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=-0.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, 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 u3RGdCDh030628 for ; Wed, 27 Apr 2016 18:39:12 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1avSN1-0001K3-Ha for rs_out_1@blacksheep.org; Wed, 27 Apr 2016 17:31:23 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1avSN1-0001Ju-1P for rsgb_lf_group@blacksheep.org; Wed, 27 Apr 2016 17:31:23 +0100 Received: from mout01.posteo.de ([185.67.36.65]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1avSMy-0003Fi-W2 for rsgb_lf_group@blacksheep.org; Wed, 27 Apr 2016 17:31:21 +0100 Received: from dovecot03.posteo.de (dovecot03.posteo.de [172.16.0.13]) by mout01.posteo.de (Postfix) with ESMTPS id 51E8D209F6 for ; Wed, 27 Apr 2016 18:31:20 +0200 (CEST) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot03.posteo.de (Postfix) with ESMTPSA id 3qw57X1Z4pz5vMK for ; Wed, 27 Apr 2016 18:31:20 +0200 (CEST) Message-ID: <5720E958.2010104@posteo.de> Date: Wed, 27 Apr 2016 18:31:20 +0200 From: DK7FC User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 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> In-Reply-To: <5720D81D.6020609@abelian.org> X-Scan-Signature: 086f3faad0220c9ae57a7913e711a86d Subject: 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: 7872 Hi VLF, Today i've installed a second loop into the tree. It is a simple copper tube having 10 mm diameter and about 4m length. https://dl.dropboxusercontent.com/u/19882028/VLF/20160427_084708.jpg The loop is not resonated. The ends are just hold together with a screw. https://dl.dropboxusercontent.com/u/19882028/VLF/20160427_092012.jpg It is a very stable / robust construction which needs no further elements to hold it into the tree. The screw is protected against rain with some bonding tape. Before the mounting, a ferrite transformer with Al ~ 6000 nH was put on the tube. First i tried 20 secondary turns. https://dl.dropboxusercontent.com/u/19882028/VLF/20160427_092420.jpg Later i choose 40 turns and finally 80 turns. The results between the N-S loop and the E-W loop are still visible at http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html DHO38 is much weaker, the Alphas are much stronger, HWU is stronger. All in all it appears that this loop performs better then my 80 turn hula hup circle loop (0.8m diameter). And by using the transformer it can be adapted optimally to the preamp input impedance. It even works down to 100 Hz, with limited performance of course. I'm now looking forward to receive something from the East or West. Is there someone out there ready to radiate a signal? Also, a VLF RDF grabber would be fine, maybe even by using idenetical antennas (to be built). 73, Stefan PS: BEWARE: This is not new! Someone has done it before, maybe even in the 1920s. VLF receptions on the Dreamers Band were done with such a loop for example by F5WK (http://f5wk.blogspot.de/2010/09/antenne-loop-vlf.html).