Return-Path: X-Spam-DCC: paranoid 1170; 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=-0.5 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,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 u1RHlOD5001136 for ; Sat, 27 Feb 2016 18:47:24 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aZiq0-0008Q9-Vd for rs_out_1@blacksheep.org; Sat, 27 Feb 2016 17:39:28 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aZiq0-0008Q0-NF for rsgb_lf_group@blacksheep.org; Sat, 27 Feb 2016 17:39:28 +0000 Received: from brian.netcom.co.uk ([217.72.171.64]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1aZiny-00032e-IB for rsgb_lf_group@blacksheep.org; Sat, 27 Feb 2016 17:39:27 +0000 Received: from sb.abelian.org (i-194-106-52-83.freedom2surf.net [194.106.52.83]) by brian.netcom.co.uk (Postfix) with ESMTP id 04685320088 for ; Sat, 27 Feb 2016 17:14:23 +0000 (GMT) Received: from [127.0.0.1] (localhost [127.0.0.1]) by sb.abelian.org (Postfix) with ESMTP id 00F5228A0227 for ; Sat, 27 Feb 2016 17:36:47 +0000 (UTC) Message-ID: <56D1DEAF.10202@abelian.org> Date: Sat, 27 Feb 2016 17:36:47 +0000 From: Paul Nicholson User-Agent: Mozilla/5.0 (X11; Linux i686; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <56D08BEF.7070708@abelian.org> <8D33ED4DA8562EE-14E0-601004@webmail-vm018.sysops.aol.com> <56D0934B.1040700@abelian.org> <56D098D3.80501@abelian.org> <56D0B22B.2020107@abelian.org> <56D0B58A.80908@tiscali.co.uk> <56D0C373.1090004@abelian.org> <56D0CC55.1060400@tele2.se> <56D0D587.7080309@abelian.org> In-Reply-To: <56D0D587.7080309@abelian.org> X-Scan-Signature: 4e3b1488273adbbe9757d6bdd5adf219 Subject: Re: LF: MF: EbNaut Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7037 On again. Freq: 477690.00000 Hz Chars: 15 Symbols: 0.5 seconds Code: 8K19A Duration: 496 seconds, 00:08:16 Repeat: XX:00 XX:20 XX:40 I rewound the transformer, the primary windings are the braid of coax and the secondary is the series connected coax cores. FETs running a lot cooler now and the only thing getting warm is the coax. DC in 27V at 3.8A and getting the same antenna volts as yesterday with 150W in so that's a lot better. The cause of last night's high unloaded current was a shorted secondary turn - the insulation had melted. I'm a bit worried about using coax like this, the inner will be at the temperature of the braid plus its own temperature rise. I expect a short from primary to secondary when the dielectric of the tightly wound coax coil softens. I'd like to find some flat braid with high temperature insulation. The toroid I'm using is this one http://uk.rs-online.com/web/p/ferrite-rings/2120803/ which I picked because I found a MF PA design on the web which used it. It's the wire that's producing the heat, not the core. -- Paul Nicholson --