Return-Path: Received: (qmail 49067 invoked from network); 8 Jan 2005 23:50:24 -0000 Received: from unknown (HELO ptb-spamcore02.plus.net) (192.168.71.3) by ptb-mailstore02.plus.net with SMTP; 8 Jan 2005 23:50:24 -0000 Received: from mailnull by ptb-spamcore02.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1CnQKz-0000oG-5X for dave@picks.force9.co.uk; Sat, 08 Jan 2005 23:49:42 +0000 Received: from [192.168.67.3] (helo=ptb-mxcore03.plus.net) by ptb-spamcore02.plus.net with esmtp (Exim 4.32; FreeBSD) id 1CnQKy-0000oD-VL for dave@picks.force9.co.uk; Sat, 08 Jan 2005 23:49:40 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore03.plus.net with esmtp (Exim) id 1CnQLe-0001CM-Rq for dave@picks.force9.co.uk; Sat, 08 Jan 2005 23:50:22 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1CnQJ9-0000aS-2K for rs_out_1@blacksheep.org; Sat, 08 Jan 2005 23:47:47 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1CnQJ8-0000aJ-Jj for rsgb_lf_group@blacksheep.org; Sat, 08 Jan 2005 23:47:46 +0000 Received: from mailout11.sul.t-online.com ([194.25.134.85]) by relay.thorcom.net with esmtp (Exim 4.43) id 1CnQJ6-0001GJ-5v for rsgb_lf_group@blacksheep.org; Sat, 08 Jan 2005 23:47:46 +0000 Received: from fwd11.aul.t-online.de by mailout11.sul.t-online.com with smtp id 1CnQJ0-0006Ve-00; Sun, 09 Jan 2005 00:47:38 +0100 Received: from oben (E16Ui+ZfreAEdHj1zgdMfQ00TzzdGVbZhS-LKXiPj9vQB2h+Orgw6H@[217.88.167.80]) by fwd11.sul.t-online.com with smtp id 1CnQIw-1Ev1CS0; Sun, 9 Jan 2005 00:47:34 +0100 Message-ID: <000501c4f5de$3bcb98c0$ee9bfea9@oben> From: dj9dw To: rsgb_lf_group@blacksheep.org References: Date: Sun, 9 Jan 2005 01:00:30 +0100 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1437 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-ID: E16Ui+ZfreAEdHj1zgdMfQ00TzzdGVbZhS-LKXiPj9vQB2h+Orgw6H X-TOI-MSGID: 537f55e4-e16a-45fc-be1e-b9d44f3b05b6 X-SPF-Result: relay.thorcom.net: 194.25.134.85 is neither permitted nor denied by domain of t-online.de X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=failed,none Subject: Re: LF: Antenna plans de J. X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 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_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Spam-Filtered: by PlusNet SpamCORE (v3.00) Content-type: text/plain; charset=windows-1252; format=flowed MIME-Version: 1.0 Content-transfer-encoding: 8bit Alexander, how much topload on your vertical? Mine is 22m high with 300pF top. R at feedpoint is 24 Ohm. After some tests (compared with DCF39) and calculations the radiating restistance seems to be abt. 45 mOhm. Realistic? 73 es gl de Peter, dj9dw ----- Original Message ----- From: "Alexander S. Yurkov" To: Sent: Sunday, January 09, 2005 2:39 AM Subject: Re: LF: Antenna plans de J. > > Dear J, > > On Fri, 7 Jan 2005, J. Allen wrote: > > > > > Elnec shows the radiation resistance of the antenna with all resistances set > > to zero, to be about 0.02053 Ohms. > > It seems to be very strange. Simple formula for top > loaded vertical R=1600(H/lambda)^2 yelds about 0.16 Ohms if H=20m. Though > it is more resonable then 0.02 Ohms. Are You sure there is no mistake in > elnec modeling? Number of computer experiments with NEC done by me > for different antennas on 136 kHz yelds results very close to this simple > formula. > > 73 de RA9MB/Alex > http://www.qsl.net/ra9mb > > >