Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id w98LTmKg013453 for ; Mon, 8 Oct 2018 23:29:49 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1g9czt-0004P6-BK for rs_out_1@blacksheep.org; Mon, 08 Oct 2018 22:23:25 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1g9czq-0004Ot-MI for rsgb_lf_group@blacksheep.org; Mon, 08 Oct 2018 22:23:22 +0100 Received: from mail-ed1-x52e.google.com ([2a00:1450:4864:20::52e]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1g9czl-0003ZY-L5 for rsgb_lf_group@blacksheep.org; Mon, 08 Oct 2018 22:23:21 +0100 Received: by mail-ed1-x52e.google.com with SMTP id z21-v6so14435056edb.11 for ; Mon, 08 Oct 2018 14:23:17 -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:references:in-reply-to:from:date:message-id:subject:to; bh=mavQ64Z+Dq9jo+qff5jQA13tV3LlP7tHyQSvfRMK28A=; b=qJUZZfq39RZO+4DJLl/gbUZ7HohwzTzl26b6ZMx3x3ejRE2H2f6423I/0u6VoA/xl7 UO1WbNcMrUhxH44AuoG1aAPJSNdFm9hvlQKrc8WAuOiJPEaNvAehzxed7cCoaabkMmbv 2MhrAfhO8StR2Xqj81o/SjGFmFVcJFi9e7TB0KzbJYwytiSl7gUlfdcAYn0z4xvbKcEw hr/JbSa3EX2bqJM7BNy96Y/3QMK7cZ2V0x5bXeH1vrOOHRziQjwdgzIqe4x2K36OxQhS WcGcBdINaszZvNFotbsIkwI51ONfwWIKuL4VY/eTc+gojM7oNiamKIE/2Bym0gOiOcgt l0Lg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=mavQ64Z+Dq9jo+qff5jQA13tV3LlP7tHyQSvfRMK28A=; b=dUnNaMQxQOawwjPqI/8XwYgk3pIzUzTLTLZGf/5hXtP+l2suLummcUNS0CPEBz0E70 z+UdGATwbc/7qh3sxpFycNt9ZZbDcX1edzx7CqEvAlVB5/bTqexi/QxtHu9csmtnK0IS yIDO8QBcXsc/TB8fxz89oIOBw3BzHVP4SNxx1Lu0XqxmunOiDyqmgB2hbktsI6D6988+ DnmOpHRgGK15jAQpATthnKvOZQv+Zj8sf48gtCYapAoadcYKfoiNpYItkFV0SOaKmE1q RFZ7kQxdrOCq4lhnyCPtoS7Ctf0gBdqYvzIswENWwXjesCYBOB1hPvQGqJzfA2+ZLf9w PeKA== X-Gm-Message-State: ABuFfoiOphe/9vnet70fWM3AFq3DqNV9JC6KYJzvd3ft/A7kZjk7C+R8 YDnSnJFQyOQkYXOr4pqV8SmuzsPYocqMUDA81NGFQA== X-Google-Smtp-Source: ACcGV63QKGubfGcVa+9OPn6CaYm5PiMpFa7psnkHl80QCJ5LY9PCi33Hbr/Nluuds/CrAk3p87e/V/2hR3/16WhHofk= X-Received: by 2002:a17:906:c7d3:: with SMTP id dc19-v6mr24839733ejb.232.1539033796843; Mon, 08 Oct 2018 14:23:16 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Andy Talbot Date: Mon, 8 Oct 2018 22:23:05 +0100 Message-ID: To: LineOne X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: That's a very good point for all Class-E designs, at any frequency. They only work because the drain voltage / current is so carefully tuned and setup when operational generatign RF. Upsetting that state by turning the drive off and on is not going to be good. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [2a00:1450:4864:20:0:0:0:52e listed in] [list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (andy.g4jnt[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 54c274b8b0f8da777e8f702c98fe24ad Subject: Re: LF: Class E PA Content-Type: multipart/alternative; boundary="000000000000c21f1a0577be3af4" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,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 --000000000000c21f1a0577be3af4 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable That's a very good point for all Class-E designs, at any frequency. They only work because the drain voltage / current is so carefully tuned and setup when operational generatign RF. Upsetting that state by turning the drive off and on is not going to be good. Time to revisit that big 50V PWM arrangement Andy www.g4jnt.com On Mon, 8 Oct 2018 at 22:19, David Bowman wrote: > Hi Tom. > > If it helps, I believe nearly all broadcast transmitters keep the drive > running and then key the supply to the many paralleled FETs in the PA. > Of course, that also is a neat way of applying AM as pulse width > modulation......but I'm sure it will be fine for your system of modulatio= n > too. > > 73 > > David > > On Sun, Oct 7, 2018 at 5:52 PM DK1IS wrote: > >> Hello Group, >> >> Planning a new single-ended Class E PA for my activities on the Dreamers >> Band (8.27 kHz) two questions came up - perhaps someone can help me: >> - Being interested only in on-off-keying I=C2=B4m concerned about the >> capacitor in parallel to the power FET which in my case on VLF will be i= n >> the uF range. If the DC supply is on and without gate drive this capacit= or >> is charged to the DC supply voltage. At the first positive gate pulse it >> discharges via the drain-source-path, the current being limited only by >> parasitc impedances - a poorly defined condition which usually has to be >> avoided. Does this mean that I have to apply drive continously and key t= he >> DC power supply only, perhaps synchronously to the next positive drive >> pulse? >> >> - Is there any rule of thumb for the inductance of the rf choke in the >> drain-power supply path? >> >> Thanks for any idea! >> >> 73, >> Tom, DK1IS >> www.qrz.com/db/dk1is >> > --000000000000c21f1a0577be3af4 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
That's a very good point for all Cl= ass-E designs, at any frequency.=C2=A0 They only work because the drain vol= tage / current is so carefully tuned and setup when operational generatign = RF.=C2=A0 =C2=A0Upsetting that state by turning the drive off and on is not= going to be good.

Tim= e to revisit that big 50V PWM arrangement

=
Andy
www.g4jnt.com<= /span>



On Mon, 8 Oct 2018 at 22:19, David Bowman <davidg0mrf@gmail.com> wrote:
Hi Tom.

If = it helps, I believe nearly all broadcast transmitters keep the drive runnin= g and then key the supply to the many paralleled FETs in the PA.
= Of course, that also is a neat way of applying AM as pulse width modulation= ......but I'm sure it will be fine for your system of modulation too.

73

David
On Sun, Oct 7, 2018 at 5:52 P= M DK1IS <DK1IS@k= abelmail.de> wrote:
=20 =20 =20

Hello Group,

Planning a new single-ended Class E PA for my activities on the Dreamers Band (8.27 kHz) two questions came up - perhaps someone can help me:

-=C2=A0 Being interested only in on-off-keying I=C2=B4m concerned about the capacit= or in parallel to the power FET which in my case on VLF will be in the uF range. If the DC supply is on and without gate drive this capacitor is charged to the DC supply voltage. At the first positive gate pulse it discharges via the drain-source-path, the current being =C2=A0limited only by parasitc impedances - a poorly defined condition which usually has to be avoided. Does this mean that I have to apply drive continously and key the DC power supply only, perhaps synchronously to the next positive drive pulse?
=C2=A0
-=C2=A0 Is there any rule of thumb for the inductance of the rf choke in the drain-power supply path?

Thanks for any idea!

73,
Tom, DK1IS
www.= qrz.com/db/dk1is

--000000000000c21f1a0577be3af4--