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 w99FvvgA018120 for ; Tue, 9 Oct 2018 17:58:05 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1g9uFU-0006kr-Nx for rs_out_1@blacksheep.org; Tue, 09 Oct 2018 16:48:40 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1g9uDt-0006kS-TX for rsgb_lf_group@blacksheep.org; Tue, 09 Oct 2018 16:47:01 +0100 Received: from smtp-out221.xworks.net ([31.25.48.221] helo=smtp-out01.xworks.net) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1g9uDr-0005Yp-HI for rsgb_lf_group@blacksheep.org; Tue, 09 Oct 2018 16:47:00 +0100 Received: from mailbackend3 (cluster06.xworks.net [10.100.1.80]) by smtp-out01.xworks.net (Postfix) with ESMTP id 0A4126151C for ; Tue, 9 Oct 2018 17:47:02 +0200 (CEST) X-DKIM-Result: Domain=kabelmail.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kabelmail.de; s=mail; t=1539100022; bh=F+BepCc3Qpu66RCl/KZVQhHC73AJsX74L2UyMn2Qxtk=; h=Subject:To:References:From:Date:MIME-Version:In-Reply-To: Content-Type; b=yMOrzwHQf5+mWIe8mSqX9TRQRC286QsYpU+GGpiaiEIDe0k03AnpxqDR8bICXwOhX lLOIft5mJwhkY+cmV0kpXtBAyz7ZaUMBZnF08tYjU+ASOitBEGSoNlqiln4fk6o0yC IT550qAzQkjoXnEPmNDnPqG9Mr36sW8CgHPSbI8k= Received: from [192.168.36.33] (ipbcc1c722.dynamic.kabel-deutschland.de [188.193.199.34]) (authenticated bits=0) by smtp.kabelmail.de with ESMTP id w99FkxQG028640 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 9 Oct 2018 17:47:00 +0200 X-mediaBEAM-Originating-IP: [188.193.199.34] X-mediaBEAM-AUTHID: [DK1IS@kabelmail.de] To: rsgb_lf_group@blacksheep.org References: <3a2d2a73-50a1-0bd1-b6fb-bb26a6fcf43d@tele2.se> From: DK1IS Message-ID: Date: Tue, 9 Oct 2018 17:49:56 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <3a2d2a73-50a1-0bd1-b6fb-bb26a6fcf43d@tele2.se> X-mediaBEAM-AuthCheck: route13 X-mediaBEAM-AuthScore: 0.0/5.0, scanned in 1.194sec 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: Hej Johan, thanks for your budding info! I would be glad to get these documents concerning the DC feed inductor. Perhaps you´ll find some additional information about the shunt capacitor problem too? [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -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: 4547f2cca70c75b03fc1ebaed398eea1 Subject: Re: LF: Class E PA Content-Type: multipart/alternative; boundary="------------BB2EB365B600904D80F40864" 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 This is a multi-part message in MIME format. --------------BB2EB365B600904D80F40864 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by smtp.kabelmail.de id w99FkxQG028640 Hej Johan, thanks for your budding info! I would be glad to get these documents=20 concerning the DC feed inductor. Perhaps you=C2=B4ll find some additional= =20 information about the shunt capacitor problem too? Tack och vy 73, Tom, DK1IS Am 09.10.2018 um 17:00 schrieb Johan Bodin: > > Hello Tom, > > most schoolbook class-E designs assume a DC feeding choke with=20 > infinite inductance i.e. a huge inductor that keeps the DC current=20 > constant without any RF ripple. This is of course totally impractical=20 > (especially at VLF !)... > > I'll try to find some class-E design documents that I have saved=20 > somewhere. One of those documents has explicit design equations for=20 > class E amplifiers with finite DC feed inductance. > > If memory serves me, the reactance of the DC feed inductor can be as=20 > low as the DC feed resistance (Vdc/Idc) but such a low value would=20 > require a very large decoupling capacitance on the DC supply side=20 > because of high RF ripple current flowing through the inductor. > > I will send these pdf documents to you if you are interested. > > 73 > Johan SM6LKM > > Den 2018-10-07 kl. 19:51, skrev DK1IS: >> >> Hello Group, >> >> Planning a new single-ended Class E PA for my activities on the=20 >> Dreamers Band (8.27 kHz) two questions came up - perhaps someone can=20 >> help me: >> >> -=C2=A0 Being interested only in on-off-keying I=C2=B4m concerned abou= t the=20 >> capacitor in parallel to the power FET which in my case on VLF will=20 >> be in the uF range. If the DC supply is on and without gate drive=20 >> this capacitor is charged to the DC supply voltage. At the first=20 >> positive gate pulse it discharges via the drain-source-path, the=20 >> current being limited only by parasitc impedances - a poorly defined=20 >> condition which usually has to be avoided. Does this mean that I have=20 >> to apply drive continously and key the DC power supply only, perhaps=20 >> synchronously to the next positive drive pulse? >> >> - Is there any rule of thumb for the inductance of the rf choke in=20 >> the drain-power supply path? >> >> Thanks for any idea! >> >> 73, >> Tom, DK1IS >> www.qrz.com/db/dk1is >> > > .=20 --------------BB2EB365B600904D80F40864 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by smtp.kabelmail.de id w99FkxQG028640
Hej Johan,

thanks for your budding info! I would be glad to get these documents concerning the DC feed inductor. Perhaps you=C2=B4ll find some additional information about the shunt capacitor problem too?<= br>
Tack och vy 73,
Tom, DK1IS


Am 09.10.2018 um 17:00 schrieb Johan Bodin:

Hello Tom,

most schoolbook class-E designs assume a DC feeding choke with infinite inductance i.e. a huge inductor that keeps the DC current constant without any RF ripple. This is of course totally impractical (especially at VLF !)...

I'll try to find some class-E design documents that I have saved somewhere. One of those documents has explicit design equations for class E amplifiers with finite DC feed inductance.<= /p>

If memory serves me, the reactance of the DC feed inductor can be as low as the DC feed resistance (Vdc/Idc) but such a low value would require a very large decoupling capacitance on the DC supply side because of high RF ripple current flowing through the inductor.

I will send these pdf documents to you if you are interested.

73
Johan SM6LKM

Den 2018-10-07 kl. 19:51, skrev DK1IS:

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 capacitor 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 paras= itc 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 r= ule 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


.


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