Return-Path: Received: (qmail 17046 invoked from network); 21 Dec 2002 10:58:51 -0000 Received: from murphys.services.quay.plus.net (212.159.14.225) by mailstore with SMTP; 21 Dec 2002 10:58:51 -0000 Received: (qmail 10657 invoked from network); 21 Dec 2002 10:58:42 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: from post.thorcom.com (193.82.116.70) by murphys.services.quay.plus.net with SMTP; 21 Dec 2002 10:58:42 -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 18PhKS-00080b-00 for rsgb_lf_group-outgoing@blacksheep.org; Sat, 21 Dec 2002 10:58:00 +0000 Received: from [165.212.11.112] (helo=cmsoutbound.mx.net) by post.thorcom.com with smtp (Exim 4.10) id 18PhKR-00080S-00 for rsgb_lf_group@blacksheep.org; Sat, 21 Dec 2002 10:58:00 +0000 Received: from cmsapps02.cms.usa.net (HELO localhost) (165.212.11.138) by cmsoutbound.mx.net with SMTP; 21 Dec 2002 10:57:57 -0000 Received: from usa.net [213.217.167.170] by cmsapps02.cms.usa.net (ASMTP/dibene@usa.net) via mtad (C8.MAIN.1.09A) with ESMTP id 685gLuk260280M38; Sat, 21 Dec 2002 10:53:58 GMT Message-ID: <3E044941.3060900@usa.net> Date: Sat, 21 Dec 2002 11:58:09 +0100 From: "Alberto di Bene" User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 X-Accept-Language: en-us, en MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <5.1.0.14.0.20021220113920.00af1d00@gemini.herts.ac.uk> <001501c2a839$b3db6f60$5412f4cc@jsm> Subject: LF: Re: Balanced vs. Unbalanced loops Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-0.6 required=5.0tests=USER_AGENT_MOZILLA_UAversion=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Steve McDonald wrote: > I have had good results with an ordinary (unbalanced) air-core loop of 10' > diameter. > [...] > > Just to add my experience to this debate. when I had an Rx loop, before the wind decided to take it away with itself, it was of the floating type. The loop itself had 8 turns, 2-meter each side, connected only to a primary winding of three turns on a toroid. No ground connection whatsoever. The secondary had 16 turns, whose inductance needed about 1800 pF to be resonated on 137 kHz, and was directly connected to the coax cable. The coax into the shack provided 1200 of those 1800, the rest was obtained with a variable capacitor in the shack, without any need for remote tuning. The preamp, also in the shack, was just an FET source follower to step down the high impedance of the parallel-tuned LC circuit to the 50 ohm of the Rx. I did not perform any formal tests, but sensitivity was very good, and the local noise pick up very low. My next loop will be similar to this, may be just two turns in the loop, made with thicker wire. Just my 2 cents. 73 Alberto I2PHD