Return-Path: Received: (qmail 22405 invoked from network); 20 Sep 2002 05:03:42 -0000 Content-Transfer-Encoding: 8bit Received: from murphys.services.quay.plus.net (212.159.14.225) by mailstore with SMTP; 20 Sep 2002 05:03:42 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 11231 invoked from network); 20 Sep 2002 05:03:45 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 20 Sep 2002 05:03:45 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 17sFwC-0007f1-00 for rsgb_lf_group-outgoing@blacksheep.org; Fri, 20 Sep 2002 06:02:44 +0100 Received: from [212.164.44.2] (helo=astral.omskcity.com) by post.thorcom.com with esmtp (Exim 4.10) id 17sFwB-0007er-00 for rsgb_lf_group@blacksheep.org; Fri, 20 Sep 2002 06:02:43 +0100 Received: from fitec.omskcity.com (mu06.dialup2.infomsk.ru [212.164.44.118]) by astral.omskcity.com (8.9.3/8.9.3) with SMTP id LAA3d8aaa9a6b09 for ; Fri, 20 Sep 2002 11:56:58 +0700 (OSS) Date: Fri, 20 Sep 2002 12:38:17 +0000 (GMT) From: "Alexander S. Yurkov" To: rsgb_lf_group@blacksheep.org In-reply-to: <001701c24cc5$28f972e0$5d6152d5@it> Message-ID: MIME-Version: 1.0 Subject: Re: LF: IK2DED beacon and E field probe. Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Spam-Status: No, hits=-1.0 required=5.0tests=IN_REP_TO,DATE_IN_FUTURE_06_12version=2.31 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Hi, Giulio and Group. On Mon, 26 Aug 2002, Giulio Scaroni wrote: > Hi Alex and all, > soon i'll measure exactly the antenna current, but one things that appear > in this discussion, is that the antenna work very well, it is only a single > wire 60 meters long about 1 meters far at the top of the tower, and about > 25 meters far at the base. > I have read that wire near a tower has many losses, but this seems to > confirm the opposite, also the tower that i use in winter in Mantova have > the same wire antenna, little bit longer, and with only 100 W my signal is > perfectly audible in UK... > So, may be that the big tower act like a big additional vertical capacitance > to increase signal output?? I think in such a configuration tower act as radiated part of antenna also. It makes not simple to estimate EPR in this case "by a pencil". But if use someone version of NEC program (EZNEC, ELNEC, MMANA, MININEC e t.c.) it is posible. But antenna currend is need if use program also. Such a program can not correctly estimate loss resistance. So its "direct" using is imposible on LF. But if set souce off current type with measured (experimental) current then EPR, imagine part of input impedance (ractance) and field strenght should be aproximatly correct, only TX power and real part or input impedance will be incorrect. But TX power, is known with out any calculation! Such a combination of experiment and modeling sould give reasonable estimation of EPR in such a complex condition. Of cose tower should be incloud in NEC model also. But any way antenna current is need... 73 de RA9MB/Alex http://www.qsl.net/ra9mb