Return-Path: X-Spam-DCC: paranoid 1290; 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 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 t9G82W80015946 for ; Fri, 16 Oct 2015 10:02:32 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Zmztr-0002g6-UQ for rs_out_1@blacksheep.org; Fri, 16 Oct 2015 08:58:03 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Zmztr-0002fx-BH for rsgb_lf_group@blacksheep.org; Fri, 16 Oct 2015 08:58:03 +0100 Received: from mail-lf0-f49.google.com ([209.85.215.49]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.86) (envelope-from ) id 1Zmzsu-0004rq-95 for rsgb_lf_group@blacksheep.org; Fri, 16 Oct 2015 08:58:02 +0100 Received: by lffv3 with SMTP id v3so74426319lff.0 for ; Fri, 16 Oct 2015 00:56:47 -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=20120113; h=content-type:mime-version:subject:from:in-reply-to:date :content-transfer-encoding:message-id:references:to; bh=gvFTBSPdIhKLD5y8ARqA+/HeGETuB/f+dondrb0kTr4=; b=GeQx/SvRHxH+5upx90IHklKV+uO3OK1oxTBPisveGp3HomX6+HL9sCPyLd5D5dS6VD PDgdHe5QY0wsV/PPh0ejqzXHAdCcmsJU7UxL88Tukh9aAbQoJmbPM4e7hzTApTSlGuaA AMRXdE2FmUn/q70TdxxHeszHu1W3eNwfLs5ZXUZjVGYw2yDnyjOtexM9S0eDBiihGKkl oTbYvwbo2KFkcSb82VIz5LfXtTq2WIrC8DPNYNL+YN8fmwOV2NiPkkTnAamHHV6FV/eW N29gj6OEHnsw95ZTN/6E6wu75V9u6jMZOr9oIYYFCszXmgmeVB1XtFrfF833iIq/s+jp I0tw== X-Received: by 10.180.19.41 with SMTP id b9mr3070700wie.71.1444982207803; Fri, 16 Oct 2015 00:56:47 -0700 (PDT) Received: from [192.168.1.101] ([82.98.23.94]) by smtp.gmail.com with ESMTPSA id x9sm20992049wjf.44.2015.10.16.00.56.46 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 16 Oct 2015 00:56:46 -0700 (PDT) Mime-Version: 1.0 (Mac OS X Mail 9.0 \(3094\)) From: John Rabson X-Priority: 3 (Normal) In-Reply-To: <323462263.20151015234436@chriswilson.tv> Date: Fri, 16 Oct 2015 09:56:42 +0200 Message-Id: References: <1541636554.20151013163425@chriswilson.tv> <43464DACBFAA49C08A73FB93FFF52105@gnat> <603371935.20151014123307@chriswilson.tv> <9E19F2EA072B4AE3A7A112534A29B460@gnat> <323462263.20151015234436@chriswilson.tv> To: rsgb_lf_group@blacksheep.org X-Mailer: Apple Mail (2.3094) X-Scan-Signature: f62c7cf8eeb8e5a327b71719e9bffff1 Content-Type: text/plain; charset=utf-8 Subject: Re: LF: Re: Should I be aiming for a better match than this? 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 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by paranoid.lipkowski.org id t9G82W80015946 Status: O X-Status: X-Keywords: X-UID: 4400 Hello Chris, I use the term “isolation” to emphasise the fact that it does provide galvanic isolation, which an auto-transformer does not. The transformer here is a ferrite ring type N90AB from Maplin, with a 5 turn primary winding and a 10 turn secondary. The transmitter is a 30 W class E design based on the spreadsheet by G3NYK. In this configuration, with the antenna system presenting 50 ohms, the amplifier sees the desired load of about 12 ohms. 73 John F5VLF > On 16 Oct 2015, at 00:44, Chris Wilson wrote: > > … Another poster, John Rabson, talked of isolating mains > ground and RF ground. As I have had occasional RCD trips at the house > distribution panel when TX'ing at high power with this setup, I am > wondering about this. He spoke of an isolation transformer, but I am > not sure just what he meant by that. john.rabson07@gmail.com Researching history of RABSON, BLACKSHAW, GAUNTLETT, VERLANDER and ROBSONNE