Return-Path: X-Spam-DCC: paranoid 1290; 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 u3S9AD3F032689 for ; Thu, 28 Apr 2016 11:10:14 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1avhoz-0003an-7T for rs_out_1@blacksheep.org; Thu, 28 Apr 2016 10:01:17 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1avhoy-0003ae-IC for rsgb_lf_group@blacksheep.org; Thu, 28 Apr 2016 10:01:16 +0100 Received: from smtp-out01.xworks.net ([31.25.48.13]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1avhow-0006UA-6R for rsgb_lf_group@blacksheep.org; Thu, 28 Apr 2016 10:01:15 +0100 Received: from mailbackend2 (cluster06.xworks.net [10.100.1.80]) by smtp-out01.xworks.net (Postfix) with ESMTP id BE6BB6137A for ; Thu, 28 Apr 2016 11:01:11 +0200 (CEST) X-DKIM-Result: Domain=kabelmail.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kabelmail.de; s=mail; t=1461834071; bh=pIP/h7bGAFypIZOivQ7Da3IxWqkFHzNcXD/wlSHM8xY=; h=Subject:To:References:From:Date:MIME-Version:In-Reply-To: Content-Type; b=rP6SeF1Kxh0EYzg+xXlbn4Z8Q+5Bw4IKDakLFhINk6CnJH9Pu0it+cOlPWvOGdtSB oG32T5lLlgLD6hYyOj/8hq4ubrJy4P6a4I8DFwyGmP7JJ8dgt6CDmDCctwzYDxmLCi 22KfJzTbyR8lZNttDju3nMBO1h1so2LlQ12iu448= Received: from [192.168.178.33] (ipbcc1500e.dynamic.kabel-deutschland.de [188.193.80.14]) (authenticated bits=0) by smtpa.mediabeam.com with ESMTP id u3S9187t023913 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 28 Apr 2016 11:01:10 +0200 X-mediaBEAM-Originating-IP: [188.193.80.14] X-mediaBEAM-AUTHID: [DK1IS@kabelmail.de] 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> <572102E9.7020607@posteo.de> From: DK1IS Message-ID: <5721D33A.8040106@kabelmail.de> Date: Thu, 28 Apr 2016 11:09:14 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <572102E9.7020607@posteo.de> X-mediaBEAM-AuthCheck: route13 X-mediaBEAM-AuthScore: 1.6/5.0, scanned in 0.949sec X-MIME-Autoconverted: from 8bit to quoted-printable by smtpa.mediabeam.com id u3S9187t023913 X-Scan-Signature: 3b8620872b19e25fb6f4dfaf1256edc3 Subject: Re: VLF: T106-52 cores on VLF Content-Type: text/plain; charset=utf-8; format=flowed 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 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by paranoid.lipkowski.org id u3S9AD3F032689 Status: O X-Status: X-Keywords: X-UID: 7886 Hi Stefan, I think the problem are the airgaps between the cores. Perhaps you´ll get a little better result if you grind down the coatings at the inner front ends of the cores. Although its nearly impossible to get really smooth fitting surfaces in this way there should be some improvement. Due to the low conductivity of the core material the loss of coating shouldn´t have appreciable disadvantages. 73, Tom, DK1IS - still working at his remote garage RX site. Am 27.04.2016 um 20:20 schrieb DK7FC: > 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 > > > . >