Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dh01.r1000.mx.aol.com (Internet Inbound) with ESMTP id B616F380000AE; Thu, 5 Apr 2012 19:07:09 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SFvl4-0000XP-R6 for rs_out_1@blacksheep.org; Fri, 06 Apr 2012 00:06:26 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SFvl4-0000XG-FP for rsgb_lf_group@blacksheep.org; Fri, 06 Apr 2012 00:06:26 +0100 Received: from relay2.uni-heidelberg.de ([129.206.210.211]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1SFvl3-00046q-0y for rsgb_lf_group@blacksheep.org; Fri, 06 Apr 2012 00:06:26 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay2.uni-heidelberg.de (8.13.8/8.13.8) with ESMTP id q35N5TwJ012096 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 6 Apr 2012 01:06:24 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id q35ELxXe024437 for ; Thu, 5 Apr 2012 16:21:59 +0200 Message-ID: <4F7DAA67.1000404@iup.uni-heidelberg.de> Date: Thu, 05 Apr 2012 16:21:27 +0200 From: =?ISO-8859-15?Q?Stefan_Sch=E4fer?= 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 X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,RATWARE_GECKO_BUILD=1.426 Subject: VLF: Audio transformer test Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63 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-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:429079072:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d41154f7e259d35b0 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none VLF, I just checked the amplitude and frequency respose of the audio transformer i use to decouple my signals between soundcard and antenna. Just a simple test. They are in use in various applications, are cheep and small. Type, Distributor and datasheet: http://www.reichelt.de/Trenntrafos/NFU-1-4/index.html?;ACTION=3;LA=444;GROUP=C54;GROUPID=3320;ARTICLE=73039;START=0;SORT=artnr;OFFSET=16;SID=32fRwi5qwQASAAACIkJWk502917f27b61570f9f85c5c030e3f831#av_tabdata Looks they operate down to 5 Hz which is excellent: http://dl.dropbox.com/u/19882028/VLF/Uebertragertest.png Also the wide range looks fine up to 20 kHz: http://dl.dropbox.com/u/19882028/VLF/Uebertragertest_wide.png In the pictures, the upper SL instance is a frequency generator driving the headphone output of the soundcard. The lower instance records signals coming from the Mic input. As a conclusion i found that the transformer is even suitable for ZEVS receiving at 82 Hz. 73, Stefan/DK7FC