Return-Path: Received: (qmail 28065 invoked from network); 24 Jun 1999 17:10:48 +0100 Received: from magnet.plus.net.uk (HELO magnet.force9.net) (195.166.128.26) by guiness.force9.net with SMTP; 24 Jun 1999 17:10:48 +0100 Received: (qmail 19737 invoked from network); 24 Jun 1999 16:10:58 -0000 Content-Transfer-Encoding: 8bit Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnet.plus.net.uk with SMTP; 24 Jun 1999 16:10:58 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 10xBtf-0000m9-00 for rsgb_lf_group-outgoing@blacksheep.org; Thu, 24 Jun 1999 16:58:39 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: from mailserv.cc.kuleuven.ac.be ([134.58.8.44]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 10xBtf-0000m4-00 for rsgb_lf_group@blacksheep.org; Thu, 24 Jun 1999 16:58:39 +0100 Received: from LCBD15.fys.kuleuven.ac.be (LCBD15.fys.kuleuven.ac.be [134.58.80.15]) by mailserv.cc.kuleuven.ac.be (8.9.0/8.9.0) with SMTP id SAA10749 for ; Thu, 24 Jun 1999 18:04:05 +0200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Message-ID: <3.0.1.16.19990624181356.2cd71e98@mail.cc.kuleuven.ac.be> X-Sender: pb623250@mail.cc.kuleuven.ac.be X-Mailer: Windows Eudora Pro Version 3.0.1 (16) Date: Thu, 24 Jun 1999 18:13:56 To: rsgb_lf_group@blacksheep.org From: "Rik Strobbe" Subject: Re: LF: ERP Calculations In-reply-to: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Sender: I have also a question regarding the topic of radiation resistance of short verticals (with and without tophats) : All the formulas I saw so far alway assumed the vertical over a perfect ground. This means that 'below the earth' there is a perfect mirror of the vertical. In theory this 'mirror' increases the ERP by 6dB (sometimes know as 'ground-gain') compared to the same antenna without mirror. But on LF the ground will be far from perfect (and so will be the 'mirror'), unless you are above saltwater or dig miles of radials in your garden. So what is the value of this formulas in the real world ? 73, Rik Rik Strobbe ON7YD rik.strobbe@fys.kuleuven.ac.be Villadreef 14 B-3128 Baal BELGIUM (JO20IX)