Return-Path: Received: (qmail 14155 invoked from network); 19 Oct 2002 15:25:03 -0000 Received: from warrior.services.quay.plus.net (212.159.14.227) by mailstore with SMTP; 19 Oct 2002 15:25:03 -0000 Received: (qmail 5730 invoked from network); 19 Oct 2002 15:24:23 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by warrior.services.quay.plus.net with SMTP; 19 Oct 2002 15:24:23 -0000 Received: from majordom by post.thorcom.com with local (Exim 4.10) id 182vS2-0002eK-00 for rsgb_lf_group-outgoing@blacksheep.org; Sat, 19 Oct 2002 16:23:42 +0100 Received: from [212.126.133.91] (helo=orion.bikerz.local) by post.thorcom.com with esmtp (Exim 4.10) id 182vS1-0002eB-00 for rsgb_lf_group@blacksheep.org; Sat, 19 Oct 2002 16:23:42 +0100 Date: Sat, 19 Oct 2002 14:45:52 -0000 Message-ID: MIME-Version: 1.0 Thread-Topic: Re^2: LF: Non-linear signal processing Thread-Index: AcJ2tCB6qRcpxKPTTWakMR8iGkwhFQAx8Haw From: "Martyn Kinder" content-class: urn:content-classes:message X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 To: rsgb_lf_group@blacksheep.org Subject: LF: Ant Questions Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=0.8 required=5.0tests=SPAM_PHRASE_00_01version=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Hi all, I'm about to put up a 136kHz Antenna and have a couple of questions. I don't have much space in the garden, approx 20m from the apex of the roof to a 20m high poplar tree in the opposite corner. I am considering an offset 'T' with a multi-wire top. I am assuming (within practical limits) that as much capacitance as possible in the antenna is beneficial. It will resonate with lower inductance and therefore lower resistive losses. The RSGB LF experimenters h/b (p52) suggests that 2 wires separated by 100mm will provide 39% increase in capacitance. Is it safe to assume that putting multiple wires up at 100mm will provide a compound percentage increase? I am considering 6 wires at 100mm separation. Are there any better solutions - I have neighbours I wish to remain on speaking terms with... What effect does height have on the antenna? I can fairly safely get the antenna up to 10m above ground level without too much difficulty. Will there be any significant benefit to raising the tree end of the antenna to say 15m. I will probably feed the aerial at about 5m from the house with two coils, one at ground level and a second 2 litre coke bottle sized coil at the junction between the vertical and the capacitive top. Sorry for the newbie type questions. Getting this right first time is important, neither the tree nor the apex of the house are particularly easy to get at and I don't want to do it too many times... 73, Martyn G0CZD