Return-Path: Received: (qmail 16107 invoked from network); 19 Sep 2002 14:26:00 -0000 Received: from marstons.services.quay.plus.net (212.159.14.223) by mailstore with SMTP; 19 Sep 2002 14:26:00 -0000 Content-Transfer-Encoding: 8bit Received: (qmail 27976 invoked by uid 10001); 19 Sep 2002 15:30:12 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 19 Sep 2002 15:30:12 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.10) id 17s2EE-00068X-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 19 Sep 2002 15:24:26 +0100 Received: from [134.58.10.50] (helo=mail2.cc.kuleuven.ac.be) by post.thorcom.com with esmtp (Exim 4.10) id 17s2ED-000681-00 for rsgb_lf_group@blacksheep.org; Thu, 19 Sep 2002 15:24:25 +0100 Received: from dell-rik.fys.kuleuven.ac.be ([10.33.165.177]) by mail2.cc.kuleuven.ac.be (8.12.1/8.12.1) with ESMTP id g8JENtiY180658 for ; Thu, 19 Sep 2002 16:23:55 +0200 Message-ID: <5.1.0.14.0.20020919162016.02900258@pb623250.kuleuven.be> X-Sender: pb623250@pb623250.kuleuven.be X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Thu, 19 Sep 2002 16:28:49 +0200 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" In-reply-to: References: <17a.ed80937.2abae90c@aol.com> 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=-2.3 required=5.0tests=IN_REP_TO,DOUBLE_CAPSWORDversion=2.31 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group >ERP is mainly determed by antenna current and efffective height. If this >is known then it is very simple to estimate radiated power. Certanly this >is very aproximative estimation. But something is better then nothing :-) Hi Alex, be careful with that. I speak from my own experience : Antenna = 14m heigh inverted-L with elevated loading coil and 4 x 23m topload wire, calculated and simulated Rrad = +/- 0.06 Ohm Antenna current = 1.8A Theory : radiated power = 0.06*1.8^2 = 194mW EMRP (= 583mW EIRP or 355mW ERP) Reality : about 35mW ERP (based on field strength measurement) Difference : -10dB ! Reason : antenna surrounded by many trees Maybe most other hams have more luck (less trees), but take into account that real ERP is 2 to 6dB below the calculated ERP. 73, Rik ON7YD