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 u3RINrEk030898 for ; Wed, 27 Apr 2016 20:23:53 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1avU4c-0002Mc-6s for rs_out_1@blacksheep.org; Wed, 27 Apr 2016 19:20:30 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1avU4b-0002MT-Ua for rsgb_lf_group@blacksheep.org; Wed, 27 Apr 2016 19:20:29 +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 1avU4a-0003sR-DX for rsgb_lf_group@blacksheep.org; Wed, 27 Apr 2016 19:20:28 +0100 Received: from dovecot03.posteo.de (dovecot03.posteo.de [172.16.0.13]) by mout01.posteo.de (Postfix) with ESMTPS id 224D420D2C for ; Wed, 27 Apr 2016 20:20:25 +0200 (CEST) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot03.posteo.de (Postfix) with ESMTPSA id 3qw7YP6Mzyz5vN0 for ; Wed, 27 Apr 2016 20:20:25 +0200 (CEST) Message-ID: <572102E9.7020607@posteo.de> Date: Wed, 27 Apr 2016 20:20:25 +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> <5720E958.2010104@posteo.de> In-Reply-To: <5720E958.2010104@posteo.de> X-Scan-Signature: 7aa9ad08848e488e22e0ff1d71f4ef1d Subject: VLF: T106-52 cores on VLF Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 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: 7881 Hi VLF, I've done a quick experiment with the T106-52 cores which could give some more ideas regarding these cores for a compact VLF coil. I wound a coil with 0.5mm enameled cu wire, 85 turns at 33mm diameter. Inside the coil there are 5 of these cores stacked on another. In parallel there is a suitable C of 1 uF. https://dl.dropboxusercontent.com/u/19882028/VLF/20160427_195530.jpg The resonance was found at 7.49 kHz. The 3 dB bandwidth is (7.64-7.36) kHz = 280 Hz. Q = 27. L = 452 uH. Without the cores inside, the resonance frequency rises to 14.54 kHz and the bandwidth is (15.12-14.07) kHz = 1.05 kHz. Q = 14. L = 120 uH. Hmm, so in this configuration, the effective µr (ur) seems to be just 3.75! :-/ That means i still need half of the number of turns for a single layer VLF transmit coil?!? 73, Stefan