Return-Path: Received: from mtain-dd03.r1000.mx.aol.com (mtain-dd03.r1000.mx.aol.com [172.29.64.143]) by air-db02.mail.aol.com (v129.10) with ESMTP id MAILINDB024-86964dbd4a03266; Sun, 01 May 2011 07:54:43 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dd03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 6CABF3800008E; Sun, 1 May 2011 07:54:42 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QGVDD-0001pr-0A for rs_out_1@blacksheep.org; Sun, 01 May 2011 12:53:19 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QGVDC-0001pi-DY for rsgb_lf_group@blacksheep.org; Sun, 01 May 2011 12:53:18 +0100 Received: from nm8-vm0.bullet.mail.ukl.yahoo.com ([217.146.183.238]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1QGVDB-0006fK-0B for rsgb_lf_group@blacksheep.org; Sun, 01 May 2011 12:53:18 +0100 Received: from [217.146.183.184] by nm8.bullet.mail.ukl.yahoo.com with NNFMP; 01 May 2011 11:53:11 -0000 Received: from [217.146.183.42] by tm15.bullet.mail.ukl.yahoo.com with NNFMP; 01 May 2011 11:53:11 -0000 Received: from [127.0.0.1] by omp1027.mail.ukl.yahoo.com with NNFMP; 01 May 2011 11:53:11 -0000 X-Yahoo-Newman-Id: 359102.56931.bm@omp1027.mail.ukl.yahoo.com Received: (qmail 85977 invoked from network); 1 May 2011 11:53:11 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=DKIM-Signature:Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=wFdb51q25jRr8c3ludNbGesMc7mKPiCfuHYPruvgZRRbZq0/Iq1JJD2UrohfN6uN5S5nThQC2YlNtNaswNG3aYxDM8DV3K0ifxbB6lJ4D74FNI+rAW7bFN6UKN5zXnf6untb4JbxPKEsaAGwD41szjXWDaN4bbrpFscTyRxO9kA= ; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btopenworld.com; s=s1024; t=1304250791; bh=+sJWp0r7gUz2+5wrUERXLBLP4fINqpbDz1DtogCkS4I=; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=OTPfkzh6DCBeSr6m2Y/QmD0KC90c+18MuMjDF+mmfY2BTCEfbdd9LeVcbhRDjqCukWX19BaGyv3d0TAC9e0hb+5j4ao1LROAxoHNeOeUYIWo+ZU9Su+8N2edEXqZOnE5g36VEVWK8w/GYcYLvwkPbscrKrVRksTTnEmRdYW6slY= Received: from JimPC (james.moritz@109.156.118.245 with login) by smtp816.mail.ukl.yahoo.com with SMTP; 01 May 2011 11:53:10 +0000 GMT X-Yahoo-SMTP: Cxhli3eswBD1ozmtAojhjrja86kWx0Qm9tycD5QR1DKWrOLgjJcXkw-- X-YMail-OSG: ZSTENMgVM1l3GWRiGkIWE.lI7229Rz7NcEaoNZito30wObo mT514ychNeZgmpjoU8ZsojMQrJsWMR2vJrPY8w6BjkorXUuxqSPKA7Eyvzjl Z8.l8me4grfwWm9XchkbCvL90v9GM99uZzv.BOb4U1rsAviT2W97rbh83f71 eybBKXhtfLp..ot70ZADExwlPydUqpJStWNdvtbU_qV1PJr.pdEwbuliQtyo NqhkiL1Q085eV4.vEuf2OAHMcuuzNmCj3uGZIVsYWSMHjqlthmBtm6pTvPFA OLW5by3EaiPcnHwV88N1NA_lTEQeLLG4bA8LIxSlsOITe2UmGoUA8y8BKmrC p1IR1 X-Yahoo-Newman-Property: ymail-3 Message-ID: From: "James Moritz" To: References: <707765.95482.qm@web28101.mail.ukl.yahoo.com> In-Reply-To: <707765.95482.qm@web28101.mail.ukl.yahoo.com> Date: Sun, 1 May 2011 12:53:38 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6002.18197 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6002.18417 DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,UNPARSEABLE_RELAY=0.001 Subject: Re: LF: ERP estimation Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=MISSING_OUTLOOK_NAME 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-aol-global-disposition: G X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d241.2 ; domain : btopenworld.com DKIM : pass x-aol-sid: 3039ac1d408f4dbd4a020021 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Dear Pete, LF Group, >There must be some software written that does this? You can use NEC-based antenna simulation software (EZNEC, etc.) to obtain Rrad for your antenna, by running an "SWR plot" using perfect conductors and perfect ground. The resistive component of the antenna impedance given by the simulator is then equal to the radiation resistance, since there are no other sources of loss. This is quite useful for more complicated antenna configurations with multiple wires, elevated feeds, etc., but for most simple wire antennas, just calculating Heff as the average height of the wires gives nearly the same result, and like Andy says, it is easier and quicker just to use a calculator. Cheers, Jim Moritz 73 de M0BMU