Return-Path: X-Spam-DCC: paranoid 104; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,RATWARE_GECKO_BUILD,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u3RHu6ew030840 for ; Wed, 27 Apr 2016 19:56:06 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1avTdi-00021E-Ur for rs_out_1@blacksheep.org; Wed, 27 Apr 2016 18:52:42 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1avTdi-000215-JO for rsgb_lf_group@blacksheep.org; Wed, 27 Apr 2016 18:52:42 +0100 Received: from parrot.netcom.co.uk ([217.72.171.49]) by relay1.thorcom.net with esmtp (Exim 4.87) (envelope-from ) id 1avTdg-0003hO-L2 for rsgb_lf_group@blacksheep.org; Wed, 27 Apr 2016 18:52:41 +0100 Received: from pn.abelian.org (i-194-106-52-83.freedom2surf.net [194.106.52.83]) by parrot.netcom.co.uk (Postfix) with ESMTP id 635E93273E5 for ; Wed, 27 Apr 2016 18:51:31 +0100 (BST) Received: from [127.0.0.1] (localhost [127.0.0.1]) by pn.abelian.org (Postfix) with ESMTP id 9839C400401 for ; Wed, 27 Apr 2016 17:52:39 +0000 (UTC) To: rsgb_lf_group@blacksheep.org References: <571CF2AD.9030207@posteo.de> <571D2966.5080104@posteo.de> <571D3034.8020204@mbsks.franken.de> <571D31EE.9030106@posteo.de> <571DD4DE.3080703@abelian.org> <571E54B9.9010208@posteo.de> <571E5C16.2090102@mbsks.franken.de> <571E5F26.1080605@mbsks.franken.de> <571E92A0.3000608@posteo.de> <571E98A7.5070503@posteo.de> <571F87A2.7000700@abelian.org> <571FC3E8.1000706@posteo.de> <5720D81D.6020609@abelian.org> <5720E958.2010104@posteo.de> <5720F2DB.3030704@freenet.de> From: Paul Nicholson Message-ID: <5720FC67.7040001@abelian.org> Date: Wed, 27 Apr 2016 17:52:39 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: X-Scan-Signature: 7aa9ad08848e488e22e0ff1d71f4ef1d Subject: Re: VLF: A single turn RX loop for VLF Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7878 You can eliminate the transformer by having more turns in the loop. But you'll probably find when you do the arithmetic, that it is cheaper to have fewer turns (or one turn) and a transformer. Also for helping with balance and isolation the transformer is useful even if you didn't need impedance increase. You may also find a lower thermal noise floor with few turns and a transformer, compared with the same loop area and many turns. I use 3 turns (mains cable) of about 20 square metres, an audio transformer with ratio 1:12.6 and LT1028 preamp. Modeled fairly well in this example http://abelian.org/lcnetgen/ex6.html -- Paul Nicholson --