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 w99HYjtn018599 for ; Tue, 9 Oct 2018 19:34:51 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1g9vjW-00071t-MQ for rs_out_1@blacksheep.org; Tue, 09 Oct 2018 18:23:46 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1g9vgW-00070x-2Z for rsgb_lf_group@blacksheep.org; Tue, 09 Oct 2018 18:20:40 +0100 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.91_59-0488984) (envelope-from ) id 1g9vgO-0005jO-D1 for rsgb_lf_group@blacksheep.org; Tue, 09 Oct 2018 18:20:33 +0100 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id 7372B2400E6 for ; Tue, 9 Oct 2018 19:20:30 +0200 (CEST) X-DKIM-Result: Domain=posteo.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.de; s=2017; t=1539105630; bh=6gGjrU2Dq7J6MlGa+OPmY7mc5YoC/H/Enl7k08/UOS4=; h=Date:From:To:Subject:From; b=ACTpSO3awaXDJr3wkGMW4EOxRNtARJPW6T16w9xLAVxcOs7wAVJbP7fL2+tiHev0i 2Wml5NAtNt5+krCaBPqzdC+FLULmcLl5gXa9NWoMetdGIx2cXXZdHtTsmNnJ9i1XLO XFi0ltGEgM58dVNw6kqvPXmAoJWKxqrOB2jpguBOrlRuF1br4oxQiZlA/bfub+Hsb/ W8qlQm5Y57OtBIXPu7VLBQONEi7Eu53Cf0E5XIyuIuy0F6cJKLvyNpuhYnmh30KbyA NqPAgCqPk8Im3aW9vDzSi84RCFSx/Y3GJz6d2HRWj665B/KQfxKQNjBlOTGQhIBdkw Xq83YATYpy7Wg== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 42V3sB0Jlwz9rxH for ; Tue, 9 Oct 2018 19:20:29 +0200 (CEST) Message-ID: <5BBCE35D.6050300@posteo.de> Date: Tue, 09 Oct 2018 19:20:29 +0200 From: DK7FC User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <3a2d2a73-50a1-0bd1-b6fb-bb26a6fcf43d@tele2.se> In-Reply-To: X-Spam-Score: -2.3 (--) 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: Hi Tom, Why do you secide for a class-E at all? Do you see any actual advantage over a class D? 73, Stefan [...] Content analysis details: (-2.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [185.67.36.66 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 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: aefd9a2840b8183a225e05cdb844feaf Subject: Re: LF: Class E PA Content-Type: multipart/alternative; boundary="------------010909090803040301010406" 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. --------------010909090803040301010406 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Tom, Why do you secide for a class-E at all? Do you see any actual advantage over a class D? 73, Stefan Am 09.10.2018 17:49, schrieb DK1IS: > 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? > > 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. >> >> 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: >>> >>> - Being interested only in on-off-keying I´m 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 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 the 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 >>> >> >> . > > --------------010909090803040301010406 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Tom,

Why do you secide for a class-E at all? Do you see any actual advantage over a class D?

73, Stefan

Am 09.10.2018 17:49, schrieb DK1IS:
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?

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.

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:

-  Being interested only in on-off-keying I´m 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  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 the 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


.


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