Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_MED,SPF_PASS, T_DKIM_INVALID autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: : mailn 1480; Body=3 Fuz1=3 Fuz2=3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v3IJQ3ox009074 for ; Tue, 18 Apr 2017 21:26:04 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1d0YbZ-00086C-44 for rs_out_1@blacksheep.org; Tue, 18 Apr 2017 20:16:01 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1d0YbV-000863-LB for rsgb_lf_group@blacksheep.org; Tue, 18 Apr 2017 20:15:57 +0100 Received: from mail-wm0-x231.google.com ([2a00:1450:400c:c09::231]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1d0YbS-0006Vk-KH for rsgb_lf_group@blacksheep.org; Tue, 18 Apr 2017 20:15:56 +0100 Received: by mail-wm0-x231.google.com with SMTP id u2so5147730wmu.0 for ; Tue, 18 Apr 2017 12:15:54 -0700 (PDT) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=/ksnLMNaI1L6nXfEKrWr4qtrn/Y9IZTARg7Hqf/z0ms=; b=tdsLUmbRXYbZEg30WPuhZrL3i2M5Jdc6v3RiTFO9dx4rnNdJkEajz4ydlyAvPL0uWS /KqRm5g1GSBNv4rVjiXmeavd+mIwZZWg7kTtmERmsqJfgsOPeIp8vhGKAhYmFZeNSUaS n1K5kQ1K/rlcQ7IdUuvjFCDlWLZVBuhFsWoe17RNy61dYCU0IVRzFIRLFDt8a3ZYJcVK 7ctZYXWcDLpJpurNTX7/kMIjvy+wST/xhVHVPCh8Ziu8b4pCXwskJhOTN1hS9pYAcz7g Os0TyMxea2kGMyGrpfUHPxLO4j5Hjevpwwg77jCTgeaWt00cj9+sZNoKqWZYyuKf3cUA qvog== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=/ksnLMNaI1L6nXfEKrWr4qtrn/Y9IZTARg7Hqf/z0ms=; b=l9mLebznRLdLogFHMRWGvLODI6wOMNr1nCCVwqBzo7NrPsZyn2OimOhlt5QYGEYP8v O3ZJ3d6eOsJ5zf6pcLGzXDbCQuWwbT/t3vzc2fm9APaMoknyUffgWAn9tN9ZPzVJZrfU 1EP2rMbE315f8VDlwhQ8k18r35XU4TZejsdseybT/pV6BrKhpGVT4SH8z+LiObi8GJVR 7376myaABjbzZq1G6WS3W0Erx8HtCY4+doex/fGNfW8+Kgm+ku3otPAEVU1cCKPsocmq 44Rtyc2DiER0frJaVGTbqxm8uzqg4qcKdp+apLHEXtNHn4eni0tCkFM9zm9wntoiTK9Q cmZQ== X-Gm-Message-State: AN3rC/4lbBV466WL0lgfaPogxV6qjiuaHOH3/zMcuZPcDNFZ7aqI47Mp gK5F3lASK/IAtlqubA4= X-Received: by 10.28.234.84 with SMTP id i81mr10212342wmh.138.1492542952910; Tue, 18 Apr 2017 12:15:52 -0700 (PDT) Received: from [192.168.1.101] ([82.98.23.94]) by smtp.gmail.com with ESMTPSA id d17sm547511wmi.21.2017.04.18.12.15.51 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 18 Apr 2017 12:15:52 -0700 (PDT) Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: John Rabson In-Reply-To: <58F63C48.4020006@posteo.de> Date: Tue, 18 Apr 2017 21:15:49 +0200 Message-Id: <4F0D3050-F629-44E7-BCA2-98BCC8B29D17@gmail.com> References: <15b72b3360e.marcocadeddu@tin.it> <731997437.20170416124847@gmail.com> <58F525B4.9090008@posteo.de> <1229336941.20170418125840@gmail.com> <58F60567.20001@posteo.de> <58F63C48.4020006@posteo.de> To: rsgb_lf_group@blacksheep.org X-Mailer: Apple Mail (2.3124) X-Scan-Signature: e6de17d69e46ff4ea8db042ef2cd7e46 Content-Type: text/plain; charset=iso-8859-1 Subject: Re: LF: A transductor for power regulation? 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 2.75 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by lipkowski.org id v3IJQ3ox009074 Status: O X-Status: X-Keywords: X-UID: 11378 I believe something like that is used at SAQ (Grimeton Radio) on 17.2 kHz as a saturable reactor for keying the transmission. John F5VLF > On 18 Apr 2017, at 18:18, DK7FC wrote: > > Hi all, > > I'm just thinking about transductors and find them them quite fascinating again. I read a bit Wikipedia and thought about the use as a steerable transformer. > Imagine you have a hard switching class D PA, H bridge or so. The output is a constant voltage source and it is no problem to connect no load, as long as a proper type of low pass filter is used. > Then imagine a simple 1:1 ferrite transformer, 50 Ohm to 50 Ohm. The transformer has a 3rd winding for a DC current (to compensate the AC component transformed from the RF windings, 2 cores must be used, which are in parallel for the RF and anti-serial for DC). > Then i can saturate the transformer with the DC so the µr falls down to 1. > With this arrangement i could build a linear PA out of a switch mode PA, even a fast one, which avoids key-clicks, at least in QRSS-3 (you remember the mode) or OP32 or even EbNaut on LF? > Sounds like an interesting experiment at least. The question is how warm the transformer would become when the RF output current is permanently reduced to 50%. > Has someone ever tried that on LF/MF? > > 73, Stefan > john.rabson07@gmail.com Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and ROBSONNE