Return-Path: X-Spam-DCC: paranoid 1233; 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=-2.4 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, 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 u1TLaccA007250 for ; Mon, 29 Feb 2016 22:36:39 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aaVQf-0000iJ-U6 for rs_out_1@blacksheep.org; Mon, 29 Feb 2016 21:32:33 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aaVQf-0000iA-G5 for rsgb_lf_group@blacksheep.org; Mon, 29 Feb 2016 21:32:33 +0000 Received: from mout.gmx.net ([212.227.17.21]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.86) (envelope-from ) id 1aaVQd-00053L-TQ for rsgb_lf_group@blacksheep.org; Mon, 29 Feb 2016 21:32:32 +0000 Received: from Clemens0811 ([79.237.130.200]) by mail.gmx.com (mrgmx101) with ESMTPSA (Nemesis) id 0MdnN3-1aFvk13xpl-00PeMN for ; Mon, 29 Feb 2016 22:32:29 +0100 From: "Clemens Paul" To: 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> <56D1DEAF.10202@abelian.org> <56D1FD5F.3010301@abelian.org> <56D2DA6D.20209@tele2.se> <56D326F1.1000102@abelian.org> <56D33297.9080209@abelian.org> <56D37529.9070607@abelian.org> <6732A7AB5E094156B6AE3A33E58A964F@White> <56D3875A.4060405@abelian.org> In-Reply-To: <56D3875A.4060405@abelian.org> Date: Mon, 29 Feb 2016 22:32:27 +0100 Message-ID: <4F4F6D69C89949808409DA43533DE43D@Clemens0811> MIME-Version: 1.0 X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.1.7601.17609 Thread-Index: AdFygxzOMpWRCfeWS/2cA0wxou/7lAAs7/lg X-Provags-ID: V03:K0:FFMFBndM6Nx3Gn4ymlmUpgEgbwsiExELJqfw1NG2/uuNRUwqiDq BXFtD7w1uaI5/mWgZi2TXAY+mswwHXkERt2VjsRI1Rps8onPqKObl/k0K02r7oFiDZUA/ay TJ9jPPniel360g64v+ZqPv5wQMEDP+4nRaBm9hRQap09dj2v3Yo9X75XxBUd3U95AJnqgJ4 ww2dGfzCv7QRso9xTq2NA== X-UI-Out-Filterresults: notjunk:1;V01:K0:kBynLwB1WUA=:N2l0p6nVTBCOUUxGZkec7z O5J08AdzSFKLhOhj+esvI7dM+AtgtwNi7HnFdseUfjRudCCLvYvfo5VN7kRQknj0sK+5zqXL7 nE9REGE1rlml8EVCpZyZqXuzyUe/Yzh2E3jH05CjMUaH0FMQy9mSDZfHgEAkP33ARKDEUdU61 pKAsenPQSl5llVy+MINEK7V6yDPUktibCo7CmLymItKy2HVmthwrQ1IN9KMKGqcNAVPqApSk3 Qgqjv7lcujMIxBHSRuM2U0DbccrpKRrtd4zTkE+Ln2R5JBZUP0kuxHtiMaqN1Xl66l93DNR+9 49+38WMZwa9bC7Aji6nfgDVPQuO2ZRRcLGvxQ2RrE9/FU47i+pNrLyCW241gIUzh/wBz2jnU0 GmsJHfYk+wPxozojywC6E7bivBB4KiXOYbMvU7uTDXxlxvKjEwc0rvUbCACx5xIWstM5LV3Xh 2m67H2L3uekGlXY3JQECOdf2671nmIRFfa0ojSRTz771u1gD3AvxUi3keZMrfatTOLFPwVbj0 KCO3ZtmjNSeH6ujpcCT0rDd38G5j0fnzdvLU8c8dH2frJpWOY3F5a+IlcVbaNn9qGBDBZBfpT X/JaZedUIPZW5bD9ZCo04Furv3XK1L3zy05TiLWwtXmAU7QeyH5NGQGhtYIUaJWS7HTdrhQlj W4g4R6nDSvcajvfbHZSXgOgKorGwWApD8huVGksFJbhschO3PWSHarqa0B4EvVdCf61xD70m2 7GGbNir9GFafpYXSbtPb7mExsH3KTRkhD5Wwiil+2N5Mr8oISmSrg4P3eoj1L5CRqGQ6VzJf7 5t9+E2+ X-Scan-Signature: 5c335215f1b3de26d890ee84d49616ce Subject: RE: LF: MF: EbNaut 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 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7133 Hi Paul, I would recommend feeding DC not via the center tap of the output transformer because the DC current is biasing the core which reduces its "dynamic range" and increases losses and heat. Instead I would feed DC via two separate DC chokes. That's like it is done with HF PAs. The cores of my own push pull MW PA run much cooler since I use separate feeding chokes. One can confirm the bad effect of DC biasing also with a spice simulation. There are also some professional articles around in the www covering this topic. Maybe I can find one which I have stored on my PC a while ago. 73 Clemens DL4RAJ >-----Original Message----- >From: owner-rsgb_lf_group@blacksheep.org >[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Paul Nicholson >Sent: Monday, February 29, 2016 12:49 AM >To: rsgb_lf_group@blacksheep.org >Subject: Re: LF: MF: EbNaut > > >Attached a circuit of part of the push-pull PA. > >The center tap of the primary is at AC ground with the >DC supply coming in via a choke. >