Return-Path: Received: from mtain-dd11.r1000.mx.aol.com (mtain-dd11.r1000.mx.aol.com [172.29.64.151]) by air-mc01.mail.aol.com (v126.13) with ESMTP id MAILINMC012-a8464b71d759297; Tue, 09 Feb 2010 16:44:57 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dd11.r1000.mx.aol.com (Internet Inbound) with ESMTP id 07994380001B3; Tue, 9 Feb 2010 16:44:52 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NexrY-0005D6-O0 for rs_out_1@blacksheep.org; Tue, 09 Feb 2010 21:43:16 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NexrY-0005Cx-13 for rsgb_lf_group@blacksheep.org; Tue, 09 Feb 2010 21:43:16 +0000 Received: from mail-bw0-f227.google.com ([209.85.218.227]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NexrT-0004mo-Ub for rsgb_lf_group@blacksheep.org; Tue, 09 Feb 2010 21:43:15 +0000 Received: by bwz27 with SMTP id 27so48601bwz.30 for ; Tue, 09 Feb 2010 13:43:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:cc:content-type; bh=yV3bpvtjTcgRDiLX8NZ9Xdl54TTC1Z2laN5VOJ4FpAY=; b=OPk/kNB/gSU2q+ZQBuVa+mm4eOxosGtLYsErXEfOxawyAh3Xctl95Wd6DVBMGjFXmV xwr7p+lWAy0lmt7VF7UFyWkP1kx8df11mfrr5f9YuCUh0uLdD7nGFEAqalDDc8bYk07G 0PUNWGIQEJ3X8XKWQb1HsxXzUTL3pmw2O2gQI= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=VmUvaoF7KCsogk3ssZSf/n1rXxaFkDzHWXZjtLlf/TJUls09YcLagEF3ZY0Lb+pbFx 4kSaQFuFP7HYpPF81EjmeYh7t29ZCX22MJzbAfhn5ptGRh/EexRwBWFszoZVPNScLQsz Pd4a/uUVO5+cY0uakYoLQam0KGY6fPOBbU5B0= MIME-Version: 1.0 Received: by 10.204.49.78 with SMTP id u14mr525960bkf.135.1265751784322; Tue, 09 Feb 2010 13:43:04 -0800 (PST) In-Reply-To: References: Date: Tue, 9 Feb 2010 21:43:04 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org Cc: ukmicrowaves@yahoogroups.com DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: RE: PA matching oddity Content-Type: multipart/alternative; boundary=00032555b1f67a78c7047f31cd6a X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE autolearn=no version=2.63 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-aol-global-disposition: G x-aol-sid: 3039ac1d40974b71d7545179 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --00032555b1f67a78c7047f31cd6a Content-Type: text/plain; charset=ISO-8859-1 BINGO - Tnx Rik, thats it, convincing. Sorted So my thing IS 1:4 turns ratio, (1:16 Z ratio) just as the calculations said it needed to be, and is indeed, effectively, an auto transformer. Otherwise known as a bootstrapped coaxial transformer, but just configured with different reference points to confuse everyone. Your second reference, the Semelab paper, (UKuW see below) gives the answer. Look at page 10, the 1:9 Ruthroff UnUn . With just two bits of coax, which are then bootstrapped up on top of the input to give a 3:1 ratio (for 1:9 impedance). Add another turn, so three windings are bootstrapped on top of the primary, rearrange the grounding points and there, in all its glory, is my mystery. The reference / grounding points can be shifted as the mosfet PA has two separate, non magnetically linked cores. This is is just normal push-pull HF PA practice, and being so normal in its concept, completely hides hides a big real advantage - it enables the designer to float just whatever ternainals need to be floated for balanced / unbalanced operation, and even to provide DC isolation, Any conductor passing through the core allows one end to be completely Rf decoupled from the other end, so that's how balanced operation is permitted with the basic Ruthrof design shown in the paper. On the same page, a single length of coax is shown giving 1:2 transformation by the same bootstrapping arrangement, and when the transmision line is shown as a twisted pair rather than coax, then wrapped on a torroid, it becomes the 1:4 balun beloved of HF antenna constructors. A natural progression that helps illustrate the concept of a loop of coax giving one turn more than it appears to. It all falls out. ... life is worth living again ... ... can retire happy ... Andy www.g4jnt.com ... now, next job, how to sort out the world financial crisis ... On 9 February 2010 19:53, Rik Strobbe wrote: > Andy, > > have a look here : > > http://www.polyfet.com/HFE0503_Leong.pdf > > http://www.semelab.com/rf/documents/Push-Pull%20Circuits%20and%20Wideband%20Transformers.pdf > > 73, Rik ON7YD - OR7T > > ------------------------------ > *Van:* owner-rsgb_lf_group@blacksheep.org [ > owner-rsgb_lf_group@blacksheep.org] namens Andy Talbot [ > andy.g4jnt@googlemail.com] > *Verzonden:* dinsdag 9 februari 2010 18:10 > *Aan:* rsgb_lf_group@blacksheep.org; ukmicrowaves@yahoogroups.com > *Onderwerp:* LF: PA matching oddity > > > --00032555b1f67a78c7047f31cd6a Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
BINGO -=A0 Tnx Rik, thats=A0it, convincing.=A0=A0Sorted
=A0
So my thing=A0=A0IS 1:4 turns ratio, (1:16 Z ratio) =A0just as the=A0= calculations said it needed to be,=A0and is indeed, effectively, an auto= transformer.=A0 Otherwise known as a bootstrapped coaxial transformer, bu= t just configured with different reference points=A0to confuse everyone.= =A0Your=A0second reference, the Semelab paper, (UKuW see below) =A0gives= the answer.=A0=A0
=A0
Look at=A0page 10,=A0=A0=A0the 1:9 Ruthroff=A0=A0 UnUn .=A0=A0=A0With= just=A0two bits of coax, which are then bootstrapped up on top of the inp= ut to give a 3:1 ratio (for 1:9 impedance).=A0=A0 Add another turn, so thr= ee windings are=A0 bootstrapped on top of the primary, rearrange the groun= ding points and there, in all its glory, is my mystery.=A0=A0=A0
=A0
The reference / grounding points can be shifted as the mosfet PA=A0= =A0has=A0 two separate, non magnetically linked=A0cores.=A0 This is is jus= t=A0normal push-pull HF PA practice, and being so=A0normal in its concept,= completely hides hides=A0a big=A0real advantage - it enables the designer= to float just whatever ternainals need to be floated for balanced / unbal= anced operation, and even to provide DC isolation,=A0=A0 Any conductor pas= sing through the core allows one end to be completely Rf=A0decoupled from= the other end, so that's how balanced operation is permitted with the= basic Ruthrof design shown in the paper.
=A0
On the same page,=A0a single length of coax is shown giving 1:2 trans= formation by the same bootstrapping arrangement, and when the transmision= line is shown as a twisted pair rather than coax, then wrapped on a torro= id, it=A0becomes the 1:4 balun beloved of=A0HF antenna=A0constructors.=A0= =A0 A natural progression that helps illustrate the concept=A0 of=A0 a loo= p of coax giving one turn more than it appears to.
=A0
It all falls out.=A0
... life is worth living again ...
... can retire happy ...
=A0
... now, next job, how to sort out the world financial crisis ...
On 9 February 2010 19:53, Rik Strobbe <Rik.Strobbe@fy= s.kuleuven.be> wrote:
Andy,<= /font>
=A0
have a look here :
=A0
=A0
73, Rik=A0 ON7YD - OR7T<= /font>
=A0
Van: owner-rsgb_lf_group@blacksheep.= org [owner-rsgb_lf_group@blacksheep.org] namens Andy Talbot [andy.g4jnt@googlem= ail.com]
Verzonden: dinsdag 9 februari 2010 18:10
Aan: rsgb_lf_group@black= sheep.org; ukmicrowaves@yahoogroups.com
Onderwerp: LF: PA matching oddity

=A0
--00032555b1f67a78c7047f31cd6a--