Return-Path: Received: (qmail 95172 invoked from network); 9 Jan 2005 09:23:48 -0000 Received: from unknown (HELO ptb-spamcore01.plus.net) (192.168.71.1) by ptb-mailstore01.plus.net with SMTP; 9 Jan 2005 09:23:48 -0000 Received: from mailnull by ptb-spamcore01.plus.net with spamcore-l-b (Exim 4.32; FreeBSD) id 1CnZIB-0003o5-SV for dave@picks.force9.co.uk; Sun, 09 Jan 2005 09:23:24 +0000 Received: from [192.168.67.1] (helo=ptb-mxcore01.plus.net) by ptb-spamcore01.plus.net with esmtp (Exim 4.32; FreeBSD) id 1CnZIB-0003o2-Q1 for dave@picks.force9.co.uk; Sun, 09 Jan 2005 09:23:23 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore01.plus.net with esmtp (Exim 4.30; FreeBSD) id 1CnZIZ-000Jcy-HO for dave@picks.force9.co.uk; Sun, 09 Jan 2005 09:23:47 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1CnZGQ-0003Bz-CW for rs_out_1@blacksheep.org; Sun, 09 Jan 2005 09:21:34 +0000 Received: from [193.82.116.30] (helo=relay.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1CnZGO-0003Bk-Di for rsgb_lf_group@blacksheep.org; Sun, 09 Jan 2005 09:21:32 +0000 Received: from relay.sotline.ru ([80.89.139.226]) by relay.thorcom.net with esmtp (Exim 4.43) id 1CnZGN-0008RH-PP for rsgb_lf_group@blacksheep.org; Sun, 09 Jan 2005 09:21:32 +0000 Received: from astral.omskcity.com (mxs.sotline.ru [80.89.139.227]) by relay.sotline.ru (8.12.8p2/8.12.8) with ESMTP id j099LT5n052961 for ; Sun, 9 Jan 2005 15:21:29 +0600 (OMST) (envelope-from fitec@omskcity.com) Received: from noname.nodomain.nowhere (host196.m02.dial.sotline.ru [81.176.51.196]) by astral.omskcity.com (8.x.x) with ESMTP id j099LI3w005157 for ; Sun, 9 Jan 2005 15:21:28 +0600 (OS) Received: from localhost (fitec@localhost) by noname.nodomain.nowhere (8.8.5/8.8.5) with SMTP id OAA00203 for ; Sun, 9 Jan 2005 14:10:26 GMT X-Authentication-Warning: noname.nodomain.nowhere: fitec owned process doing -bs Date: Sun, 9 Jan 2005 14:10:25 +0000 (GMT) From: "Alexander S. Yurkov" To: rsgb_lf_group@blacksheep.org In-Reply-To: <000501c4f5de$3bcb98c0$ee9bfea9@oben> Message-ID: MIME-Version: 1.0 X-SPF-Result: relay.thorcom.net: domain of omskcity.com designates 80.89.139.226 as permitted sender X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=failed,FORGED_RCVD_HELO=0.05 Subject: Re: LF: Antenna plans de J. Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed 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-transfer-encoding: 8bit On Sun, 9 Jan 2005, dj9dw wrote: > > 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? Seems should be bit grater. For infinity large top load 1600(22/2200)^=0.16=160 mOhm. Capacitance of vertical wire aproximaly 6*22=130 pF wich is less then 300pF. Certanly top load is not infinite in comparison with 130 pF. Antenna effective height is reduced by factor [Ct/(Ct+Cv)+1]/2 where Ct is capacitance of top load Cv is capacitance of vertical wire. Thus Heff=22[300/430+1]/2=18.7m R=1600(18.7/2200)^2=0.12 Ohm=120 mOhm. Thus effectivety is 0.12/24=0.005 or 0.5 percent. To radiate 1W one need TX of 200W. Certanly all of this is true only if top load is absolutely horizontal. If free end goes doun then resistance should be less then 120 mOhm. Besides reradiation by enviroment can reduce radiated power. 73 de RA9MB/Alex http://www.qsl.net/ra9mb