Return-Path: Received: (qmail 90894 invoked from network); 1 Jan 2004 23:03:53 -0000 Received: from unknown (HELO ptb-mxscan01.plus.net) (212.159.14.235) by ptb-mailstore02.plus.net with SMTP; 1 Jan 2004 23:03:53 -0000 Received: (qmail 72897 invoked from network); 1 Jan 2004 23:03:52 -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; 1 Jan 2004 23:03:51 -0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim) id 1AcBr5-000Ir4-QG for dave@picks.force9.co.uk; Thu, 01 Jan 2004 23:03:51 +0000 X-Fake-Domain: majordom Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1AcBqj-0003LB-DI for rs_out@blacksheep.org; Thu, 01 Jan 2004 23:03:29 +0000 Received: from [212.135.6.12] (helo=smarthost2.mail.uk.easynet.net) by post.thorcom.com with esmtp (Exim 4.14) id 1AcBqi-0003L2-Vw for rsgb_lf_group@blacksheep.org; Thu, 01 Jan 2004 23:03:29 +0000 Received: from tnt-2-117.easynet.co.uk ([195.40.196.117] helo=erica) by smarthost2.mail.uk.easynet.net with smtp (Exim 4.10) id 1AcBqh-000ERb-00 for rsgb_lf_group@blacksheep.org; Thu, 01 Jan 2004 23:03:28 +0000 X-Bad-Message-ID: no DNS (erica) Message-ID: <000001c3d0bd$774df560$75c428c3@erica> From: "g3ldo" To: rsgb_lf_group@blacksheep.org References: <000001c3d009$acf7a620$c7e47f50@Smisan> Date: Thu, 1 Jan 2004 22:31:13 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: Re: LF: Re: "T" versus "L"aerial 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: 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 Mike, PC4M said ----------------------------------- Does the computer calculate the earth losses in the return path from the aerial system to the transmitter? If it would then the earth losses in a T should have been significantly less then the L alternative. There are two separate return currents (parallel resistance) and each with a smaller physical length (lower R-earth) in a T system resulting in more ERP if compared to an L system. ----------------------------------- In the early days of LF experimenting we all thought Ts and Ls from available LF commercial knowledge. It soon became apparent that for a suburban QTH the shape of the antenna was unimportant. The trick seemed to be to put up as much wire covering the greatest area and as high as possible. John, G4JVC had a long wire running the length of the garden, 3m high at the feed end and 12m high at the other. With this antenna and a TS-850 he was able to hear a lot of DX that we couldn't (he was the first to hear OH5TN). All very electrically small antennas have the same half doughnut shaped 3-D polar diagram on a computer model. Ground parameters have a huge effect on small LF antenna performances so I guess they must compute return path losses. Regards, Peter, G3LDO e-mail