Return-Path: Received: from mtain-dh06.r1000.mx.aol.com (mtain-dh06.r1000.mx.aol.com [172.29.65.26]) by air-dc10.mail.aol.com (v126.13) with ESMTP id MAILINDC101-86064b4dfab2343; Wed, 13 Jan 2010 11:54:10 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dh06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 77E2F3800008F; Wed, 13 Jan 2010 11:54:08 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NV6SZ-0004TB-1k for rs_out_1@blacksheep.org; Wed, 13 Jan 2010 16:52:43 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NV6SY-0004T2-Gf for rsgb_lf_group@blacksheep.org; Wed, 13 Jan 2010 16:52:42 +0000 Received: from mail-bw0-f221.google.com ([209.85.218.221]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NV6SU-0001PM-MM for rsgb_lf_group@blacksheep.org; Wed, 13 Jan 2010 16:52:42 +0000 Received: by bwz21 with SMTP id 21so15806407bwz.4 for ; Wed, 13 Jan 2010 08:52:28 -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:content-type; bh=CGWM2IHMyRS4Q9efjYNC/bHe2sdVbAyO+ykm0FTnt0w=; b=Ok2ZJLdWJizL/VOjVVKSCNkzCKnRMHmTR9fwLcvKtoBqrFByv+IXI7ZirZUgyYLS9n Kryu3FUkuBNwquKfNhB02kk/orsoLHqLXGeCTPiiqWHyLs3vHWWFforUkKnJNxF/ZEv0 Z/X7uvoknkUPj5aUAQmgnU60l1dtqipsV8px8= 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 :content-type; b=OTMGQWraHpoU1tlbOHyeV3IqIChKr+o4NeF23z9Z8yiervYCoUtF6LVzGXEufgG7LH 9+RNY1rGys7LGgGRn+yjnoEbaKmz+YaiBgFRwg7pxSZszqf6/wck+wQUDL5GZxDl/4T4 r7FOlXlpGKJvlmT60oXBNl58L9cpIf8rAfID4= MIME-Version: 1.0 Received: by 10.239.188.199 with SMTP id q7mr313206hbh.12.1263401548333; Wed, 13 Jan 2010 08:52:28 -0800 (PST) In-Reply-To: <003301ca946d$3f750460$0301a8c0@your91hoehfy9g> References: <001201ca9444$ed415810$0301a8c0@your91hoehfy9g> <3C7515D8E8B4467A8CF7A04C8C26F2C2@JimPC> <003301ca946d$3f750460$0301a8c0@your91hoehfy9g> Date: Wed, 13 Jan 2010 16:52:28 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Karma: unknown: DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Re: Re: DECCA 5501 tx Content-Type: multipart/alternative; boundary=001485f1e7627f4166047d0e9884 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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: 3039ac1d411a4b4dfab0042d X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --001485f1e7627f4166047d0e9884 Content-Type: text/plain; charset=ISO-8859-1 Those transmitters consist of a full bridge output, where the connection to the series LC is hard switched to alternately +V or -V. The result is a low impedance voltage source driving the tank. Such a transmitter requires a series tuned circuit at Fo to select the wanted component while appearing as a high impedance to all harmonics. So you will not see any drain (source of the upper device) waveform oteh rthan the square wave outptu plus any incidental small spikes, that ideally shouldn't be there. Contrast with a class E that alternately switches to ground then opens, allowing the voltage peak to fly off to whatever the C-L-C network allows it to reach. Tnx for the replies to my - originall light hearted - comment about needing a 1kW PA. It looks simpler than at first thought, so I just 'may' get round to adding it to the project to-do list (after retirement / quitting - getting ever closer). The 137kHz 700 Watt jobbie was straightforward enough - it was uncontrolled transients that caused problems there as I was running from such a high Vcc (340 Volts) that layout mattered. Keeping with a 50V rail ought to simplify things somewhat. Andy www.g4jnt.com This email has been scanned for damaging side-effects by the health and safety police, is guaranteed to contain no substances hazardous to health, but may contribute to dissolving the nether and polar regions 2010/1/13 mal hamilton > Tnx Jim for reply, but since a class D with a resonated output L/C becomes > a > single frequency tx it is getting close to class E design. > It would be interesting to observe the switching wave form while adjusting > L/C for resonance instead of just peaking for max output. > mal/g3kev > > > ----- Original Message ----- > From: "James Moritz" > To: > Sent: Wednesday, January 13, 2010 3:26 PM > Subject: LF: Re: DECCA 5501 tx > > > > Dear Mal, LF Group, > > > > In a class D circuit, optimum switching conditions occur more or less > when > > the tank circuit is resonant. > > > > Cheers, Jim Moritz > > 73 de M0BMU > > > > -- Original Message ----- > > From: "mal hamilton" > > To: "rsgb" > > Sent: Wednesday, January 13, 2010 11:38 AM > > Subject: LF: DECCA 5501 tx > > > > > > Does anyone know if the series L and C was tuned for resonance at the > > operating freq or meant to be adjusted for optimum switching > characteristics > > like in class E > > mal/g3kev > > > > > > > --001485f1e7627f4166047d0e9884 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Those transmitters consist of a full bridge output, where the connect= ion to the series LC is hard switched to=A0alternately +V or -V.=A0=A0The= result is a low impedance voltage source driving the tank.=A0=A0=A0=A0 Su= ch a transmitter requires a series tuned circuit at Fo to select the wante= d component while appearing as a high impedance to all harmonics.=A0=A0 So= you will not see any drain (source of the upper device) waveform oteh rth= an the square wave outptu plus any incidental small spikes, that ideally= shouldn't be there.
=A0
Contrast with a class E that alternately switches to ground then open= s, allowing the voltage peak to fly off to whatever the C-L-C network allo= ws it to reach.=A0=A0
=A0
Tnx for the replies to my - originall light hearted - comment about= needing a 1kW PA.=A0 It looks simpler than at first thought, so I just = =A0'may' get round to adding it to the project to-do list (after= retirement / quitting - getting ever closer).=A0 The 137kHz 700 Watt jobb= ie was straightforward enough - it was uncontrolled transients that caused= problems there as I was running from such a high Vcc (340 Volts) that lay= out mattered.=A0=A0=A0 Keeping with a 50V rail ought to simplify things so= mewhat.
=A0

Andy
www.g4jnt.= com

This email has been scanned for damaging side-effects by th= e health and safety police, is guaranteed to contain no substances hazardo= us to health, but may contribute to dissolving the nether and polar region= s


2010/1/13 mal hamilton <g3kevmal@talktalk.net>
Tnx Jim for reply, but since= a class D with a resonated output L/C becomes a
single frequency tx it= is getting close to class E design.
It would be interesting to observe the switching wave form while adjusting=
L/C for resonance instead of just peaking for max output.
mal/g3kev=


----- Original Message -----
From: "James Moritz"= <james.moritz@btopenwo= rld.com>
To: <rsgb_lf_group@blac= ksheep.org>
Sent: Wednesday, January 13, 2010 3:26 PM
Subject= : LF: Re: DECCA 5501 tx


> Dear Mal, LF Group,
>
>= ; In a class D circuit, optimum switching conditions occur more or less wh= en
> the tank circuit is resonant.
>
> Cheers, Jim Moritz
&= gt; 73 de M0BMU
>
> -- Original Message -----
> From: &q= uot;mal hamilton" <g3kevm= al@talktalk.net>
> To: "rsgb" <rsgb_lf_group@blacksheep.org>
> Sent: Wednesday, January= 13, 2010 11:38 AM
> Subject: LF: DECCA 5501 tx
>
>
&= gt; Does anyone know if the series L and C was tuned for resonance at the<= br> > operating freq or meant to be adjusted for optimum switching
chara= cteristics
> like in class E
> mal/g3kev
>
>


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