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=-1.0 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,SUBJ_RE_NUM 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 t9VCL7SO011700 for ; Sat, 31 Oct 2015 13:21:07 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZsV5x-000493-8F for rs_out_1@blacksheep.org; Sat, 31 Oct 2015 12:17:17 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZsV5w-00048u-Vk for rsgb_lf_group@blacksheep.org; Sat, 31 Oct 2015 12:17:16 +0000 Received: from smarthost01d.mail.zen.net.uk ([212.23.1.7]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1ZsV4s-0001zI-Qf for rsgb_lf_group@blacksheep.org; Sat, 31 Oct 2015 12:17:15 +0000 Received: from [82.70.254.222] (helo=OfficeWin7.lan) by smarthost01d.mail.zen.net.uk with esmtp (Exim 4.80) (envelope-from ) id 1ZsV4c-0009Zj-U7 for rsgb_lf_group@blacksheep.org; Sat, 31 Oct 2015 12:15:55 +0000 Date: Sat, 31 Oct 2015 12:15:52 +0000 From: Chris Wilson Organization: Gatesgarth Developments X-Priority: 3 (Normal) Message-ID: <316685691.20151031121552@chriswilson.tv> To: Mike Dennison In-Reply-To: <5633D56C.20659.23BE4D8@mike.dennison.ntlworld.com> References: <1887849276.20151030143118@chriswilson.tv>, <5633B50A.5030903@posteo.de> <5633D56C.20659.23BE4D8@mike.dennison.ntlworld.com> MIME-Version: 1.0 X-Originating-smarthost01d-IP: [82.70.254.222] X-Scan-Signature: 66d07794ca19cd68f7d6cc289cd4ac18 Subject: Re[2]: LF: Zmag of 45.6 Ohms OK, or should I try for better? 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: 4724 Hello Mike, Friday, October 30, 2015 yes, I still have trouble with the workshop alarm going off when I TX, but seemingly only at night, for whatever reason! Isolation is something I need to add. I have a 3C90 core spare and will wind a 1 : 1 transformer for now, just for isolation. How many turns should I use for best efficiency? I will probably use either 1.5 mm enamelled wire, or maybe some Teflon covered stuff. I also need to tame the variometer, it's obviously got far too many turns on it as just a couple of degrees moves resonance a long way. I picked up a 2 axis variometer, possibly a goniometer, that I may ise, with a motor drive. Photos at http://www.chriswilson.tv/goniometer.zip I only gave a fiver for it, so no big deal if it doesn't work out, but I am about to check what inductances it covers. I think it should withstand the voltages OK. What do you reckon? It would be easier to motor drive then the variometer in my loading coil. Thanks for the kind words about my progress. Most thanks should go to G3YXM for helping me get my amp done and reliable, he's been a Godsend, as have you gentlemen on here. > I agree with Stefan. A transformer (using a suitable core material > such as 3C90) gives you more flexibility in the future It also > provides the opportunity to isolate the RF ground from the mains > supply ground which can improve EMC both on transmit and receive. > Well done so far. Your signal is very impressive with such low RF > power. > Mike, G3XDV > ========== -- Best regards, Chris mailto:chris@chriswilson.tv