Return-Path: X-Spam-DCC: paranoid 1356; 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=-2.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO 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 tAJCEaVP004758 for ; Thu, 19 Nov 2015 13:14:36 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZzO3c-0000ZG-KO for rs_out_1@blacksheep.org; Thu, 19 Nov 2015 12:11:20 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZzO3c-0000Z7-Bg for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 12:11:20 +0000 Received: from smarthost01d.mail.zen.net.uk ([212.23.1.7]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1ZzO2Y-0006qN-2o for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 12:11:19 +0000 Received: from [82.70.254.222] (helo=OfficeWin7.lan) by smarthost01d.mail.zen.net.uk with esmtp (Exim 4.80) (envelope-from ) id 1ZzO2K-000EzL-BT for rsgb_lf_group@blacksheep.org; Thu, 19 Nov 2015 12:10:00 +0000 Date: Thu, 19 Nov 2015 12:10:00 +0000 From: Chris Wilson Organization: Gatesgarth Developments X-Priority: 3 (Normal) Message-ID: <511722761.20151119121000@chriswilson.tv> To: "rsgb_lf_group@blacksheep.org" MIME-Version: 1.0 X-Originating-smarthost01d-IP: [82.70.254.222] X-Scan-Signature: 0a4643e586472c13187d293ec5d096c2 Subject: LF: Variometer positioning Content-Type: text/plain; charset=us-ascii 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 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 5168 19 November 2015 I am adding remote variometer control to my 136kHz loading coil. I would like to know what impact the placement of the variometer has. For example, I could add it before the bottom winding of the loading coil, in the middle, by splitting the windings, or at the top, between top winding and aerial. I am guessing I should place it before the coil's bottom winding to minimise voltages on it, but am unsure what other impact this may have. I am hoping to use this ex Russian device in the link below, motor driven via its reduction gear quadrant, via a 1 RPM drive motor. It goes from about 16 to 100uH with the windings wired in series. Images of variometer here: http://www.chriswilson.tv/variometer.zip Thanks. -- Best regards, Chris 2E0ILY mailto:chris@chriswilson.tv