Return-Path: Received: (qmail 14266 invoked from network); 10 Jan 2000 11:35:20 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by teachers.core.plus.net.uk with SMTP; 10 Jan 2000 11:35:20 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 127cvI-00002v-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 10 Jan 2000 11:23:44 +0000 Received: from cmailg3.svr.pol.co.uk ([195.92.195.173]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 127cvG-00002q-00 for rsgb_lf_group@blacksheep.org; Mon, 10 Jan 2000 11:23:42 +0000 Received: from modem-216.name65.dialup.pol.co.uk ([62.136.192.216] helo=lvm) by cmailg3.svr.pol.co.uk with smtp (Exim 3.12 #0) id 127cv9-00005t-00 for rsgb_lf_group@blacksheep.org; Mon, 10 Jan 2000 11:23:36 +0000 Message-ID: <000201bf5b5d$182c3620$d8c0883e@lvm> From: "LAWRENCE MAYHEAD" To: "rsgb lf group" Subject: LF: LF Loops etc. Date: Mon, 10 Jan 2000 11:19:37 -0000 MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-transfer-encoding: 8bit

Re. the ongoing discussion about loops. I agree that loops are very inefficient,not surprising since the radiation resistance is so low for a neccessarily very small loop on 136.(even a single turn loop several hundred feet long is far short of a wavelength)And of course the DC resistance cannot be made anywhere near low enough.HOWEVER for recieve purposes where the ant signal far exceeds reciever noise the loops directional properties can be used to good effect.Both single and multi-turn loops exhibit a "fig of 8" pattern with very deep nulls on the side, or if configured as an EWE the pattern can be cardoid giving some gain in the favoured direction and some b/front. Grounded bi-poles as described earlier are single turn loops using ground as one leg of the loop.No doubt the grounding helps with local noise/static etc. but by putting a resistor in one leg the "fig8" pattern can be made into a cardoid. I am using a grounded loop here to reject the Loran station in France (only 150 Km from this QTH) with very great success.

In conclusion I would not use a loop for transmitting ! but dont forget its valuable properties as a recieving antenna. 73s Laurie.