 6 Jan 2004 19:26:41 -0000 X-Filtered-by: Plusnet (hmail v1.01) X-Spam-detection-level: 11 Received: from ptb-mxcore01.plus.net (212.159.14.215) by ptb-mxscan01.plus.net with SMTP; 6 Jan 2004 19:26:40 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim) id 1Adwqe-0001MY-IM for dave@picks.force9.co.uk; Tue, 06 Jan 2004 19:26:40 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AdwqM-0000Ov-Kw for rs_out@blacksheep.org; Tue, 06 Jan 2004 19:26:22 +0000 Received: from [212.135.6.10] (helo=smarthost0.mail.uk.easynet.net) by post.thorcom.com with esmtp (Exim 4.14) id 1AdwqM-0000Om-6u for rsgb_lf_group@blacksheep.org; Tue, 06 Jan 2004 19:26:22 +0000 Received: from tnt-2-55.easynet.co.uk ([195.40.196.55] helo=captbrian) by smarthost0.mail.uk.easynet.net with smtp (Exim 4.10) id 1AdwqK-000BKm-00 for rsgb_lf_group@blacksheep.org; Tue, 06 Jan 2004 19:26:21 +0000 X-Bad-Message-ID: no DNS (captbrian) Message-ID: <011e01c3d48a$ffa6c240$6ec428c3@captbrian> From: "captbrian" <captbrian@ukonline.co.uk> To: rsgb_lf_group@blacksheep.org References: <000201c3d2f3$c4fb5f40$61e4fc3e@l8p8y6> <6.0.1.1.2.20031229161651.027e8660@POP3.freeler.nl> <000001c3d009$acf7a620$c7e47f50@Smisan> <6.0.1.1.2.20040103121138.0280f960@POP3.freeler.nl> <000601c3d2c3$2bd34e70$b733f7c2@johnb5a82ea1a4> <6.0.1.1.2.20040104163146.027efbe0@POP3.freeler.nl> <000201c3d2f3$c4fb5f40$61e4fc3e@l8p8y6> <5.1.0.14.0.20040106090928.03a8c2a0@u0019445.kuleuven.be> <001401c3d45a$7fb4b400$55e4fc3e@l8p8y6> Date: Tue, 6 Jan 2004 19:15:35 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: Re: LF: Horizontally polarised radiation Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Checker-Version: SpamAssassin 2.60 (1.212-2003-09-23-exp) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.60 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@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-PN-SPAMFiltered: yes X-Spam-Rating: 2 The DDDR is simply a quarter-wave grounded vertical with its major part bent over into a horizontal loop. The fact that it is looped back on itself is intended to have some self-cancelling effect on the radiation from the horizontal part. By design most radiation is from the short vertical part so radiation resistance is low and it has gamma matching for feeding from 50 ohm coax. Nothing magic about it but its usual proportions for HF are still impossible for amateur 136 . (how would one keep the loop up ? ) Bryan g3gvb ----- Original Message ----- From: "hamilton mal" <g3kev.ham@virgin.net> To: <rsgb_lf_group@blacksheep.org> Sent: 06 January 2004 13:25 Subject: Re: LF: Horizontally polarised radiation ----- Original Message ----- From: Rik Strobbe To: rsgb_lf_group@blacksheep.org Sent: Tuesday, January 06, 2004 8:16 AM Subject: Re: LF: Horizontally polarised radiation Hello group, It is an "idée fixe" that a horizontal wire must radiate a horizontal polarized EM-wave. A nice example of a mechanical horizontal construction that radiates a vertical polarized signal is the DDRR antenna. So a large horizontal topload close to ground will in most cases improve the antenna efficiency (reduce the loss resistance ... footprint theory) but the radiated signal will be nevertheless mainly vertical polarized. 73, Rik ON7YD At 17:47 5/01/2004 +0100, you wrote: Rik I agree with your observations. Some are being misled by computer modelling and antenna theory not applicable to the type of small LF antennas used by radio amateurs. 73 de Mal/G3KEV