Return-Path: Received: (qmail 14807 invoked from network); 16 Jun 1999 22:32:00 +0100 Received: from unknown (HELO magnus.force9.net) (195.166.128.27) by guiness.force9.net with SMTP; 16 Jun 1999 22:32:00 +0100 Received: (qmail 19531 invoked from network); 16 Jun 1999 19:50:36 -0000 Received: from unknown (HELO post.thorcom.com) (194.75.130.70) by magnus.plus.net.uk with SMTP; 16 Jun 1999 19:50:36 -0000 Received: from troy.blacksheep.org ([194.75.183.50] ident=root) by post.thorcom.com with esmtp (Exim 2.04 #3) id 10uKRS-0000Fe-00; Wed, 16 Jun 1999 19:29:42 +0100 Received: (from root@localhost) by troy.blacksheep.org (8.6.12/8.6.12) id SAA26231 for rsgb_lf_group-outgoing; Wed, 16 Jun 1999 18:26:37 GMT Received: from post.thorcom.com (root@post.unica.co.uk [194.75.183.70]) by troy.blacksheep.org (8.6.12/8.6.12) with ESMTP id SAA26222 for ; Wed, 16 Jun 1999 18:26:32 GMT Received: from praseodumium.btinternet.com ([194.73.73.82]) by post.thorcom.com with esmtp (Exim 2.04 #3) id 10uKNp-0000FT-00 for rsgb_lf_group@blacksheep.org; Wed, 16 Jun 1999 19:25:57 +0100 Received: from [212.140.6.200] (helo=tracey.gardner) by praseodumium.btinternet.com with smtp (Exim 2.05 #1) id 10uKJO-0005B7-00 for rsgb_lf_group@blacksheep.org; Wed, 16 Jun 1999 19:21:23 +0100 Message-ID: <000001beb825$a9a4c080$c8068cd4@tracey.gardner> From: "Tracey Gardner" To: rsgb_lf_group@blacksheep.org Subject: LF: Directional LF Antenna Date: Wed, 16 Jun 1999 10:53:16 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit 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 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Hi Mike The K9AY antenna would meet your requirement for a broad front and a "steep" null. Although the original design was not intended to be rotational, the use of two loops at right angles as per Gary Breed's QST article provides four instantly switchable directions. However it would not be impossible to make a single loop rotational but probably more trouble than it is worth when compared with the two loop option. Regards Tracey G5VU -----Original Message----- From: Mike Dennison To: rsgb_lf_group@blacksheep.org Date: 1999 Jun 16 09:53 Subject: Re: LF: DSP? I suspect that the way forward with LF reception is with a very narrow-band, highly directional rotatable receive antenna with broad front and steep null. This will allow the reduction of amateur QRM, electrical noise, and blocking by commercial signals. Interestingly, when I built an amplified ferrite rod receive antenna for 73kHz it had a much narrower bandwidth (few hundred Hz) and sharper null than my 1m loop antenna - but the loop received better!